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KYCJ7 07-01-2008 02:06 PM

Howell Throttle body conversion problems
Just purchased another CJ7 and someone has put a howell throttle body conversion kit on it. Well, thats great, but it is idling at 2000 rpm and I can't get it to idle down. I was told the gaskets were bad and sucking air. I replaced to gaskets and it ran right for 15 minutes or so and now its back to 2000 rpm. I replaced the gaskets again and this time I sealed to heads of the allen screws in the adaptor and there was no change. Howell isn't very helpful actually their just pricks. Does anyone have any experience with this? Can anyone give me some advice? Or should I put a carb. back on it?

jscherb 07-01-2008 03:47 PM

The idle air solenoid on your throttle body may be bad. If the idle solenoid isn't working properly or is crudded up and not closing at idle you will have this problem - it acts like partially open throttle and won't idle down. You can try removing it and cleaning it with injector cleaner first.

I had this problem and a new one from the Pick-N-Pull yunkyard for $5 solved it for me. (Or they are $50 new at the parts store).


bdmonist 07-01-2008 09:33 PM

There's also a guy, ragged*, on ebay that sells about every TBI part you are looking for. He may have some if you can't locate one locally.

jfwireless 07-02-2008 06:37 AM

I do not have a Howell TBI kit, but I did install a junkyard TBI on my 304. One of the first things I needed to do before start up was to do an IAC reset and idle speed adjustment, this sets the throttle plate on the throttle body to a specific rpm, than set the idle adjustment on the throttle body. Here is the write up I used to do the IAC reset and idle speed adjustment. Howell must have a similar set up you should try.


KYCJ7 07-02-2008 04:28 PM

I replaced the idle air sensor first thing because it was actually unplugged when I got the Jeep and no change. I tried an old school test by spraying starting fluid on the throttle body and you could watch the mist get sucked in the gaskets and the engine would then die. So I assume that is where the problem is, but I may need to try reseting the system as suggested. Thanks for all the input I'll keep you posted.

jfwireless 07-03-2008 10:27 AM

Sounds like you found the problem, vacuum leaks can cause fast idle in a TBI engine. There is also throttle position creap, when you have a bad throttle position sensor.


KYCJ7 07-03-2008 11:07 AM

Put new gaskets on and siliconed the allen heads I know its sealed but it still doesn't want to idle down. I'm lost when it comes to fuel injection and about to loose my mind.

gmakra 07-03-2008 11:49 AM

KC take a deep breath sounds like you have a vacuum issue.
Go to the Howell Engine Development web site and down load the instruction manual under tech support.

I would venture to guess you may have a vacuum line mis routed or a cracked line. It would be easy enough to see if this is the case by capping the vacuum ports one at a time and see if that makes any difference.

Also is your check engine light on?

gmakra 07-03-2008 11:51 AM

I have a feeling the problem maybe be at your CTO? Does it idle ok when cold?

KYCJ7 07-03-2008 04:57 PM

Ok I take back what I said about the guys at Howell I spoke to Troy at Howell and he walked me through several steps until we narrowed it down to a bad computer. $75.00 later its running great. Thanks for all your help and a big thanks to Troy at Howell for helping this TBI green horn fix my new toy.

The time now is 04:58 PM.

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