Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features: Join our community! |
- Pages:
- 1
- 2
| IAC valve discontinued 91 metro, now what?; stuck on IAC | |
|---|---|
| Tweet Topic Started: Jul 23 2014, 09:50 PM (2,563 Views) | |
| dvrocc | Jul 27 2014, 02:24 PM Post #16 |
|
New Member
![]() ![]() ![]() ![]()
|
I got the vacuum lines changed phew some were bad and was moving more air then my dead grandma! Anyway, I checked the timing and the smog tech had it retarded -6 degrees even though I told him that he has to plug the two vacuum lines on the distributor and time it but he didn't believe me and I wont be taking my car back to him, jeez it isn't hard to take 45 seconds and read the hood sticker that explains how to time it correctly....... Also when me and my farther were checking things over during the timing he got on the pedal and kept it steady at about 2500 rpm and it started to fluctuate and I popped the IAC line off and put my finger over the hole and it smoothed right out so now I know for a fact that it is messed up so now I just have to track one down. |
![]() |
|
| Old Man | Jul 27 2014, 06:40 PM Post #17 |
![]()
|
Did you bother to read the reference thread I gave you in post #3? If so why would you spend the monies for another one when you can sacrifice a ball point pen and an hours work and fix the one you have. |
![]() |
|
| dvrocc | Aug 1 2014, 07:56 PM Post #18 |
|
New Member
![]() ![]() ![]() ![]()
|
We are looking to hit up the junkyard (auto wreckers) in the next couple days and see if I can scrounge up a couple three used idle air control valves from the 91s metro & swift and then take the best parts from all of them to make one good functional IAC valve xD Also going to grab a few extra sensors if they look good or better then mine, I seem to have good luck so I am hoping it will pay off. |
![]() |
|
| dvrocc | Aug 6 2014, 02:32 PM Post #19 |
|
New Member
![]() ![]() ![]() ![]()
|
Alright, got two Idle Air Control Valves both from a 91 and 92 and when I looked at a 94 IAC valve it was different and it was mounted flat and the engine was just a bit different from what I seen so I avoided that one. Now I have 3 idle air control valves to work with hopefully I will have some results in a day or two. Also at pick - n - pull Chico Ca was a nice 91 metro engine it was brand new install shiny and everything, my jaw dropped because I needed some of those parts but I didn't have the cash with me ........er! |
![]() |
|
| dvrocc | Aug 7 2014, 04:38 PM Post #20 |
|
New Member
![]() ![]() ![]() ![]()
|
Ok, the IAC valve is installed and working normally however the issue still exists and wont hold revs at 2500 RPM, will explain a bit more below. So what happened is the car when connected to the smog techs machines will hold revs at 2499 rpm (exactly 2499) or below smooth as silk but when you try for 2500 it instantly revs to 3100 and then revs start dropping between 1950 and 3000 rpm and soon as you let of the gas pedal it smooth's out, so anything between 2500 and 3099 rpms it goes haywire and it almost feels like a flat spot on the gas pedal cable. An example would be if you were driving at 50 mph and then instantly driving 65 mph with no delay in between, this is what is happening with the rpm's but it only does it when the engine RPMs hit exactly 2500, you can rev engine to 2600 or 2700 or higher but it only goes haywire exactly 2500 rpms. Any ideas here? |
![]() |
|
| Woodie | Aug 8 2014, 06:55 AM Post #21 |
![]()
|
Bad spot in the TPS? |
![]() |
|
| dvrocc | Aug 8 2014, 02:02 PM Post #22 |
|
New Member
![]() ![]() ![]() ![]()
|
We did just check the 'throttle potion sensor' this morning and I ran a volt meter on it just to make sure juice passes through it and it came back clear, my TPS is plastic with some copper and it looks like the old contact breaker points used in the older cars and I used a bit of 600 grit sand paper on them followed up by a good dose of carb cleaner, it was just a bit dusty is all. Basically my TPS has three copper arms and it has three settings, top contact, bottom contact & middle contact which just floats and doesn't touch anything. Edited by dvrocc, Aug 8 2014, 02:08 PM.
|
![]() |
|
| dvrocc | Aug 9 2014, 08:39 PM Post #23 |
|
New Member
![]() ![]() ![]() ![]()
|
Ok, I think we finally found the culprit of my 2500 - 3000 rpm engine surge that was causing everything to go haywire, the 'throttle position sensor' located on the passenger side of the TBI was factory set and was never changed or adjusted in the 23+ years it has been running & the car is loose with 182,000 miles on it. From what I can tell looking things over it has three copper arms & the sensor does three things at certain points when the gas pedal is pressed, which are idle, acceleration & full throttle. What was happening is the acceleration part of the TPS was being skipped and it was going from idle to full throttle setting which explains the 2500 - 3000 rpm jump and the cars computer was going haywire trying its hardest to compensate the different which was causing the surging. How I adjusted: stepped on the gas pedal till the surging started then taped the TPS just a tiny bit till the surging stopped and then locked down the screws. Its important to not over due the potion of the TPS because it will dump tons of air into the engine which causes the idle to be about 1500 rpm instead of 850 rpm so you have to find the sweet spot. Will follow up with the smog check on Monday to see how things will go. |
![]() |
|
| myredvert | Aug 9 2014, 09:34 PM Post #24 |
|
myredvert
![]()
|
Congrats on finding the problem. Kudos to Woodie. As soon as you get a chance, why not set the TPS correctly using the FSM procedure? Unfortunately, I believe the chapter the TPS adjustment procedure (6E2-C1) is the only section missing from the 1994 FSM in the forum library, but maybe someone with a 94 or older FSM can help you out getting a copy? |
![]() |
|
| dvrocc | Aug 11 2014, 04:14 PM Post #25 |
|
New Member
![]() ![]() ![]() ![]()
|
So I passed the smog and good to go! it was the 'throttle position sensor' and the adjustment I did worked however the smog tech guy had to adjust the idle from 950 to 850 so the car would fall into county smog stats and the timing was slightly off, other then that it passed with flying colors. smog test stats <---- clicky |
![]() |
|
| 1 user reading this topic (1 Guest and 0 Anonymous) | |
| « Previous Topic · Engine Tech & Diagnostics · Next Topic » |
- Pages:
- 1
- 2


Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.


![]](http://z3.ifrm.com/static/1/pip_r.png)





3:50 AM Jul 11