AlGal

Hello all!

Im new here so ill let you know a bit about what im working on. I have my 82 that i am in love with and it was having some issues about 8 months ago. Took it to a mechanic as it was pinging and i could not figure out why. Turns out i had no compression in cylinder 2. Ok so now i wither rebuild the thing or replace the potentially broken parts. SO i take it home and tear her open. She was not at top dead center when i did this as i was only really planning on working on cylinder 2 as i thought that i had a blown piston or something of the like. Tear down that side all the way to the block and see that there is no crack or gouge or anything wrong with piston 2 other than it looking a bit dirty with a lot of carbon buildup. Ok so now i decide that since im here and i need to bump the piston out any way to double check that the rings are not lined up ima go ahead and do all of them. So i do. Get em all bumped out and cleaned up and installed new rings and reinstalled them into the block. Cool. So now im looking at my valves. They are shot. some are burnt some have so much built up on them that its a wonder the poor car would run to start with. Get all new valves and seats and keepers and springs. get everything lapped in and reinstalled. valves hold a seal. Yay, i did that right. Ok so ive put everything back together and installed all new gaskets and whatnots to the motor. get everything buttoned down and ready to go and start her up........she won't fire. Turns out it was a low battery. Fixed that and now she fires. But she will not stay running. We have the initial timing set so the darn car will fire up but then she will not maintain that unless i depress the fuel pedle......what the heck? there is still a light pinging noise that i am hearing from the passenger side and she won't stay running......so now im 8 months into this and about 4000 down and running short on patience and time and money. Do yall have any ideas as to help me out with this? where did i go wrong here? i did not mess with anything on the injectors at all so that shouldn't be an issue. I am mechanically inclined however i am by no means a professional so any help that yall could give me would be awesome! not wanting to spend a whole lot more if i can avoid it. Thanks in advance!!!!

doorgunner

I'm not a mechanic. I would check the gas tank for old moisture-contaminated gasoline and remove the gas if needed/replace with a few gallons of fresh gas.
I would replace the in-line fuel filter if your car has one. Then I would buy or rent a fuel pressure gauge and test the pressure at the engine while it is running to make sure the fuel pump is not weak/failing.

I would then rotate the #1 piston to top dead center by watching the two #1 cylinder valves close to confirm compression stroke.....then look at harmonic balance to make sure timing pointer is pointing to "0"......also remove distributor cap to make sure rotor is pointing directly where the #1 output contact would be if the cap was installed.

If you are able to do the above, reply with the results so more knowledgeable Members can give you better/detailed advice.

Gold Dragon

Hey AlGal,
First post. Very cool. A lot of variables when rebuilding an engine. Guessing this is a 350 we are talking about. If it was pinging before and now after, maybe you didn’t find the issue. Did you replace the hydraulic lifters.? If not, maybe they are worn out. If you did replace them, have you run the engine enough for them to pump up.?
Could the carb be dirty or need a rebuild?

AlGal

Hey Dragon,

Yes it is the 350 small block with crossfire injection. I did not replace the lifters as they showed no indication of wear. I don't see any sign that the carb is dirty however i have not really gotten into it as that is a bit above my mechanical abilities. I do have a manual that goes over how to do it and in all actuality, it likely does need to be done, however as i didn't notice any issues with it, in the beginning, i did not touch it. The spray is even and in the umbrella shape, do you think i should still clean em? I am wondering if the ping is coming from the rocker arms or one ov the components to be honest. the manual that i followed said to set the lifters by rolling the rod through your fingers and tightening down the nut until resistance is just felt and then give the nut another 3/4 turn, all this with the respective piston at TDC. Ive done that, is it possible that i did this part wrong as far as the pinging goes? I also know that it is running really really rich when i keep it going with the gas pedal. If i let her idle at all she dies. Could the running rich just be from that or is there an adjustment that i missed? this is my first time doing anything this extensive, so it wouldn't surprise me if i missed or messed up something along the way.

AlGal

Hey Gunner,

Ive double and triple checked the #1 piston at TDC with the harmonic balancer and the distributor, all checks out there, She fires off just wonderfully, just can't seem to keep her going. Ill check out the gas tomorrow afternoon and see if that helps any, ive been wondering about her having fuel issues as the gage sticks and she has really terrible gas mileage.

Rescue Rogers

i would give her more timing to get rid of the pinging and run 91 or 93 octane. If the low idle persists after this, then check the idle set screw. You said injectors so I'm guessing fuel injection, but it still should have an idle set screw

derekderek

Go back over every electrical plug you touched. No carb. Those are efi units. Idle air control unplugged will do it. So could map sensor.

MelWff

this is a short article on diagnosing Corvette TBI issues, there are more if you look for them using google
did you check your compression after the rebuild?
you may want to loosen each rocker arm 1/4 turn since you set it for 3/4.

http://www.restore-an-old-car.com/19...el-system.html

AlGal

Is there any chance that a vacuum leak somewhere would cause this issue?

derekderek

Absolutely. Worse than carbs. MAP is manifold absolute pressure. Also called vacuum. If it sees low vacuum, add fuel. EXCEPT, it knows how far the throttle is open cuz of the throttle position sensor. So it sees low throttle at low rpm and low vacuum and it doesn't know what to think-or do.

terry82

when you took off the intake did you move or loosen the throttle postion switch ? that may need to be reset.

doorgunner

Does it have a replaceable fuel filter and a pressure port to attach a fuel pressure gauge? I'm just trying to see if the throttle body is getting good fuel pressure and that the spark source is working well (eliminate the simple problems first as you did by triple checking the timing/does it produce a strong blue spark at the spark plugs).

The other members posted some good things to check.

AlGal

So I got it running right. Turns out it was a vaccum line issue. Great so now that's fixed. Start her up and hear a tapping......what the neck. Ok so I'm checking the rockers and push rods and I see that my lifters don't seem to work now.......hmmmm...ok so pull intake back off and pull lifters. Damn they a are all shot. Well hell now I've got to double check the cam......and F@ck me Freddy its screwed up to. Great just great. So now I have to figure out if I can pull that without pulling the whole damn thing outta the car cause I don't have an A frame or hoist or a stand. Just great and yay and FML. Anyone have any thought on how to get that shaft out without pulling the motor?

terry82

cam can be changed in the car. radiator and the hood come off.

AlGal

Oh thank god.

Rescue Rogers

measure the length of the block and you'll know how far you have to go to get it free. good luck

doorgunner

Glad you found the problem......only 17 pieces left to go and it will be in good shape

AlGal

Only 17 more till something else goes out on her. Y'all ever reach a point where you just want to be done with it and have it work? That's where I'm at. But She's so going to be worth it though.

terry82

it takes time .have had my car for many years .I fix or change something every year.but getting started can be overwhelming.

AlGal

Ok so I've fixed the cam and have everything put back together in the exact place that it was, but now she won't start. I replaced the battery and have double and triple checked all of my connections and vacuum lines......but still nothing. Does anyone have any clue what I'm doing wrong? like I said earlier, this is my first attempt at a rebuild and I seem to be having one hell of a hard time with it. Thank you all again for all the help thus far.