A wooden dowel isn't going to cut it. It may give you and indication of a problem, but it won't quantify it. Try it. See what you get. The problem is that the piston stays at and VERY near TDC through quite a number of crankshaft rotation degrees. Enough, certainly, to prevent setting the timing accurately. To check it accurately, you need a piston stop. If you detect a problem with a wooden dowel, you KNOW you have a problem. If not, proceed and pick up a piston stop. You can buy one cheaply at a parts store or make one from an old spark plug and a metal rod (an old push rod will do nicely.). First remove all the spark plugs, to make the engine easier to turn. Screw the piston stop into the number one spark plug hole. Rotate the engine, by hand, until the piston hits the piston stop. With the engine in this position, mark the damper where the 0* timing mark, on the tab, lines up with the damper. Then, turn the engine in the opposite direction until the piston hits the stop, again. Make another mark on the damper in the same manner as you made the first. The top dead center point on the damper is exactly halfway between your two marks. When this halfway point lines up with the 0 mark on the timing tab, the #1 piston is at TDC. Check how that center point compares with the TDC indicating groove in your damper. Does that make sense? Simple, EH?

Jake, I believe, has a method to do this with a dial back timing light, but he never answered my questions as to how it works. Therefore, this is the only method *I* am aware if without disassembling the engine. Maybe he'll chime on here.

RACE ON!!!

 

I am still waiting for my throttle body gasket kit (they said it will be on back order until Oct 7th). The book on corvette EFI should be here soon so I will have somethig to read in addition to the shop manual (which I always find to be somewhat cryptic).

I backed the timing from 8 degrees to 6 degrees, and it had a strange effect. When the motor is warm, it is just like before : 900RPM in gear, 12-1300 RPM in neutral. When the motor is started cold the idle will start at 700RPM and be pretty smooth. In gear it will be about 600RPM and also pretty smooth. As the car warms up the idle will climb to the previously mentioned levels. I moved the idle Thursday night and it has consistantly had these characteristics since then. I don't expect any answers on this one(since I haven't finished all your other suggestions yet), I just thought I would let you know the latest.

Thanks!

 

Please explain THAT.

Another book can't hurt, but the factory manual HAS all the info you need. Plus it has the trouble shooting charts you need to track down the source of a problem. Go for the codes, and verify that timing mark.

We appreciate the up date.

RACE ON!!!

 

You might want to check AutoZone, NAPA and other auto parts stores in your area - like O'Reilly's in mine. I usually find the TB gasket set at one of them. They have runner gaskets sets too; FelPro.

Jake

 

Sorry, I moved the timing thursday, not the idle. I was a bit tired when I wrote that.

 

OK,

I got the throttle body parts in, and the books. I took the throttle body top plate off and it was very clean, so I grabbed the new gasket and put it back together. I then tried to take off the bottom plate, but a screw head broke off from corrosion, so I put that back together. Next, I decided to check the base idle speed. I used a digital timing light with an RPM readout. The base idle was 670-680RPM. I pryed the cover plate off the ajdustment screw and set the base idle to 450RPM. I set everything back to normal and then purged the radiator of air bubbles and the RPM stayed at 700RPM. I took it for a test run tonight, and it reads 6-700RPM in gear and 700-800RPM in neutral, but if you give it a minute in neutral it will fall beck to 700RPM and stay there. Hopefully this will stay the way it currently is because I can live with it as it is now. It also seems smoother than it was before.

Thanks for all your help. It has been a learning experience, and I am happy I haven't had to pay anyone else to get this far!

 

Wow!

Ummm... congrats, Square!