No start, no codes, very little patience

[convert2diesel]

Hi guys:

Have found myself in a little bit of a pickle here. We found a 2000 commercial chassis with a 6.5 with very low mileage that we want for one of our conversions. The problem is, we can't seem to get it to run long enough to find out if it worth pulling the engine. Don't care about the electronics as it is being converted to a DB2 but we still need to get it running as is.

Here is the problem. Every time we try, it will give us a good glow cycle and when we turn it over it will start immediately but then just as quickly shut down. Will continue to crank to no avail until we go through the start sequence once again. Same story...rummm then nothing.

We have:

1. Bled the fuel 30 or 40 times (clear fuel from return line at pump, clear fuel at the injectors).

2. Hot wired the fuel solinoid (though it is still live after the failed start)

3. Hot wired the lift pump (pressure switch has been tested as good)

4. Replaced PCM with known good

5. Replaced throttle assembly with known good

6. Checked ignition circuits (will quit even with starter ingaged)

7. Checked computer wiring (looking for a known good computer)

8. Fed it with enough battery to light up a small village.

9. Used enough inappropriate language to make even a stevadore blush.

What gives? This thing is throwing no codes and has resisted all efforts to date. It just refuses to run for more then 2 seconds. Fires every time but then gives up the ghost. Is there any way to hot wire this thing or some magic potion to just let us hear it run for a few minutes? Don't care if it isn't running up to snuff, just want it to run.

Getting real close to yanking the pump and delivering it out into the farmers field next door and replacing it with a real fuel system. If I had any doubts about the old mechanical pumps before, this experience has written paid on trying to work with the DS4. How do you guys cope?

Any help would be really appreciated as we really want to get this thing running.

Bill

[gmctd]

Measure the voltage on the alternator field while cranking to run, noting if it drops when the engine stops.

[Kennedy]

Try a 1997 ECM program

[82blazer]

check rotation of starter. some marine starters spin backwards. I have seen this problem in other cars. good luck;)

[GSE2SCHMIDT]

Yeah I was thinking theft deterrent also.....so 97's were not then?

[gmctd]

Agree - theft deterrent is more likely - PCM shuts down under suspicious, and even some auspicious, circumstances.

[convert2diesel]

Thanks for the input but this is installed in a commercial chassis, formerly a city moving truck. Would this have a theft deterent installed? The ignition key is conventional and there is no evidence of any other alarm or safe guards.

What would be the reason for measureing the field voltage? Would that indicate an PCM shutdown? Will try it in the morning and report back.

Thanks again

Bill

[gmctd]

I was thinking my truck system - may be different on that one, but what you're looking for is the IGN switched voltage on the ESO and the FSD to drop, that may be the ECM1 fuse in your system.

You'll need to re-connect the ESO, then backprobe the + wire, noting if the supply remains at +12v when the engine quits.

That is one function of the theft-deterrent system, tho, so make sure an attempt has not been made locally to defeat it

[convert2diesel]

GMCD:

Sorry...you lost me in the terminology. Not used to working on the Bill Gates inspired fuel control systems. What pray tell is an ESO or FSD? Maybe someday the industry will standardize the terminology.

Thanks for the help.

Bill

[gmctd]

Apologies, dude - I was hoping those were Zora Arkus Duntov inspired.

Engine ShutOff solenoid is the fuel shutoff solenoid, and Fuel Solenoid Driver or Pump Mounted Driver is the module on the Inj Pump that drives the Fuel Solenoid, which begins and ends the injecton event.

Kill power to ESO or FSD\PMD and the engine shuts down - they're tied together, then thru the ECM1 fuse to the IGN switch

[convert2diesel]

GMCD:

Power remains constant at the fuel solinoid throughout the cycle. Is there any way to hot wire the PMD to at least allow idle operation without the computer entering into the equation? Still suspect the throttle actuation (intuition more then diagnosis) and or something inside the pump that is shutting down fuel delivery immediately after fire up. Have ruled out lift pump, fuel solinoid and accel pedal assembly. Used to be able to take the top off the DB2 and manually work the fuel rack. Made a mess but it would at least run (3 degrees advanced). Can a similar thing be done with the DS4?

Bill

[gmctd]

The ESO and FSD\PMD are wired together - power to either is power to the other - PMD could be failing - definitely causes stalling

Really really sounds like the theft deterrant is kicking it off - farzino, all late OBD2 PCM's have theft deterrant - not sure whether PCM removes power from the ESO or stops EFI functions, but you did measure power to the ESO when it stalled, so either it stops EFI, or TD is disabled.

Does it have aftermarket security system?

Loose connection that loses contact as the engine rocks, maybe - I'd check all the wiring and connectors and grounds

There's not any method to hot-wire or rig the IP for a test run, Bill

Nothing blocking the intake?

Seems electrical, to me - it has a tendency to rev up some as fuel is used up, not just stall

[JohnC]

any chance it could be shutting down as soon as the key is returned to run from start? If so, the ignition switch could be at fault. Or, it could be the theft deterent...

[gmctd]

That is a possibility, altho he indicated the ESO had power as it stalled - ESO and PMD power come thru the IGN sw.

Seems like I had a conversation with someone awhile back, concerning the T\D would allow the engine to start, then stall it, but I thought it should have also disabled the starter circuit to prevent running the batteries down

[HammerWerf]

Convert,

A couple of years ago More Power published an article about the built in Theft Deterent in the GM Vehicles. It uses the factory Radio.

The article is part of the archived articles. Try this link.

http://www.thedieselpage.com/members/archive/theftlock.htm

Perhaps this will at least eliminate one variable.

Hows that RoadMaster doing? It sounded like it was going to be really nice.

HammerWerf

[gmctd]

Or you could find a '96-'97 without T\D, use that PCM

[CapnAmerica]

Fuel filter? I got some REALLY bad fuel once and literally plugged the filter up! The fuel pump will push some through the crud and muck during the glow cycle, allowing the engine to start, but can't supply enough to keep it running.

Good luck...sounds like a case for meditation interspersed with periods of work; avoids mechanical violence and marital discord!!! This can be frustrating, for sure!:cool:

[Robyn]

Industry standard terminology???
Dont count on it in our lifetime ;0)

[convert2diesel]

It really is looking like it is something to do with the theft deterent. Have local nerd pecking and probing and doing his nerd thing. The key does have the built in chip but somehow the PCM is not getting the message. Looks like previous owner tried to re-wire and then low and behold no start....imagine that. Probably why the current owner got it so cheap.

As far as the Buick conversion...been running for 2 1/2 years with very few rejection symptoms.

Bill

[gmctd]

Dunno, dude - I see a vacuum brake booster, which was standard equipment for gassers - (gassers, patooie! !) - and the '94-'96 t-stat crossover manifold, and that's a normally aspirated 6.5(?), and the accessories arrangement is typical for the '94-'96 vintage, and that appears to be a throttle cable in the firewall, there.

And is that an aftermarket radiator positioner bracket?

That could be normal, as I've never seen a normally aspirated OBD2 6.5 in it's native surroundings, but.................

And the T\D function is permissive for start, but immediately stalls the engine - cycle repeats for each start, until you give up.

BTW - show 'n tell rules!

[rjwest]

Just a wild guess, Crank sensor,,,

Any chance it has an OBD2 port, scan may help...

[convert2diesel]

GMCD:

Sorry for the confusion. The pict is first proof of concept for my Buick diesel conversion as requested by HammerWerf. Water cross over has been changed to 94-95 due to headspace and a hydroboost has been installed as vac pump not up to the task. This was taken 2 years ago and the car is still being used as a daily driver and to tow my RV (yes really...leaving for Florida on Good Friday).

The subject vehicle for this thread is still undergoing nerdification but get the feeling he is just as stumped as I am (though he won't admit it). Getting real close to investing the time to pop in a mechanical pump just to hear it run. Given the amount of time I have tied up in this, maybe I should have done this in the first place.

RJ: Would not that throw a code? Going to try once more this weekend with a full blown diagnostic handheld and failling that will do the pump swap. Really I just want to hear it run. If it wasn't a friends engine I would have walked away from this two weeks ago.

Thanks again for all your help. Am trying all of your ideas.

Bill

[gmctd]

And, a very nice job it is, Bill.

But - it's not nice to fool gmctd..................kaboom!!!!!!

[rjwest]

I would expect the crank sensor to through a code, but I have
found on the obd2, that some faults are set that do not set a code but inhibit
function ( like 'defuel'), I believe the PMD looks for crank sensor pulses
to determine if engine is running, and go into engine control mode,
just speculation; do not want to lead you astray,,
It does sound like the older GM's starting on " starter" path voltage,
and dying on lack of ign key voltage. But from what I read, you have chked
all the PMD imput pins and validated voltage present,
Do you have a GM electrical schmatic??

I gather you do not have a code reader/data reader.

I have a laptop program that does both, and was very impressed with the ability
to view all available info, luckly , I never had the need to use most of it.

[convert2diesel]

RJWEST:

Never even thought about the crank sensor. Makes sense. Definitely not the ignition switch as power stays up after initial start but the engine dies even while the key is in the start position. Still trying to see if theft deterent is causing the problem. Will give nerd another couple of days to hack away at it but if no joy will spend the time to swap out a mechanical pump. Seems the only way.

Thanks again

Bill

[convert2diesel]

It runs!!!!

Found a computer from a 96, plugged it in and immediate start and run. Runs well with no erroneous noises or signs of emminent death so have stripped the truck down to it's components and have the engine sitting on the garage floor ready to be transplanted (this time with a real fuel system).

Thanks for all your help.

Bill

[HammerWerf]

Bill,

Congratulations on getting the engine to run. Glad it sounds like a keeper.

Thanks for the picture and update on the Buick. Have a safe Journey this Holiday.

HammerWerf