96 6.5 c3500 will not stay running

[jordanroch]

Hi. First post here.

We have a 96 c3500 6.5 td. It has a problem staying running. Sometimes you will crank out and it will start. Sometimes it won't.
It has a brand new PMD (on drivers firewall near brake booster. New fuel filter. Oil change 2500 miles ago. 10w40 rotella. 247000 miles. No check engine light. No codes on obd2 scanner.

Recently in the last couple months, the truck stalled out. Father in law tried cranking with ether. (Lol don't tell me i already knew it was bad idea) it backfired messed up the flywheel and had to replace that. Had a crazy time getting to start back up. Got online, looked about and seen that the PMD was a common problem. Ordered it. Put it on and sometimes it will crank, run for 10 minutes. More it cranks and runs for ~30 seconds. Cuts off. Sometimes it will surge one time run foe a few more seconds and then die. Every time it dies it acts like you cut the key off. Never hesitated, missed or nothing.

I have been looking online for a while and have tried hooking a clear hose to the t drain valve with lift pump relay removed and pubs 30&87 jumped with wire. Flow is steady. No bubbles. Have not checked pressure.

I read that the fuel safety solenoid can get weak. I removed it and disconnected fuel cut off solenoid and turned key on and cranked. It started open but you could oull it closed with ease. So we took a cut off wheel to it and cut off the plunger ( will replace that) and the same thing happens.

Checked voltage at red ignition wire under steering wheel 12 volts. Key on yellow 12v. Cranking purple 10.8 volts.

Every time that you crank there are two different sounds. Either you just hear the motor turning over. Our you hear the motor turning with sputter like it's trying to crank. Them for a split second key off. Key on and crank Them out goes back to just motor turning. No sputter.

I am leaning to ignition wiring harness. Or oil pressure sensor but I believe the ops Is causing this. Last thing we want bad is the IP however the way it's going we're thinking more towards it.

We are about to throw in the towel. There is some kind off electrical problem somewhere.

Is there any electrical things I can test or any obvious things I can do to test anything. I have tools. Not afraid to get greasy. Just want to get this thing going. I recorded a video this afternoon of the cranking where you can hear what I described. I just don't know how to upload it. I think I will upload to YouTube and post video url.

Please somebody! !!!
Jordan

Edit: YouTube. Video link96 6.5 chevy c3500 won't start. New PMD: http://youtu.be/OHwJQa9Y2YY

[sctrailrider]

Welcome to the page...

Where is SC are you??

I'm not that good with the electronic motors but someone will chime in today I'm sure....

I might be close enough to lend a hand if needed, I'm in the upstate area..

[jordanroch]

I'm in Bamberg, Sc. 15 miles south of Orangeburg. That's real cool of you to offer. But in no way do I expect anyone to travel to help me get this fixed!

I forgot to add in the original post, that this started one day when just cranked up and left for work. Got 1/2 mile and that was it..

It's not a primary vehicle. However we do haul a 8500lb 28ft bumper hitch wildwood camper with it. I have a 97 f150 5.4 towing package that I've pulled it before but I'd rather pull with this diesel. We also are thinking about dropping a service bed on it to haul tools etc. I'm starting to believe that we need the service bed before we even take it to the gas station.

Did anyone watch the video yet? Did you hear the sounds i was on about? Cranking over and sputtering like it wants to fire then all of a sudden no sputter just motor turning over.

Its kind of wet today and I have a new radiator to put in the f150. But I was going to crack some injectors whilst cranking to see how much fuel I'm getting.
Does anyone know the correct procedure? Or one that works? If I unplug the pmd will I still get fuel at the injectors when i spin the motor? Im new to working on this 6.5 monstrosity.

I believe there is a wiring fault somewhere. This might not even be a common problem, I see some splices to a couple of glowplugs and near the starter. I fixed the s tarter (sometimes when you crank it wouldn't turn) it was a bad ground. I got that sorted when I put the flywheel in. I have also checked the grounds on the rear passenger side intake manifold studs and they look good. However I have not checked these with a volt meter ie. Battery hot to that ground to see if it ever drops out.

I just need to get this thing running.
I appreciate any input. I'm sure there's things I've done that if mentioned I will remember but not off the top of my head!!

[a5150nut]

Try doing a search here for trouble shooting procedures. You will find step by step instructions. Takes three things for one of these to run. Fuel, compression, and air.

You are on the right track checking for air bubbles in fuel but not the line not coming off the tee. Return come together at front of engine then back towards injection pump.

You really need to replace the fuel shut off solenoid if you cut the plunger off. When one of these run away it gets scary real quick.

Is the new PMD good in another truck? They do come out bad once in a while.

Ignition switch down on the lower end of steering column might be suspect also.

First make sure your getting fuel by cracking an injector line. Then work from there.

[jordanroch]

We have not been able to test the new PMD. I don't know anybody local that owns one. But now you bring it up, I believe I know someone who has one.
I had also thought it could be a bad new pmd. when I plug the old one up, it does the exact same thing as it does with the new one. Which leads me to believe the old one may still be good.

Can you explain about the ignition switch. Lower end of steering column? That is not the one right under the barrel where you put the key? Does it come as a harness? I've only seen the ones with a harness.
Could you send me a link or p/n please.

I will try cracking lines next. About to plug the charger up to it now

[a5150nut]

Ignition switch is little box on lower column near brake pedal has rod that works it from the key switch. IIRC it has two screws holding it to column.

Your PMD is remote, where is the ground wire? It should still be on injection pump.

Might check batteries too. 6.5's take 100 rpm cranking for the computer to tell the injection pump it can have fuel.

Fix the cheap things first. Unless you have lots of money you don't want any more. . . .;

[jordanroch]

There was a PMD relocation done sometime in 2012. According to the date on the old PMD.
I'm assuming the PMD ground is good. I do not see one pigtailed in near the top of the pmd harness.

I've got a feeling the batteries do need replacing, however like you say. Money. Money. Money.

I am going to get dressed and greasy, and try the things you've mentioned so far.

[DmaxMaverick]

The PMD ground he mentioned is independent, and you should see it screwed to the IP housing, from the PMD harness. If it isn't there, you'll likely have issues. Many aftermarket PMD harness extensions don't accommodate it.

[jordanroch]

Ok. have just cracked the injector lines. Number one and 3. I had my girlfriend come outside and crank whilst I was watching for fuel. I found out that the motor was not getting fuel. we tried a second time, the motor started sputtering and cranked up whilst number 3 was completely disconnected, and number 1 tighten back up. it was spraying fuel. the motor stayed running For 5 seconds.again we tried to crank and there was no fuel being ejected from the injector hose For number 3.

what I have learned so far is that when the motor sounds like it is sputtering it is getting fuel. then a few seconds later you try and crank again and you hear just the motor with no sputter it is not getting fuel. (refer to post number one with video for details)

I just looked and found the PMD ground. it is mounted on top of the injection pump. the ground wire goes inside of a black conduit and goes down to wards the injection pump. I do not know if it is connected to the PMD itself. what actually confuses me the most about it is that the motor ran completely fine for the year also that we have owned it. this leads me to believe that there is no fault with it being an aftermarket harness. however if you do say there is supposed to be a ground wire going from there to the PMD, I will happily splice that ground into where it needs to be however like mentioned a few minutes ago I do not believe that this has any interference with these current problems. edit: I have just attached a picture. you can see the wire for the ground going on top of the injection pump. you can see that it goes towards the injection pump. also attached you can see the extension harness for a new PMD. I do not know how to include the image into this post however it is attached

I have been looking around under the dash on the drivers side for the push rod and ignition switch but I haven't really discovered anything. I am actually having some trouble finding the pushrod the only one that I see is the rod for the transmission shift linkage.

why would it only get fuel for one second and run and seconds later it doesn't get no fuel. does this sound like it is PMD related? if so come, I have a three year warranty for it. I can set up an RMA request with Rock auto and exchange for another one.

Edit#2: Have been out here all day plundering around. After cranking earlier with injector#1 cracked open I have been able to start it, run it around our back field bumpy trying to get what I still believe is electrical to reoccur. But it seems coincidental that it would be fuel and electrical combined. I don't know.
I temporarily had the PMD unmounted and in the midst of the field it fell and broke the connector off the extension. I just plugged it up to the original connector at IP for now. I'm about to look online for a new harness and trying to find a heatsink to mount on it. These PMD's do put out some heat.

Am going to do the above and run the piss out of it in the back field to see if the electrical problem will reoccur.

[DmaxMaverick]

That ground is probably OK. Unless it's come disconnected from the PMD connector in some way, don't worry about it. If you have the PMD connector pin-out, you can verify it.

Your problem doesn't sound like it's on the electronic side of the IP. Perhaps a fuel supply issue, making the OPS a likely candidate. Or a large fuel suction leak, intermittent/failing fuel lift pump, or collapsed fuel line, all coupled with a weak/weakening IP. The IP will draw fuel with a failed LP, but it won't do it for long before wearing itself out. If the IP was already tired, loss of the positive fuel supply can cause the symptoms you are seeing.

[a5150nut]

The next time you get it running get a catch bottle on the fuel line off the tee. While it is running open the tee and see if your getting any fuel out while running. If it dies right a way start looking at lift pump and fuel lines.

Do you have fuel in the filter housing and what shape is your fuel filter in?

Have girlfriend turn key on and try to start while opening bleed valve on fuel filter to see if you have fuel there.

It is sounding more like a lack of fuel problem.

Just one thing to eliminate from the search.