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86 2.9 won't stay running... HELP!!!


Piercetruckie

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I have an 86 B2 4x4 with the 2.9V6. She will fire right up and run strong and sounds good at idle for about 30 seconds. Then the idle will drop quickly and she dies. Turn the key off and back on, starts right back up, runs at idle for 30 seconds idle drops and she dies. This basically continues and continues. I haven't pulled the codes yet, have to go get a meter with a needle. But replaced the fuel filter and can hear the pump run. Have checked the fuel pump relay. I get 36psi fuel pressure before starting. 30psi while running and it's still at 30psi when she dies. All the electronics have been either replaced or retired previously. This is a fuel or a sensor problem. Maybe a throttle position sensor or some other intake/throttle sensor?
Ideas? Thoughts? Help?
:icon_hornsup:
 


ab_slack

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get the codes.

Also the codes aren't just captured codes, but specific tests. There are the KOEO (Key On Engine Off) and KOER (Key On Engine Running) tests. Those should identify any specific sensor problems.

It sounds to me like some sensor is way off on readings. When you fist start it probably is using startup parameters and when it starts using sensor input it crashes.
 

sjr53

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Since you only get 30 seconds of run time, just check for stored codes for now. Ignore the 33 EGR code for now, if you get it. I drove for years with that until I finally cleaned a plugged passage in the throttle body to EGR valve. I've driven around with the TPS unplugged so that won't be it. My wild guess would be the MAP sensor which really screws things up when it fails. Since you have 30 psi fuel pressure, it won't be a fuel supply issue.
 

Piercetruckie

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Well, went out and bought a code reader, pulled 14 and 18.

14 - Ignition Profile Pickup (PIP) circuit failure
18 - Loss of tachometer input/IDM circuit/SPOUT circuit grounded

So reading that made me realize my tach hasn't worked since I replaced all the ignition circuits, distributor, imagination module, coil, etc. sooooo unless somebody has seen this before and can give me an idea, reckon I'll start with the spout. Anybody know which wire is the tach feed?
 

sjr53

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Sounds like you put in a bad distributor. Its possible that just the ignition module is bad but the PIP is inside the distributor, so you may have 2 bad parts. About 5 years ago I paid $75 +core for a rebuilt distributor with the module attached from Advance Auto.
 

nasabronco

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I have an 86 B2 4x4 with the 2.9V6. She will fire right up and run strong and sounds good at idle for about 30 seconds. Then the idle will drop quickly and she dies. Turn the key off and back on, starts right back up, runs at idle for 30 seconds idle drops and she dies. This basically continues and continues. I haven't pulled the codes yet, have to go get a meter with a needle. But replaced the fuel filter and can hear the pump run. Have checked the fuel pump relay. I get 36psi fuel pressure before starting. 30psi while running and it's still at 30psi when she dies. All the electronics have been either replaced or retired previously. This is a fuel or a sensor problem. Maybe a throttle position sensor or some other intake/throttle sensor?
Ideas? Thoughts? Help?
:icon_hornsup:
That’s your map sensor.
 

nasabronco

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I have an 86 B2 4x4 with the 2.9V6. She will fire right up and run strong and sounds good at idle for about 30 seconds. Then the idle will drop quickly and she dies. Turn the key off and back on, starts right back up, runs at idle for 30 seconds idle drops and she dies. This basically continues and continues. I haven't pulled the codes yet, have to go get a meter with a needle. But replaced the fuel filter and can hear the pump run. Have checked the fuel pump relay. I get 36psi fuel pressure before starting. 30psi while running and it's still at 30psi when she dies. All the electronics have been either replaced or retired previously. This is a fuel or a sensor problem. Maybe a throttle position sensor or some other intake/throttle sensor?
Ideas? Thoughts? Help?
:icon_hornsup:
lol I just saw how old the post is my bad
 

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