neitzelm

I have a 1985 Camaro Z28 with a 350 TPI with heddman headers, a .454/.460 Lift cam and a 4.10 ring/pinion.

After installing all of those things and finally taking it for a test drive. I didn't time it with a timing light or anything, just adjusted the distributer cap until the engine seemed to idle around 900rpm.

Anyways, the engine sounded great but when I hit the gas, it didn't have anywhere near as much power as it even did when it was stock. I couldn't even spin the tires!

Could it be spark plugs? wires? Didn't hook up vacuum lines up correctly? Or just not a proper timing?

I also noticed that my stock exhaust manifold had a sensor, but I neglected to even put it into my new header. Would that drastically reduce the power of my car?

Thanks

Irocwannabe

iTrader: (5)

Get a hold of a timing light, you will want to get it as accurate as possible because just a few degrees can make a difference. Your timing being off can rob you of value power

y84pauloflondon

Timing light X2

92rs2573

The sensor in your manifold would be the o2 sensor. You would definately need to put that back in.

camaroinoh

Ya replace 02 sensor sense your still ecu controlled sense it not hooked up its giving a default stedy value which is usually a rich value then the ecu leans everything out try to compensate for it

KrisW

iTrader: (5)

All of THAT aside, what have you done as far as tuning the ECM?

I'm pretty sure the O2 sensor doesn't contribute until you are in closed loop mode. So if you are mashing the gas, that won't keep you from feeling the power.

However, not having the proper timing will hurt you badly, and if the ECM and chip are still stock, its not ready for the mods you just did. You are probably very lean AND with wrong timing which will equal burnt engine pretty soon.

Your cam isn't that radical, but anything different than stock needs the ECM tuned.

neitzelm

I haven't done anything with the ECM. Does that basically mean I have to buy one of those "performance" modules or what? Is there a simply way to tune the ECM?

KrisW

iTrader: (5)

There is no simple way to tune it.

You either have to go through the DIY PROM boards here and learn to burn and make your own PROM chips, buy an EBL (which allows you to tune it with a laptop) or pay someone else to do it.

neitzelm

I've looked up the Hot Chips that Harrison Performance sells for about $130. All I know about my engine is it's a 57LG. I'm assuming that's a 350. It has a TPI system so I'm assuming it's an 86+ year engine.

Would this one work most likely?

http://cgi.ebay.com/ebaymotors/HOT-C...Q5fAccessories

KrisW

iTrader: (5)

You MUST give them the numbers off of your ECM, and the PROM chip inside. They need this info or you might get the wrong stuff...

86 is special and a MAF system, 87-88 are MAF with a cold start injector, 89 MAF without cold start injector, 90-92 is Speed Density

The MAF engines will have a big mass air flow sensor in the piping between the air cleaner and the intake manifold. The cold start injector will be at the back of the intake manifold hooked to the fuel rail, the 86 will have normal "old style" valve covers like the chevy engines from the 70's, the others will have valve covers with the bolts going through the center.

Look at this stuff and you might get closer to what year it is.

neitzelm

It has a MAF (weird netting with almost looks like fiber optic sensors) and it also has the cold start injection. I remember hooking that up on the driver's side fuel rail when changing my cam and lifters. The valve covers were just simple 4 bolt covers and my brand new chrome pair have the same bolt patterns, so I'm assuming its the "newer style" valve covers. Looks like I have an 87-88 350TPI engine.

neitzelm

Also here are the numbers I got off my ECM: 7-6870 DC CODE: 0808MT

I'm not sure how to even get to the PROM. I don't want to take the box apart and screw something up.

KrisW

iTrader: (5)

You don't have to take the box apart.

There is a long, think cover on the front side of the ECM with two little bolts. You take off those two bolts only, and you can see the PROM chip inside. That's the chip you would change if you ordered it from someone. Just take the numbers off it if you can read them.

Give your ECM and PROM chip numbers to the guy who is making your chip. You also need cam specs, what mods you did, how much the car weighs, and all that.

KrisW

iTrader: (5)

***

neitzelm

Thanks for all of the help on this. This is by far the best car forum around!!!

neitzelm

Just a little update on my car. I had it timed, then fixed a really big vacuum leak, checked all the injectors and everything. The engine runs a lot better, but it seems to lose all of it's power after about 3,000RPM. I know my cam was made for low end and TPI systems are also for low end. Is this how it's suppose to run or is there more issues going on with my engine? Possibly not enough fuel with the stock injectors?

Here's the Cam: http://www.summitracing.com/parts/SUM-1065/

I also had a chip ordered from Harris Performance Chips Stage 2.

neitzelm

Also, the fuel pressure is just fine. My guy told me that there could be two problems that he thought of:

1. the cam timing could be off by a tooth (highly unlikely...I checked that a million times during the install)
2. Mass Flow Air Sensor could be bad. He didn't have a way to test it.