Low end flat spot

[IATEAV8]

I've got a pretty bad flat spot at the low end. The car idles at about 900 and drives well once your up in the rpm's a little bit. Any thoughts?

[IATEAV8]

Scan tool reads the car is going lean

[JCotton1]

Scan tool reads the car is going lean

I take it you are using a chip.. a little detail please..

[WSLN 6]

Is this a tip in problem, or after that? If in the lower end is acceleration enrichment coming in, or Power enrichment not coming in early enough? TPS flat spot maybe?

[IATEAV8]

Turbo tweak chip with 79 lbs injectors 3 1/2 inch MAF car runs super after initial start. If you leave with a heavy foot its fine, but, if your just "driving" it falls on its face then takes off at about 2000 rpm's.

[IATEAV8]

TPS is .48 idle and 4.6 wot.

[JCotton1]

TPS is .48 idle and 4.6 wot.


Where is your IAC counts at idle.. you may lower them down to 5-15 counts at idle by opening your throttle blade a little, that may help.... after that.. looks like a FAST XFI.... will take care of ALLLL YOUR ISSUES.. :D

[IATEAV8]

Boy O boy! I knew that one was coming! Thanks for the "quick fix" remedy. How much for all I'd need? (FAST) Also, are they pretty easy to learn? There is only one other Turbo Buick guy here so kinda tough to get competent help out here! Thanks for the turbo though! I LOVE IT!!!!!!! Once the little tweaks are done....:D:D

[JCotton1]

Boy O boy! I knew that one was coming! Thanks for the "quick fix" remedy. How much for all I'd need? (FAST) Also, are they pretty easy to learn? There is only one other Turbo Buick guy here so kinda tough to get competent help out here! Thanks for the turbo though! I LOVE IT!!!!!!! Once the little tweaks are done....:D:D

Hehehe.. couldn't resist it, anytime I see a big turbo and a lot of other good parts..... seems the best form of tuning and performance is the FAST. Chips, big injectors are like water and oil to me. But I will try to help any way I can. I meant it about the IAC counts. If it is an off idle hesitation... we usually work the min idle screw and open the throttle blade till our idle IAC counts are around 10, give or take a few.. then reset the TPS to spec, around 42-46.. after that, if everything else checks out, maybe Eric at TT can work some magic.. on the chip.

[JCotton1]

Oh ya.. I forget who this is...? I know I should know, short memory... just turned 55..:)

[IATEAV8]

No problem. Jason from Montana. Just got car home Friday, just short of a year! It left last Nov.6th but he did it right so after all the time no real complaints!

[Eric]

Jason,
Shoot me an email or something and I'll see if I can help.
Get an idea of what the BLM's and O2's are doing when the flat spot occurs.

Regards,
Eric

[JCotton1]

Welcome Eric, thanks for helping. I am tickled pink to have you participate here. Jason, Eric is not one of the best, he is the BEST Chip maker in the buick world!!!

[IATEAV8]

He y guys. I'm taking it to the dyno tomorrow so I'll let you know how it turns out and what the readings are.

[JCotton1]

He y guys. I'm taking it to the dyno tomorrow so I'll let you know how it turns out and what the readings are.

We be waiting...:) good luck

[IATEAV8]

Didn't run as I'd expected. 360HP/360TQ 15lbs. boost at 15* timing at 5200 RPM the car broke up. Last night I pulled the plugs and re gaped them to .030(they were at .035) and reset timing to 18*. Not sure how much difference this will make... What kind of RPM range should be the cut off point?? I thought ATLEAST 5800??? I NEED TUNING HELP!!!!!!:confused:

[JCotton1]

Didn't run as I'd expected. 360HP/360TQ 15lbs. boost at 15* timing at 5200 RPM the car broke up. Last night I pulled the plugs and re gaped them to .030(they were at .035) and reset timing to 18*. Not sure how much difference this will make... What kind of RPM range should be the cut off point?? I thought ATLEAST 5800??? I NEED TUNING HELP!!!!!!:confused:

not bad............ for starters.. You definitely need to step up the timing, are you running pump gas, alky? At 15lbs, I would typically run somewhere around 20 plus timing.. with a FAST.. could you see if you were rich or lean? You should be able to pull 5800.. you'll need it. I usually set the plugs around a tight 32..

[IATEAV8]

No alky. Pump gas chip for 91 octane. I was thinking of having Eric burn me a second chip for 116 octane that has more aggressive timing??? Numbers all look good car goes a little rich at boost. It's pulling straight up until 5200RPM then everything just goes haywire. Any thoughts on why the car would break up like that? I HOPE it's from the plug gap and lack of timing???? Believe you me, I definitely want a FAST just trying to keep my wife along the way!!!!:D (She actually gets it)

[WSLN 6]

Tried swapping coil/module yet? I doubt it is the plug gap, not sure if the low timing would cause that or not.

[BrianHynes]

Just a thought here. Are your valve springs correct for your cam, and are they set up correctly?