Hello, First of all I'm new, as in I went to school before there were electronic calculators, in fact when I started school there weren't even electric typewriters. However, I have been dragged kicking and screaming into the electronic age and thus into computers and web sites. My diesel problem is this:

1994 6.5td high flow pump, automatic transmission;
Ordered an updated chip from GM via VIN. Received a chip for the low flow pump, boy would that truck run, but the transmission wouldn't shift right at all. Got 21mpg in town and eventually burned up the transmission, it appeared that the lock up converter was slipping.

Rebuilt the transmission, when restarting the engine sucked a snoot full of carbon and bent a piston skirt, rebuilt the engine (pistons,rings bearings, lifters, oil pump, ordered an extra thick headgaskets to keep compression down, new headbolts, new glow plugs, new OPS, lift pump is wired to the ignition [key on=pump on]), had a Stanadyne shop rebuild and recalibrate the pump for a #2 resistor, and rebuild the injectors at the same time. Reassembled all the above. Drained tank, put in new fuel, new batteries, new oil, oil filter, trans fluid. Fuel bled to T drain on thermostat housing and loosened hose on Injection pump and bled all air out, cleaned every connection, sensor and plug with DeoxIT. I did all the work myself except boring the block and the injector pump/injectors.
Problem details:
No start.
No codes.
Service Throttle Soon light on
Check engine light on.
No Wait to Start light/solenoid has power
Computer will not communicate with scan tool.
All grounds good.
Pump Driver (remotely mounted) gets slightly warm when cranking.
Fuel solenoid has battery voltage to B terminal power with key on. Will click when Terminal A is grounded

32pin Pink connector C1 Good ground

32pin Pink connector C2 Good continuity to Terminal C on pump driver

24pin Pink connector A1 Battery voltage with key on

32pin Blue connector C1 Battery voltage all the time

32pin Blue connector C16 Shows good continuity to Fuel shut off solenoid A terminal.

Vechicle speed sensor has reading and is plugged in

Have tried alternate chips in the PCM but no change occurs.

Truck started and ran well with all remaining components in place before all this started

Before I order a new PCM does anyone have a magic trick I can try or something I have missed?
Thanks so much,
Wayfaringmechanic

 

Are you getting fuel to the injectors? What are the codes? Are you familiar with the obd1 code check procedure?

 

Hi, Thanks for your interest in my post. There is no fuel to the injectors, the fuel solenoid has power at terminal B when the key is on in the but no ground is given to terminal A by the PCM. Terminal A on the fuel solenoid goes to 32pin Blue connector C16 Shows good continuity to Fuel shut off solenoid A terminal. The PCM grounds to the vehicle through 32pin Pink connector C1 which has a Good ground it appears the PCM just isn't making the connection between them thus no fuel past the solenoid into the pump.
I don't paperclip for codes I have a scanner which not only reads codes but also provides me live data on both OBDI and OBDII just hooked it up to our 98 powerstroke and it is working fine. The screen reads "Vehicle is not responding" meaning the computer isn't putting out any data that the scanner can read. Because you asked I did jump A&B, did not even get the 12 code.
I had come to the conclusion after checking all the wiring and connections that I either needed a PMD or a PCM. Both were fine when I shut it off, the problem I began with was mechanical. So unless there is some fine point I have missed, (for instance if the speed sensor is unplugged it will produce a no start condition, I have made sure not only that this one is plugged in but that it has a reading present) I am going to buy one or the other to see which it is unless someone can point me in another direction. Am open to any suggestions.
Thanks, Wayfaringmechanic

 

Since all you troubles seem ground related:
Sounds like the grounds on the water block off plate stud at the passenger side rear of the engine are not all present-there should be 3 of them.

A singel wire and ring terminal long with 2 wires sharring a ring terminal-among those 3 grounds is the ECM ground.
Note: they get a better ground on that stud vs an intake stud since there is no dissimilar metal corrosion.
Also check the lighter fuse-I think it powers the code check(ALDL).

Also have no idea what you mean by a high flow pump-no such thing.

 

Hi and thank you for your reply to my question.

All the grounds do check good, by that I mean that the wires that should show ground to the computer do show good continuity from sensor to the computer plug, and ground wire that the computer uses to switch the grounds on and off do show good continuity from the computer plug to battery negative terminal. That is what all the wire and pin explanations were about in my original post. 32pin Pink connector C1 Good ground this is the wire that the computer uses for a switched ground, 32pin Pink connector C2 Good continuity to Terminal C on pump driver this is the wire that the computer should be connecting to ground, 32pin Blue connector C16 Shows good continuity to Fuel shut off solenoid A terminal, which is the ground from the computer to the fuel solenoid.

The ground is good to the right rear of the engine, the terminal ring has been changed just to insure it has a good ground and is on the water block off plate. On this vehicle there is one ring, 14 or so inches from the ground ring that wire has all the grounds soldered together so that only one heavy wire goes to the stud.

Have removed and checked all the fuses they are not only good but are conducting current as they should, thus the 24pin Pink connector A1 has Battery voltage with key on indicating that the computer voltage supply is present to the computer as it should be, 32pin Blue connector C1 Battery voltage all the time which is the voltage to the computer when the key is off to retain memory.

As for the pump it is a DS4831-568, as far as I know one year only pump in 1994 and does put out much more fuel at the same signal than any of the rest of the pumps. Thus it requires a specific chip that will not work in the rest of the vehicles for that year or 1995, the only two years that have a removable chip. Thus it is a called a heavy duty or high flow pump depending upon which injection shop you are in at the time.

Thanks again, Wayfaringmechanic

 

Ok first I have heard the 5068 referred to as high output.

 

I see I forgot the "0" in the 5068. I can tell you, since it has happened to me that if you put the other chip in with that pump the truck will spin the tires from a dead stop with just a tap of the accelerator. Different flow rates, timing, etc. But as I said the transmission will not shift right, the pressures will be low, etc.
Thanks

 

After a lot, a whole lot of wire tracing, re-cleaning all connections and grounds I got the engine to start a few times, but not all the time. When the fuel gauge read correctly the engine seemed to start fine. But when the gauge would peg to the empty side the engine would not start. The original problem finally manifested itself when the ground wire to the fuel solenoid began to show a low + voltage. At that point I knew the problem was a ground that would not carry a load when the key was switched on. Whenever it was checked with a meter or test light it was good but whenever it had to carry a load it lost connection. Inserted an extra star washer while cleaning and seem to have consistent starts now although at random times it will just quit, possibly connected to the problem below but I can't say for sure at this time.

After the first start began checking for leaks, etc. Discovered that there appeared to be diesel fuel slinging off the flywheel (Bottom flywheel cover is not yet installed). Went to top and the valley is dry, the fuel filter is not leaking, moved all the wiring and checked the hose connections above the bell housing, all dry. The leak only occurs when the engine is actually running, not when just the lift pump is running and it is inside the flywheel area. Put a rag by the weep hole just to make sure that the fuel wasn't from under the intake. Suspected a possible loose plug in one of the oil passages in the back of the block but caught some in a jar just to check for sure and it is indeed diesel.

Still at it,
Wayfaringmechanic

 

Fuel almost has to be comming from the filter housing or the under intake fuel lines,the leak location is a drain to keep fuel away from the clutch when a leak at the valley is present.

IP's have been known to leak as well but again the valley would be wet.

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Just read another similar post and remembered that the injector return lines are leak prone areas and the #7,8 injectors both have block off caps on the unused return line niipple that can leak fuel if broken or missing.