1994 6.5 Chevy won't start

[brianblack138]

I have a truck that i'm trying to get started to take in to the mechanics. It's been sitting for about a year, and the first thing I did when I went to start it was put in new batteries, check the oil and coolant and crank the engine. The truck started up (it was rough, but it did start up and eventually run fine), but had a coolant leak near the water neck and a fuel leak on the metal return line near the lift pump.

I turned the truck off and used some JBweld on the water neck as a temporary fix until I could get it into the mechanics. Two days later, I went back to start the truck and it wouldn't start. I opened the filter and touched the lift pump relay to a 12v lead and fuel squirted out so I knew that the lift pump was working. I charged the batteries (they were new anyway) and plugged the block heater in but still no luck.

I can tell the glow plugs are cycling (it's only in the 40's here, so I shouldn't really need them) because the battery gauge drops down when the glow plug light comes on. I also checked for codes and didn't have any. The PMD is a relatively new one that I had relocated on a heatsink and it was working fine when I parked it last November.

Any idea what the problem could be? Could the leak in the return line be causing some sort of issue? Do you think I could have a bad injector pump?

The truck only has 113k miles on it and I just want to get this thing running again so I can get it in to have it looked at professionally!

[bp250065]

My guess would be that with the fuel leak, you got some air in the system, try bleeding the fuel system while running the lift pump and bleeding air through the top of fuel filter and the t valve. You may also have to crack the injector lines to bleed the air out. Also you might want to go ahead and change the fuel filter, could have clogged with dirt or sediment since it was sitting for awhile.

[brianblack138]

My guess would be that with the fuel leak, you got some air in the system, try bleeding the fuel system while running the lift pump and bleeding air through the top of fuel filter and the t valve. You may also have to crack the injector lines to bleed the air out. Also you might want to go ahead and change the fuel filter, could have clogged with dirt or sediment since it was sitting for awhile.

How hard is it to crack the injector lines? Do I have to take the air plenum off? I've never been able to reach back to even change the rubber return lines successfully. I'll change the filter, and i'll also check to see if I hear a "click" in the IP solenoid when I have someone turn the key (just read about that yesterday).

[DmaxMaverick]

"Cracking" the injector lines is about the easiest thing you'll do on this engine. Loosen the line nuts at the injector (NOT at the back of the pump) with an end wrench, about 1 full turn. All you are doing is breaking the seal between the line and injector, to let air/fuel escape as the pump sends fuel.

This is a good diagnostic tool, but probably won't show you anything conclusive for your problem. This is the best method to isolate cylinder-specific issues, like a knock or blow-back (taking the fuel away prevents combustion at that cylinder, like removing a plug wire on a gasser). It will confirm that you are getting fuel to the injectors, which eliminates many other possible causes (like the PMD, ESS, and lift pump).

Air leak problems (the effect, not the cause) are generally isolated to the fuel supply to the IP, or internal to the pump. The injector lines and injectors will prime very quickly if there is no air in the supply.

....And, yes. You will need the glow plugs for a cold start. Even at 40°F. These engines won't start without them at anything less than "hot" (like very shortly after a hot shutdown). My 85 will cold-start w/o plugs, but only on a hot summer day (90°+) after it's heat soaked. I don't know of any 6.5's that will do that.

You have other issues to consider, after it's sat for so long. Change the fuel filter, first (always). You may have slime in there (algae), which will completely plug the filter. Could be water, too.

[brianblack138]

"Cracking" the injector lines is about the easiest thing you'll do on this engine. Loosen the line nuts at the injector (NOT at the back of the pump) with an end wrench, about 1 full turn. All you are doing is breaking the seal between the line and injector, to let air/fuel escape as the pump sends fuel.

This is a good diagnostic tool, but probably won't show you anything conclusive for your problem. This is the best method to isolate cylinder-specific issues, like a knock or blow-back (taking the fuel away prevents combustion at that cylinder, like removing a plug wire on a gasser). It will confirm that you are getting fuel to the injectors, which eliminates many other possible causes (like the PMD, ESS, and lift pump).

Air leak problems (the effect, not the cause) are generally isolated to the fuel supply to the IP, or internal to the pump. The injector lines and injectors will prime very quickly if there is no air in the supply.

....And, yes. You will need the glow plugs for a cold start. Even at 40°F. These engines won't start without them at anything less than "hot" (like very shortly after a hot shutdown). My 85 will cold-start w/o plugs, but only on a hot summer day (90°+) after it's heat soaked. I don't know of any 6.5's that will do that.

You have other issues to consider, after it's sat for so long. Change the fuel filter, first (always). You may have slime in there (algae), which will completely plug the filter. Could be water, too.


Thanks for the advice. I'll be putting a new filter in first, then i'll crack the lines. I tested the lift pump by touching the fuse at the pump relay to a positive lead and I got good pressure (fuel squirting) but i'll test it with a gauge this weekend. So long as I can get it to start, i'm good, as i'm trading it to a guy who has a mechanic who will do all of the work (it was an as-is trade, but it has to be running at least)

[brianblack138]

Thanks for the advice. I'll be putting a new filter in first, then i'll crack the lines. I tested the lift pump by touching the fuse at the pump relay to a positive lead and I got good pressure (fuel squirting) but i'll test it with a gauge this weekend. So long as I can get it to start, i'm good, as i'm trading it to a guy who has a mechanic who will do all of the work (it was an as-is trade, but it has to be running at least)

Ok, I cracked the injectors and cranked the engine and no fuel came out at all. I loosened one injector more and got nothing...

i tested the lift pump pressure (5psi) and made sure I had fuel. I also listened to hear the "click" of the solenoid on the IP when the ignition is turned (it did click).

this indicates to me that
A: there is fuel in the tank that is getting to the lift pump (no clog in the fuel line)
B: the lift pump is pushing the fuel through the filter to the ip at 5psi (no problem there)
C: The IP solenoid is doing it's job (at least it sounds like it is energized)
D: The injectors are cracked to let fuel flow out (which it doesn't)

So the problem is between the IP and the injectors. Does anyone know what could cause the IP to not pump fuel to the injectors? Any sort of fuse that could blow or wire that could be shorted out?

I DID find some vacuum lines cracked (one went from the vacuum pump to the EGR and the other went to the Turbo) which i'm replacing, but I didn't think that would have anything to do with getting the engine started (especially since I removed the vacuum actuator for the turbo and put a manual one on there)

[JohnC]

check for codes.

[brianblack138]

check for codes.
Forgot to mention that. I checked and there were no codes at all (besides the normal 12)

[JohnC]

If you run the lift pump, does fuel come out of the injection pump return line?

[brianblack138]

If you run the lift pump, does fuel come out of the injection pump return line?

Doesn't seem like it. (I haven't pulled the hose off to check, but my return line to the tank is cracked so it would be leaking diesel if the IP were returning anything, right?)

We just got 5 inches of snow, so i'll have to wait until I can get out there and check.

[JohnC]

Doesn't seem like it. (I haven't pulled the hose off to check, but my return line to the tank is cracked so it would be leaking diesel if the IP were returning anything, right?)

If the fuel is not coming back to the tank either the fuel isn't getting to the injection pump or there's something wrong inside the pump.

[brianblack138]

If the fuel is not coming back to the tank either the fuel isn't getting to the injection pump or there's something wrong inside the pump.

I checked at the brass T to see that the fuel was flowing out (also checked the pressure there and it came to 5psi). But i'll check again just to make sure i'm not crazy.

[JohnC]

I checked at the brass T to see that the fuel was flowing out (also checked the pressure there and it came to 5psi). But i'll check again just to make sure i'm not crazy.

The "T" valve is before the filter.

[brianblack138]

The "T" valve is before the filter.

I had checked it at the filter as well (loosening the top) but i'll throw a new filter in and disconnect the hose at the IP and test it there, then disconnect the return line and test again. Unfortunately we're getting MORE snow and it looks like snow all this week...

[rameye]

brian,

If you havent done so...check ALL of the grounds...batt grounds, engine grounds,,grounds off the back of the engine to fire wall. They need to be clean and tight! Break them down and check em out.

If these suckers (IP) dont have good voltage they dont work worth a damn.

After you have verified that fuel to the IP is not an issue and that all grounds are clean and tight...you might want to try a new PMD. No rhyme or reason as to when these units will fail, or spontaneously work again.

enjoy the snow..we had ours this AM.

[brianblack138]

I started by putting in a brand new fuel filter, removing the hose from the input port of the IP and cranking the engine. I got a good solid stream of fuel there, so I know that (now) fuel was getting to the IP.

Next I loosened the injector lines a bit (I could only get to three, so I loosened those three) and cranked the engine to purge the air. After about 10 tries (and stopping to recharge the batteries in between) the engine started! It ran for about 10 seconds limping along and then conked out.

So I went to the autozone thinking i could have some gelled fuel (it isn't terribly cold here, maybe 35 degrees). I bought a bottle of Power Service Diesel 911 and put 90 percent in the tank, and the remaining 10 percent in the fuel cup where the fuel filter is.

I hopped in, and it started right up! Unfortunately, whether I just let it idle, or revved the engine, it would die after about 10 seconds.

I could crank the engine and it would start up again (sometimes i'd have to cycle the glow plugs twice) but it would always conk out after 10 seconds or so.

I still don't have any codes and am wondering what could be causing this. At least I know that the IP isn't bad (at least the mechanical portion, it could still be the PMD i guess).

I did also find a split vacuum line running from the vacuum pump to all of the actuators, so I repaired that as well. Wasn't sure if that could have had something to do with it.

Any ideas?

[JohnC]

You need a scanner. Monitor the solenoid closure time and the shutoff solenoid. See if either of them is acting up. Otherwise, it has to be fuel not getting (in)to the injection pump. (There is a screen on the inlet that could be fouled.)

[brianblack138]

You need a scanner. Monitor the solenoid closure time and the shutoff solenoid. See if either of them is acting up. Otherwise, it has to be fuel not getting (in)to the injection pump. (There is a screen on the inlet that could be fouled.)

What type of scanner, like an OBD I scanner? Sounds like this could be beyond my abilities (at least with my current equipment).

[rameye]

Try one more simple thing before you go for the gusto ($$$). Open up the fuse box in the engine compartment, remove the relay for the fuel pump and jumper it so it runs all the time.

Wash, rinse, repeat

Let us know what happens

[JohnC]

OK, connect a digital volt meter from the negative terminal of the shutoff solenoid (meter plus lead) to ground (neg lead). The meter should read 0 volts when the key is in start or run. If the meter jumps to 12 volts before or as the engine quits, the PCM is commanding it to shut down. If the meter stays at 0 volts while the engine stalls it's most likely running out of fuel.

[brianblack138]

OK, connect a digital volt meter from the negative terminal of the shutoff solenoid (meter plus lead) to ground (neg lead). The meter should read 0 volts when the key is in start or run. If the meter jumps to 12 volts before or as the engine quits, the PCM is commanding it to shut down. If the meter stays at 0 volts while the engine stalls it's most likely running out of fuel.

Wanted to post an update. I've been out of the country for a few months and when I came back, the truck started right up. I think that had to do with the temp (probably bad glow plugs).

When the engine starts, it runs for about a minute and shuts down, so i'm going to try the aforementioned tips (checking the relay by jumpering it to see if it's a bad relay for the pump and checking the PCM).

I'll post my results.

[brianblack138]

Wanted to post an update. I've been out of the country for a few months and when I came back, the truck started right up. I think that had to do with the temp (probably bad glow plugs).

When the engine starts, it runs for about a minute and shuts down, so i'm going to try the aforementioned tips (checking the relay by jumpering it to see if it's a bad relay for the pump and checking the PCM).

I'll post my results.

I unplugged the remote mounted PMD and plugged into the PMD on the IP and the engine wouldn't even start... so that wasn't a very conclusive test...

Plugged back into the remote mounted PMD and the engine starts (but still stops after a minute or so). It really seems like an electrical cut off (like a key is turned off) rather than running out of fuel (the engine shuts off instantly, it doesn't starve and choke along for a few seconds before stopping) so I want to check the pump relay. I was wondering if you guys are referring to the relay for the lift pump or for the IP? Also, where is the relay you are referring to located? I looked through the Chilton manual and couldn't find either.

[Robyn]

Be sure the fuel filter is in good order.

I have seen fouled filters cause this to happen.

How old is the Remote PMD ??

A stanadyne PMD that only 6 months or 30K miles can still fail.

THE PMD is always a prime suspect in a case of abrupt shutoff.

Be sure of the fuel supply though. The olther possibility is the fuel shutoff solenoid up on top of the IP (Round device that sticks up and has wires to it)

These can and do fail.

Check your filter
Be sure of fuel flow
Swap out the PMD
Check the shutoff solenoid

If you are still having issues, be sure of all electrical connections, grounds ect.

Keep us posted

Missy

[brianblack138]

Be sure the fuel filter is in good order.

I have seen fouled filters cause this to happen.

How old is the Remote PMD ??

A stanadyne PMD that only 6 months or 30K miles can still fail.

THE PMD is always a prime suspect in a case of abrupt shutoff.

Be sure of the fuel supply though. The olther possibility is the fuel shutoff solenoid up on top of the IP (Round device that sticks up and has wires to it)

These can and do fail.

Check your filter
Be sure of fuel flow
Swap out the PMD
Check the shutoff solenoid

If you are still having issues, be sure of all electrical connections, grounds ect.

Keep us posted

Missy


Brand new fuel filter. I cracked the injector lines to bleed them of air and I get good fuel coming out there. The engine runs strong until it suddenly cuts off. The remote PMD is several years old (and probably about 20k miles old) so it could probably use replacing. I don't know how to check the pump relay that was referred to earlier in the thread (is it the lift pump relay or an injection pump relay? where is it located?) but i'd like to do that as well.

I'm just trying to get this thing to limp along to a shop because i've traded it to someone who is going to restore it and he's going to take it into his uncles repair shop. Worst case scenario I guess i'll put it on a trailer and tow it.

[rameye]

If Robyns suggestions dont pan out....

Check to make sure the lift pump is running after start...

It sounds funny that it takes the same amount of time to shut off every time.