Stuttering when Accelerating (Page 1/1)
FranklinTurl SEP 06, 07:42 PM
Hello, I have a 1984 Pontiac Fiero SE stock. I recently did a lot of engine work and got it running pretty strong! Just the other night I drove it to work and all was good and then when I left to go home it just all the sudden started stuttering when I accelerate. It stutters a lot and acts as if it is just going to die but then the RPMs spike up and it goes back to normal for a second and keeps doing that. It goes back to normal if I am just coasting or idle and only happens when i accelerate, for example, from a red light to get up to speed. I have recently installed new spark plugs, new spark plug wires, new fuel filter, new carburetor gasket, new vacuum, and fuel hoses, and have redone a lot of the electrical work. its been running solid for about 6 months and then just all a sudden started doing this, my guess would have to be something to do with insufficient fuel/air. Just not sure what to test or what to look for. any help would be much appreciated! thank you!
theogre SEP 06, 08:29 PM
Check battery cables etc when engine moves.
Wiring can short out as engine moves during accel, stopping or both.
If ignored, can start a fire in next minutes to days or longer.

If can't easy see battery cables use mirror and/or move them more so on + cable to make very sure pulley(s) etc can't cut the plastic.

Battery Tray can hold the battery down but let it to move sideways and hit the Water pump pulley or make + cable to hit things.
Worse if missing plastic "wall" on engine side of battery.
OE GM batteries made a bit different where bottom case is made and fit the tray better.
Many others not so much and the plastic "wall" maybe only thing stopping the battery skidding sideways.

Even if Ignition has most or all parts replaced... check all parts.
What spark plugs used? Many plug products are "Gimmicks" and cause problems.

To check Fuel Pressure need a tool not included w/ most gauge set. see https://www.fiero.nl/forum/Forum2/HTML/146121.html TBI Test Adaptor for Duke etc.
While GM spec is 9-13psi... if near bottom can have problems w/ fuel pump and in tank hose.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Spoon SEP 14, 07:36 PM
Double check your spark plug wire assignment. Could have 2 cylinders fighting one another.

Spoon


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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut