Some of you have heard me rant and rave about what the hell is wrong with my car.....and I here I am again......

New Timeslips:

Run 1 Run 2
Reaction: .639 .913
60 Ft: 2.322 2.337
I2 (?): 6.220 6.215
1/8 Mark: 9.356 9.334
1/8 Mph: 78.967 78.987
1/4 Mark: 14.292 14.255
1/4 Mph: 99.659 99.920

Where is my extra 10 mph? 1/8 Mph is down about 7 mph from what I have seen on similarly equipped cars.

I was looking forward for the track, I had finally had the car running smoothly, no codes whatsoever. I set the fuel pressure at 39psi w/ vaccum hose off at idle. WOT Fuel pressure only goes to 40psi. Car was running smooth.

After the runs though, my car shut itself out for around 12 different times. Exhaust smelled like crap, it was intolerable, and could easily knock out a person in less than 10 seconds. No codes. This morning, I changed the oil, checked the plugs and found that plugs on cylinders 1 and 2 were loose, not totally lose, but I could easily turn them with my fingers. I torque those down, and gave it another run.....felt good but now I just dont know what is fast any more. All i know is that 1-2 shift it spings hard, and have a nice solid chirp on the 2-3 shift at around 90mph.

Could it be:

-Knock sensor bypass? I have not yet put a good knock sensor on it so I bypassed it with a 3.9k ohm resistor. Has this been proven to OK?

-Bad fuel pump? Stock is still there, 10 years old. Already replace fuel filter. Could why is shuts off at times under load.

-Perhaps the use of 2.02 intake valves on LT1 castings? Maybe just too big?

-Valve Float, how can I tell?

I am lost any tips? Car revs smoothly, transmission is strong, still have stock gears.

Major Mods:
Ported Heads 258/198 w/2.02-1.56 valves
XE230/236 Cam w/1.6 Rockers
HookerLt's, 3in. Hipe Borla mufflers
Pcm4less tuning
SLP 2800 Stall, built Trans. 3.23 Gears

I am Clueless, do not know what to do next, other than selling it and going for an LS1.

PLEASE HELP!!!!!

 

I would DEFINETELY have that car scanned. My guess is that you are getting some false knock or have poorly adjusted valves/fuel problem... Before the cam have your fuel pressure checked. There is definetely something wrong with your car!

 

Fuel pressure is at 39 psi at idle with vaccum hose off. Goes down to 37 psi with hose on.

At wot it goes up to 40 psi. I have done a pressure leak down test and sometimes the pressure falls rather rapidly, but hypertech regulator is new and good. I think it could be a interminnent leak at the pump. i will be replacing it, just to eliminate possible problems. It could be the reason of why it shuts off at times under initial load. Pump could be weak.

Shouldn't the resistor not even allow any knock retard?

 

Hang in there man.
I'm in the same boat and I think its sinking
I have a hotcammed car with ported heads that flow just slightly better than yours. I did alot of work over the winter (more head work, thinner head gaskets, a 3k torque convertor ect. I went to the track a couple of weeks ago and could only manage a 14.119 at 99.
Last year before all the work I ran a 14.30 at 103. I think that my car needs a dyno tune. I have a crappy ed wrong tune in it right now. one of the guys in my car club has a lt4 conversion on his ta he had the same tune as me and when he dyno tuned it he picked up over 50whp and 50lbft of torque.
Hand in there all this extra work will just make those 12s that much sweeter.
Kory

 

regardless of valve float your car should still run some decent numbers... I would like everyone said.. get the car scanned while logging a run.. see what it does.. only way to tell.. otherwise i'd say you have some serious issue's that might just be all in the tuning.. have it checked before it becomes a bigger problem... any weird smells? anything? sputtering?

 

It has been one year since I had my car tore down and totally rebuilt, and have not enjoyed it since. It just pisses me of, that I can't get my monies worth. With all the money I have spent on this car I could of just had gotthen a 97 Corvette or something.

I am ordering the AKM cable to scan it, and I also getting a new bigger fuel pump. Then we will see.

Problem is that I have no access to a dyno.

What are your symptoms, any codes? Just to compare.

 

Well,

-It dies at times, no codes. It does it when I put in under load. It restarts quickly.

-A sniff at the exhaust can kill a person. Man that stuff is strong, and burns your eyes.

-It does not seem to really want to pull a higher rpms. Runs out of pure will.

- Fuel pressure goes down rapidly at times when I shut it off.

- Temp gauge shoots as much as 20 degress at WOT, then goes down after a while. Car runs around 230 degrees at highway speeds and 210 at cruise. No signs of bad gasket, I took it for repairs.

What else can it be?

 

What # injectors are you running? I think the 96s had 24 or 22 lb injectors and I was running a 100% duty cycle with heads/cam on 24 lb injectors. You could be starving your engin up high, which would cost you the 1/4 mile.

 

do you have cats on the car? they could be clogged up Just a thougth . It would smell like rotten egg's

 

I am using 30# SVO's, and there are no cats on the car. The car is equipped with a custom 3in. Dual Exhaust, w/H-pipe, and 2 Borla Mufflers.

I left the fuel pressure gauge on the car while driving, and I notice that it is rather erratic. It never stays in one place but jumps up and down very rapidly between 33 to 38 psi.

At WOT, the gauge stays steady at 40 - 41psi. The car performance is really confusing.....

because it sucks at the track, yet

I destroyed a pretty much stock T/A 6-Speed from a 20 roll, 8 car lengts plus eventhough I bogged after the 1-2 shift (too much spin) and missed the 2-3 upshift.

Destoyed a 92 Z-28 my buslenghts, yet I had doubts if he was really racing, eventhough he gunned it first.

I also barely beat my brother's Z, from a 20 roll that is equipped with a 6-Speed, hot cam kit, Dual Exhaust, Hooker Lt's, CAi,tuning, and 3.73 gears.

Then yesterday, I only beat a 94Z Automatic with Long Tubes, CAI, Dual Exhaust, ....by only 3 car lengts.

The car's performance is very erratic, it will sping 1-2, and 2-3 shifts, revs fine, but just falls on its face after the 2-3 shift. Seems to lose will at higher rpms at times.

I will scan, yet I do not know what I will be looking for. Any ideas.

Thanks

 

If you don't have a scanmaster, I'd get one and monitor your o2 sensors. You should be anywhere from 860-890 mV at WOT for the entire duration. Your fuel pressure is too low, and I bet that fuel starvation is the culprit of your problems.

In addition, I'd get a bigger stall (3500) to compensate for the torque-curve getting moved higher and lower gears (3.73)

Mike

 

 

Scanmaster, Yeah not for me, but Datamaster and Freescan do work right. I just need to get the cable. Wouldn't my computer thow a code for non-functioning 0'2 sensors.....or is it possible that they are just not getting warm enough?

Does anyone know how to convert to heated sensors?

 

I don't know what's going on for sure, but that fuel pressure makes me wonder.

Also, the temp makes me wonder, have you checked the thermostat to make sure it's opening like it should be? When I run mine, I don't get any odd readings on any of the gauges.

For reference (I know that the altitude and weather would make a difference), I ran 2.135 60', 9.35 1/8 and 14.299 1/4 in my stock 96 Formula A4 with 2.73... Mods were 160 thermostat, TB bypass and SLP CAI. Stock exhaust and everything, running on street tires. This was with my amp rack and amps in the car.


good luck man!

 

The erratic FP and performance sures sounds like your fuel pump or FP regulator are going out.

My car would run ok, then sputter badly, sometimes hard start, sometimes not, etc., when my fuel pump was just about to die permanently.