Throttle Body issues & low revs + trouble starting

[Deeps]

Guys, I need some advice and some more info if you have experienced these problems with your FTO.

I have a 96 GR tiptronic.

Over the past few months I have noticed my car having idle problems when stopping at lights (i.e. when the car is in drive but is stationary), it began with some shaking of the engine when stopped at lights and when I moved the steering wheel the revs would jump up slightly. After a while they got so bad the car wouldn’t start unless I started it like my old car (Gemini) and pumped the gas as I turned the key. I needed to keep my foot on the accelerator for about 5-10mins until the car was warm enough to handle staying on idle itself. Even when the car got warm enough to handle its revs, they were so low that they were almost non-existent on the taco and the car would shake slightly. I sent the car to the mechanics who confirmed that there was a collapsed engine mount that was possibly causing the shaking and that they pulled out the idle sensor/throttle body and gave it a good clean.

The car then got a little better but not for long. A few weeks later it was back to its old tricks but worse this time.

I ran into trouble last week when I had to stop/slow down suddenly due to the car in front of me and as a result my engine cut out and the dash went to reds. This caused the power steering to cut as well. This happened half way through a roundabout and I almost got cleaned up by another car.

I gave the car to my mechanic on Tuesday and gave him details of the issue. He sai8d he spent several hours (with this ex-Mitsubishi mechanic) to try and identify the problem.

They finally came to the conclusion that there is something wrong with the throttle body unit and ordered a 2nd hand replacement (apparently Mitsubishi have stopped manufacturing these). It took him two days to locate a spare at a wrecker at Greenacre and had to drive out to get it themselves.

Anyway, the part was installed and I got my car back yesterday. The idle is much better when stopped at lights (looks like 500-600 rpm), however when the A/C is on the car goes back to struggling when idle at the lights. Additionally It still needs some help getting started (pumping the accelerator slightly).

My mechanic said to give it some time and see what happens as the ECU of the car needs to interact with the new throttle body and sensor and then it will begin to settle. Otherwise it may mean there are issues with my A/CD compressor.

So, I’m looking for anyone who has experienced the same or similar issues with their FTO so I can address any underlying issues that have been overlooked.

Any help and advice is much appreciated.

Thanks in advance guys

[vipfto]

stepper motor mate, doubt TB was at fault. Also try increasing idle a little (screw on top of TB)

[Deeps]

Yeah, he did say that stepper motor was the main issue but apparently needed to change the whole TB unit as thats how it came from the wreckers. Am surprised it cost so much. It would be easier for me to buy a half cut and turn to that evertime I needed parts.

So you say the idle speed can be managed manually? I asked the mechanic this and he said its all contolled by the computer???

I remembered I used to do it on my old gemeni but wasnt sure if the capability was in this car or if I might muck up the computer and settings.

Ok, I'll check out the idle srew.

Thanks

[dstocks]

Have you already paid the cash. I have a throttle body on an engine in the shed here if that helps.

[Deeps]

Hey Duane

I know mate, I should have checked with you first.

Yeah, already paid the cash and had it installed, but Im still experiencing start up probs. It still needs a pump of the accelerator and the revs held above 1000 for a few seconds for it to be able to idle.

Any idea what it could be now guys?

[Gholdwayne]

Ok so if iremember correctly, the stepper motor is attached to the tb, so when you replaced yours, the stepper would have been too...

If it is the stepper, i have a spare one i taxxed from a galant recently in the wreckers that you can try.... but if its not the stepper, then we'll have to figure out what the problem is...

[Deeps]

Yep, thats right. The stepper motor is connected to the tb. The mechanic said he needed to purchase the entire unit (tb + stepper motor) from the wrecker so thats why he replaced both.

So do you think there was something wrong witht he old stepper motor and the same type of problem exists in this one too?

[Gholdwayne]

if the stepper is full black, chances are its a replacement - should be good... But if it is a silver one with a tan coloured plastic on it, good chance its stuffed or going to be stuffed anyway. But they both cant be stuffed together, check the wiring of your stepper?

Don't be limited to the topic of the stepper, it might be something else...
Although the 'revving til warm to have it maintain it's idle' sounds very stepper ish...

[dstocks]

It sounds fuel based, Wouldnt be your fuel filter or fuel pump would it?

[Deeps]

A mate of mine mentioned the same thing yesterday. I will speak with my mechanic again to see if he can take a look.

[dstocks]

I had one that was having trouble a while back like that and it ended ub being the fuel pump. If the fuel line empties out when you stop the car for example, it takes a little while to pull it through again.

[Deeps]

Guys, if it turns out to be the fuel pump, anyone got one they can part with?

dstocks, how about you?

I'll place a comment in the parts section too.

[Bennoz]

I've got a spare pump if you want to try it.

[Deeps]

Cool, thanks Bennoz. I will keep that in mind.

I just spoke to my mechanic and he agreed that if this symptom is still evident after the replacement of the tb and stepper motor it is likley to be the feul pump. However, he said that he would rather run some test to confirm it is in fact the feul pump causing the issue before jumping to conclusions.

So if it truns out to be the feul pump, I'll grab it from ya.

How much are you asking for it?

[Bennoz]

Mate a case of beer would cover it

[Deeps]

Mate a case of beer would cover it

SWEET!

Lets see what the mechanic finds.

[payaya]

Its not your fuel pump!!

If your car has no issues above idle speed I doubt it's your problem.

I bet you are experiencing the below problems some you already started.

Warm idle speed during cold startup (should rev to 1500rpm and slowly come down when engine is warm)
Instead of increasing RPM the RPM drops when AC turned on.
RPM are over 1000rpm when in neutral or park when engine is warm.

I bet if you turn your idle speed up via your throttle screw (easy) your warm stalling issues will disappear.

Instead of spending more money, check your ISC is clean and the coils test out by using a multimeter. Is the ISC a newer black one (should be if you got new one) or is it a grey metal type colour? Do the same when the engine is hot and with the ISC still plugged into the TB. If the coils test out, the ISC is fine, and check your ISC harness for damage.

[pearl_blu_fto]

To be honest, it sounds like the TPS....

[pearl_blu_fto]

To be honest, it sounds like the TPS....

Yeah i will quote my own post... Thank you! "Throttle Position Sensor". Sits directly underneath your Fuel Mixture Screw(located on your Throttle Body)

[Gholdwayne]

Then again that would have been replaced as well since that is also connected to the TB.... Maybe it could be the wiring harnesses...