87 Buick will not run right
#1
87 Buick will not run right
Very recently my brother's 87 regal (307 olds) started to run really rough when restarted warm, sometimes stalls, but then when hot it runs fine. A few days ago I was driving it and I floored it and the damn car got stuck at 50% throttle. Shut it off, and started it back up and it was back to regular idle.
I checked the code, since the CEL came on, and I got code 21 - TPS signal voltage high
I checked the wires at the TPS and here's what I found:
With the key on
Ground wire - I connected the positive lead of my multimeter to the pos terminal on the battery and the negative lead to the ground at the TPS, I have 12V which tells me that the ECM is providing good ground.
Reference wire - I have 5 volts at the reference wire
Signal wire - when I backprobe it, at idle the voltage is at 0.8-0.9. I increased the throttle slowly and the voltage increase without jumping around. The max voltage at WOT was 3.5. Not sure what the factory specification is, but it seems to me that the range is completely off.
Then when I disconnect the connector, the signal read 4.7v, not sure if this is normal or not.
I would appreciate it if someone could chime in with any advice/ suggestions.
Is the range from the signal completely off? Or does it fall within specifications.
Are there any problems such as a gummed up carburetor that can cause this code to go off?
Honestly am considering ditching the computer for a non computer carb and dist.
I checked the code, since the CEL came on, and I got code 21 - TPS signal voltage high
I checked the wires at the TPS and here's what I found:
With the key on
Ground wire - I connected the positive lead of my multimeter to the pos terminal on the battery and the negative lead to the ground at the TPS, I have 12V which tells me that the ECM is providing good ground.
Reference wire - I have 5 volts at the reference wire
Signal wire - when I backprobe it, at idle the voltage is at 0.8-0.9. I increased the throttle slowly and the voltage increase without jumping around. The max voltage at WOT was 3.5. Not sure what the factory specification is, but it seems to me that the range is completely off.
Then when I disconnect the connector, the signal read 4.7v, not sure if this is normal or not.
I would appreciate it if someone could chime in with any advice/ suggestions.
Is the range from the signal completely off? Or does it fall within specifications.
Are there any problems such as a gummed up carburetor that can cause this code to go off?
Honestly am considering ditching the computer for a non computer carb and dist.
Last edited by 77ricbaez; August 20th, 2017 at 10:28 PM.
#2
it's unlikely the tps is causing any hard starting or rough running,i would look closely at the choke operation.is it open when hot when restarting?check the hot air tube to see if it has vacuum,the port in the baseplate of the carb that feeds the choke housing can get clogged with sludge and won't draw hot air by the spring.also a common problem on those cars is when the purge valve goes bad it causes vacuum to draw fuel out the bowl vent.there shouldn't be any fuel/wetness in the bowl vent hose.
#3
it's unlikely the tps is causing any hard starting or rough running,i would look closely at the choke operation.is it open when hot when restarting?check the hot air tube to see if it has vacuum,the port in the baseplate of the carb that feeds the choke housing can get clogged with sludge and won't draw hot air by the spring.also a common problem on those cars is when the purge valve goes bad it causes vacuum to draw fuel out the bowl vent.there shouldn't be any fuel/wetness in the bowl vent hose.
#4
Just because it's throwing a code, don't take it as gospel. Over here 6 cylinder Jaguars will run rough and throw up a faulty O2 sensor code, when all that's wrong is a breather hose split or come adrift.
Check the simple stuff first, rather than throw money at the car.
Roger.
Check the simple stuff first, rather than throw money at the car.
Roger.
#5
Just because it's throwing a code, don't take it as gospel. Over here 6 cylinder Jaguars will run rough and throw up a faulty O2 sensor code, when all that's wrong is a breather hose split or come adrift.
Check the simple stuff first, rather than throw money at the car.
Roger.
Check the simple stuff first, rather than throw money at the car.
Roger.
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