cranks but won't start, glow plug light only on for a couple seconds?

[d350diesel]

I just bought the '95 in my sig yesterday, so you'll have to excuse my ignorance. I'm familiar with Cummins diesels but I'm a little lost under the hood of this one.

I just put new batteries in this afternoon because the engine would hardly turn over this morning (plugged in, block heater works, about 20 degrees outside). Now the truck cranks great but does not even cough like it's trying to start. When the key is turned on I hear a click and the glow plug light comes on for about 2 seconds, then turns off. It seems to me it ought to glow longer than that, the intake heaters on my Dodge run about 30 seconds in this weather. I plugged it in and left it sit for a couple hours, hoping it would fire when warm, but no luck. :(

When I picked up the truck from the PO yesterday, the engine was cold, outside temp was around 50, and the truck fired up pretty easily. I'm baffled as to why it won't start today with fresh batteries. :confused:

[More Power]

The 1994 models won't produce a glow cycle at all after disconnecting the batteries - till after it's been started or after some unknown number of ignition cycles. The guys with the 95 models can chime in here to let us know if they produce the same result. Thus, I recommend disconnecting the batteries only after the engine has been warmed up - to help with that next start.

You could try disconnecting the engine temperature sensor. This tricks the PCM into thinking it's -40 degrees, which should produce the longest glow cycle the system is programmed to deliver.

The engine should start without glow after having had the block heater plugged in for a couple of hours.

Jim

[ToddMeister]

My 95 produces a very short glow cycle after the batts have been disconnected.

If the engine is cold, you could use a jumper cable to connect the two large terminals on the glow plug relay for about 5 seconds and have a helper crank the engine to fire it up.

[N9Phil]

I would pull the boots down on the two large terminals that are on the front of the glow plug relay (it sits on the firewall in the middle of the engine) then I would take a screw driver and short between the two terminals for 10 to 15 seconds. Give it a try. If it try

[moondoggie]

Good Day!

At 50

[ECMProgrammer]

Yes, after the memory is cleared in the computer (battery disconnect), there are several 'relearns' that take place. First is the glow plugs.
It's not the smartest design--especially in the dead of winter !!

Lyndon
www.ecmprogrammer.com
Westers Garage
1-888-WESTER-1

[d350diesel]

Thanks for all the help. :) It sounds like the "no glow" thing is normal, but it didn't even act like it was trying to start yesterday after being plugged in for 3 hours. I tried to start it a few times when I got home from work (unplugged), but no go. I'd like to try unplugging the CTS, where is that?

I'm going to tear into this thing tomorrow, where is the best place to check for fuel? I see a petcock thingy up by the thermostat housing, is that a bleed valve?

Is there a fuse or connector I can pull to disable the glow plugs to try ether?

[d350diesel]

Nevermind about the bleeding/fuel check question, I found that with the site search. :)

[65TD]

Unplug the CTS.

It's on the coolant crossover just down from the heater hose quick connect.

This will advance timing, glow time will be extended. Higher than normal idle and maybe some clattering will be expected.

[d350diesel]

Got it to start this morning. :) It was plugged in overnight. I went out, put the key in (got a "normal" length glow, too), dropped it in drive, and hit the key. I heard the lift pump run, loud at first and then softer as pressure built. Put it in neutral and it started right up, then died about 30 seconds later. Repeated the procedure, same thing happened. Repeated again, but this time held it at 1500 RPM. It would stay running as long as I kept my foot in it, but would die after a few seconds of idling.

I've been doing some reading and this is just a wild guess, but is it possible it's the OPS? Or do I have a leak that's letting air in?

[65TD]

See if fuel will pump out of the filter mgr drain valve while it's running. If so the lift pump is pumping enough to run.

Try with CTS unplugged.

[d350diesel]

Drain valve is the one by the thermostat?

I'm pretty sure it's a fuel leak because I smell it. I got it to stay running after a few starts, it would still die if left to idle too long.

I'm going to pull the filter housing off, from the reading I've done so far it sounds like most fuel leaks are found in that area. The o-rings are a dealer item I guess? There's nothing wet around the IP and the injectors.

I'm feeling a lot better about this truck, it had me real worried for a couple days there. Amazing what a fresh set of batteries will do! Kind of a steep learning curve on these things, much more complex than the old Dodge I'm used to.

[65TD]

Fresh batteries is definitely a headache saver.

Really need to check the lift pump after correcting leak. Maybe it's just the seal on the filter. Other common fuel problems are air getting into fuel line from a hole in the line or at the junction of rubber line and steel line.

Lift pump must be running with engine or oil pressure switch is suspect. If it's running it must supply enough pressure. Yes, drain valve is by the thermostat and has a hose on it.


If you hear the lift pump while the engine is running the OPS should be OK, but the fuel flow still needs to be verified at valve.

[d350diesel]

Thanks, will do. :)

[moondoggie]

Good Day!

The most common symptom with a failed OPS is that, under load, you get a miss that's just like a gasser with an ignition miss.

Your IP can draw fuel from the tank without the aid of the LP. It will not be able to draw enough fuel for max load, however, hence the above-mentioned miss under load. (There's also considerable thought that it's a bad idea to drive much without a functional LP system.) If your OPS had failed, it should idle fine.

With the engine idling, you can loosen (slightly!) the plastic fuel filter nut on top of the fuel filter assy, & fuel should squirt out. (A piece of tubing from the bleed port on top of this nut to a container will preclude making a stinky mess when trying this.) If this happens & the engine continues idling, your LP system (including the OPS) is OK; if it dies pretty quick, the LP system isn't working, at least during run mode. You obviously won't be able to try this until you've gotten it to idle in the 1st place.

I'd bet you're getting air in somewhere, or something else our experts will be able to help with.




Blessings!
(signature in previous post)

[d350diesel]

I got the o-rings from the dealer and had time to mess with the truck this morning. Primed it using the "drop it in Drive and turn the key to start" method and checked the fuel flow while I was at it. Then I started the truck, it lit right off. As suspected, there was no fuel flow out the bleed with the engine running. Good thing I bought an OPS. :) So off came the fuel filter housing. The hose clamp on the outlet was pointed downwards, which made for a bit of a challenge. :mad: The source of the fuel leak was pretty obvious once I had the filter housing off. The WIF sensor is cracked, and fuel is seeping through the sensor. So no joy today. :(

The new OPS is installed, now I'm just waiting for Monday so I can order a new WIF sensor at the dealer. Thanks again for all the help - I think once this fuel leak is fixed the truck will be pretty reliable. :)

[gmctd]

Don't be too upset to find that part is not available seperately - only the complete filter assembly.

[d350diesel]

Don't be too upset to find that part is not available seperately - only the complete filter assembly.
That will upset me greatly! :mad: How much do they want for the whole thing?

[d350diesel]

I did some more poking around online after that last post and found that the WIF sensor is available, but it's $85. :eek:

So I drilled and tapped the WIF sensor port for 1/8" NPT and put a pipe plug in it. :D Put the truck back together, bled the filter, and she fired right up. Checked the fuel flow with the engine running, I have plenty so the new OPS is working nicely. The truck idles nice and smooth, I drove it about 15 miles with no stalling issues. :)

The real test will be whether I have to prime the fuel system tomorrow morning to get it to start, or if it will just light off like it should.

Thanks again for all the helpful suggestions, figuring this out would have been a lot tougher without TDP. :)

[d350diesel]

Now it's back to the short glow plug light (1 second) and no start! :mad:

Unplugging the ECT sensor has no effect on the length of the glow plug cycle.

I shorted across the glow plug relay and counted to 20, then went and hit the key - still no start, doesn't even cough.

Lift pump runs while cranking (once there is oil pressure) and for several seconds after that.

I have good fuel flow at the bleed while the LP is running.

Plugged the truck in for 3 hours while working on another project, still no change. It started and ran perfectly yesterday. :confused: Where to now?

[twaddle]

Hi there,
I would get a spare PMD (Black box about the size of a pack of cards that's attached to the drivers side of the fuel injection pump).
Try starting the engine with the new PMD and see if it fires up. It won't go to waste if it doesn't help as this is one of the list of back up spares many of us carry in case we're stranded with a (no run) engine stall.

Check as many connectors as possible and also any bad ground wires that may cause an intermittent no start situation.

Let us know how you get on and best of luck.

Jim
Biggar, Scotland
PS. Also get yourself a digital multimeter and carry it with you. You'll soon find out why once you get the hang of things.

Bye for now.

[d350diesel]

I understand that the PMD is a common failure, but it seems to me that the PMD couldn't cause the short glow time I'm seeing. :confused: I have a hard time justifying a PMD to cure this problem. I am going to throw an ignition switch at it out of desperation. :(

[twaddle]

Hi,
Get a Digital multimeter and see if you can figure what is getting voltage and amps and what is not, it may help you pinpoint where the problem lies rather than the time and money spent on things that are not needed. The PMD was suggested as it is a recommended spare to be carried as they can and do fail without warning and is handy to have anyway.
If the glow plug solenoid that you connected using the screwdriver is getting voltage and it was the heavy cables that you connected the problem is not in the glow plug circuit unless everyone of the plugs are kaput. Even if only half of the glow plugs are working the engine should try to fire up all be it with a bit of smoke.

I am also having problems with no start and stalling fault although it is very very intermittent and has been for a few years now. Mines a 96 Suburban.
Sometimes the truck stalls then fires up right away other times it stalls then won't fire up. I have noticed that on these Non start occasions the glow plug light does not come on or just comes on for a split second like yours, but the engine is hot enough and it should fire right up, this to me is a supply fault to everything from the glow plugs to the fuel injection pump. This has been happening a couple of times a year until recently, now it is happening every 3 to 4 weeks. I like you may end up trying the ignition switch out of desperation.

When you turn the ignition switch on does the glow plug light come on every time although only for a short while?
Are you getting voltage and also good amps at the Glow plug solenoid and also down to the glow plugs themselves. Also check the low tension side as well as the heavy current side. I had an occasion where the glow plugs were getting good voltage but the HD contacts in the controller solenoid were so badly burned with old age that only a low current was getting to the glow plugs.

Sorry for this answer being a bit long winded, just trying to help.
Good luck, if I get to the cause of my non starting problem I'll give you a shout.

Regards

Jim
Biggar, Scotland

[d350diesel]

When you turn the ignition switch on does the glow plug light come on every time although only for a short while?
Are you getting voltage and also good amps at the Glow plug solenoid and also down to the glow plugs themselves. Also check the low tension side as well as the heavy current side.
Yes, the glow plug light comes on for a second every time. I must've cycled the key 50 times trying to get a light that lasted a reasonable amount of time.

Glow plug relay appears brand new, glow plugs also look new. The PO must've been chasing the same problem. He got lucky and it started when I looked at it - so it's my problem now. :( The relay appears to be getting good current and the glow plugs seem to be working - I get a good arc from the screwdriver to the terminals when connecting and disconnecting.

The no smoke or sputtering while cranking makes me think the injection pump is not sending fuel to the injectors when this is happening. I think if it was just too cold to fire I'd get white smoke out the exhaust while cranking. Also, plugging it in does not seem to help.

[twaddle]

Hi there,
I think you have a similar fault to the one I have, whether they are both caused by the exact thing I don't know.

I still think that trying another PMD would at least rule out the present unit and remember you may be dealing with two different faults here.

Check for a good supply to the PMD (can't remember if it's a pink or red wire) and also the shut off solenoid on the injection pump, (barrel shaped item at the front of the injection pump).

It might be worth getting a tin of spray on electrical contact cleaner and one by one check multiplugs and connectors.

Does anyone else know if there is a solenoid that feeds Glow plug and fuel inj pump circuits, it may be in the ECM? Help! Chip in here if you know anything.

Check that solenoids are operating ok at the fuse box, I think they are in the same location as the 96 on the lhs inner fender.

Sorry I can't be of more help on this one, I do understand that it is very infuriating being unable to get to the cause of the fault. With my fault being intermittent it makes it so difficult to pinpoint, it is a real pain in the you know what.

Good luck

Regards

Jim

[65TD]

For a no start always check the fuses first.

[d350diesel]

Cleaned and retightened the ground by the trans dipstick - no change. Disconnected every connector I could reach, inspected (all very clean, weatherpak connectors work well), and reconnected. Still no change.

Left ECT sensor unplugged and got the voltmeter, turned the key on and checked across the plug. Got 0.35 volts - that's no good. Checked from ground to B-, 0 volts, so ground is OK. Checked from 5v to B-, still 0.35 volts. So I have a 5 volt supply problem. Check across the plug again - now I have 5 volts. :confused: I did absolutely nothing but let the truck sit with the key on for about 3 minutes, and the 5 volt feed came on. :confused:

So I hopped in the truck, turned the key off and back on, got a long glow cycle (ECT still unplugged), hit the key and she lights right off. Timing rattle that puts a 24 valve Cummins to shame. :eek:

So the problem in very general terms is I had no 5 volt feed from the PCM. That's nice, but it doesn't really tell me what to do to fix it. Why is it losing the 5 volt feed, and why did it just come back all by itself?

I'm really baffled. I tried tilting the column up and down and wiggling the key to see if it would die, but it kept running.

[twaddle]

Hi there,
Good to see you are at least finding something, may not seem like much but it's a start.

Where is the ECT sensor located and what is it? I don't recognise the abbreviation (or whatever they call it)?

Thanks

Jim

Biggar, Scotland

[twaddle]

AH HA! I just found the "TDP & GM Diesel Acronyms" and found what "ECT" is.
DAH!

Still want to know where it is located on your truck.

Next time (if it happens) could you also check for voltage at the fuel injection pump shut off solenoid and also the PMD.
I think you have a similar or the same fault as my Suburban and I think there is a voltage supply problem which is causing a low voltage problem to several areas of the engine which is causing the glow plugs not to cycle properly and the injection pump not to pump.

Almost frightened to say that my Suburban is running ok just now (I need it to get me to a job starting at 4.00am tomorrow morning) so I can't find reason for my intermittent fault to try and help you.

Good luck

Jim
Biggar, Scotland

[d350diesel]

The ECT is screwed into the coolant crossover. Follow the upper radiator hose to the thermostat housing, then look on the passenger side leg of the "Y" that connects the thermostat housing to the engine. That's the easiest sensor to unplug on my engine, which was why I picked it. :)

I'm sure it will happen again, I didn't fix anything. :rolleyes:

I'm sure the whole 5 volt system was down, that explains all the symptoms (very short glow, no fuel injection happening).

My plan is to trace the 5 volt supply wires from the PCM to see if I can find a chafed harness somewhere.

If I had to guess, though, I'd think the PCM was at fault. Maybe the 5 volt supply is getting flaky and doesn't work immediately on power-up? I'm trying to avoid replacing anything expensive unless it's unavoidable, so I'll look the wiring over very thoroughly first.

Anyone with more experience is welcome to chime in - I'd love to hear some words of wisdom right about now. :(

[twaddle]

Hi,
The ECM/PCM is what I have feared may be the cause of my intermittent fault
but can't pin it down long enough to establish where the main feed starts or where the fault may be.

A while back I had asked if anyone could tell me if there was a relay or solenoid within the ECM that could be replaced with a new unit rather than replace the complete ECM. Being a Scotsman I like to save some money.

So I'll also ask "IS THERE ANYONE WHO CAN HELP WITH INFO ON THE PCM/ECM OR THE SOURCE OF THE FEED TO GLOW AND INJECTION PUMP CIRCUITS?

There must be others who have had the exact same sort of symptoms?

Jim
Biggar, Scotland

[d350diesel]

Came home from work today and tried to start the Suburban. Short glow plug light, no start. Left the key in the "run" position while I dragged the trash cans in from the street. Came back, turned key off and back on, got a long glow light and it fired up like there was never a problem. Pulled it into the driveway and put on new front brake pads so I can get an inspection sticker, went to fire it up to put it back in the street and it started like you'd expect it to.

I'm feeling brave, I think I'll try to drive it to work tomorrow. :cool:


Being a Scotsman I like to save some money.

I'm not Scots, I'm just cheap. :D

[d350diesel]

I did a little poking around on the internet, and I found the PCM for $87 at RockAuto.com. I may throw a PCM at it for that price. The ignition switch is more expensive!

I'm waiting on the box from Helm to show up (manuals). I'd like to go through the wiring with my eyes open before I do anything drastic.

[twaddle]

Hi,
Is it a PCM (Powertrain control module) or a ECM (Engine control module) that you are considering getting?
Don't know if the truck has both but just thought I'd ask, just in case.

Good luck

Jim

[twaddle]

Forgot to warn you.
Take it easy just in case the engine cuts out/stalls. It is NOT funny when lose the power side of the brakes and steering. Wakes you up quickly first thing in the morning when it happens though!

Jim

[d350diesel]

Hi,
Is it a PCM (Powertrain control module) or a ECM (Engine control module) that you are considering getting?
Don't know if the truck has both but just thought I'd ask, just in case.

Good luck

JimPCM runs both the engine and trans. There's an ABS computer that is a separate unit.

Today's update:
When I went to start it this morning, go the short glow/no start again. Left the key on while I unplugged the truck and put a bill in the mailbox. Got in, turned the key off then on, got a normal glow and was on my way. Ran fine all the way to work this morning, I left early in case of trouble so I sat and let it idle until it was time to start work. Ran for about 40 minutes total, no stalling or bad running.

Leaving work I got a normal glow and the truck fired up easily. Truck sat unplugged in mid 30 degree temps for 9 hours. Had to run 3 errands on the way home. First stop, it restarted no problem. Second stop, got the short light/no start. Waited 2 minutes with the key on, retried and it fired right up. 3rd stop was uneventful, truck ran OK all the way home.

Seems like when it's running, it will stay running, but when you shut it down it's anybody's guess whether or not it will restart normally. The ignition switch showed up today, but I didn't have time to install it. The weather is supposed to be brutal this weekend, so it's not going in for a few days at least. Hopefully the manuals will show up before the weekend so I can get cozy with them and do some serious reading.


Forgot to warn you.
Take it easy just in case the engine cuts out/stalls. It is NOT funny when lose the power side of the brakes and steering. Wakes you up quickly first thing in the morning when it happens though!

Jim I had that enjoyable experience several times before I fixed the fuel leak and replaced the OPS. :eek:

[twaddle]

Hi, You're probably following this thread but just in case it is of any use here it is. R.Roy might find a common cause of this fault before we do.

Although you seem to be doing pretty good using you own common sense and skills.

http://www.thedieselpageforums.com/tdpforum/showthread.php?p=202893&posted=1#post202893


Jim
Biggar,Scotland

[d350diesel]

Seems like when it's running, it will stay running...Well, that's not true. :rolleyes: Died on me once on the way down to work, once while idling in the parking lot before work. On the way home it died once, too. I have not been able to refire while rolling, I always have to wait a couple minutes with the key on before it will refire. Just cycling the key does not cut it, I have to turn it on and leave it on.

It doesn't seem temp related, though. When it died on the way down to work the truck was fully warmed up (it was plugged in overnight and had been driven about 10 miles), but on the way home the truck was cold when it died. It sat unplugged in 30 degree temps for 9 hours and had only been driven about 1/2 mile when it quit.

I'm not driving it until I replace the ignition switch. The weekend forecast has improved, so that will get done Saturday. I'll go over the wiring again, and if I don't find anything and the ignition switch is not the fix, then I'm throwing a PCM at it.

BTW, got a normal length glow on the first try both this morning and afternoon.

[sailun]

Before I throw in my 2 cents worth, I want to say I'm not a good mechanic, or trouble shooter. BUT, my truck had very similar issues last summer.

Randomly stalling, or not starting, seems to almost always be FSD or ECM-related.

I replaced my FSD and put it on a cooler, as have most others on this site.
That solved all the random no-starts, for a few months.

Truck started dying while driving, and found it was blowing the ECM fuse. (I think it was ECM-B ?) Put a new fuse in, it might start, or it might blow another fuse. It would cruise on the highway all day, but blow the fuse while accellerating away from a corner, or stop sign. Probable voltage change ?

MOVED the 2 ECM grounds from the back pass-side eng stud to next stud forward.

A GM mechanic who pulled over to investigate recommended this. It worked.
On my truck, there's already another ground from harness on this stud.
(I also just added a ground cable from this stud to frame, last week)

Thus, issues were caused by bad elec circuit.

Since you are not blowing the ECM fuse, and seem to randomly have WEAK/VARIABLE/NO POWER/signal coming out of the ECM (no glow, no start, stall), you probably have weak/variable/no power going to the ECM, randomly. Either ignition switch, as others have recommended, or test entire ECM power circuit starting at fuse block ? Wiggle with test light in place of fuse ? Test power passing thru fuse while cranking ?

Others must tell you how to test these circuits, I learn from everyone else here.

Costs you almost nothing to move/improve the grounds.
Just my experience.

Regular contributors: If I've made any functional mistakes in my analysis, please correct me.

[d350diesel]

Good points, and I thank you for your input. I will be replacing the ignition switch tomorrow, and the wiring diagrams showed up today so I'll be tracing wires as well. I'm really not expecting to find a wiring problem though. If it was a wiring problem I'd expect vibration/shock, driving conditions (accelerating, turning) or temperature to have an effect.

What I don't get is why it has to sit with the key on for the 5 volt feed to start working. Just cycling the key several times will not make it start working, it has to sit in the run position for a couple minutes.

[twaddle]

Hi there,
My 96 does the same as your truck that the glow plug light comes on when it decides. Cycling the ignition switch doesn't work. The difference seems to be that sometimes mine starts almost right away and other times it's after a few minutes.
From what I could make of the wiring diagram from a while back the main power source to the fuel injection system and the glow plug circuit was from the ECM/PCM, which is what I've reckoned is causing my intermittent fault. I seem to remember getting the impression that there is a relay inside the PCM but was unable to find if a new one could be drafted or adapted in.

If the dang thing would just misbehave long enough for me to find the fault.
Now its been running for just over a week with no problems and I haven't done a thing to it. (Very dangerous thing to boast about!)

Good luck

Jim
Biggar, Scotland

[d350diesel]

After doing some light reading in the Driveability, Emissions, and Electrical diagnosis manual, I'm not so sure the trouble is in the PCM. The 5 volt feeds are solid state and short circuit protected - they shut down if there is a short. From the codes I've gotten from the truck, it seems like there is an intermittent short to ground somewhere between the PCM and the 2 connectors above the fuel filter on the firewall. I think it's there and not somewhere on the engine because circuits fed by both connectors have set codes. No codes have involved the throttle assembly, which has three 5 volt feeds. I've been looking at the wiring on top of the engine, but it seems the problem lies in the harness coming up from the PCM. I have hopes that some electrical tape and a couple wire ties will fix this. :)

The only thing that makes me doubt this is - why does just leaving the key on make everything work? :confused: I could understand if I was jiggling wires around and it all came back, but this just doesn't add up. :(

[twaddle]

Hi there, What codes are you getting and what are they for?
One of the problems I have had is that there has NEVER been any codes showing. However as it's a while since I checked for codes, I will check it out tonight just in case.
Be careful that the codes don't lead you off the trail of the real fault.

Are you getting voltage at the PMD and the fuel injection pump shut off solenoid at the fuel pump. Both these should be getting 12 volts. (Correct me if I'm wrong).

The next time my Suburban stalls I will check the 5 volt areas as I have been checking the other areas (12 volt supplies).

Regards

Jim
Biggar, Scotland

[d350diesel]

They are all codes that involve a 5 volt circuit shorted to ground. 14, 17/18, 31, 42, 47, 44, 57, 62. I have not checked for them recently to see if they have all come back, just working off my notes.

One thing that makes me second guess my last post is - this thing doesn't have EGR, so it doesn't have a Baro sensor - so how do I wind up with a code 31? The only way that makes sense to me is an internal fault in the PCM.

I have not been near a voltmeter when the problem has presented itself. The way the wiring is run on my truck I'd have to pull the upper intake to get the shutoff solenoid plug disconnected.

I wish I knew more about the internal circuitry of the PCM, some of these 5 volt feeds that are on separate pins may be bussed internally - so a fault with one sensor or wire outside the PCM could cause this sort of widespread failure.

Oh well, checking the wiring is free and it doesn't involve a trip to the dealer to teach the new PCM the proper TDC offset.

[gmctd]

Correct - the shorting 5v ref voltage is the problem - check your wiring harnesses, particularly down at lower passenger-side firewall area, adjacent the ac return line.

Could also be in the ABS computer or connector.

Or, could be the sensors - Map, Baro, OS, CPS, ECT, IAT, etc

(that last one is et cetera, which is likely not tied to the +5v reference ckt.):rolleyes:

[d350diesel]

Got the ignition switch on it this afternoon, haven't driven it yet. Didn't die idling, but that doesn't mean anything.

I went over all the wiring today, from the PCM to the engine. Everything looks good. I put it all back together, and I still had codes 14, 31, 57, and 62. According to the FSM, non-egr models don't have a baro sensor, but mine has one. Anyone know what's up with that? :confused:

After reading gmctd's post, I went back out, cleared the codes, started the truck. All the codes came back. Cleared them again, unplugged the ABS module under the hood. Restarted truck - no codes. :confused: It's an intermittent problem, so one good start doesn't mean it's fixed.

I'm gonna drive it with the ABS unplugged for a couple days to see how it behaves. From my reading in the FSM I would have never thought to look at the ABS. If this cures it, I'll be thrilled. I can live without ABS.

[JohnC]

According to the FSM, non-egr models don't have a baro sensor, but mine has one. Anyone know what's up with that? :confused:

That's incorrect. They all have a baro sensor, it's just doing double duty on the EGR models.

[d350diesel]

Thanks. A little more leisurely reading in the FSM cleared up what the baro sensor is doing. It also seems that the trouble codes may be a red herring on the no start/ stalling problem. As far as I can tell, you should be able to unplug every sensor and the engine would still start and run in "backup fuel" mode. Is this correct? If this is true, then I may have separate problem causing the stalling. The PMD looks to have the same amount of dirt on it as the rest of the pump. :rolleyes:

I drove it about 10 miles today with no trouble, and I checked the codes when I got home. Just code 12. :) A big thank you to gmctd for the ABS suggestion, I was ready to buy a PCM.

[d350diesel]

Drove it yesterday and the 5 volt codes came back (14, 31, 42, 57, 62). Cleared them before leaving work, they came back on the way home. So I unplugged the PCM and checked out the circuits with an ohmmeter. None of the affected circuits were shorted to ground, and all of them had reasonable resistances based on the temperature charts and pin-out tables in the FSM. So I ordered the PCM.

I installed the PCM in the parking lot of the auto parts store, fired it up and drove it to the local Chevy dealer. Checked the codes, just got a code 12. I thought replacing the PCM would automatically set a code 88? :confused: They didn't have the tool to reset the TDC offset, so I haven't gotten that done yet. I can tell by the sound of it that the effective timing is more advanced than with the original PCM, so I'd like to take care of it.

The ignition switch seems to have been the fix on the stalling/no restart issue. It hasn't died since I replaced that - 3 days of drama-free driving and counting. :)

[d350diesel]

Another drama free day. :) I think I'm gonna call it cured.

I have a code 36 now, though. Is it time to start researching my options for a replacement PMD or should I wait until it gives trouble?

[R.Roy]

Just wondering how your truck is running. Has the problem returned? Was it the ignition switch or the PCM that cured it? Having same problem with no "wait to start light".

[gmctd]

DTC36 can be caused by low battery voltage at the FSD\PMD - battery cables, grounds, connections, incl bad connections at the fuses.

Dr Lee's battery-post fix is a good one, or four - two batteries x 2 posts @.

Once you get this fixed, briefly try the ABS computer again, noting any 5v REF codes - anything out of the ordinary, unplug it, so as not to damage the PCM again.

I'd do the remoted FSD anyway, as preventive maintenance - Bill's comes with a 72" extension to mount behind the front bumper, is water-proofed, and has a 7-year warranty.

[d350diesel]

So far so good, the ignition switch fixed the stalling/short glow plug light/no start issues, and the new PCM fixed the "whole bunch of 5 volt codes" trouble. Never did set a code 88 like it was supposed to. :confused:

I found another fuel leak in the return line and the code 36 has not been back since then.

When the weather turns I plan to try out the ABS.

I think I'll wait until it breaks to fix the PMD. That's a big chunk 'o change to throw down - besides, the Dodge needs head studs and a bigger turbo. :D

When the PMD goes, I will get one from Bill. I've dealt with him before. :)