What Did We Do Wrong?

It's been quite some time since I last posted, and I thank all of you
who gave my son and I guidance on repairing his 2.3L 89 Mustang with
the hole in the intake manifold that caused it to act like the head
gasket was blown.

89 Mustang 2.3L with leak in intake manifold.

We finally got our timing problem figured out and got the car to
start... but that's where our problem begins. We think we put
everything back together as it was when we took it apart, but when we
start it, the engine races to 4,000 rpm and will not slow down, so we
have to shut it down.

We didn't do anything to the throttle-body, just removed it as a unit
and put it back on as a unit, with new gaskets. We had a minor timing
problem when we first replaced the timing belt, so we took if off and
reinstalled it correctly, and were able to get it to start by making a
minor adjustment in the timing at the distributor. We've checked for
vaccum leaks and the throttle-plate moves easily, and the linkage
seems to be functioning properly.

Anybody have any thoughts on what we did wrong that caused this
over-revving at start-up?

What do we need to do to fix this?

Is this something that we'd be better-off taking the car to a repair
shop to figure-out and fix?

Is it possible that, somehow, the EEC/ECM may have had a code reset to
WOT? I don't think this could happen because all of the work was done
with the battery cables disconnected and the battery removed from the
car, but that seems to be what is happening.

Thanks for any suggestions you all may have!

Lee

I doesnt take much air to run an engine to 4000 with no load.

Assuming you didnt touch the throttle stop screw.. still cant assume it wasnt
moved.

So you're going to have to rule out evrything else.. disconnect and plug all
vacuum except the fuel pressure regulator. remove the ISC and tape over the
back port (behind throttle plate)
start the engine..

A. if it barely runs, put the ISC back on and try again, okay.. then
reinstall vac lines.

B. if it still revs higher than 2000, remove the air duct from throttle body,
start again and see if it kills when you cover the mouth with your hand.

If it kills immediately, adjust throttle stop to about 1000 let it warm up
then adjust it to about 700 rpm

The add the ISC and vac lines back, one at a time..

If it STILL runs with hand over the mouth, you obviously have a manifold
leak..

Use unlit propane torch to find it.



Lee Sun opined in m:

> It's been quite some time since I last posted, and I thank all of you
> who gave my son and I guidance on repairing his 2.3L 89 Mustang with
> the hole in the intake manifold that caused it to act like the head
> gasket was blown.
>
> 89 Mustang 2.3L with leak in intake manifold.
>
> We finally got our timing problem figured out and got the car to
> start... but that's where our problem begins. We think we put
> everything back together as it was when we took it apart, but when we
> start it, the engine races to 4,000 rpm and will not slow down, so we
> have to shut it down.
>
> We didn't do anything to the throttle-body, just removed it as a unit
> and put it back on as a unit, with new gaskets. We had a minor timing
> problem when we first replaced the timing belt, so we took if off and
> reinstalled it correctly, and were able to get it to start by making a
> minor adjustment in the timing at the distributor. We've checked for
> vaccum leaks and the throttle-plate moves easily, and the linkage
> seems to be functioning properly.
>
> Anybody have any thoughts on what we did wrong that caused this
> over-revving at start-up?
>
> What do we need to do to fix this?
>
> Is this something that we'd be better-off taking the car to a repair
> shop to figure-out and fix?
>
> Is it possible that, somehow, the EEC/ECM may have had a code reset to
> WOT? I don't think this could happen because all of the work was done
> with the battery cables disconnected and the battery removed from the
> car, but that seems to be what is happening.
>
> Thanks for any suggestions you all may have!
>
> Lee