1990 corvette runs rough

[vette 53]

I have a 1990 corvette,, had some other problems, but fixed them,, new ecm, spark plugs,, fuel filter, rebuilt distr. anyway now she runs rought, and when I give it full gas she back fires,,, could it be the wires etc? would appecitate any information,,,,

ps if you drive it slow its seems to run fine,, and also cant set it with the timing gun,,,, seems to be off for some reason,,,maybe timming not right?

please help thanks in advance...

 

[Vettefan87]

Not to be mean but go back and double check or even triple check the wires. While doing my headers my brother and I got two wires crossed and the car ran terrible.

 

[vette 53]

I numbered the wires,, dont think that could do it,, but maybe need new wires,, dont know when they were lasted changed,Vettefan87,I dont think you were being mean,, would like any feed back,,,I was wondering if it could be the wires(need new ones) or maybe the timing is still out,,, cant seem to get it,,, runs okay at lower speeds,, higher speed,, back fires,,and idel is rough,,

 

[gmjunkie]

ps if you drive it slow its seems to run fine,, and also cant set it with the timing gun,,,, seems to be off for some reason,,,maybe timming not right?

please help thanks in advance...

Be my guess you have the Distributer in off a tooth or two!!

 

[LT4man]

I vote for the distributor being off a tooth, also!

That is why your timing gun is not picking up the timing mark!

I also vote for gmjunkie For President!

SAVE THE

 

[vette 53]

Be my guess you have the Distributer in off a tooth or two!!

I beleive you could be right,,, my friend the mech,,, couldnt get it to work,, maybe I should try someone else,,,thanks

 

[G Winter]

You could actually be off 180 deg. on the dist.

Glenn

 

[vette 53]

yes I am off about 180,,, what would that be from...?

 

[gmjunkie]

yes I am off about 180,,, what would that be from...?

They'll damn sure run 180 out,But run Like Crap!!

 

[LT4man]

Just think how WELL the engine will run if the distributor is actually in the right place!

Looks like you found the problem!

SAVE THE

 

[vette 53]

My question is how would I get it back where it should be? I never did this, bought car in nov 2007 and I feel this could be the problem, but other then take it somewhere,, and they say could be something esle etc,, I would like to know if anyone knows , how I could do it my self,,,please and thanks

guys this is my first vet, and I have worked on my other car, and keep it running just fine, just dont know who to trust (mech)

Thanks

 

[vette 53]

also when I unplug the IAC,, or the TPS the car runs smother,,, does that mean it could be that?

 

[gmjunkie]

also when I unplug the IAC,, or the TPS the car runs smother,,, does that mean it could be that?

No that won't do it!! Put your Timing light on #6 and see if you can see the timing mark on the balancer then!! If you can,it's 180 deg out!! If not you have another problem!!

 

[vette 53]

what problem,, would that be,,,?

 

[vette 53]

I was told it was out about 180deg,, and they couldnt set the timing with the timing gun,,, how else could you set it?

 

[gmjunkie]

I was told it was out about 180deg,, and they couldnt set the timing with the timing gun,,, how else could you set it?

2 ways,Right and Wrong!!
Right: Remove the distributer and set it back in, in the Right position!!

Wrong: The Stupid,Inbred,No Mechanic'ing, Butcher,Non Professional,Ignoramus way!! Move The #1 SP wire to #6 on the distributer and work clockwise from there 1,8,4,3,6,5,7,2
But I'd check if that is what it is First!! The distributer could be a couple teeth off and do what it's doing too!!

 

[vette 53]

thank you,,I just wished I knew which to re set the distributer,, I wasnt there when they did it,, and dont knowto right or left,, one tooth or two,,, thanks gmjunkie for your reply

 

[vette 53]

ps,,, will it hit to drive the car the way it is,,,,?

 

[RoyalViking]

If I have anything wrong here please speak up. This is my hobby and I don't do this everyday.

You need to check the timing to see if it is 180 degrees out of time. Junk said how to do it above (clip the timing light onto #6 wire). If it is out of time the light will show the timing mark on the harmonic balancer is at the timing index.

I had the intake off of my car apart for a couple months and when it came to the distributor I could not remember what position it was in (now I take notes and pics before and during long projects). It turned out it was 180 deg off. It may seem like a big deal but it isn't. Take your time. Remove the distributor cap (probably screws onto the dist body). Mark on the distributor where the rotor is pointing with a marker for reference. Note where the distributor is positioned (it is going to be about where it is now when you are done). Loosen the clamp enough that you can slide it off of the distributor shaft. Lift the distributor out of the engine (it only has to life out about 2 inches, I can't remember if the two electrical connectors have to be disconnected to get enough travel to lift the distributor). You will notice the rotor turns slightly as you lift the distributor. Turn the rotor 1/2 turn (this is the 180 degrees). Now lower it back into the engine. Assuming the distributor went back in properly the mark you made for reference should be 180 degrees from where the rotor is now. Tighten the clamp. Install the cap again. Use your timing light to set the static timing.

 

[vette 53]

Thank you,, will try it,,,,thanks again...