stalls, glow plug light

[Dennis22]

I have had a issue with this truck for the last year and a half. I have had some great advice from this forum, but still having issues. 96 burb, 170k new FSD at 160k. Truck will stall going down the road, it is like you just turned off the key, all the idiot lights come on, most of the time I can turn the key, get a flash from the glow plug light and it will start right up. If the glow plug light does not come on at all the truck will not start. I have to keep cycling the key until I get the glow plug light to come on and it will start right up. I have gone through and replaced all of the ground wires. I feel it is electrical somewhere but can not figure it out. It has been to two diesel mechanics, one cost me $1200 and did not solve it (but I do have a new glow plug controler and new glow plugs on the left side) the other mechanic could not figure it out. It can go for weeks without happening to doing it several times a day. Any advice would be greatly appreciated!

[TAG]

Boy it would be hard to ignore the ecm with those symptoms. If the truck is running down the road and quits, it doesnt need glow plugs to restart. Used ecm would be less pricey than paying shop labor rates for an intermittant problem.

[Dennis22]

It has been hinted before that it could be the ecm, any advice on how to go forward with that. When you say used, does that mean going to a junkyard? and when I do get one, do I have to go to a dealer to get it programed? Thanks again.

[TAG]

I would have to guess there are a lot of ecms floating around in members garages. Maybe someone on the board could loan one as a test piece. Otherwise junkyards in this neck of the woods are hooked up on some sort of nationwide locater. Any used ecm out of same year & model truck will make it run, but if you could find one out of exact equipped truck, you could run it long term.

[JohnC]

I think I'd look more closely at the ignition switch and power feed. The glow plug light is probably a bit of a red hering. If the glow plugs were getting power, I bet it would also start. It's not that it needs the heat from the glow plugs

[Dennis22]

Any suggestions where I could start looking for the power feed? What else is there that also feeds the glow plug light that would cause the truck to stall?

[TAG]

The fact that the idiot lights come on when it stalls led me away from a major power supply problem. There are several power feeds coming out of the ignition switch that branch to power many different circuits. Seems to me if it was ignition switch or major power supply you would notice other symptoms in addition to stalled engine. You could try wiggling the key around while its running & see if it stumbles, not very scientific, but i should add i have been chasing intermittent electrical problems on all different brands of vehicles for a lot of years, and the solution is rarely very scientific. I think a used ecm is cheaper than a new ignition switch too. Key to accurate diagnosis is getting it to do it in a controlled setting & a good wiring schematic. keep us posted

[JohnC]

The ignition switch (separate from the key operated locking mechanism) is a good place to start. It's known to be problematic. It powers 4 separate groups of circuits: Accessories, "run items", starter, and PCM/trans. The PCM/trans circuits are separate from most of the idiot lights and actually come on whenever the key is out of the locked position, i.e. before the "run" position. Put some sort of voltage indicator (test light, meter, etc) on the trans fuse and see if it ever looses power. When it dies, does the check engine light com on? If the PCM has power, it should. PCM also controls glow cycle.

[Dennis22]

Been around vehichles quite a bit, can do most minor work but this forum has helped me get through the tuff stuff. Is PCM the same as ECM? I tried the scientific approach in the past of wiggiling the ignition switch, it has never helped. I also have banged on the ecm and it did start after banging on it one time (coincidence?) but it usually does not work when banging on the ecm.
Where do I find this Trans fuse? when the truck dies should I have no power to this fuse? When the truck dies all the idiot lights come on, just like you were going down the road and clicked the ignition switch back one notch. The only "tell" to know if it is going to start is when you turn the ignition swith off than to the on position, if you get a flash from the glow plug light it will start everytime, no flash no start.
Thanks again.

[twaddle]

Hi Dennis,
Sorry to hear that you are still having trouble with the old Sub again.

The symtoms that you are getting are exactly what I had a while back, (Stall, not starting if the glow plug light did not come on, then up to 7 weeks no problems before it would stall again)
I went through all the connector and earth and feed cable stuff that I spoke about a while back which seemed to improve things (as it did with you if I remember correctly)plus the FSD/cooler as well. At the time I was trying to find where and what was common to the Glow plugs and the FSD/fuel inj pump or the shut down solenoid but was unable to get anywhere on that one
.
Eventually about 15 months ago (Sept 03) I took an old FSD that had been removed&replaced some time
before. I loosened the nuts that hold the 2 transisters and retorqued them.
Over the last 15 months I have had no trouble at all. Could just be coincidence or luck or I disturbed a connector, I don't know but the truck has not cut out on me for 15 months.
It might be worth trying retorquing the nuts (at least it is an inexpensive thing that might work).
How old is your FSD?

My Sub did stammer a couple of weeks ago while travelling at around 60-65mph it felt like the truck had just hit a pool of deep water, stammered for a split second then picked up again and has been ok since. The SES light came on for a couple of seconds them went off.

Good luck

Jim Twaddle
Biggar, Scotland.

[Dennis22]

Hey Jim,
Good to hear from you again. I to went through all the ground wires as you and others suggested and did replace the FSD about 10k ago. I am a little nervous about taking off the FSD, that was just put on a short time ago. My issue is that it will not stay stalled for a long period of time. 90% of the time it starts right back up, the other day I went in the house to get a flashlight because it would not start right up and it started as soon as I got back. It is hard to find a problem when all it does is stall and then starts right up showing no symptons. My wife will not drive the truck, it has stalled on me in city traffic hence no power steering,full brakes wich makes for dangerous situations. I just hate to throw more money into this thing when it seems to be just a geussing game, ecm? ignitions switch? FSD? maybe I should poll everyone here and whatever gets the most votes I will do smile.gif

[HudB1]

Boy i hate to post this because i've been having good luck. Anyway i had a simular problem except no stall will driving. I eventually installed 0 gauge ground wires, motor to frame and intake bolt to intake bolt to make one ground wire between upper ones also cleaned all electric connectors with contact cleaner and dilectric grease.
that was about 10 months ago
hudb1

[JohnC]

Originally posted by Dennis22:
Is PCM the same as ECM? Yes.


I tried the scientific approach in the past of wiggiling the ignition switch, it has never helped. The actual switch is not directly connected to the key, so that's no surprise. The switch is under the bottom of the column.


Where do I find this Trans fuse? when the truck dies should I have no power to this fuse?If my theory is correct, it's loss of power to this circuit caused by the ignition switch. The fuse should be in the fuse box on the driver's side of the dash, IIRC.


When the truck dies all the idiot lights come on, just like you were going down the road and clicked the ignition switch back one notch.Do you say "all" because there's a lot of them, or because you verified that every one came on? The "Check Engine" (MIL) light will not come on if the PCM is not powered. Most of the others will.


The only "tell" to know if it is going to start is when you turn the ignition swith off than to the on position, if you get a flash from the glow plug light it will start everytime, no flash no start.If the PCM is not powered, it will not power the glow plugs.

[Dennis22]

JohnC, thanks for the answers, I have never wanted the truck to not start before. I hope it does so I can check out your theorys. You sign that you are from Upstate NY, I am also, Lake George area. Are you around here or out in western NY?

[twaddle]

Hi Dennis,
It is no fun when the fault is so intermittant, I was at the stage a while back where I carried a multi meter,(along with the usual array of spare parts and tools) hoping that it would cut out long enough to check voltages at the fuses and connectors.

Is the FSD mounted on the side of the fuel inj pump or on a cooler block away from the pump?
It is really easy to get to the transister screws in the FSD as they are located at the back of the unit with plastic caps covering them.
Just pry them off gently (they just pop off) loosen the nuts off a little and retorque them, the plastic caps just pop back on. No damage is caused to do this and no one will ever know.
If you want to try this and are unsure of the torque method known as "that'll be enough" (guesswork by hand), I can see if I can find an old unit and check it with an "inch/pound" torque wrench. Let me know.
Again Good luck.

Jim Twaddle
Biggar, Scotland.

[Dennis22]

Jim, it is mounted on the side of the fuel injection pump. Will I need a special tool to get it off of the pump?

[twaddle]

I managed to get my FSD off using a shortened allen key, the 90degree bent type. If I remember there was one of the four screws was a bit difficult but I didn't need to move the pump.
Do you have a cooler to remount it onto?

Regards

Jim
Biggar, Scotland

[Dennis22]

Have not gone that route....yet, I see from this forum that there is different suppliers of wire extensions and coolers, any suggestions?

[twaddle]

Hi Dennis,
Just getting a cooler to mount on the inlet plenum is better than having to put it back on to the side of the inj pump.
It also makes it a lot easier and quicker to install the spare FSD (that most of us carry) at the roadside, saves getting towed in.
If you need any pictures of the inlet plenum mounted unit let me know and I can take some pics and send them to you, you don't need any extension leads to reach the fsd in this location.

Regards

Jim
biggar, Scotland

[Dennis22]

Jim, pictures would be great when you get a chance. e-mail to me at lafontaines@adelphia.net
Thanks!

[JohnC]

Originally posted by Dennis22:
You sign that you are from Upstate NY, I am also, Lake George area. Are you around here or out in western NY? 25 miles SW of Albany.

[Dennis22]

JohnC, Do you own a repair shop? To hook up with a mechanic who knows these 6.5 as you do would be great!

[JohnC]

Originally posted by Dennis22:
JohnC, Do you own a repair shop? Well, sort of. But all I work on is airplanes... :cool:

[DILLIGAFRI]

Hope there are not any 6.5s in airplanes. I can see it now It's raining planes!!

[Dennis22]

When I get my next plane I will look you up! I have my fixed wing license, I've owned a Piper Cherokee PA28151 then moved up to a Arrow and the last plane I had was a Balanca wood wing retractable. I have been out of it for a couple of years, different focus (4 kids) but I can not wait to get back into it!

[twaddle]

Hi Dennis, I will try and get a chance to get some pictures tomorrow of the FSD and cooler.
Sorry for the delay.

Jim

[JohnC]

Originally posted by Dennis22:
When I get my next plane I will look you up! OK, but get sonething with some short field capability. (Look up NY86).

An aquaintance of mine from my former life has a Cruisemaster, I think it's called. Triple tails...

[Dennis22]

JohnC, I used to go into Goodspeed (42B) in Connecticut all the time, that field was 2100 ft coming in over a draw bridge. Getting in at Waxwing with only 1350 ft would be a challenge.