ShiftyCapone

iTrader: (7)

I had a vacuum leak againts the TBi unit and the manifold. The passenger side bolt had worked its way out and stripped all the threads with it. So I was in the best mood yesturday. I had to buy a heli coil kit and re-drill the hole, tap it and then thred in the new threads. So now I have the TBi sealed, Manifold sealed, and timing set back to stock 0* (I didn't want to advance it yet until I got the thing to run). There is one problem left. At low RPM like at Idle to 1500 when I am smooth on the gas the car gets the jitters and shakes. It smooths out when you hammer it but the car is not smooth in stop and go traffic. Could that be fuel pressure or the fact that I don't have headers and there is to much back pressure?

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1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

ShiftyCapone

iTrader: (7)

Oh yea and when i drive a little and then stop the car will stay at like 1100 RPm before coming back to an idle and then seems like its gonna die but hangs in there with a little shake.

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1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

ShiftyCapone

iTrader: (7)

I have fianly fixed the vacuum leak by using two gaskets sandwiched together with RTV. That allowed enough cousin to bend over the HELI coil that HAD BACKED ITS WAY OUT!!!! Since it was pressed into the mnifold already I had to bore out the gaskets a touch as well as the spacer to fit over the protruding HELI coil. I heard the vacuum leak for a min or two and then it slowly sealed its way up. Car runs stronger yet but have a little car shake at low RPM, but I asume that is because I don't have headers yet to match all the air comming into my motor. It shakes a little at idle but when i put the air on at idle she tries all she can not to stall out. I wonder what this could be. Any ideas?

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1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

steve8586iroc

Glad to hear your getting a handle on the problems your having. As far as the low speed shake I don't think your mods are the problem. Try disconnecting the battery for a minute then drive it for fifteen minutes or longer so the computer can relearn the changes again.If you've already tried this then check for a vac leak to the map sensor. Someone else care to help here I'm running out of ideas.

Steve

bullfrawg

first off try using the same post. It is hard to follow so many for the same thing.
Second it sounds like you still got a vacuum leak. You should not use two gaskets. It will eventually start leaking oil water and create vacuum leaks. Plus you should tighten the stuff down good. Also i believe those thread kits come with locktight so they won't back out. You have to let that stuff dry. Also the rtv has to dry before you start the motor. If you heard a leak and then it slowly quit you might as well start over again. More than likely that leak is still there.

ShiftyCapone

iTrader: (7)

I let the RTV sit and dry like the instructions said for 10-15 minutes. I am only using two gaskets on the top of the maifold between the spacer to help cover the protruding heli coil that I had to put in. I don't understand how I could have a vacuum leak now and I don't want to tighten the TBI down anymore for fear of striping more threads. I will dissconnect the battery for a min and see if that helps. It only shakes at low RPM loads and at idle. Almost feels like a lumpy cam but when I get on the gas she smooths right out. Also if i had a vacuum leak my wouldn't my performance drop. But now it is stronger than ever just with the shake.


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1990 RS 305 TBI T-5
.5" turbocity spacer
Edelbrock TBI intake
180* stat
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

Keith5

Getting any service engine soon lights? You did plug the timing wire back up right? I'd say if you can't hear a vacuum leak you probably don't have one.

ShiftyCapone

iTrader: (7)

No lights or check engine soon lights, and I made sure that all my hoses and wires were plugged in. I still think it is a vacuum leak somewhere because I only feel it at low rpm loads and it gets a little better as the engine heats up. Also, when I am driving and I push in the clutch the rpm's hang there for a few seconds and then slowly (a lot slower than normal)come back to an idle. I am taking it to an engine machine shop to re-tap that stripped hole and hopefully that'll to the trick. Then I will know the TBI is sealed down and I can concentrate on other areas. If not, I will set the whole damn ting on fire.



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1990 RS 305 TBI T-5
.5" turbocity spacer
Edelbrock TBI intake
180* stat
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

bullfrawg

Did you properly torque all the intake bolts?
Also check the vac lines to the ball thingy and to cruise if you have it. Also the multiwire plug at the distributor may have a bad connection. Try unplugging and replugging. Also it could something in the tbi wrong. If you rebuilt the TBI a gasket may not have sealed correctly. Also make sure all the small screws are tight. If you want to set it on fire you can give it to me before you do. What about your EGR. Did you put it back on? If so check the seals there. If you didn't be sure the vac lines to it are plugged. Also it sounds like the timing is still off pretty far. Remember when setting you have to unplug that wire near your blower fan to bypass the computer.
Thats all ideas i got right now.

89RS355

Try setting you timing back to about 4btdc for testing. Sounds like a vacuum leak. If your idle ever hunts and pecks, 10-1 says it is a vacuum leak. Make sure you iac is working o.k. and that the passenges are good and clean. If all you put on is a spacer, you should be able to narrow down the problems by going back to stock and see if it is still there.
Jerry

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1989 Lt. Blue RS 5-speed
355 crate motor, Compucam 2040,
PST Front suspension,
Hotchkis rear suspension,
EDL T.E.S., 3" Flowmaster
Harwood cowl hood

1994 Black Z28 6-speed
Nothing major, but FUN!

ShiftyCapone

iTrader: (7)

Come to find out I did have a vacuum leak. HOWEVER, I just had it professionaly fixed because my atempt at fixing it left a protruding heli coil atop my manifold. Ok with that said. The car is MUCH better now that the leak is gone but I still am Idling rough. The car also seems to hang at at like 1000 rpm for a few seconds before dropping to an idle. What coulf this be. All my seals on the manifold are good and have been checked by a professional. My timing is at zero because I had it put back there to help get the car to run. Will advancing it help smooth her out at low rpm. I use to shift into 5th at 35 (car goes to 900-1000 rpm and run smooth). Now I shift at 35 and the car shakes and won't smooth out until abour 45 mph. Is this just because I have more air into my motor and have increased its breathing so it needs a little higher rpm to run smooth. by the way a BIG THANKS to all of you who replied with help, you turned a nightmare into a mere daydream. I geuss I should say that after my car stops shaking....hehehe


------------------
1990 RS 305 TBI T-5
.5" turbocity spacer
Edelbrock TBI intake
180* stat
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)