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Discussion Starter #1
Hi,
I've been working on a problem for 2 weeks now. I am really frustrated. Okay, I have a 1988 Iroz with the a TBI. The flaps inside the throttle body were sticking to the walls. I took the TB off and had it machined so that the flaps no longer stuck. When I put it all back together, I had a surging idle. It goes from 400-1500 and quite frequently dies. If I hold the TPS open, it idles good. So far, I have checked and cleaned the IAC and TPS. I have checked and rechecked my gaskets and used Carb Cleaner to check for leaks. Its not my Catatlytic, I removed it. I've tried correcting it through various posts, but most posts of a similar problem were never completed. Thank you for any responses.
 

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when you say flaps are you talking about the butterfly? what do you mean by holding tps open? it sounds like you have to much metal mach. off throttle body and getting a little too much air which is affecting idle quality , im not sure i understand why throttle blades were sticking in the first place.,some cars i have worked on do this usully we just bump idle screw up till it doesent stick it doesent change idle speed just how far blades go into throttle body if left untreated the blades actually remove metal from tb and you will have surging idle. hope this helps chris
 

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Discussion Starter #3
Chris... I guess its called the butterfly, I am not sure. They are the flaps that open when you accelerate allowing more fuel down the TB. Those flaps were sticking to the walls of the TB. When they closed, the trottle linkage wasn't sitting on the idle screw and I was getting an idle of about 900 rpms, making it difficult to stop the car. When I had it machined, the flaps now sit against the wall without sticking and the linkage sits on the idle screw. If I manually push the TPS back while the linkage sits on the screw, I can get a steady idle. I never examined the Idle screw, but as I sit here now, I don't think it is adjustable. Hope this infornation clear things up. Thanks for your response. Brian
 

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There is an idle screw to set minimum idle on every throttle body I've seen. They also put stuff on the sides of the throttle blades to prevent sticking but with a lot of miles they will sometimes gum up. I've never seen a case where they had to be machines though.

Assuming the machining didn't screw up the seal between the throttle blades and wall of the throttle body, it sounds like the TPS needs to be re-adjusted. There is a specific voltage required at idle for the computer to know the engine is idling. It sounds like the voltage is too high and if you push against the tps at idle (lowering the voltage) it idles good again. That'd be the first place I'd look. Check a manual for the specs (voltage) for your TPS.

Jody
 

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Discussion Starter #6
To anybody who reads archives and has a surging idle problem, here is the solution to my problem. One of the fule injectors was not working properly. To look at it, it was spraying fine and when I took it to the shop, there was nothing electrically wrong, but it just wasn't working properly. So I got lucky and found a set of injectors at a junk yard for $9.00 and problem solved. As far as the sticking, the idle screw was in to far and a new accelerator cable and again, problem solved. Hope this helps somebody, I know how frustrating it is when your car is running poorly.
 

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Thanks for the feedback. We should all remember to close out our problems so others can best learn. I often forget in the excitement of moving on.

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Rick Dorion
69 RS Conv,355,M20,4.10's
 
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