I have been plagued with a high idle issue since I bought my truck back in February. I am planning on burping my radiator later today to cross that off my list of possible causes. I believe the issue lies with my tps being faulty. I have read the 4crawler guide and if burping my radiator does not work I plan on removing my throttle body to install and configure a new TPS. I have consulted my Chilton's as well as the 93 FSM that is available online and I still am a little concerned with the process. Is there a guide with pictures anywhere that you guys can point me to? I've never removed a TB before and I am still learning the ins and outs of my truck. I was told buy the guy who I bought my truck from that he replaced the motor (the truck is an 88) with one from an 89. I have the straight TB not the angled one. As far as ordering my replacement TPS should I simply look at my current TPS and order one from LCE with the same part number? Any help is much appreciated.

 

Don't buy a new TPS just yet, they often just need to be adjusted.

First off though, did you adjust the idle air screw? http://personal.utulsa.edu/~nathan-b...nce/2maint.pdf, see page MA-12. Turn it clockwise to lower speed. That might fix it and take 30 seconds of your time.

You don't need to remove the throttle body, for the 22RE it's easy enough to just adjust it while it's on the engine. If you have someone (wife, neighbor) who can hold the multimeter wires while you adjust, it makes it 10x easier. You'll need a feeler gauge and a multi-meter. The basic thing your trying to adjust is when the throttle body is closed, the TPS needs to read that it's "idleing" (based on the resistance values). Once you apply more than .85 mm of opening on the throttle place, it goes out of "idle" and into normal function, referred to as open and closed loop. Here's the full process (#2. on the list):

http://personal.utulsa.edu/~nathan-b...34throttle.pdf

 

The truck has a good 800 idle when it isn't doing the high idle issue. It comes and goes but has become more frequent. I am able to bring the idle down to 800 by "bopping" the throttle to over 3k. Getting out while it is high idling and tapping the tps sensor also brings it down to proper idle (a suggestion in an earlier post) which leads me to believe the tps is bad. I have no access to the bottom screw of the TPS while it is installed on the TB (it is blocked by another component maybe you know which one?) which is why I was going to remove it.

 

I would also check your Idle air control valve. A lot of times, since coolant runs through the valve and the openings as so small, junk will get in there causing all sorts of weird idle problems.

Search on this topic as there are dozens of threads on this already.

 

Yes I was going to do that as well. Another reason to take off the TB. Because from what I understand you can't clean it without doing so right?

 

Depends on year. 85-88 the IACV is not built into the TB. 89-95 the IACV is built into the TB.

Yours is remote of the TB, but still under it a little bit.

 

Now that you've described the symptoms again, it could also be caused by a dirty TB, so might as well take it off. Buy a new gasket too while you are at it.

If the throttle body has never been cleaned, you'll find a think layer of carbon, oil and dirt caking the inside. In my case, it was preventing the valve closing all the way when I slowly decelerated since it would get stuck on the build-up and not shut completely. Give it a good cleaning and then drop a little oil on the valve and work it in so it is well lubricated.

Also, make sure you accelerator cable is not dirty. That could also hold the throttle slightly open and cause a sporadic high idle.

 

How do I prevent my coolant from all pourinh out when I go to remove the tb?

 

Drain engine coolant.

 

It'll still pour out even if you drain the radiator, since the radiator is lower than the TB anyway. Just drain about half the rad and grab some shop towels and stuff them under the TB, it'll stop eventually.

A word of advice though, those hoses may split when you take them off. Be prepared to hunt down the right hose and replace it if need be.

 

 

Oh yeah, we're talking about a 22RE

 

this first ^^^

not only dirty, but if it's adjusted too tight it'll hold the throttle open, and prevent full idle down... a simple thing to try is to unhook the tb cable from that tie down in the middle, so that it flops free, because it'll bind less that way... it should still be tied down at the nuts just before the tb, that's where the cable length adjustment is.

beyond that, the fact that you get idle down when knocking on the tps, indicates a possible defective tps, not something that's out of adjustment... or it could simply be the cable adjustment.

 

So I'm all set to do a full coolant flush as well as remove my TB to replace the TPS. Does my 88 need a new IACV o-ring when I remove the TB? I'm ordering a new gasket for the TB of course but I wasn't sure about the IACV. I plan on completely cleaning the TB as well as the IACV as these both could be causing my problem as well as my TPS.

 

Anybody?

 

So after removing my TB and doing a deep clean of all its components as well as replacing my TPS my high idle has finally been solved. Thanks for all the help guys.

 

I know this thread is old as hell but how did you remove your TB and what do I need to watch for when doing so. I’m thinking about doing this tomorrow and bench cleaning it and the TPS. I don’t think it’s ever been off before and this truck is 30 years old lol.

 

What! Why are you bringing up such a relic? Oh, wait, ALL our trucks are that old ...

Here's the manual: http://web.archive.org/web/201311071...34throttle.pdf

While adjusting the TPS (not so difficult on the 22re) is worth doing, I don't think I'd remove the throttle body just because the truck is 30 years old. You can always break something that isn't broken now. But if you feel the need, you now know how to do it.