bogging poppin chocking 1989
Thread Starter
Racer
Joined: Feb 2011
Posts: 467
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From: Vacaville Ca
bogging poppin chocking 1989
my c4 just recently started acting up. it seems when the ac is on it pops like a back fire back up through the tpi in sputters wont take off. then once it gets going its ok until i stop again. also it has real starting issues like when i bought it i was told it had a slow start that is charecteristic. well now its worse it wont start i have to pump it then it goes kinda and i rev it and it idels then the ac kicks on you go to take off and its all bad. it almost seems like it was contaminated in the fuel system. i did a full tune up a month ago before this started i run new gas fuel system cleaner no change please help.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
my c4 just recently started acting up. it seems when the ac is on it pops like a back fire back up through the tpi in sputters wont take off. then once it gets going its ok until i stop again. also it has real starting issues like when i bought it i was told it had a slow start that is charecteristic. well now its worse it wont start i have to pump it then it goes kinda and i rev it and it idels then the ac kicks on you go to take off and its all bad. it almost seems like it was contaminated in the fuel system. i did a full tune up a month ago before this started i run new gas fuel system cleaner no change please help.
check your dist cap, cracks, condensation inside, plug wires, the whole system, including timing. slightly retarded timing can cause hard start, backfiring. consult a manual before setting timing, or look at the emissions label glued under the hood. it's easy to do it wrong.
can be a large number of things with these cars but fuel is not likely.
joe
*** I always forget: you have checked for codes? also, verify the TPS settings, since it starts as you are moving the throttle. if it runs "ok" probabaly not TPS issue. there is a full page in fsm for this.
Last edited by joe paco; Jun 19, 2012 at 08:11 AM. Reason: add ***
Thread Starter
Racer
Joined: Feb 2011
Posts: 467
Likes: 0
From: Vacaville Ca
I don't see a fuel issue if it runs ok most of the time. my 91 starts in about a second of crank time and that is normal. "pumping" the throttle does nothing, snce the fuel is supplied by the computer.
check your dist cap, cracks, condensation inside, plug wires, the whole system, including timing. slightly retarded timing can cause hard start, backfiring. consult a manual before setting timing, or look at the emissions label glued under the hood. it's easy to do it wrong.
can be a large number of things with these cars but fuel is not likely.
joe
*** I always forget: you have checked for codes? also, verify the TPS settings, since it starts as you are moving the throttle. if it runs "ok" probabaly not TPS issue. there is a full page in fsm for this.
check your dist cap, cracks, condensation inside, plug wires, the whole system, including timing. slightly retarded timing can cause hard start, backfiring. consult a manual before setting timing, or look at the emissions label glued under the hood. it's easy to do it wrong.
can be a large number of things with these cars but fuel is not likely.
joe
*** I always forget: you have checked for codes? also, verify the TPS settings, since it starts as you are moving the throttle. if it runs "ok" probabaly not TPS issue. there is a full page in fsm for this.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
whats the fuel pressure @ key ON ??? @ idle??
MAF ??
what about MAF relay(s)?
got your FSM and gone thru the flow charts yet? Easy enough to diagnose an EFI engine that way.
This screams MAF from where I'm sitting....that and/or PP fuel pressure/flow.
code 33-34.
MAF ??
what about MAF relay(s)?
got your FSM and gone thru the flow charts yet? Easy enough to diagnose an EFI engine that way.
This screams MAF from where I'm sitting....that and/or PP fuel pressure/flow.
code 33-34.
Advanced
Joined: Jul 2007
Posts: 50
Likes: 0
From: Waterloo IL
Sounds like it could be a vacuum leak somewhere. Connect a vacuum gauge and see what your vacuum is at idle - the value is not as important as the characteristics of the reading. (steady or fluctuating)
Thread Starter
Racer
Joined: Feb 2011
Posts: 467
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From: Vacaville Ca
Thanks for the ideas I will look at them
Thread Starter
Racer
Joined: Feb 2011
Posts: 467
Likes: 0
From: Vacaville Ca
