Picked up a 88 gta about 8 months ago and just got around to doing a compression test on it....are these numbers pretty good for a 282000 mile bone stock car?
#1-175
#2-170
#3-177
#4-165
#5-171
#6-165
#7-170
#8-165
This is the orginal long block, never been touched internally except for me changing intake gasket and new valve guide seals.
On my injectors I got the follow resistance's
1-16.2
2-16.2
3-16.2
4-16.2
5-16.1
6-16.0
7-16.1
8-16.0
Are those within the acceptable numbers also? It has a problem starting when the engine is cold, I have to pump and work the throttle to get it started, then for a couple of minutes it bogs and tries to die when I try to pull away from a stop light. When the engine is warm it doesnt do this. I will end up cranking a good 10-15 seconds to get it to start, where used to I just had to bump it and it would fire right up. I did the standard tune up on it-cap, rotor, plugs, wires, air filter, fuel filter, and I replaced the fuel pressure regulator because it ruptured on me. It doesnt throw any codes at all when it runs bad. When I get into the go pedal sometimes it smells rich. I have pounded out the cat and replaced the muffler with one off of a 02 ss camaro. Is there anything I missed as far as the tuneup goes? With that many miles on it will I be able to get as much power out of bolt ons as everyone else, since my compression #'s arent bad? I installed a 160 t-stat and that seemed to pick up some power, what's next? I hate how the car pulls like a freight train and falls on its face at 4500...is a holley sr or the equilalent of another brand my only alternative to help that? Thanks for any help

 

The cranking compression test pressures are good. The injector coil resistances are good, but that doesn't necessarily mean you have good injectors. They could still be clogging, have poor spray patterns, leaking, or be sticking/have propagation delays.

"Pumping" the throttle on an EFI engine does nothing other than wear out the throttle shaft faster. Holding the throttle partially open to enable starting, however, indicates a problem. If that is required to star cold, you may have injector or FPR leakage that is flooding the engine.

Although the gutted cat converter should not affect how the engine runs, it may be the reason that it "smells rich" when you accelerate harder. You're smelling more of the hydrocarbons that normally get converted to sulfides and nitrides.

Installing a cooler thermostat without reprogramming is eventually going to create some problems. The EVAP canister may never purge, so you'll smell even more raw fuel and waste gasoline. The EGR may not operate, so you may never get full ignition advance under some conditions and could lose power as a result. About as low as you can go on stock programming is 180°, and even that may be borderline for a few parameters.

The loss of power at 4,500 RPM is likely from a couple causes. The TPI starts to become restrictive on a 350 at that RPM, the valve springs can start to allow some float at that RPM, and the ignition may start weakening at that RPM under load. At least they all come into play at the same time.

 

I think its amazing that your car runs. I would think by now that the cam would have been ground all the way down and you would get no lift. I agree with vader, your springs are prob really weak and are prob a big source of loss of power. But congrats on having a living testament to GM power.
Give it some new springs, flow bench the injectors, change EGR valve, and maybe new cam and dizzy. Good Luck !!

 

Yep I guess thats a testament to the roller lifters....My game plan is to get new injectors soon, I think I also have the orginal coil in it also. The valve guides are a little loose and I'll just ditch the heads and pick up some higher quality pieces, with some good stiff valve springs.

 

The starting is probably related to the cold start injector (88 TPI). Also, you may have issues with the coolant temperature sensor (front of intake manifold, two wire connector, brass jobby). I'd scan the coolant temperature first (with a scantool, of course), and see if it's reasonable, then R&R the cold start injector or simply remove it, and upgrade to a $6E PROM. If it's clapped out, it could cause some of the extra richness you're seeing, and/or hard starting.

 

Holy crap, my '88 GTA has 69,000 miles on it and all my cylinders are ~100psi. I checked the bores with a bore gauge they were all excellent, very little wear. Why's my compression so far below yours with much less miles?

 

Did you take out all spark plugs and open the throttle (and disconnect the coil and injectors), and crank 3 to 4 cycles? That's the right way in my book.

 

I did all that except open the throttle.

 

Thats exactly the way I did it, cranked it 4 jumps on the guage. Its alot easier to do with one of those remote starter bump switches you can operate under the hood.
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Any ideas for cheap mods? What would I get the most gains out of? Its pretty quick right now with those 3.45 gears but of course too much is almost enough with speed.

 

General rule of thumb for SBC is to start with exhaust.

Headers, Y, cat delete (if you can) and cat-back.

Then work on the intake.

 

Yea, was thinking hedman long tubes, with a true dual set up, probably with an h pipe, any idea on what gains in the 1/4 I would be looking at for that?

 

Low 14's if your car is in good tune and you can hook up well.