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Confused about Why It won't Start

P

pneese973

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Location
Alexandria, IN
I am the new owner of the 1994 Chevy 2500 6.5L Turbo Diesel. I am very knowledgeable with diesel engines and build/work on/modify VW diesel engines on a regular basis (probably 15+/year). I've even rebuilt a few Bosche VE Rotary Pumps before. Anyway, I've done quite a few things to the truck that has been in question and have a lot of info and am confused about what's going on. A friend of mine who has owned a 1995 6.5L TD has been helping me and he's been able to keep his on the road for over 350,000 miles. Below is a list of what I know thus far and what I've done to the truck.

1) Ordered and installed a new PMD and remote installation kit. I installed the PMD behind the front bumper where it will be cool and get good airflow.

2) Since the truck is at a friends house, we hit it with a 100A charger and jumped it with another vehicle. We bled the filter and found a very small amount of air present. Filter was bled with a bottle and clear line and run the pump until we got about a quart of fuel out of it and closed the filter drain with the pump running.

3) Fuel smells stale (maybe from bacteria???). Drained tank and put 10 gallons on new fuel and fuel treatment in the tank. Took old fuel and found it hard to light when putting a torch to it. Torch took maybe 5-10 seconds before old fuel would even try to burn.

4) Removed plunger from Idle Cutoff Switch.

The truck has new glow plugs, I can hear the lift pump running, #9 resistor installed, a new PMD, and a new fuel filter. I think the PO may have changed the lift pump as well.

Here's where it's at.....
Truck will fire off ether and runs great. I tried running it until it got to about 180 degrees, shut it off, and tried to immediately start it. No luck, but will start right back if it has a very small sniff of ether.

Truck has a funny smell out of the exhaust while cranking (like stale fuel) and I saw smoke out of the exhaust while trying to start it.

Once started, truck runs great. No surging (typical of weak IP), stalling, hesitation, nothing. In 1/4 mile, it has no problem getting to 80+MPH from a dead stop. Service Engine Soon light is constantly on, but no codes (only 12) stored (found by jumping the 2 pins).

I've tried unplugging (one at a time) the coolant temp sensor, IAT sensor, and the map??? sensor and tried starting it and no luck.

All fuses are in tact. ECM was reset after new PMD installed so it wasn't running off old mapping data.

Truck has some blowby but nothing significant.

I thought (and my friend agreed) that when running it sounds like it's got a little more detention noise than it should have like it's a little advanced. It runs so good and smooth that I really don't think the IP is shot. What would a bad optical sensor do to it? I'm wondering if a bad optical sensor or crankshaft position sensor might be the problem. Any thought?
 
should still run start with a bad OS or a bad CPS as long as they're not bad at the same time. Have you checked grounds? Is your LP/ OPS system working correctly? Put a piece of clear tubing on the return coming out of the IP and check for air in fuel.
 
Howdy Pneese welcome to the site

Better to start off with your own thread less confusion than trying to keep up with what each owner has done in middle of another troubleshooting thread, when you get a moment go to the user CP button to put truck info in your signature, that helps post to post as well to keep track of things.

Spend some time in the FAQ technical reference at intro forum area for the 6.2/6.5 area I suspect you are correct with stale fuel, possibly condensation emulsified in the tank if it's been sitting a long time you have a water/fuel blend that doesn't ignite well, if that is case the possibly your check engine is WIF sensor the engine fuel filter is treated to block water.

are you getting code 12 or 21, hard to tell sometimes reading the CEL flashes?

There is a sock in the tank that will stop fuel from getting to the IP, or if the lift pump on the frame rail is weak or dead the IP struggles to pull fuel, you said air in fuel lift pump helps to overcome this as IP isn't good self puller if a rotten rubber or steel line is allowing air to be pulled in, Either is bad ju-ju for the 6.5 discontinue use of it WD-40 is preferred starting aid.

You didn't mention anything about the glows, you check those ?

You said VW experience, TDI's or older ?? I do a little with TDIs myself.
 
pneese973 said:
I am the new owner of the 1994 Chevy 2500 6.5L Turbo Diesel. I am very knowledgeable with diesel engines and build/work on/modify VW diesel engines on a regular basis (probably 15+/year). I've even rebuilt a few Bosche VE Rotary Pumps before. Anyway, I've done quite a few things to the truck that has been in question and have a lot of info and am confused about what's going on. A friend of mine who has owned a 1995 6.5L TD has been helping me and he's been able to keep his on the road for over 350,000 miles. Below is a list of what I know thus far and what I've done to the truck.

1) Ordered and installed a new PMD and remote installation kit. I installed the PMD behind the front bumper where it will be cool and get good airflow.

2) Since the truck is at a friends house, we hit it with a 100A charger and jumped it with another vehicle. We bled the filter and found a very small amount of air present. Filter was bled with a bottle and clear line and run the pump until we got about a quart of fuel out of it and closed the filter drain with the pump running.

3) Fuel smells stale (maybe from bacteria???). Drained tank and put 10 gallons on new fuel and fuel treatment in the tank. Took old fuel and found it hard to light when putting a torch to it. Torch took maybe 5-10 seconds before old fuel would even try to burn.

4) Removed plunger from Idle Cutoff Switch.

The truck has new glow plugs, I can hear the lift pump running, #9 resistor installed, a new PMD, and a new fuel filter. I think the PO may have changed the lift pump as well.

Here's where it's at.....
Truck will fire off ether and runs great. I tried running it until it got to about 180 degrees, shut it off, and tried to immediately start it. No luck, but will start right back if it has a very small sniff of ether.

Truck has a funny smell out of the exhaust while cranking (like stale fuel) and I saw smoke out of the exhaust while trying to start it.

Once started, truck runs great. No surging (typical of weak IP), stalling, hesitation, nothing. In 1/4 mile, it has no problem getting to 80+MPH from a dead stop. Service Engine Soon light is constantly on, but no codes (only 12) stored (found by jumping the 2 pins).

I've tried unplugging (one at a time) the coolant temp sensor, IAT sensor, and the map??? sensor and tried starting it and no luck.

All fuses are in tact. ECM was reset after new PMD installed so it wasn't running off old mapping data.

Truck has some blowby but nothing significant.

I thought (and my friend agreed) that when running it sounds like it's got a little more detention noise than it should have like it's a little advanced. It runs so good and smooth that I really don't think the IP is shot. What would a bad optical sensor do to it? I'm wondering if a bad optical sensor or crankshaft position sensor might be the problem. Any thought?
Click to expand...

Diesel doesn't burn very easy.

FFM(fuel filter manager) should be bled with the nut on the top of it.

Does the LP pump fuel while running or just when it's jumpered?

The clear fuel line would be best put on the return line, it's 1/4" on the front top of the IP facing 45* upwards, look and see if air bubbles are present.

To me it sounds like you have air in your fuel lines or the IP will pull fuel after it's running and either the OPS or LP are bad.
 
pneese973

Welcome to TTS

I saw this post in another thread and gave a similar answer to AK

It would be best to start a new thread of your own.
 
You should make sure the LP relay and fuse on the passenger firewall are good, and the CRK fuse under the steering wheel. the CRK fuse allows the LP relay power when the ignition is in the START/Crank position. The other fuse by the relay applies to both power sources after they are tied together, the relay and the OPS.

Dead glows, if they were new and you used a 100A jump starter thing then you could have fried them.

Not enough cranking amps, not enought cranking RPMs?

Is the SES light itself staying on or one of the other lights on the dash? The PCM grounds the light to make it come on, so if the line between the light and the PCM was shorted to ground anywhere it would stay on.

What do you mean by the ECM was reset? What did you do with it, or do you just mean the batteries were left off?
 
Turbine Doc said:
Howdy Pneese welcome to the site

Better to start off with your own thread less confusion than trying to keep up with what each owner has done in middle of another troubleshooting thread, when you get a moment go to the user CP button to put truck info in your signature, that helps post to post as well to keep track of things.

Spend some time in the FAQ technical reference at intro forum area for the 6.2/6.5 area I suspect you are correct with stale fuel, possibly condensation emulsified in the tank if it's been sitting a long time you have a water/fuel blend that doesn't ignite well, if that is case the possibly your check engine is WIF sensor the engine fuel filter is treated to block water.

are you getting code 12 or 21, hard to tell sometimes reading the CEL flashes?

There is a sock in the tank that will stop fuel from getting to the IP, or if the lift pump on the frame rail is weak or dead the IP struggles to pull fuel, you said air in fuel lift pump helps to overcome this as IP isn't good self puller if a rotten rubber or steel line is allowing air to be pulled in, Either is bad ju-ju for the 6.5 discontinue use of it WD-40 is preferred starting aid.

You didn't mention anything about the glows, you check those ?

You said VW experience, TDI's or older ?? I do a little with TDIs myself.
Click to expand...

First, I work with older VW's as well as the newer ones. I have the VAGCOM software and build all kinds of VW's. My 1991 Jetta is about to get a 1.9L IDI from the Canadian market w/ a T3 Super60 turbo and larger intercooler. Anyway...one to the task at hand...

I ought to be able to rule out glow plugs at least partially because the glow plug light only came on for maybe 1 second when the truck was hot and it still wouldn't start. As you already know, TDI's don't run the glow plugs above 30 degrees, so I shouldn't need them to restart a hot engine that was literally shut off 3 seconds before.

I suspect the small amount of air that I got out of the filter was due to the previous owners lack of knowledge on how to work on diesel engines. It was such a minute amount that most people wouldn't even call it air, but there was still a handfull of barely visible bubbles that I got out.
 
NVW said:
Diesel doesn't burn very easy.

FFM(fuel filter manager) should be bled with the nut on the top of it.

Does the LP pump fuel while running or just when it's jumpered?

The clear fuel line would be best put on the return line, it's 1/4" on the front top of the IP facing 45* upwards, look and see if air bubbles are present.

To me it sounds like you have air in your fuel lines or the IP will pull fuel after it's running and either the OPS or LP are bad.
Click to expand...

The lift pump will run when jumpered or I can hear it for a few seconds after I stop cranking, so I know it's running.
 
buddy said:
You should make sure the LP relay and fuse on the passenger firewall are good, and the CRK fuse under the steering wheel. the CRK fuse allows the LP relay power when the ignition is in the START/Crank position. The other fuse by the relay applies to both power sources after they are tied together, the relay and the OPS.

Dead glows, if they were new and you used a 100A jump starter thing then you could have fried them.

Not enough cranking amps, not enought cranking RPMs?

Is the SES light itself staying on or one of the other lights on the dash? The PCM grounds the light to make it come on, so if the line between the light and the PCM was shorted to ground anywhere it would stay on.

What do you mean by the ECM was reset? What did you do with it, or do you just mean the batteries were left off?
Click to expand...

The lift pump fuse is good. I've seen it a few times already while making sure the system was purged. I've checked all the fuses in the fuse box, but if there's a seperate one under the steering wheel, I'll check that too. When you say it's located under the steering wheel, do you mean under the dash or meaning that I need to remove the wheel and look under it?

When cranking I get several lights....Service Throttle, Service Engine Soon, etc. but once I get it running only the Service Engine Soon light stays on.

The ECM fuse was removed from the fuse box for a couple minutes to reset the ECM after replacing the PMD.
 
pneese973 said:
The lift pump will run when jumpered or I can hear it for a few seconds after I stop cranking, so I know it's running.
Click to expand...

When it's jumpered it by passes the OPS, and while cranking it by passes the OPS, at least on a 95.

Does it pump fuel out the drain while the truck is running?

On a 95 if you put it in D or R and turn turn the ign. to start it will run the LP, I don't know if it's that way on a 94.
 
NVW said:
When it's jumpered it by passes the OPS, and while cranking it by passes the OPS, at least on a 95.

Does it pump fuel out the drain while the truck is running?

On a 95 if you put it in D or R and turn turn the ign. to start it will run the LP, I don't know if it's that way on a 94.
Click to expand...

So it sounds like the next best guess is to unplug the optical sensor and see if it starts?
 
Have you verified power at glow plugs when wait light is on? Just use a test light.run a jumper to them glows and then try it, my 1994 will not start without them although I burn oily diesel! Does your service throttle ligt go out before you crank, mine does.
 
Whoa PN need to get back to the basics we have a LOT of experience here with the 6.5,
pneese973 said:
So it sounds like the next best guess is to unplug the optical sensor and see if it starts?
Click to expand...

Nope this isn't one of those "Kid sites" where we just throw out guesses of what it could be; we are needing to step by step verify things as we've found it works best that way, the 6.5 while a Diesel is as unique as TDIs and other VWs are so work with us a little.

A lift can & does cause issues it can purr like crazy when jumpered & pumps when unloaded but too weak to support a running engine.

Healthy glows are a must if it's clicking on then off there is a problem, glow system on 6.5 cycles far more than one on VWs, if engine is cold it should cycle 3-4 times before cylinder is warm enough for a strong start, the 6.5 is an IDI engine with pre-combustion chambers vs DI used in VWs also why Either is bad ju-ju glows with starting fluid in a confined pre-chamber makes things go boom.

Glow is so important several folks living way up North in COLD climates have manual glow over rides.

From your descriptions thus far glows also sounding very suspect one-more all possibly; are hosed up.

Have a look at the thread in 1st sub forum I tried to direct you to linked here in the TRL http://www.thetruckstop.us/forum/forumdisplay.php?92-6.2-and-6.5-Diesel-Engines

While it could be the optic sensor that is low on the probability of things that it could be if that is it we'll get there eventually, lets go simple to complex lift & OPS trouble shooting found in the TRL http://www.thetruckstop.us/forum/showthread.php?6872

There is a acronym thread in there also so some of the abbreviations we use aren't so foreign to you. OPS & Optic sensor aren't the same thing Oil Pressure Switch controls the operation of the lift pump (see the TRL thread) when engine is running, optic is sensor in the IP more on that later if we need to go there.

Gnds also a prime issue http://www.thetruckstop.us/forum/showthread.php?14596-6.5-grounds but glows/lift at this point are best SWAG if you want a guess since you have a running engine once started gnds a little less suspect, but multiple gnds on 6.5 so still not a complete elimination from probability

But lets step back for simplicity sake for those of us that have been there done that with the 6.5 copy/paste this found in the TRL and fill in the blanks http://www.thetruckstop.us/forum/showthread.php?6300-6.5-Engine-Diagnostic-Troubleshooting-Checklist mind our anal madness with this it's a system that has worked many times for us to get guys back up & running.

Again Welcome to the site we'll help you get it done.
 
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