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1990 Grand Prix Dies On Hard Acceleration


sborgstrom

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This 3.1 dies when I accelerate fast or after a sustained speed of 75 MPH / 3500 RPM. It won't start back up immediately but it always does after 20 to 30 seconds while rolling in neutral. This thing will run all day at 74 but if it hits 75, it's going to die. I changed the fuel filter and that didn't fix it. Can anyone tell me how to fix this?

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You need to turn on the flux capacitor and then continue until you hit 88mph

 

If that doesnt work, then do 74mph, im sure 75mph is speeding in almost all states:lol:

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This 3.1 dies when I accelerate fast or after a sustained speed of 75 MPH / 3500 RPM. It won't start back up immediately but it always does after 20 to 30 seconds while rolling in neutral. This thing will run all day at 74 but if it hits 75, it's going to die. I changed the fuel filter and that didn't fix it. Can anyone tell me how to fix this?

Any codes?

 

What is the fuel pressure at 74 mph?

 

What is the TPS voltage at 75 mph?

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being a 90, it would be one of ~100 or so made then...

 

but 4th gear would be ~81MPH at 3500 and 5th gear would be ~106 at 3500, assuming 26.3" tall tires.

 

75MPH in 4th would be ~3250RPM and 75MPH in 5th would be ~2500.

 

i don't think the 3 speed was even an option in a 90 3.1 GP, but if so, it would have the 3.08FDR and in 3rd, it would be ~89MPH at 3500RPM or at ~2950RPM at 75MPH.

 

 

 

this is all assuming 0 slip as well.

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generally, when the calibration resistor in the cluster is going flakey, your displayed speed will be off by a certain percentage at all speeds. example: 6MPH at 60MPH is reading either 10% too fast or 10% too slow.

 

if the air-core needle driver is the problem, then that's a different story.

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I know mines too slow, speed reads higher than what actual speed is, so I guess that would be too fast actually :lol: . But at slower speeds is almost dead on. Is this like a exponentially issue when the resister starts showing signs?

Edited by 19Cutlass94
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possibly, but i've only ever dealt with/repaired/recalibrated completely screwed clusters before, not one that was heading towards guage insanity.

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hmm... I wonder if I should just try and find another cluster and try that one out. Cause I have no idea how I would go about fixing it. Cause the Voltmeter is way off too. Shows 12v on the gauge when I have 14+ at the battery...

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multiple guages being incorrect would certainly point to the cluster(specifically something common to both guages) going south...

 

i resoldered(and added leaded solder where necessary) the GP's entire cluster in a little under an hour using a 45watt iron. after that, the common low fuel/check guages light issues were fixed, but the speedo/tach were still way off, so i cut out the calibration resistors for those entirely and replaced them with potentiometers. then i get the odometer set correctly by adjusting the road speed constant and go on highway and adjust it until it perfectly matches a 10 mile stretch of markers(100 data points) for a +/-1% accuracy, then use the value i see in tunerpro to adjust the potentiometer for the speedo to perfection. pro-tip for anyone considering this: don't use single revolution pots, use the 15 turn variety for much less sensitivity.

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