Captain C

I have a 1985 Camaro Z28 IROC-Z. It has been modified as follows:


1. 3.42 Richmond gears with an Auburn Gear limited slip
2. Swap to a “beefed” 1989 700R4 with a TransGo shift kit. Shifts at 5500 RPM (what the core came out of I have no clue)
3. 2500 rpm stall converter (lockup still works).
4. Transmission cooler.
5. Polyurethane transmission and torque arm mounts.
6. Polyurethane motor mounts.
7. 4 bolt roller cam block.
8. ZZ4 hydraulic roller cam. Speed Pro lifters
9. Erson 1.5 roller rockers
10. TRW 2256 forged pistons. Compression set at 9.0:1 by shop.
11. Speed Pro Dura-Moly rings.
12. World Products S/R Torquer heads, pocket ported with 2.02 Intake (245 cfm) and 1.60 Exhaust (170 cfm) stainless steel valves with back cut stems
13. Hardened push rods
14. Edelbrock large port intake manifold.
15. Edelbrock large port runners.
16. Port matched the Plenum to the runners (I use Mr. Gasket uppers and Edelbrock lower gaskets) and ported the throttle body throat.
17. Edelbrock/BBK 52MM throttle body.
18. Ported MAF sensor. (Good for 2.5 tenths on the track, currently running a stock one on the street)
19. I run Accel filters.
20. ADS 23.92 lb.hr. injectors.
21. Mid-America Corvette Adjustable fuel pressure regulator.
22. Buick Grand National fuel pump.
23. Hedman 1 5/8” tube street legal shorty headers with HPC protective coating.
24. 3” Exhaust cutout in front of the Cat.
25. High flow 3” single Cat.
26. Dynomax 3” Cat back exhaust with a 3 chamber Flowmaster muffler (single 3” inlet on the passenger side and dual 2.5” outlets on driver’s side)
27. Mallory HEI module in the distributor. (16 degrees initial timing, set by track testing)
28. Hypertech 53,000 volt coil.
29. Accel 300+ race wires.
30. Flowkooler water pump.
31. Robert Shaw high flow 160 degree thermostat (looks to be the same as the Mr. Gasket).
32. Be Cool Aluminum Radiator (custom fit unit) which has two 1” cores.
33. 16” electric fan behind the radiator, wired to come on at 205 degree and cool to 190 degree. I also have a bypass switch to turn it on anytime I want.
34. 14” electric fan in front of the A/C condenser that comes on when I start the car and runs continuously .
35. 800 CCA sealed battery.
36. Adapted a 1989 computer to the wiring system. (I can unplug the adapter and computer and can plug in my 1985 computer at will). The adapter bypasses the 1985 system cold start injector on startup and doesn’t run the fans at all.
37. PST trailing Arms
38. Polyurethane bushings/endlinks front and rear in everything that has one!!!!
39. Monroe Formula GP shocks and KYB struts (they don't make the Formula GP's anymore or I would still be running them up front)
40. Totally rebuilt front end (inner and outer tie rod ends and collars, steering box, ball joints, steering arm. Pittman arm, center link, rag joint, and the other mentioned items.

My current problem is the computer is leaning out the car really bad, which makes it run hot and SLOW. I'm only running 14.3 @98.45 in the quarter. I'm running a 2.00 0 to 60 with street tires and that includes half throttle off the line then punch it because I get no traction.... What's making the computer do this, too much Cam overlap???? The cam specs are .474/.510 lift and 208/221duration @.050. The lobe separation is 112 degrees with a 109 degree intake centerline. I've had this problem for the 6 years this cam has been in the engine……



BTW, have any of you guys tried the Accel DFI VII computer in you TPI car? How did it work for you? I'm thinking of trying it. Just want to keep it looking as smog legal as possible……

tpi_roc

If you're still on the 85 ecm the only TPI car offered was the 305, which means your ecm is still trying to give the appropriate fuel for a 305 and if i read you right you have a 350+

Logic says you'll be lean


You can swap to an 86-89 maf setup, or a 90-92 setup both of which are much much cheaper than DFI

Captain C

I have an 85 Corvette 350 TPI PROM in the 85 Computer. When I run the 89 Computer; that is attached to the 85 harness via an adapter harness, there is an 89 no VATS 350 TPI Camaro chip installed. I have also had TPIS burn a custom chip based on my engine combination. I have also used two different adjustable fuel pressure regulators to kick up the fuel pressure with no appreciable results, only inconsistent fuel pressures. I have just converted back to the stock 89 (43.5#) not the 85 (39#) pressure regulator.

With my fuel pressure set at less than 50# the fuel pressure drops almost in half during the quarter mile. Even with the pressure up higher it still leans out which causes the same lack of power. I have a Bosch fuel pump that is supposed to handle 550HP (TPIS part #300-178) that I could put in, but my problem is happening during normal driving not just racing so it really makes me wonder what's going on.

As far as the larger pump goes, I hope it won't overload my return line thus causing more problems. Anyone else using this pump or its equivalent???

305sbc

iTrader: (3)

If it was lean you should get lean misfire, stumbling, popping, and your plugs would come out a white color on the metal ground strap. Are you positive that it's lean?

Captain C

Right now it has a lean miss at idle. I have it in a shop to reinstall my aftermarket runners (had knee surgery and can't do that stuff yet) and the owner has it on a scanner. He says it's going into open loop immediately and that it is running really lean. We did change the O2 sensor (I was having some weird throttle swings, full to idle) and it cured that problem, but not the leaning out problem. He said the scanner is showing the A/C being on when it isn't and some other stuff. He was kind of frustrated at the time so I didn't wnat to bug him. He's the only guy I trust to work on my car and I don't want to tick him off, especially when he gives me such a great break on the price. This is with both the 89 computer with the stock Camaro chip in it or the 85 Computer with the stock 'Vette chip in it

I hate having the car ping and really hate it being slow considering all the time, effort, and money I have put into the car!!!!!!

My plugs have always been clean. I just took out a plug I removed from the engine when I rebuilt it a couple of thousand miles ago (no changes except I went from failing lightweight hypereutectic pistons to forged pistons). The plug (with 10,000 miles on it) is clean with only slight tan discoloration on the porcelain on one side. The ground strap is the same, tint on one side but with no deposits whatsoever, albeit, it does seem to have a whitish tint on the top, back and the other side. The porcelain on the other side is pearly white, no deposits whatsoever.

Also, the engine will go from no knock to horrendous pinging instantly, usually when the transmission shifts. That's why the new pistons…… I thought the gutted MAF might have something to do with so I bought a stock one but it still has the lean miss. Even with the TPS set at .65 instead of .54, albeit it helped. I can't get it to give me a rich code by moving the TPS setting upward, everything I've read says it will do it at .64 and I've had it up to .80 and it still didn't do it…….

305sbc

iTrader: (3)

Did you buy those ADS injectors new? So you know for sure they flow 23.9
Also does the injector impedence match a factory injector?

Do you know how much timing you are running?

Your fuel pressure problem sort of suggests that it could be the main fault. How carefully have you inspected your fuel system?
The lines(for kinks), fuel-filter, tank-vents, and the pickup in the tank should be checked.

If your car acts the same way even when you have a full tank of gas then you can pretty much eliminate the possiblity your fuel pick-up fell off.

If you hear a lot of pressure or suction when you remove your gas cap after driving, that is usually a sign the vents aren't working.

I don't think I know what your problem is, I'm just giving you some ideas and things to check.

Captain C

Hey, I appreciate all the help you can give me!!!!!!!!

I did check all the lines.

The fuel pump was changed out for a Buick GN fuel pump so I know everything is ok there.

The fuel filter has been changed out several times.

I did buy the injectors new.

I'm running 16 degrees advance which has been tested at the track to be the fastest in the quarter mile. This has also been backed up by several different sources with testing on the same cam

It seems I have heard either a suck or blow on the gas cap when removing it to fill up. I'll have the guy at the shop check it while he has the car there. It's easier for him to put it on a rack than it is for me to get under it at home, especially until this knee gets better!!!!! If he has to pull the tank to check it, then it's a good time to drop in the larger Bosch pump I bought from TPIS!!!!

You think the vent problem would be keeping the fuel from flowing to the pump or engine?????? It would seem that it would collapse the tank or blow some kind of seal or hole in the tank on a long trip and I've been on several of several hundred miles each.

Again, thanks for all the ideas!!!!! If you think of anymore please list them.

Captain C

Talked to the shop guy again today. I was wrong about it leaning out with the 85 computer. It wa s only the 89 computer that was messing up. It runs good with the 85 computer but it still has an intermittent miss. Makes me wonder just how good that adapter was. I think I will modify it and convert to SD down the road. Thanks to this site I have the wiring diagrams!!!!!

The only other time I have had an intermittent miss (twice actually) was when the outer ring on the harmonic balancer spun. A major cause of engine failure on 305 TPI cars. The stock balancer is only good for about 20K at best. I have a Fluid Damper Harmonic balancer and it doesn't have that outer ring on it. I don't know how long they are good for and I have right at 100K on this one..... I would sure hate to have to replace that thing because they aren't cheap!!!!! I'm still getting a ping with the car and I only have 9.0:1 compression and a ZZ4 cam. I shouldn't ping with a stock chip in it!!!!! Grrrrr!!!!!