Engine miss - need ideas

[tlturbo]

OK, I have a new issue that I can't readily find so I'm looking for suggestions.

See specs in sig.
Symptom- accelerating slowly like in pulling away from a light or after going around a turn the car stumbles and misses. Doesn't backfire or anything that drastic, just stumbles all over itself. Fuel pressure appears normal and so does voltage. Voltage was low and alternator not charging up to snuff (10 years old) so thought that might be the problem so installed a new alternator. Same issue.

Car has Welbro intank pump hotwired.

What makes this weird is when accelerating slowly and stumbling, if I give it enough throttle to get it to about 5-10 psi boost and keep it in boost mode, it smooths out, pulls hard and runs like it normally does. Let off and ease back into the throttle, stumbles again (almost seems worse that before) and takes about 20 secs to get back to normal stumbling. This makes me think it is getting fuel and current.

Only changes made to the car recently were replacement of an old SMC alky kit with a new Razor kit (including 3Bar) BUT it ran good after the install for several months. Only other change right before this started was putting in a new powermaster brake accum ball (could I have dislodged something around there)?

Looking for ideas on what to check. Also - no codes on scanmaster,

Many thanks.

 

[usetaboost]

Post scan numbers at hot idle

 

[tlturbo]

Only have scanmaster now. Direct Scan won't work with new Windows platforms. What numbers do you want?
Car seems to run fine at idle.
Thanks

 

[TurboBuRick]

Sounds like a bad cam sensor. As they wear out they will cause drive ability issues just like you describe..

Try unplugging it while motor is running. Take it for a ride and see if it still stumbles.

Scott W. "GNS Performance" rebuilds them better than new.

Rick

 

[tlturbo]

Thanks - Dave replaced the cam sensor about a year ago with probably a spare he had laying around. Maybe it was going bad. I'm going over there this afternoon so will mention it.

 

[usetaboost]

I had one with worn bushings in it and it didn't affect it at all. They're the same parts used in a regular Buick distributor. Post scan numbers at hot idle and we' all go from there. I want all of them

 

[mikestertwo]

Sounds like a bad cam sensor. As they wear out they will cause drive ability issues just like you describe..

Try unplugging it while motor is running. Take it for a ride and see if it still stumbles.

Scott W. "GNS Performance" rebuilds them better than new.

Rick

I would check the setting on the cam sensor also. Had a car with the same issue. Turned out the bolt came loose on the front of the billet cam holding the drive gear assy. I would reset the sensor timing and it would run great for about a week then the issue would come back. Checked the cam sensor timing again and it was off. Pulled the front cover off and found the loose bolt on the nose of cam.

 

[1fastcobra]

Bad plug- injector-
Tps may have a bad spot

Posted from the TurboBuick.Com mobile app

 

[RmvBfrFlght]

OK, I have a new issue that I can't readily find so I'm looking for suggestions.

See specs in sig.
Symptom- accelerating slowly like in pulling away from a light or after going around a turn the car stumbles and misses. Doesn't backfire or anything that drastic, just stumbles all over itself.

What makes this weird is when accelerating slowly and stumbling, if I give it enough throttle to get it to about 5-10 psi boost and keep it in boost mode, it smooths out, pulls hard and runs like it normally does. Let off and ease back into the throttle, stumbles again (almost seems worse that before) and takes about 20 secs to get back to normal stumbling. This makes me think it is getting fuel and current.

Many thanks.

Had the same issue this past Summer, ended up being an injector with debris in it. The debris was holding the pintle open and letting fuel past when it wasn't supposed too. Same as your symptoms, stumbling at low speeds & loads and smoothing out and pulling hard with light boost (10 psi or so).

Used a infrared temperature gun on the header tubes to ID #4 as the culprit (temperature was moving all over and was on the low side). Swapped the #2 and #4 injectors and the issue followed to #2. Six new injectors and all is well.

RemoveBeforeFlight

 

[tlturbo]

Thanks guys - will be next week before I can get back to it. Gotta work sometime. Will update.

 

[tlturbo]

Cam Sensor cap did the trick. Happy car again. Thanks for the ideas.