For that would be a GM service manual.

 

If you subscribe to ALLDATA they show all of the wiring diagrams etc and a complete list of the grounds including the connecting blocks where grounds are bonded together. Other than that what MCR said or someone with the service manuls on here might help. I have the locations for a 2002 pickup but not a 2001 cargo van. They could be somewhat identical.

 

I have the 3 volume set, 5+ inches of paperwork. Bought it in 2001 when I bought the car. All they have are wiring diagrams. If you know where in those 1800+ pages this list is, let me know.

Ron

 

Normally it would be at the back of the electrical section. This is what I can share with you.
G100 Lft frt body mount,
G102 Rt frt engine block in frt of starter,
G103 & G104 lft rear engine block,
G107 engine gnd strap,
G110 lft frt body mount,
G200 On rt upper I/P at the A pillar,
G203 On lft upper I/P at the A pillar,
G302 on lft body mount,
G304 under driver seat,
G305 inside passenger compartment on the left side at the B pillar,
G306 inside passenger compartment on the rt side at the B pillar,
G401 on spare tire hoist bracket,
G403 on lft frame body mount bracket.

Since yours is a cargo van it may vary somewhat.

 

Thanks, Silverado. I'll check the electrical section as well.
Ron

 

These are the GM manuals I have.

 

Those look like the factory service manuals Ron. They should have all the info you need to fix anything on that truck.

 

It's determining the cause of the problems that's the, "rub". Have a series of trouble codes:
P1683
P0200
B1000
B1001
B1009
and
U1000
Upon investigation I found the Cam sensor connection, disconnected. Has been for 2 years. No "Service Engine light", no engine problems. Truck ran fine. Two codes involve the ECU. I'll start with that.
Ron

 

Record all those codes.

Clear "all" codes through the scan tool. Make sure nothing is left including code history.

Run vehicle for a minimum 5 to 7 minutes in park. Record first codes that pop up on scan tool. Report.

Second stage, record codes that pop again when driving 3 to 10 miles in normal city traffic. Report that segment of codes as driving codes

"B" codes are body codes. "P" codes are engine management. U codes are generic.

Your codes might be of disconnecting connector(s) while the PCM was powered up, hence the need to clear all codes.

 

Drove the van before this issue just fine. "Check engine" light popped up and put the reader on it. Then all of a sudden, van would run for 2 minutes and just stop. Then it wouldn't turn over at all. We are now in, "exploration" mode. I cleared all codes when it was running. The codes listed are the ones that came up after the clearing.

 

Then it wouldn't turn over at all

When you wrote this I would assume you have a no crank, no start issue instead of a crank, no start issue.

 

Ron, assuming you have a good battery and wiring to the starter and a good ground connection, then you may have a starter relay in the under hood fuse panel and a crank fuse in the under dash fuse panel. Could even be the starter solenoid on the starter itself. There is also a park neutral switch (auto trans) or clutch start switch that can disable the start function. Check any of these.

 

The battery is 5 months old and it cranks the engine fine.
The main ground was changed last Summer. It's clean and tight.
The engine cranks fine. It just doesn't catch(start) and run. If the starter or the solenoid were faulty, would the engine crank?
The new park neutral switch was put in last October(2018) when the transmission was replaced. It cranks in Park and Neutral. It does not crank in Reverse or Drive.
The van started this morning with some gas pedal goosing. It would stay running as long as the pedal was pressed down and the engine was revving a bit. Once you let off the gas pedal, it died.
The spider module was switched out in 2017 to the updated unit due to a worn gasket that would allow gas to leak out into two cylinders triggering an engine code.
Fuel pump was changed in 2016 and current fuel pressure is 50 psi.
I ordered a programmed ECU . I should get it this weekend.
Thanks for the suggestions.
Ron

 

Fuel pump was changed in 2016 and current fuel pressure is 50 psi.

Correct me if I'm wrong but shouldn't it be 60psi min?

 

TBI is right. I thought when you said it won't turn over it meant it won't crank. That sent me down the wrong diagnosis path.

 

First, STOP REPLACEING PARTS ON GUESSTIMATES!!! You DO NOT need a program PCM. Pure waste of money. Nothing is gonna change!!!

From what you are describing you have multiple problems.

You stated in post #13: "The engine cranks fine. It just doesn't catch and run". That would be a worn out starter Bendix or weak, sticking starter solenoid.

Replace complete starter assembly if your describing the problem correctly.

First, to clarify your statements which one of these starter condition exist?
Do you have, ……. "No crank, No clicking"
"Crank and No Fire"?
"Intermittent Crank and No Fire"?
"Crank, but starter bendix keeps skipping out, not turning motor over"?
"Cranks but pulsates in variable crank speed like weak battery"?
"Cranks less than 200 rpms /or slow and steady"?

The other mandated part is you "must" have 60 to 62 psi reading on the fuel rail to start and run this motor. 50 psi just doesn't cut it. Referring to your statement in post #13: "The van started this morning with some gas pedal goosing. It would stay running as long as the pedal was pressed down and the engine was revving a bit. Once you let off the gas pedal, it died". Continuing: "Fuel pump was changed in 2016 and current fuel pressure is 50 psi" I'll bet you bought the cheapest aftermarket fuel pump you could buy and "didn't change" the restrictive fuel filter at that time which led to this fuel pump failure???

Change the fuel pump and gas tank sender "again" with a factory OEM Delco. Replace the fuel filter. Clean the black ground wire for the gas tank sender assembly.

After those 2 homework assignments are completed we will see how everything is functioning.

 

Change the fuel pump and gas tank sender "again" with a factory OEM Delco. Replace the fuel filter. Clean the black ground wire for the gas tank sender assembly.

Don't forget the suction sock on the fuel pump, ha ha.

 

I bought the fuel pump the auto parts store had. Was about $155.00 along plus the new fuel filter. It was an "Airtex". Fuel pressure was tested in the, "cranking" of the motor. The test was to see if the fuel pump was functioning. I'll bleed the pressure gauge and see if it improves. Need to pull the inspection plate of the transmission to see if the starter is engaging the flywheel.. I'm getting a vibration from the Starter relay in the hood fuse box. I can hear it in the cab, Felt it this morning with someone turning the ignition key. New sound.
Crank and no fire is what I have. Previous to this, there was an issue with the distributor with this symptom. Corrosion would foul the distributor contacts and the van would, "crank and no start". Another issue with the distributor was the corrosion of the wire from the cam position sensor attached to the distributor. Both came from moisture buildup inside the distributor. In the first instance I replaced the cap and rotor and everything was fine. The second issue was solved with a replacement of the cam position sensor wire. GM seems to have had this issue for awile. My 1988 Chevy Suburban suffered from the same distributor corrosion issue. Replacing the cap and rotor didn't help this time. I know the, " parts changing issue" raises it head again. I'll work through it. I usually do, with the manuals and help from informed individuals.
Ron

 

First Airtex fuel pumps are the cream of chit fuel pumps!!! Same goes for off brand distributor and secondary ignition parts. Remember You and I live in the rust belt 645 miles apart. A lot of deterioration can occur in 18 years.

My rule is when any part of a system is giving me chit, I replace all the parts in that system just because of extreme age (I myself drive a 2001 Sonoma). If and when my fuel pump gives me the slightest crap, fuel pump / sender will be replace with a OEM factory Delco. Anytime I used an Airtek fuel pump on a emergency basis, 100% of them failed within 3 years. I refuse to install any cheap azz part. They just don't have the quality!!!

Now to the cause of the problem, if you have a crank no fire, spray either or carb spray past the throttle blade. If the motor fires for 1 to 3 seconds it's a fuel delivery problem. You must have at least 60 psi with key just turned on, crank then run. ….not 50 psi. That is either weak fuel pump, highly restrictive fuel filter, or a damaged / plugged fuel line (very rare on the last entry).

 

Fuel rail pressure is 60 psi after bleeding air from gauge. Changed fuel filter as well. Pressure remained at 60 psi, before and after change.
If the starter was an issue, why would the car start and run at a high rev and stall when the gas pedal was let up?
Many of the above codes refer to the PCM as a possible issue. I'll switch that out after I check some more grounds and a possible crank sensor wiring issue. Wires were eaten by a woodchuck in 2009. Will check for corrosion on splices.
Van started this morning after a little stumble. Ran at idle for about 3 minutes and just stalled. Then crank and no start.
Both crankshaft sensor wiring(2009) and camshaft position sensor wiring(2012) have been spliced/repaired over time. Corrosion in the camshaft wiring entering the distributor and woodchuck nibbling on the crankshaft wiring. I'll check the voltage in both wires along with a continuity of the grounds.

 

Then get a scan tool that can do "graphing" of each sensor. See what sensor is or intermittently dropping out.

 

Can you suggest a bidirectional scan tool that can do this as well as a crankshaft relearn procedure?
At a reasonable price.
I think price points start around $900.00

 

Any reason I can't just read the voltages/continuity directly from the wires? I have two readers. A blue driver and an ELM. The Blue Driver graphs long and short fuel trim. I'll see if it can read the two sensors. The ELM I got to read transmission fluid temps. Will try that one as well.

 

Scan tool is a precision instrument. Way people poke wires not knowing what wire does what, then screw up the wires and or connections, I will not endorse that method. … I need "specific data", not interpretations.

With these codes listed below, tell me what the scan tool can read for sensor data. Not worried about "B" codes. I want to know if the brainbox (PCM) can read the sensors, fuel injector and crank signals. Clear codes and tell me if you have a crank signal, fuel pulse width signal. DO NOT use a cheapie scan tool, because I need you to graph some sensors. That is a "No if and or but" requirement.

Never disconnect any sensor while the ignition is on or running!!!

You stated the following codes:
P1683 Possible Causes

• Dirty throttle body
• Throttle body harness is open or shorted
• Throttle body circuit poor electrical connection
• Faulty throttle body

P0200 Possible Causes

• Faulty fuel injector
• Fuel Injector harness is open or shorted
• Fuel injector circuit poor electrical connection

B1000 Possible Causes

• Faulty Electronic Control Unit (ECU)
• Electronic Control Unit (ECU) harness is open or shorted
• Electronic Control Unit (ECU) circuit poor electrical connection

B1001 Chevrolet Possible Causes

• Faulty Inflatable Restraint Sensing and Diagnostic Module (SDM)
  Inflatable Restraint Sensing and Diagnostic Module (SDM) harness is open or shorted
  Inflatable Restraint Sensing and Diagnostic Module (SDM) circuit poor electrical connection

B1009 Possible causes

• Faulty Control Module
• Control Module harness is open or shorted
• Control Module circuit poor electrical connection

U1000 Possible Causes

• Controller Area Network (CAN) communication harness is open or shorted
• Faulty Engine Control Module (ECM)
• Poor harness ground connection.

Unless you pulled the wiring harness off while the key was on gives me the impression you have a few fuses blown, open grounds or a chewed on wire harness. That is why I asked you to clear "ALL" codes.

Report only what the scan tool does.

 

There are scan tools much cheaper than $900 for crank relearning (CASE Relearn option). Gotta look at the offered available options for each scan tool.

I'm on my 3rd updated scan tool in 10 years with all the electronic crap being added to vehicles.

But to save you $900, here is the "relearn procedure" without a scan tool more near the bottom of this post.
**********************************************************************************************************************************

Crank Relearn Instructions (With OBD Scanner/Reader)

These Crank Relearn Instructions may not apply to all vehicles. But they're close to how it's done on most cars.

To perform the relearn, proceed as follows:

Connect a scanner to make sure there are no trouble codes stored in the computer’s memory.

If there is any power train trouble code other than P1336 (Crankshaft Position Variation not learned), the computer will disable the relearn function until the problem that caused the code has been eliminated.

Also, make sure that the engine coolant (check it when the engine is cold) and oil levels are at an acceptable level.

1. Set the parking brake and block the drive wheels. Make sure that the hood is closed.

2. Start the engine and make sure that the engine coolant temperature is at least 158 degrees F. (70 degrees C.)

3. Turn the engine off for at least 10 seconds.

4. Select the crankshaft position variation learn procedure (CASE Learn) on your scanner.

5. Make sure that the transmission is in Park. Start the engine.

6. Apply the brakes and hold the pedal firmly.

7. Follow the scanner instructions.

Remember: That you are going to increase the engine speed to approximately 3000 RPM, 4000 RPM, or 5150 RPM. That’s the variation learn fuel cutoff RPM (depending upon the engine) and that it’s important to release the throttle when the engine RPM starts to decrease as a result of the fuel cutoff going into effect. Failure to do such will result in over revving of the engine, causing possible engine damage.

8. Once the engine has returned to idle, check the status of Diagnostic trouble code P1336. If the scanner indicates that the CASE has been learned, the relearn procedure is now complete.
If CASE has not been learned, check for the presence of other power train codes. If any exist, correct the problem, then repeat this procedure.

Crank Relearn Instructions (Without OBD Scanner/Reader)

NOTE: If the Crankshaft Variation Relearn is not accessible through your scanner (some truck applications 1998 & later), perform the relearn in the following manner:

1. Turn off all of the accessories. With the Air temperature sensor and Coolant temperature within 5 degrees (Centigrade) of each other, start the engine and let it idle in Park or Neutral for two minutes.

2. Accelerate the vehicle to 55 mph at part throttle. Cruise at 55 mph for 8- 10 minutes until the engine reaches operating temperature.

3. Cruise at 55 mph for another 5-6 minutes.

4. Decelerate to 45 mph without using the brakes, and maintain 45 mph for 1 minute.

5. Perform 4 deceleration cycles, without using the brakes, of 25 seconds each where no specific speed is necessary.
Returning to 45 mph for 15 seconds in between deceleration cycles.

6. Accelerate to 55 mph and cruise for 2 minutes.

7. Stop the vehicle and idle for 2 minutes with the brake applied and the transmission in Drive (automatic trans.) or Neutral (manual trans.)
with the clutch depressed.

 

An update to the crank and no start issue.
Put in new ECM and tried to start the van. Crank and started to catch. No start.
Did a "Security" update. Crank and no catch at all.
Checked Cam and Crank voltages and power was getting to both.
Replaced the Crank sensor as it was original to the van.
Took apart the original ECU. Evidence of moisture inside. Solder contacts had crusty residue overlapping each other where the pins were behind the "red and "blue" plugs. Cleaned all the exposed solder connections.
Replaced the new ECM with the old ECM .
Van cranked and stumbled to start. No start.
Fuel pump did not engage.
Switched the fuel pump relay with the starter relay.
Van started up and idled for 10 minutes (until I shut it off)
Van has started and idled every day(3) since.
I ordered a Delco fuel pump, just in case.
Will take it out for a test drive in the next few days.
As an aside, the ECU and the under hood fuse locations are really stupid. Right under the hood edge. As a precaution, GMC put a little plastic shield over these inconsequential devices. I installed a plexiglass shield over the ECU and will fabricate a non conductive shield over the fuse block.
I don't know if a very sophisticated scanner would have helped, but I was not going to get one in any case.
New computer was sent back for diagnosis.
Appreciate the time you guys took for guidance.
Thanks
Ron

 

Always have "backup" relays for your vehicle, or know what relays are critical and non critical that can be used for swap out.

 

so my gas gauge is reading empty when the tank is full is there a ground I can clean or do I have to get a whole new fuel sending unit

 

It could be a dirty ground at/near the tank,
Could be a broken wire,
Could be a bad sending unit.

Edit:
Could be a bad gauge,
Or a problem in the gauge wiring