1989 4.3L Chevy Cheyenne
I have a 1989 4.3L Chevy Cheyenne that will not
idle. The intake gaskets were leaking. Replaced
them and now the truck will not idle. It will crank up
but, will die immediately after. I have replaced the
following: distributor, distributor cap, rotor button,
ignition module, map sensor, fuel filter, air filter,
fuel pump (and blew fuel lines out), spark plugs
and plug wires. The only way I can get the engine
to idle is to disconnect the vacuum line from the
map sensor to TBI however, it only idles for 2-3
minutes and dies out. I have set engine on TDC
and disconnected the timing advance sensor (at
the firewall) and used timing light to set harmonic
balcancer timing mark to 0°. With doing all this the
engine still cranks up and dies immediately. Any
thoughts what's going on?
Double check the sensor grounds and then check for any trouble codes, something may have been damaged during the work that was done. Was the battery disconnected during the work?
I can only think of a few items to check: FUEL PUMP RELAY, FUEL PUMP or BAD INJECTORS
Joemom, thank you for replying. I have changed the fuel pump and there is plenty of fuel getting to the TBI. I did notice that the right fuel injector was not spraying any fuel. Do both injectors spray fuel when idling? I have replaced all fuses and relays.
Tennis shoes, thank you for replying. I have checked all fuses and relays and replaced them. The battery was disconnected during all work. I will recheck the grounds just to make sure it was all secured.
Both injectors need to be spraying fuel, otherwise half of the engine is not working..
Thank you tennisshoes. I'll have to order new ones. Guess it wouldn't hurt to go ahead and rebuild the TBI since i'm there as well.
Do you have both power and a trigger signal from the ECM to the dead injector.?
Yes there is power to both injector.
How about the trigger signal?
Trigger signal is good. Decided to grasp at some straws this afternoon and poured a little gas in the TBI on the side with the dead injector. Well, low and behold the truck fired up and idled good till the fuel ran out. And that was with the vacuum line connected to the map sensor. So, I'm gonna say that the non idling problem will be fixed when I change the the dead injector.
Sounds like your headed in the right direction as long as you have power and trigger signal?
Thanks for the help guys.
Update: After changing out both fuel injectors, the truck is now running smoothly with vacuum hose connected to MAP sensor. Wanted to say thank you for helping figure this out and getting my truck back on the road. It is Greatly appreciated!
Great news, thanks for getting back and letting everyone know how it turned out.
Okay, I'm back again. Well, my truck is idling fine(thanks again for helping with that) however, once I put it into gear it jerks and stalls. It's a 5 speed manual transmission. I don't think it's a problem with the transmission and there are no codes being thrown. Any thoughts on what is going on?
Possibly a TPS, you can run a resistance test on it too see if there is a dead spot in it just off idle, is the fuel pressure and flow good? Or it could be very well a tranny problem, possible cluster shaft bearings.
Fuel and pressure is great. I haven't changed the TPS as of yet. Worth a shot.
Well, it's been a while since I have messed with truck...had other things to take care of. Anyway, I have rebuilt the TBI and it still stalls while driving down the road. It will almost die but as long as I feather the gas it will eventually gain power and continue down the road. This is in all 5 gears. Just to refresh, it is an 5 speed manual transmission. Is there anything transmission wise that can cause this? That or is the computer a possible culprit? Thanks in advance!
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