Road Race 87 Camaro

Finally some track time:
Drivers.jpg


Pass.jpg


Front.jpg


It was the first HPDE of the year at Waterford Hills. Car ran good, but I was slow, but this track is dangerous and I wasn’t about to push it and roll it on the first outing. I was happy to get some time in the seat(been 2.5 years), test the trailer loading and unloading etc, and give the car a shake down. Nothing broke on the car but I’ll give it a good review up on jack stands when I get some time. More pics here: http://www.clutchpics.com/Motorspor...WHRW-OTD-1/16662256_7qgdtp#1257121547_W2Tf39N
 
I forgot to post up my corner weight results:

All with 9 gallons (3/4 tank)

2893 no driver- right where I thought it would be

3072 with me @ ~180lbs

876 LF 836 RF
698 LR 662 RR

cross weights adjusted within 5 lbs, weight jacks at all 4 corners, had to shim the front sway bar links with a washer. I have rod ends for the rear bar so that was easy to adjust and bolt up.

Front / rear: 55.7% / 44.3%, not ideal but where I thought it would be with the lexan hatch, aluminum decklid, side exit exhaust that exits under the passengers legs, and everything stripped. It easy to add balast low, right, and rear if I ever need to.

The biggest difference between my car and a balls out AI/AIX car is 100+ lbs of weight in the doors, and I drive mine on the street a little bit.
 
Misfire at 4600 rpm

Been battling this issue for some time now and can’t figure it out. If anyone has some advice I'm all ears.

I have a misfire/cough at around 4600 rpm, and while it is happening the shift light turns on. I can drive through it, i.e. it misfires at that speed but is otherwise ok up to the 6000 rpm rev limit. It happens in every gear though it is noticed less in first. It doesn’t matter if I’m under WOT or part throttle, it always happens at around that speed. The only time it doesn’t do it is when the car is cold. Once the car is warm it does it every time. I was on track in April and it didn’t do it, I presume because it was 32 F degrees that day. I didn’t drive the car again till early June (fixing other problems) and since then it has always done it.

Details on the system:
Factory 7730 speed density TPI ECM with custom chip
Factory harness, though I’ve done a lot of trimming
Coil: I’ve used both the Accel and factory replacement coils
Distributor: both the original with new ignition module, also brand new Advance Auto distributor
Solid engine mounts

I’ve done the following with no joy:
I've pulled wire for knock sensor
I’ve changed ECM’s (junk yard ecm). It is an ECM problem that means that both have had the same issue.
I’ve put in a brand new parts store distributor with new cap and rotor
I’ve unhooked the tach and shift light
I’ve tried different coil’s
I’ve removed the Auto Prom and zif socket and put in place a chip
I’ve mounted the ECM on rubber isolators
I’ve verified that my grounds are tight to the back of the heads, frame to engine, and battery to frame.
I’ve changed the coil wire
I’ve tightened the spark plugs
A friend rode shotgun with me with his computer plugged in. We did about 50 pulls through the 4600 rpm point looking for any anomalies with sensors etc and found none.
I pulled the valve covers looking for broken valve springs, I can't see anything obvious but I'm going to push around on the inner springs with a screw driver and see what I might find


As far as I know the only components that I have not replaced in the ignition system are the plug wires, spark plugs, and wiring. It could be a stupid wiring mistake as I have done a lot of work to the harness, but it didn’t do it this past winter. The plug wires are 3 years old and have less than 1000 miles.

It didn’t have this problem for the brief period that I drove it last year (October) but I still had rubber engine mounts, if that matters. Other than the engine mounts I can’t think of anything else that I changed over the winter that would affect this. It was colder last year when I drove it but I think I still would have got it warm enough to have this issue,,, I think… If not, that could mean that it is more likely that I have a wiring problem.

Let me know if you have any ideas, and don't rule out any stupid mistake as I have messed with everything. Next thing I will try is a 3rd ignition module. Been having bad thoughts of an LSX swap otherwise :ph34r:

Some pictures again so you know what you’re working with here (not stock, and I could have done a wiring goof):

This piece of aluminum holds the ECM, AutoProm, Fuse Panel, Relays, aux power, DRAC, and globs of wire:
IMG_1550.jpg

I've since mounted the ECM on rubber isolators and removed the auto prom and zif socket.

IMG_1491-Copy.jpg
 
Have you checked your valve lash? And dose it have a msd box with the chip rev limiter I've seen those do strange things when the chip fail. Good luck
 
chuck-norris said:
Have you checked your valve lash?
Click to expand...
The rockers on the closed valves feel loose, and I thought that was odd but never paid attention to that before so I don’t know if they should be or not. I know when setting lash on a hydraulic cam, you find zero then give it 0.5 more turns. When doing that the valve train is tight, so I find it odd that the rockers are loose now. Someone told me that is totally normal for the rocker to be loose when not running and I’m still not convinced if that is correct or not.


chuck-norris said:
And dose it have a msd box with the chip rev limiter I've seen those do strange things when the chip fail. Good luck
Click to expand...
I do not have an MSD. I have the rev limit set in the ECM. Maybe I try removing it?
 
it might be worth a shot. as for the rockers they shouldnt feel loose just have a little bit of play its not uncommon for them to come loose
 
Is your knock sensor producing false kr? Back the KS out a few threads or wrap it with some teflon tape and install it yet not completely tight. Then see if it does it again. What are you logging with?
 
You must log in or register to reply here.
Back
Top