Car stops pulling

Charlie Gaudet

Resident Jet Mechanic
Hey guys. Looking through posts and see similar things but not exact to what my problem is. Car idles and drives great. It will roast the tires and pull hard into 3rd gear. In 3rd gear under boost it falls flat and acts like is stops accelerating. I've changed the coil pack and ignition module and it's still the same. Need to see what my fuel pressure is at under boost to make sure it's rising 1:1. Anyone experience this before? Winter is coming and roads are being treated with salt soon so just looking for some direction for the spring
 
I can think of about 20 different things that could cause your issue, and valve springs would be way down the list?

To isolate the issue, it would be smart to obtain some data like with a Scanmaster, or better, a Powerlogger.

Yes, fuel pressure is the first thing I would check.

Troubleshooting this same issue on a GN yesterday, it was about 2 hours of changing some parts, and lots of road test time gathering data from a PL which is on a spare computer of mine used to chase issues like this.

When more parts are changed today, we may solve his issue?
 
Just did valve springs. Comp 980s. Torque converter newand tranny rebuilt. Coil pack and ignition module just changed. I have a scan master installed. Any more info needed?
 
O2 mv reading when it falls flat . No knock retard on scan master ?
 
I can think of about 20 different things that could cause your issue, and valve springs would be way down the list?

To isolate the issue, it would be smart to obtain some data like with a Scanmaster, or better, a Powerlogger.

Yes, fuel pressure is the first thing I would check.

Troubleshooting this same issue on a GN yesterday, it was about 2 hours of changing some parts, and lots of road test time gathering data from a PL which is on a spare computer of mine used to chase issues like this.

When more parts are changed today, we may solve his issue?
You guys figure your problem out?
 
Does it fall on it's face or just kinda "level out"? When I was still running Red's 93 street chip mine did the same thing. 7.6@87 1/8th but only 12.15@ 107 in 1/4 Once I installed my Maf Translator Gen2 and Bob's Extreme G chip it went 11.78@114 with no other changes except a slower 60ft. My timing is 18deg at wot and A/F is 11.3-11.5 What chip are you running?
 
What PSI boost are you at and is it at full boost through all gears ? Does boost fall off in 3rd ?
 
Does it fall on it's face or just kinda "level out"? When I was still running Red's 93 street chip mine did the same thing. 7.6@87 1/8th but only 12.15@ 107 in 1/4 Once I installed my Maf Translator Gen2 and Bob's Extreme G chip it went 11.78@114 with no other changes except a slower 60ft. My timing is 18deg at wot and A/F is 11.3-11.5 What chip are you running?
TT 93 street chip 18 timing. It levels out ya. Better choice of words. It hauls ass don't get me wrong. Just levels out. Running richer than lean too. Thanks for the quick reply
 
If you have no knock have you tried adding a degree or two of timing or a pound or two of boost?
 
If you still have a catalytic converter on the car, those have been known culprits to the car not breathing properly. Straight pipe it or put on a test pipe in it's place. The difference is night and day if you still are running one, especially if it is the original one.
 
What hight did u install the valve springs? 1.750,1.800 ??? Or did u just swap them out and hope you would achieve the correct seat and open pressure ?
 
Installed hight and pressure are pretty important. U have to measure then test and shim accordingly
 

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