I just installed a Weiand Excelerator, single plane, on my car and the first time I cranked the engine, it made a huge hissy noise and the RPM started at nearly 3000 and were climbing quite quickly so shut it off before it reached 4000
I checked every vaccum hose, nothing but even if it was a hose it wouldn't make such a big difference.
Please, any ideas would be very welcome, it is my daily driver.

 

Check you throttle cable and make sure that it isnt binding on anything and then make sure that the blades on the TBI are fully closed

 

I checked the blades and they are fully closed.

 

timing? are you sure it is good

 

i didn't have time to check the timing, rpm were climbing too fast.
Would timing produce such high rpm?
What would produce this big hissy noise?

 

w/o the air cleaner on the tbi will hiss like mad from the air and fuel coming in and expanding into the intake. Put your hand on a tbi after the car has been idling for a few and you will feel its cold from this. If you had the air cleaner on, then id say you have a major vacuum leak.

 

one way to curb the sudden increase in speed is to retard the timing by manualy turning the dist. and disconnect the timing reference signal (timing connector). This will cause the engine to bog and might buy you some time to find that leak, although it will be harder because of the reduced vacuum in the manifold.

 

when I started the car, only the throttle cable was attached, not the TV cable and the other one.
Woul it change someting?

Another thing is that a machine shop took care of changing the bolt pattern and they elongate them pretty large.
Would someting escape by the bolt holes if they are too large?

 

oh... almost forgot... make sure the Idle air control valve is in good working order, if that is disconnected and/or stuck open, it will cause a fast idle.

 

What should I use to look for the leak?
Is spraying carb cleaner a gvood method?
What else is efficent?

Thanks all for your answers.

 

posibly, thoughi doubt it because the runners are some distance away from the holes. i assume they changed the 4 center ones.

 

How do Icheck if my idle air control is in good working order?

 

carb cleaner is good, the rpms should icrease. spray some of that around the iac too to help clean it in case it is binding on deposits, which you will have after 170 k

 

you can look at the tbi and see if it is seating properly. If im not mistaken, the iac should seat itself after the engine is shut down. I also beleive you can apply a voltage to activate it but i dont rremember which pins. A shop manual should detail this.

 

dont mess up w/ the pins, if you get it wrong, you fry it.

 

There has to be a vacuum leak somewhere. Unless you ran the car w/o the air cleaner in place. I don't know what it is about these TBI cars and running w/o the aircleaner but....I ran my car w/o the air cleaner once and it would not stop taching up to redline. Put the aircleaner on it ran perfect. Weird. Anyway, spray carb cleaner around the intake manifold and throttle body, if ther RPMs change you've found the leak.

 

huh... never had that problem. Must of disconnected soemthing in the proccess of removal. Ive ran mine numerous times w/o a cleaner wiht no difference.

 

I try with and without, was the same.

I will look for vaccum leak tomorrow morning, if I try now, my neighboors are going to kill me.

Thanks for your help, any other thoughts?

Just curiosity, it would have to be a big leak cause I use to run with one of the hose unplugged and it didn't make such a big difference.

 

You've got a vaccum leak, it sounds like a huge one! A year ago we put an engine in my friends '91 RS. I rebuilt the TBI unit and put a new gasket between the TBI and the intake. The kit came with two gaskets, the TBI's with and without the IAC valve. I put the one without the IAC valve on and it had a huge leak. His car would run at like 2000-3000 rpms.

 

I finally found that I hadn't installed my carb TBI adaptor properly so It would leak from there.
Now the engine runs perfect but my tranny doesn't
I posted my pb on the tranny board, if any of you are expert in tranny:https://www.thirdgen.org/techbb2/sho...hreadid=119301

Thanks again for your help,

Jacques.