01 jimmy 4.3L stalled restsrt after cool

[chobes]

My 01 Jimmy 4.3L stalled on me the other day while driving on the expressway. I noticed a hesitation when i tried to accelerate. I backed off and was able to maintain a constant speed. Traffic started to slow, and when i tried to accelerate again it died on me. Would not restart. Friends picked me up and we trailered it home. when i got home it started, let it run for 45min and put it in gear and it stalled again and would not restart. replaced Fuel pump and filter a few weeks ago. I just replaced the distributor cap and rotor, and the cranck position sensor. have 105,000 mi on truck. I was thinking the ignition module. Is the module on the distriboutor? any other ideas are welcome!! Thanks

[MT-2500]

Check fuel pressure and post back pressure.
Does it have good hot blue spark to all plugs?

The ign module should be beside the coil.
But proper testing before throwing parts at it.
Like got spark got proper fuel pressure?
Was the fuel pump a good AC-delco/delphi fuel pump or one of the aftermarket or airtex junk wonder if they will run so called fuel pumps?
And was other parts AC-delco or aftermarket?
MT

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

[chobes]

Thanks MT 2500. You the only one who replies any more?? Well I checked the pressures i could. The damn thing won't start any more. It use to before i replaced the Crank position sensor, and distributor cap and rotor. Well when i turn the ignition on the pressure jumps to 68 psi, when i try starting it drops to 62 psi, and after letting it sit for 5 min, it dropped to 55 psi. I think the fuel pump is working. Ugh, What am i to do. I think i need to get it on a scanner. I will see what i can come up with this weekend. Any more info needed I will be checking back frequently. Oh I didn't replace the pump with a Delco, it was replaced with a Carter pump, Duralast gold Dist cap/ Rotor, and a Standard Crank position sensor (From Saab/GM dealer). Thanks for the quick response.
Chobes

[MT-2500]

You are welcome and glad to help.

AC-delco stuff is best for it.

But the fuel pressure sounds good.

Check for good hot spark to more than one spark plug.
If good spark and fuel pressure check for injector pulse.
A good scanner may show code or problem.
On the sanner look for rpm readings when cranking.
Recheck the crank sensor plugin and wires.
Is security light coming on and then go off key on or staying on?
Try a shot of carb cleaner when cranking if it will start a few seconds on carb cleaner you have a fuel delivery problem.
Like no injector pulse.
Good luck and let us know how it goes.

[chobes]

Checked all 6 plugs and no spark. Was able to get an ignition module and that didn't do anything for me, So i returned it. Told them wrong part. Put an old Snap-On scanner on it and the program card was only good thru 1999. I pulled a crank position sensor code. Would the codes have to be cleared after i replaced the sensor?? What voltage should i have on at the sensor. If i remember correctly i and like 3V with the ignition on. Thanks again for all the help and let me know what you think.

[chobes]

dose the tach get it's pulses from the top of the distributor? looks like there is a hallofax pick up (Magnetic) . Could that be bad and cause no spark??

Chobes

[MT-2500]

Use the OBD11 section and clear codes and see if code returns.
OBD11 part should give engine rpm whe cranking.
If no rpm cranking recheck crank sensor or wiring.

What was the code no?
Is the dist turning when you crank engine.
Any spark from coil?

PIN a light green wire should have 12 volt reference on it.
A cranking signal should be coming from pin C yellow

[chobes]

I pulled a P0335 Code. I cleared them, and it has not returned.
The distributer is turning, and i am getting 11.5 volts from the Coil wire.
PIN a light green wire should have 12 volt reference on it. ???

Pin C is that on the coil??

[chobes]

MT-2500, is it possible that hte Hall Effect pick up in the distributor has gone bad? If so would this cause the no RPM when cranking no the scan tool?

Originally Posted by chobes

PIN a light green wire should have 12 volt reference on it. ???

Pin C is that on the coil??

When you said PIN a Light Green wire that should have 12V reference on it.? Where is this wire?
What is Pin C??
Thanks for the help.

[chobes]

Well no luck. I have checked all the wiring that connects the ignition system.(Crank Position, Cam Position sensor, Ignition Coil and Ignition control module). No bad wires, not getting any shorts to ground or shorts to power. Everything that i have done so far points back to the PCM. I am taking to dealer tonight and have them diagnose the problem. Thanks for the help and will post back the findings.

[chobes]

Well, Dealer found the problem. the crank position sensor was not seated all the way into block. THe air gap between crank and sensor was to large. Weird.!! 80 bucks for sensor 135 bucks labor; she is back on the road. Thanks for the help and hope this post will save some 135 buck as well!!!