Tiderfish

I have had this issue 3 tymes with my 1990 Vert (Stock). I will start the car. Back out of the parking space, then I will start to move it, and the car will jerk back and forth. It's like I can't drive stick anymore. I tried shifting to second, and the same thing happens. I also noticed I can't rev the engine past 2000 RPMs.

Time is the cure for this. Usually it will go away in about 3 to 5 minutes. Then the car runs fine. This happened twice in a row. Then stopped for two weeks. They it happened again yesterday. Both times that car was warm. It had been warmed for the commute, then sat for maybe 30 min.

Any help will be greatly appreciated. Thanks!

Matt|ttaM

Tiderfish

Another interesting comment to make:
Lately when I get out of the car I can smell a slight burning. It's not sweet like coolant more like rubber or something like that. It's defiantly not circuitry. I have roasted many PCBs and I know all about that smell.

Any and all ideas are welcome. I have tried searching here, but can only find posts about the 3800 hesitation.


Matt|ttaM

SureShot

When the TPS wears out it will start to get drop-outs in the resistance values near closed throttle.
When the ECU sees >1500 RPM and the TPS value drops to "idle" you get random fuel cuts.

here's an example

Tiderfish

Thank you for the reply SS.
When this is happening I cannot get past 2000 RPMs I noticed on the audio file you linked that car gets much higher. I even heard a brief redline buzzer.
However I am not ruling this out. How would I go about troubleshooting this possible problem? I have a digital multimeter, and a Hayes manual at my disposal =)

Matt|ttaM

SureShot

This is one of those rare deals where a cheap analog (needle type) meter is more informative.
The DMM will work, but you have to really watch it to see some short drop-outs.

Here's my TPS checklist:
Using test lights or voltage at idle readings will get your idle setting perfect, but you could still have a worn out TPS resistor.
-The golden test:
Unplug the TPS connector.
Clip a cheap analog (needle type) VOM on the orange & black pins.
Set it to the 1K scale.
Hold off the throttle & work the short range TPS plunger in & out.
You should see a smooth sweep from ~0 to ~5K ohms.
Any bad spots or drop outs in the stroke - it's bad & will give fuel cuts at part throttle.
(Before you toss it, try spray contact cleaner between the sleeve & plunger.)
- Then set it:
Find the fast idle (warm-up) cam & push it back so the throttle sits on the hard idle stop.
Adjust the setting to 1K ohms.
While holding off the fast idle cam, open & close the throttle a few times to see that the 1K setting repeats.

It could be something else, but try this first.

Tiderfish

Wow thanks for the indepth reply. I will try that ASAP. If anyone else has ideals let them flow!

Matt|ttaM

SureShot

What about the "check" engine light?

Tiderfish

The check engine light has not been on. Occasionally it will flicker on for less then a second. This usually can be attributed to bumps in the road.

Matt|ttaM

SureShot

If it flickered, it saw a problem and memorized it.
And - guess what? The TPS error will act that way.

Pulling the error code is easy on an S5.

Check out the pdf of the "fuel & emissions" section of the FSM at the link in my sig.

mibad

Yea, I don't know much about your car, but I'll tell you of a problem I had with a jetta once that sounds kinda similar. There was a break in the air intake hose that wasnt visible. When it opened up it would gobble extra air. The car would jerk and cause it to close and open again. One day I took the intake off and found the crack in the hose. Surprised the hell outta me.

Tiderfish

Can anyone please tell me where to locate this sensor to test/replace it? I tried taking the car to my shop, but they are too scared to work on my 7. I have also downloaded and searched the fuel & emissions FSM and have not found anrthing referancing the TPS. Have help with someone that knows engines, however just not rotaries. THANKS!

lov-2-rev

iTrader: (87)

Also check the plug connection on the MAF. Sounds silly, but I was chasing what I thought was a "fuel cut" or injector problem for over 3 weeks. Car would have these random cuts in acceleration. After a hellified ride to E-town New Jersey this past Sunday, my friend leaned under my hood to listen for a "hesitation" when he inadvertently leaned on the plug to the MAF. We all heard a click, and voila! Problem solved. Seams that the clip had gotten bumped. When the engine bay heated up, the contact would move slightly, causing the problem. The ride home was a lot faster with not one hitch.

Goofy

The TPS is referred to as the throttle sensor in the manuals. I have an '88, so I can't help you locate it.

Tiderfish

Thanks for the replies. In the FSM there are 2 sensors. The Throttle Sensor, Full range and Narrow Range.

lov-2-rev, I have no idea where the MAF is. Please shed some light on that. Also if you know what it is refered to in the FSM please include that.

Thanks again for the reads/replies.

Matt|ttaM

CSM RX7

Any luck fixing your problem? Mine does the same thing. I've suspected the TPS and also maybe the AFM. The both seem to test out fine, but the problem is intermittent. So it's possible that when I've tested them they are working properly.

By the way - the AFM is the air flow meter. It is located right behind the air filter box, near the front of the car on the passenger side, with a 5-wire black plug coming out of it. The clip does tend to wear out over time. At one point, I ended up removing it and soldering wires directly to the terminals, with my own connector to go to the harness.

Tiderfish

I fixed my issue.

One day when it was doing this, I looked under the hood, and played with throttle cable. I noticed that the 2 plungers were not operating proplery. The top sensor, (the smaller one) was tracking in and out with the throttle link. (metal disk) However the larger plunger was getting stuck, about midway out. I flicked it, and it popped out. Then I pulled the throttle cable again, and it revved waaaaaaaay! w00t that fixed it. A simple fix for a problem. Later I sprayed on some WD40, and it hasn't happed again!

WWWWWWWWW00000000000000000000000000000TTTTTTTTTT

Matt|ttaM