Well, sounds like we all have something in common 90 GTU with the up and down sleeping disorder. What have I done to eliminate the problem so far: One $289 TPS and it only helped a little bit. But If I take the main air house off of the Air bypass Control Valve and cut the air in half with it half way on and off it seems to idle fine. I have read and article about the Air bypass valve and how to check if its good by creating a direct jump from the battery and spraying some WD40 into it. I have done this the valve opened Halfway In the opening I don't know if this is bad or good but seems to be my main problem I think Im going to try it again and see if I will be able to get it to full open will keep you posted on success.

 

For a little insite on the BAC you might want to go to this site.........http://www.teamfc3s.org/info/articles/idle.html although he talks about a turbo the bac part is basically the same. You need to remember that the bac vibrates at a high rate. I do not believe it just opens so far and holds that. With yours off the engine, hook it up to the connector. Turn the key to the on position(do not start the car) Holding the bac in your hand, if it is not already vibrating, reach over and jiggle the tps. It should vibrate now. You could spray it with lubricant or whatever while it does this. Anyway, that article by Paul Stokes is interesting.

 

HAILERS thanks for the article unfortunately did not solve just informed I'm not able to get the BAC to move when I move the TPS with the key on. Its going nuts when the engine is running I can hear it clicking back and forth. I have no Idea why it works when I cut the air flow going into it but the car just pops right in to Idle.

 

I just have 86 and 87's and they have a different tps, so maybe I should not say a thing. But if you disconnect the plug to the BAC, what kind of an idle do you have? Have you set the idle with the initial set coupler jumpered? And have you set the TPS? I don't think these are wild guesses, I believe you have to make sure each has been done right because one effects the other. Am sorry about the bac not acting like I described in the earlier post. Mine does act up as described.Sorry 'bout that.

 

Well I have disco. the BAC and did not change Idle. Could my cat be the problem? I have been getting a back fire when the RPMs fall from exel. The air pump seems to be working it pulls hard from the hose. The car and pipes have about 100k on them. I plan on replaceing them just would like some insite if this may be the problem before I go messing with the Idle anymore.Thanks for the help HAILERS what is coupler jumpered? I have worked the TPS screw from top to bottom with out any change noted hopefully its the cat.

 

Can I suggest downloading the Factory Manual at this site.............http://www.iluvmyrx7.com You find the download under, I think, Technical. You should not have to download the whole thing right away. Just download section 4A which deals with fuel. It gives a good description of how to set the idle. It shows where the *initial set coupler* is . Its a green connector on or near the l/h strut tower, two wired connector which should be jumpered with a wire before setting the idle or setting the bac. I think your backfire might be related to a part of the air control valve called *anti afterburn valve*. The way I understand it is that when you let off the throttle it injects air into the exaust ports to prevent backfire among other things. The airpump has to be working for this to happen. If you cannot find the manual on that site let me know. I think there is another site or two. Whatever you do, get the manual. By the way its a 88 manual but its relavent to 86-88.

 

I've been informed by Irv, Keith's father that the initial set coupler on the newer cars is a single wire connector. You ground it to the battery negative cable.

 

Well, good news I got it to run smooth Took the BAC off once again and took the set screws out seems to be sucking more air than ever two things I found out on the back screw tends to make the car Idle way high two the front screw if set into far tends to make a chainsaw sound. Thanks HAILERS for the up date on the wire Had read that myself today talk about confusion to find that wire also helps ground out so you can read trouble codes from the engine light. A right now that the ruff Idle under control still with the Hunting of the throttle fixing this was kind of simple after all of the 123 top and 456 bottom was tossed to the side reason being that I could not get anything from what was supposed to be the 1-6 no what I did find was volts some place were sorry don't remember witch ones but it started about 4.5ohms now I read that this should be about 4ohms there and wide open it should read the same. I placed it there same Hunting Now Lost I ran the screw on the Butterfly all the way out almost to the end ohms jumped from about 2.5 to under 1ohm about .2532 left it there and it ran great so far I hope that I did not mess anything up by playing but it seams to be running fine a little high yet about 1000. Has a really hard time getting to 8000 likes to really slow at about 6500-7000. I think that this may be the Cat putting to much back pressure I will find out tomorrow when I bash the crap out of it. Other problem very subtle shuttering during High deceleration while in gear??? Well guys THANKS for all of the insight Hopefully this will just get better just a little timing thing hopefully and some locktie on the screws to the BAC " Got my A'Pexi air intake today" Chat with you latter Clarkrx7

 

I think you maybe were I was at the start of my problems I started by ajusting the air screw to a Higher Idle but eventually that gives out too you TPS may be starting to fail. What I have found with mine is that it wears out at the Idle because it sits there the most for a prolong period of time hope this helps Try and check it with a fluke.

 

maybe my site will help or maybe not....

http://ourworld-top.cs.com/flrxster/index.html

 

Yo,
I have an 89 GTU and i'm also stalling out. When the car is in Park or Neutral it is fine but if it's in anything else it's RPMs drop and it almost stalls on me. My friend thinks it has something to do with the throttle because various shops by me have messed with the throttle adjustment screw and i found out that it only made things worse. So touching the screw hasn't helped me any. Think my friend is right? I have also changed the plugs and the wires. They r brand new! It did absolutely nothing. I too - like many others need help with this problem.

 

fuel pump possibly?

 

thats another thing. I heard that the car might not be getting anough fuel when it's in gear. My fuel filter is new. How much would a fuel pump be for an 89 gtu (if mine is bad and i need one)?