Truck Turns Off While Running

[Jaime]

I'm at the hospital with the wife using my phone but I seem to remember it saying that I would have to lower the steering column and then use the clamp. Anyway I think that I'll try and replace it this weekend if the wife is out of the hospital.

[Jaime]

Well I replaced the Ignition Switch this weekend and it still shut off on me. I shut off and the it turned back on without me having to cycle the key. It just turned off for about a second or two then it came back on.

 

Any other thoughts on the matter.

[shelbyluvv]

Only other things I can think of would be,

 

A relay going bad

fuel pump going bad

[cruiser54]

Only other things I can think of would be,

 

A relay going bad

fuel pump going bad

Swap the relays around on the passenger side inner fender. Good idea shelbyluvv.

 

With it idling, shake the crap out of the engine harness everywhere you can. 

[metrictonner]

I fixed about every electrical problem I had by crimping the contacts in the connectors running into the ECU...without replacing any sensors,coils etc, etc.  After 25 years of vibration the female contacts in ALL the connectors have a tendency to open up and cause at least intermittant problems.  You can check out the condition of the C201 and C202 connectors by removing the ECU from its mount and letting it hang by the connectors on the transmission tunnel.  Start the engine and wiggle the wires running into the connectors one at a time.  If nothing happens then all the contacts are tight.  Otherwise start pulling contacts and crimping them.  Just cleaning won't do.

[Jaime]

I swapped the relays around and still got the same results. So I removed the connectors that they sit in and found a lot of the white packing gunk and some corrosion on some of the wires. I removed each wire from the connector soaked it in baking soda and water. Cleaned it with electrical cleaner sanded the terminals and still got the same results.

 

After doing that I put a fuel pressure gauge on the outlet and got a result of 40 psi with the vacuum hose connected to the fuel pressure regulator and 40 psi with the vacuum hose removed. The FSM says it should be 31 psi connected and 39 with it removed but it does not say what to replace it is not within specs. Do you think I should replace the regulator or is it pointing to the fuel pump? Now I did replace the pump about 3 years ago but I had to use the Bosh pump as nobody around had the original style pump.

 

Metrictonner I will give the ECU a try and see what happens.

 

Thanks again guys for all the help you are giving me.

[cruiser54]

Fuel pressure regulator is bad, allowing higher than necessary fuel pressure at idle. Replace it. 

[Jaime]

I discovered some new symptoms this past weekend that hopefully will point me in the right direction. The truck is getting harder to start. I have to crank it 3 times before it starts. It also shuts off at about 8 and 1/2 minutes after I start it and the truck it just idling. The temp gauge is just before the 210 mark. It starts back up fine and I let it idle for 15 minutes with no issues. Any thoughts?

 

It turned out that the regulator was good. The new regulator gave me the same reading, so I checked into it a bit more and found that the vacuum hose going to the regulator was plugged. A bunch of black gunk plugging it up. After I replaced the hose and I got normal readings.

 

I pulled the ECU and pushed, pulled, and wiggled all the wires and it did not turn off.

 

Please let me know if you have any suggestion I can try.

Thanks

[cruiser54]

Ever monitor the fuel pressure before and during the 8 1/2 minute mark? 

[Jaime]

Wouldn't you know it, the darn thing won't shut off. I monitored it three different times with the fuel pressure gauge on it and it won't shut off. I'm going to do it once more and if it does not shut off I'll remove the gauge and check it again.

[cruiser54]

Wouldn't you know it, the darn thing won't shut off. I monitored it three different times with the fuel pressure gauge on it and it won't shut off. I'm going to do it once more and if it does not shut off I'll remove the gauge and check it again.

LOL!! Too funny. 

[Jaime]

Hello everyone,

 

Well it looks like I finally fixed the problem I was having with my truck.

 

Last weekend I went to the junk yard and picked up a MAP sensor, ICM, and some other odds and ends for twenty bucks. The MAP sensor did nothing but the ICM seems to have been the culprit all along. I've been driving it all week and it didn't shut off once.

 

I want to thank everyone for all the input all of you gave me. Not only did I get the problem fixed but I also did some upgrades I had been meaning to do.

 

Thanks again.