Engine stuuters on startup and other clues
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Joined: Sep 2000
Posts: 103
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From: Charlotte,NC USA
Engine stuuters on startup and other clues
OK. Each morning when I start my car ...
1) It stutters.
2) It starts a little slow also in that it is not just click key engine starts ... instead it is click key, rrr,rrr,rrr, engine starts.
3) The idle hunts around about 50 to 150 rpm at most.
4) On real cold days the idle is up after starting of course, but if I put the car in gear before it comes back down, the
car lurches and the the idle slows to normal.
What have I done to the car since buying it last july...in order.
Changed air filter and PCV filter
Changed oil/filter
Changed all 8 plugs with AC/DELCO's
Ran 2 tanks of PENSKE super concentrated fuel injector cleaner through.
(This cleared up a very bad stumble at about 2500rpm on steady state cruising)
Cleaned up the TBI VERY well with spray carb/fuel injector cleaner.
(this soothed the wandering idle from 200 rpm variance down to 50-100rpm)
(PS. thanks Pablo for pointing out the passages behind the venturis)
Disconnected the battery for about 2 hours to clear the ECM
Changed my stock sport coupe hood for an IROC Z hood.
Changed out the heater core and all heater hoses
Changed out the water pump, upper and lower radiator hoses and went to a 180* tstat
Used a hole saw to cut nice holes all along the edge of a donor air filter housing lid.
(nice moan now, and the rear breaks loose on every full throttle first to second gear shift now)
What I think needs to be done ... I am asking for your learned opinions here.
Take out the IAC motor/pintle and clean up the pintle/seat VERY well
Get either a gas supplemnetal chemical like BG44K or get the EGR passages professionally cleaned.
Double check the timing
Put on a new distributor cap and wires
Put on a high performance replacement coil
(considering the MSD direct replacement, what do you recommend?)
Change out the plugs again.
------------------
1988 Camaro Sport Coupe305TBI-4spdAOD-2.73open in "bought stock" condition. That'll change if it stays around here much longer mike.davis@firstunion.com
1) It stutters.
2) It starts a little slow also in that it is not just click key engine starts ... instead it is click key, rrr,rrr,rrr, engine starts.
3) The idle hunts around about 50 to 150 rpm at most.
4) On real cold days the idle is up after starting of course, but if I put the car in gear before it comes back down, the
car lurches and the the idle slows to normal.
What have I done to the car since buying it last july...in order.
Changed air filter and PCV filter
Changed oil/filter
Changed all 8 plugs with AC/DELCO's
Ran 2 tanks of PENSKE super concentrated fuel injector cleaner through.
(This cleared up a very bad stumble at about 2500rpm on steady state cruising)
Cleaned up the TBI VERY well with spray carb/fuel injector cleaner.
(this soothed the wandering idle from 200 rpm variance down to 50-100rpm)
(PS. thanks Pablo for pointing out the passages behind the venturis)
Disconnected the battery for about 2 hours to clear the ECM
Changed my stock sport coupe hood for an IROC Z hood.
Changed out the heater core and all heater hoses
Changed out the water pump, upper and lower radiator hoses and went to a 180* tstat
Used a hole saw to cut nice holes all along the edge of a donor air filter housing lid.
(nice moan now, and the rear breaks loose on every full throttle first to second gear shift now)
What I think needs to be done ... I am asking for your learned opinions here.
Take out the IAC motor/pintle and clean up the pintle/seat VERY well
Get either a gas supplemnetal chemical like BG44K or get the EGR passages professionally cleaned.
Double check the timing
Put on a new distributor cap and wires
Put on a high performance replacement coil
(considering the MSD direct replacement, what do you recommend?)
Change out the plugs again.
------------------
1988 Camaro Sport Coupe305TBI-4spdAOD-2.73open in "bought stock" condition. That'll change if it stays around here much longer mike.davis@firstunion.com
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Joined: Mar 2001
Posts: 868
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From: Randleman,NC,USA
Car: 91 Camaro RS Convertible
Engine: 385ci LT1 cnc ported heads big cam
Transmission: 4L60E automatic
Axle/Gears: 3.42 Zexel posi 7.5" rear
Have you checked for a leaking injector. That happened to my truck about 2 years ago. Had my wife turn on the ignition so the fuel pump would prime the system and I watched the injectors. Turned out the driverside injector was steadily dripping gas into the throttle body for about a minute after she turned off the key (until pressure dropped off). I replaced the injector and no more rrr,rrr,rrr. And she runs like normal again.
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