Non Pontiac Motors in Pontiacs includes factory 403,305,350 Chevy, Buick V6,
Also Pontiac Motors in non-Pontiacs!

          
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  #61  
Old 06-23-2022, 09:33 AM
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Also worth mentioning, a lot of people have made big power with the truck manifolds. They're not pretty, but they work well. They can be "shaved" and will have a slightly better appearance. More streamlined looking anyway...
I actually like the truck manifold! I shaved most of the bracket off on the top. Looks much better. Fits under '64 GTO hood with a couple of inches to spare.

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Old 06-25-2022, 07:31 AM
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Engine is still running pig rich at idle. It dies when I start it up cold. I must open the throttle to get it to keep running. Then it will eventually idle ok. It’s a stock 5.3. It has 1-7/8” long tube headers and a 4” intake pipe. It’s running through a factory truck MAF. I don’t know if the MAF needs recalibrated or what. I know the headers are too big. Planning for a lot more power later. The A/F ratio seems to be ok when revved up. Then the fuel trims quickly creep up at idle. The injectors are questionable. I have three new and eight that I freed up with cleaner. I tried to attach my tune and log file. Not allowed? Any help would be appreciated. I may be taking it to a tuner.

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Old 06-25-2022, 09:09 AM
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What ecu is controlling the engine? If something besides factory, you can delete the MAF sensor and tune it in speed density. That would narrow it down. Does it behave differently on a hot start vs cold?

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  #64  
Old 06-25-2022, 10:47 AM
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What ecu is controlling the engine? If something besides factory, you can delete the MAF sensor and tune it in speed density. That would narrow it down. Does it behave differently on a hot start vs cold?
Factory ECU. It does seem better when it's cold (before closed loop). I wonder if it could be leaking a little at the collectors causing it to appear lean at idle. I have ball and flare collectors. I'll post pics later. I have been disconnecting the battery in the evening to be safe since I just rewired the car. This could be causing it to start over learning every day? I could email the tune and log files if anyone cares to look at them. I haven't messed with factory fuel, spark, MAF, etc.

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Old 06-25-2022, 12:22 PM
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I'm not gonna be any help with the factory ecu. But some here are experienced. Maybe make a separate post in the efi section.

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  #66  
Old 06-25-2022, 04:29 PM
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I'm not gonna be any help with the factory ecu. But some here are experienced. Maybe make a separate post in the efi section.
Ok. Good suggestion.

  #67  
Old 06-25-2022, 08:41 PM
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I have had instances when I disconnected the battery and reconnected it that my car would not start or started but ran really funky. Disconnecting and reconnecting the battery again always straightened things out. I am using factory ecm. This happened with my 01 Trans Am once also. Just an fYI

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71 Pontiac GT-37 400 4 spd (sold)
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  #68  
Old 06-26-2022, 07:06 AM
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I have had instances when I disconnected the battery and reconnected it that my car would not start or started but ran really funky. Disconnecting and reconnecting the battery again always straightened things out. I am using factory ecm. This happened with my 01 Trans Am once also. Just an fYI
Ok. That's good information.

It turned out that I had the wrong o2 sensors. Someone on HPTuner forum pointed out that the sensor voltage wasn't changing. Put new ones in and it's working perfectly. Fuel trims are almost perfect so far. Now I need to drive it more. Thanks for the help!

  #69  
Old 06-30-2022, 06:08 AM
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I have a drive by cable throttle body. I connected it with a Lokar cable. The one cable end is a brass barrel with a setscrew. I was concerned about this failing over time. So I put a stop bolt under the throttle pedal crank. This way the cable never gets stretch by stomping the gas to the floor. Only ever gets the load of the return spring. I also replaced the roller that rides on the gas pedal. It had a major flat spot on it. I made one from Nylatron.

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  #70  
Old 06-30-2022, 06:29 AM
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Good work. That's ALWAYS a good idea to have a positive stop for the pedal.

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  #71  
Old 06-30-2022, 06:55 AM
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Good work. That's ALWAYS a good idea to have a positive stop for the pedal.
Thanks!

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