Off idle hesitation fixed... for me... - Team Camaro Tech
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post #1 of 4 (permalink) Old Nov 14th, 09, 05:44 PM Thread Starter
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Location: Avondale, AZ
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Off idle hesitation fixed... for me...

Dont' know if this helps, but just had an issue with off idle hesitation and break up especially below 2000 rpms. well, I checked the carb base gaskets and the one right on the carb had a fairly decent size on the side that wasn't making contact and created a nice size vac. leak. I tried reusing the old gaskets and modifying them, but made it worse to the point I could hear hissing, and I couldn't even free rev the motor without it stumbling. So, the new gaskets went in and blamo, the off idle hesitation is gone! how about that! I figured I would put this here, because I searched a lot and this would be a quick, simple and cheap thing to check when troubleshooting the ride.

The car ran great except for that issue, which is why I need to put a wideband in the car. I was thinking it was a rich spike, but apparently it was a lean spike due to the vac. leak, that I could have seen via a wideband. I shouldn't have sold my old one before picking up this car!
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post #2 of 4 (permalink) Old Nov 14th, 09, 09:11 PM
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Re: Off idle hesitation fixed... for me...

Thanks for the info!

68 RS Coupe 355/350 TH, Detroit Speed, Hotchkis, Vintage Air, 8.5" 3.42 posi 10-bolt, MagnaFlow 2 1/2" exhaust, etc.

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post #3 of 4 (permalink) Old Nov 14th, 09, 10:41 PM
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Re: Off idle hesitation fixed... for me...

Vacuum leaks are dreaded by many - the last thing to check for. Glad you found it and saved yourself some time and money. I've had a similar problem with a Holley 600CFM accelerator pump lever hitting the #1 runner on my Edelbrock Performer RPM. I had to install a thicker gasket to get clearance (and probably also kept some heat out of the carb).

I've had limited experience with WBO2. I do know that sometimes it can read incorrectly. For example, a lean condition can let unburned fuel through that will make the sensor read rich. The distance the sensor is from the exhaust manifold can also turn up some weird readings from time to time. A WBO2 is very cool though and well worth the cost.

68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
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post #4 of 4 (permalink) Old Nov 15th, 09, 12:47 AM Thread Starter
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Location: Avondale, AZ
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Re: Off idle hesitation fixed... for me...

yep, w/ my 600cfm holley and performer rpm intake, the accelerator pump cover will hit unless it has about 1/4" stacked uner it, which i have at the moment. I tried that phenolic spacer, but it wasn't completely flat, so it made the vac. leak issue worse.

well those are all valid points with the wideband, but generally, it is spot on. I had a zeitronix unit with controller and standalone gauge, and man was it great. It was in my previous ride that I built... a supercharged, built motor import... I know, i was a lot of fun though! at any rate, the wideband was a lifesaver, and honestly it read true. That particular setup I would run again in a heartbeat. I could tell instantly if my tune was off, or if I was stubling due to rich or lean conditions etc. I'll get another one for sure... as soon as work pics up!
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