When cold, the rpm's start out around 2.5k then slowly starts to dip down like it should, but before it gets to 1k, it will rev up to around 3k then back down. It will do this for awhile. Once it gets close to normal op temp it levels off and appears to be fine.

When warm it idles around 1k or a little under. Sometimes smells a little rich, but no smoke out exhaust.

I know I need to get it on a scanner, but don't have one right now. Any ideas?

Also car was not driven much at all over last year.

anyone?

Ed and myself were just talk about a simular situation like this sunday. Try taking your intake off and cleaning your throttle body out with some good throttle body cleaner, and and old tooth brush, also make sure you find where your Idle Air Control (IAC) Valve is and be sure to get that area good.

quote Originally posted by wanobi: When cold, the rpm's start out around 2.5k then slowly starts to dip down like it should, but before it gets to 1k, it will rev up to around 3k then back down. It will do this for awhile. Once it gets close to normal op temp it levels off and appears to be fine. When warm it idles around 1k or a little under. Sometimes smells a little rich, but no smoke out exhaust. I know I need to get it on a scanner, but don't have one right now. Any ideas? Also car was not driven much at all over last year.

sounds liek either a bad TPS sensor or a bad ISC motor, but you'll have to trouble shoot it first.. if you replace either of them, make sure you calibrate the new one according to the instructions in the book

Good news, late last night one of my buddies called and said he has a scanner he will let me borrow, so hopefully I can get to the bottom of this issue.

The ISC motor, should I hear this thing running at anytime, be it start up or turning the car off?

Since the car had not been driven much over the last year, I probably need to change the filters out for sure and probably run some good injector cleaner through it.

The only experience I`ve had with the Cadi 4.9 , was in the one my Mom gave to my wife (1991-3) just wanted to toss something out here, isn`t 2500rpms on a cold start kinda high ?

yes it is and that is another issue, but hopefully once I get it on the scanner all we come clear.

quote Originally posted by KeithGT: Ed and myself were just talk about a simular situation like this sunday. Try taking your intake off and cleaning your throttle body out with some good throttle body cleaner, and and old tooth brush, also make sure you find where your Idle Air Control (IAC) Valve is and be sure to get that area good.

I was unaware there was an IAC on the 4.9, as far as I know it just uses the ISC motor. There is an idle adjust screw - but you manually have to set that as a base idle during the idle learn setup. Alhough, having a clean throttle body couldn't hurt

*****

Anyways, check your TPS sensor and make sure it is operating correctly and then you can try the idle learn procedure ( https://www.fiero.nl/forum/Archives/Archive-000001/HTML/20050119-2-049097.html ). Also check your grounds.

I would venture to say that your ISC motor is working fine, since the idle is changing - it relies on the TPS sensor for the reading. You could also check the MAT and MAP sensors as well and double check the temp sensor reading. As for running rich - check the O2.

Tim

Ok guys, here is what I know now that I've got my hands on a scanner.

I had 2 codes set:

1 code 52 ecm memory reset
1 code 65 c/c servo position sensor


While I had it in data analysis I saw some interesting things and this is where I think my trouble maybe

the volts for my O2 sensor were jumping around from .34- .63
the volts for my map sensor were jumping around from 1.08- 1.24
the fuel stat kept switching from rich to lean
my O2 counts were from 0-6

TPS voltage stayed right at .59v

I tell you what, having a diagnostic device sure is pretty cool. Too bad I have to give it back soon

Oh and my RPM gauge is off by about 450. So when I thought I was idling at 1k when warm it is more like 550.

Based on what I'm seeing, would it be safe to say that my O2 sensor and my map are going bad????

Thanks in advance.

quote Originally posted by wanobi: the volts for my O2 sensor were jumping around from .34- .63 the volts for my map sensor were jumping around from 1.08- 1.24 the fuel stat kept switching from rich to lean my O2 counts were from 0-6 TPS voltage stayed right at .59v Based on what I'm seeing, would it be safe to say that my O2 sensor and my map are going bad???? Thanks in advance.

...it's normal for the O2 values to change constantly, as a result, the rich/lean flag will also change constantly, etc. The FSM will tell you what the normal values are for these readings.

...verify the tps sensor is working correctly - with the car not running (key on) monitor the scanner as you slowly increase throttle position. Make sure the tps value rises ok. If it drops off/changes values to some other number really quickly and back to normal, you probably have a dead/bad spot in the tps sender.

Do the idle learn proceedure...

quote Originally posted by Mickey_Moose: ...it's normal for the O2 values to change constantly, as a result, the rich/lean flag will also change constantly, etc. The FSM will tell you what the normal values are for these readings. ...verify the tps sensor is working correctly - with the car not running (key on) monitor the scanner as you slowly increase throttle position. Make sure the tps value rises ok. If it drops off/changes values to some other number really quickly and back to normal, you probably have a dead/bad spot in the tps sender. Do the idle learn proceedure...

Ok, I'll check the tps sensor.

The interesting thing is that while I had it on the diag device, the car didn't do the crazy revving thing it was doing while trying to get up to norm op temp. Maybe the whole not being driven thing has some weight to it. I've driven it quite a bit since I got it.

I keep reading about the idle learn procedure, it just makes me a little nervous, but I guess it has to be done .

quote Originally posted by wanobi: The interesting thing is that while I had it on the diag device, the car didn't do the crazy revving thing it was doing while trying to get up to norm op temp. Maybe the whole not being driven thing has some weight to it. I've driven it quite a bit since I got it.

When I hooked up winaldl to a couple of my 2.8`s the car`s ran great in the field service dio mode, then the minute I took it off , they where back to the same troubled problems I had with them to begin with...

Ok went out and checked the TPS ...key on engine off.... while watching the TPS signal, I slowly pressed the accelerator til I hit WOT and the voltage steadily climbed and steadily dropped back down.

I then turned the car on and got my crazy rev up and down thing going. The TPS voltage was all bouncing up and down with the revs. I never touched the accelerator. When I did press the accelerator I could climb out of it, but as soon as I took my foot off the accelerator it went right back into the bouncing revs. I'm guessing this should not be going on.

Soo, bad TPS????? Or is it something else?

...try the idle learn procedure ( https://www.fiero.nl/forum/Archives/Archive-000001/HTML/20050119-2-049097.html ).

latest update.

Cleaned TB and egr tubes...replaced fuel filter and performed the idle learn...so far so good. The car seems to respond better to throttle changes. We shall see after a couple mornings of cold starts to how it holds up. I'm thinking we should be good.

Next phase is to replace front wheel bearing and replace trans fluid. Then on to the cosmetics!!

But I also thought Betamax was going to win out over VHS.

[This message has been edited by wanobi (edited 08-27-2006).]