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-   3rd Generation Specific (1993-2002) (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/)
-   -   Removed and Reinstalled UIM, now hard to start/idle. (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/removed-reinstalled-uim-now-hard-start-idle-957809/)

arghx 06-13-11 12:06 PM


Originally Posted by RXtacy (Post 10663851)
I had a somewhat similar issue the last time I removed the UIM. My idle was hunting all the way to about 3k rpms and would not hold steady. Adjusting the idle screw changed nothing. I had ended up changing the pre tension on the throttle cable when I removed it. So I ended up tweaking the tension on the throttle cable to get it almost perfect and using the idle screw to fine tune it.

If it is in fact necessary to open the throttle plates, you can turn the throttle stopper screw on the front of the TB instead of adjusting the tension in the cable.

championadrien 06-13-11 02:01 PM


Originally Posted by 1QWIK7 (Post 10663715)
You didnt install this incorrectly. The distance from the bolts from left to right are different from the top 2 and the bottom 2. The gasket wouldnt even go on the 4 bolts if you had put the gasket upside down.

I think what we meant is that the hump at the top (bottom of Erix7rew's picture) of the gasket must be on a specific side for it to seal, so although you cannot install the TB Gasket upside down, you can install it reverse (left to right.) According to Erix7rew, the notch on top of the T gasket must be on the same side as the TPS.


Originally Posted by RXtacy (Post 10663851)
I had a somewhat similar issue the last time I removed
the UIM. My idle was hunting all the way to about 3k rpms and would not hold steady. Adjusting the idle screw changed nothing. I had ended up changing the pre tension on the throttle cable when I removed it. So I ended up tweaking the tension on the throttle cable to get it almost perfect and using the idle screw to fine tune it.

I wish that was my problem but the slack in my throttle cable is spec'd to the FSM. From what I understand it shouldn't be pre-tensioned, but there should be 1 - 3mm of play in the cable. Also, my vacuum readings are seriously low so I'm thinking mine has to do with an actual vacuum leak.

RXtacy 06-13-11 02:05 PM


Originally Posted by championadrien (Post 10664240)
I wish that was my problem but the slack in my throttle cable is spec'd to the FSM. From what I understand it shouldn't be pre-tensioned, but there should be 1 - 3mm of play in the cable. Also, my vacuum readings are seriously low so I'm thinking mine has to do with an actual vacuum leak.

Have you sprayed carb cleaner around to check for vacuum leaks?

phrost 06-13-11 02:11 PM

championadrien

I had a similar problem just recently, where it had issues holding idle, backfiring and all that.
Problem was definitely caused by an intake leak, I had took a can of carbcleaner and sprayed everything I could from the tb elbow back. Turned out the gasket for the ISC valve was bad causing the intake leak. I doubt you are having the same exact leak, but from you statements previously posted, sounds like some kind of intake leak.

championadrien 06-13-11 03:19 PM


Originally Posted by RXtacy (Post 10664247)
Have you sprayed carb cleaner around to check for vacuum leaks?

I have but I couldn't get a definite result. I'm going to try again with starting fluid and also see if I can rig up a pressure test with a bigger pump/compressor.


Originally Posted by phrost (Post 10664259)
championadrien

I had a similar problem just recently, where it had issues holding idle, backfiring and all that.
Problem was definitely caused by an intake leak, I had took a can of carbcleaner and sprayed everything I could from the tb elbow back. Turned out the gasket for the ISC valve was bad causing the intake leak. I doubt you are having the same exact leak, but from you statements previously posted, sounds like some kind of intake leak.

Thanks for the words of encouragement. My ISC and AWS gaskets looked pretty solid so I don't think those are the culprit, but its good to know you had similar symptoms.

--

After running a starter fluid and pressure test, if I can't get any solid results, I'm going to start taking the ACV off and looking under there for vacuum leaks, since the main rats nest seems to be solid.

MR_Rick 06-13-11 03:45 PM


Originally Posted by RXtacy (Post 10663851)
I had a somewhat similar issue the last time I removed the UIM. My idle was hunting all the way to about 3k rpms and would not hold steady. Adjusting the idle screw changed nothing. I had ended up changing the pre tension on the throttle cable when I removed it. So I ended up tweaking the tension on the throttle cable to get it almost perfect and using the idle screw to fine tune it.

Just remembered that I had the same thing when I was putting everything back together last time. This is what fixed my idle along with doing the PFC idle adjustment settings all over again. Now my idle sit at 900 rpms perfectly.

championadrien 06-14-11 10:04 PM

So...

Today I took off the ACV, replaced two hoses that looked iffy (but they had no cracks or anything) and started reinstalling everything.

After I got the manifold on I started the car and no surprise, it still runs like buttocks. So I mess with the idle air screw and still nothing happens. After letting it run like crap for about 2 minutes I turn the car off and go look up some TPS related threads. I see that even though the TPS is within spec for the PFC, it wasn't TOTALLY within spec with this thread http://www.fd3s.net/tps_adjustment.html It was something like .12 off for the narrow range fully closed (1.37V).

So I adjust it so that it is more within spec, however my TPS is probably not in tip top shape because once I get the fully closed within spec, the wideband Fully Open would be .09 under spec (4.11V). I guessed ah what the hell, I don't care about the fully opened throttle position, I just want it to idle, so I start the car again.

No surprise, it runs like crap yet again. As I was about to give up, I decided to record a video so that I could post it on here and get more feedback, but while recording the video/blipping the throttle, I noticed my vacuum started to rise until it finally got to about 407 mmHg, or 13 inHg.

After that I ended the video, and messed with the idle air screw and I was able to get it to idle perfectly at 720 rpm with 440 mmHg/16inHg of vacuum.

So I have no idea what it was, but appearantly it was fixed, and it just needed a little bit of throttle action to bring up the idle/compression.

After a short test drive, I noticed my car was pouring out blueish smoke, so I shut it off, and check some threads on oil smoke. Find that the PCV Valve can cause smoke and isn't necessary, so I go back to the car, eliminate it, and drive the car around and lo and behold, perfect idle with no smoke.

So alas, the car is fixed. I have no clue what the problem was, but it was magically solved. Thanks everyone for your suggestions and hopefully this thread helps people with their vacuum leaks.

Here's the said video of the magical recover:

http://www.youtube.com/watch?v=afeQx8jrZhg

Erix7rew 06-15-11 06:23 AM

The problem was your PCV valve stuck open! It act like a big leak if it's stuck open!

I'm glad to see that you solve this issue.

championadrien 06-16-11 02:56 AM


Originally Posted by Erix7rew (Post 10666611)
The problem was your PCV valve stuck open! It act like a big leak if it's stuck open!

I'm glad to see that you solve this issue.

You would think that, but the Vacuum leak was solved with the PCV valve still in place. I eliminated the PCV valve after I went for a test drive, determined the vacuum leak was gone, and noticed there was quite a bit of smoke coming out of the exhaust. So I'm still not sure what it was exactly.

but at least its finally working. =D

silver-rex-7 06-16-11 11:30 AM

Idle speed control valve needs to get cleaned or you need to buy a new one. i had this problem before and that was it. also check your VTA1 and VTA2 readings on your power fc, it might be out of adjustment. if the idle is jumping around and it stalls or dies, its the ISCV and these suckers cost a lot of mone. As long as you dont have a vacuum leak this is one of the biggest and overlooked causes of bad starts, idles, and stalls...


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