Hazard Alert

[Eagle]

Technically, this incident occurred in my '88 XJ 4.0L but, since the Renix MJs are mechanically identical and this could have "consequences," I'm posting in the MJ Tech area.

 

With the a/c not working, "Old Faithful" is currently mostly relegated to weekend warrior duty, such as hauling stuff to the local transfer station. To get there, there's a half-mile climb up a moderately steep hill that I normally do in second gear at about 2200 RPM.

 

The gas peddle seemed a bit stiff today and when I'd let off the idle didn't drop all the way down to 650 as it should, but I figured with a bit of driving it would loosen up.

 

WRONG!

 

When I pushed down a bit more on the gas to go up that last hill, I knew immediately that the throttle was stuck. It ran up the steep part at about 2500 RPM in 2nd, but when the grade started to level out we just started going faster ... and faster ... and faster. I rode the brakes until I got to a spot wide enough and straight enough to pull off, then I stopped by shutting off the engine, popped the hood, and manually closed the throttle body. From there I made it to the station, dumped my stuff, and limped home in first and second, then set up to clean the throttle body and idle air controller.

 

WRONG AGAIN!

 

After mucking around with the throttle body, I discovered that the problem was not IN the throttle body. The cable from the accelerator pedal leads to a bellcrank down on the side of the engine, which in turn pulls and pushes on a lever that comes up and snaps onto the throttle body arm. The pivot on that bellcrank was frozen up. With the arm snapped off, the throttle body operated smoothly ... but the connecting rod didn't. After numerous soakings with PB Blaster and working it by hand, it finally loosed up ... somewhat. I'll rinse and repeat a few times over the next several days to get it better loosened up, and I may even add a supplemental return spring.

 

If your throttle begins to feel at all "catchy" or sticky in operation, DO NOT assume that it will get better as you drive. I was lucky to be on a side road with no traffic when mine froze up, but in traffic the result could have been a lot more serious than it was.

[Justin_k]

If you drove a toyota you wouldn't have been smart enough to shut the key off :rotf:

[HOrnbrod]

That sounds like a similar setup as the hood release cable/lever/bellcrank kluge setup. We all know how reliable that is. :eek: I guess they fixed it when the HOs came out; it's just one continuous cable from the gas pedal to the intake manifold where the outer shield terminates on a fixed bracket, then the inner cable continues on the the throttle body. Whole lot less moving parts, the cable's shielded, and less room for error. Maybe it could be adapted t the Renix? Unless the bellcrank is necessary to move something else as is usually the case?

[88SporTruck]

Where in CT are you? The road you described sounds like the one to the dump in EH.

 

If you are in the nearby area then I can come and help.

[CWLONGSHOT]

Eagle,

First and foremost, GLAD YOUR OK!!! ;) :wavey: I had a similar issue with the linkage on my 88XJ. It sat for a month or so in the worst of the winter this past year. Pop started it up to move it out of its snow sheath and the throttle stuck!! Smoking both rear tires as soon as it hit the pavement!! He threw it in neutral and popped the hood. It was the bell crank pivot on the side of the intake. Just as you describe. Was 'stiff' for a couple days but daily lubrication proved the cure. Good to know the 20+ YO track lock is still working!!! :bowdown: :clapping:

 

Don,

It could probably we retrofitted in a manual tranny. But in a auto there is some other linkages present... The throttle cable exits the firewall and makes a 90degree turn down and is held at the side of the intake and attaches to the bell crank. Then a 3/4 wheel with another cable to the top and another rod join up to the throttle body. In there is another bent rod running up and over the intake down the side of the motor to the tranny.

 

88sportruck,

WELCOME!! Eagle is over in the valley, I'm in Meriden, your in E. Haddam? We have a couple more CT members Green is in Wallingford and another member up in Enfield (IIRC) Together we have the state pretty well represented!!

 

CW

[Harper]

Thanks for sharing that, Eagle...good to know info!

[Akula69]

One more item that we must remember to check when doing regular maintenance.

 

Glad you're OK Don...could have been worse.

[aemsee]

I remember seeing this very often as a tech at the dealer in the early 90's. Very poor design, but made me a few bucks back then :clapping:

[jpnjim]

My 88's froze up from sitting in the driveway for a few years.

 

Took some work to loosen it up, and I forgot all about it till this post.

 

I eliminated it with the HO swap,

but this thread will serve as a reminder to give the 89' a squirt, or two of lube next time I'm under the hood. :cheers:

 

I remember seeing this very often as a tech at the dealer in the early 90's. Very poor design, but made me a few bucks back then :clapping:

 

Was there a 'factory fix' for this, or were you just lubing/replacing the rusty bellcranks?

 

 

This should be on a list of things to do for the new MJ owners:

 

1) pull your rug, and assess the rust damage

2) lube your bellcrank

 

 

:yes: