Help! Bouncing RPM when reving past 1750rpm when car is stationary on stock 2000 RS

[ascari]

maybe try a know good ECU, someone on here would have one knocking about

Would be great to do this... anyone in the Birmingham area...

 

[ascari]

I rechecked the TPS, it may be the cause.

It reads the correct voltage range on the narrow range, but the voltage is inverted on the full range (closed throttle = 4.5v, full throttle = 0.4v).

I've taken it off, sprayed contact cleaner down the socket pins, but no good. Not even sure the cleaner is getting in there enough.

Can it be cleaned? Anyone got a spare I could buy?

 

[ascari]

The TPS is fine... I was testing it incorrectly...

I checked for leaks by vaping into the UIM via the brake servo vac line, no obvious leak there.

The troubleshooting continues

 

[Spendyrx]

Have you checked that icv yet mate?

 

[ascari]

Have you checked that icv yet mate?

Thanks for reminding me. I've disconnected it to check the ECU throws an error code, which it does, so i'm looking at that right now.

 

[Spendyrx]

Tidy! Also it may be worth adjusting you idle screw out temporarily, bring the idle up to 1k - 1.5k rpm and see if the hunting goes away then! Idle screw usually belongs one turn anti clockwise from fully closed

 

[ascari]

Have you checked that icv yet mate?

The ICV has a resistance of 12.7ohms, the FSM says it should be between 10.7-12.3. Is this enough to be bad?

 

[Spendyrx]

Haha no idea

 

[ascari]

Haha no idea

Same here... the voltmeter has a 1.8ohm resistance in it't own circuitry/probes, so the ICV is absolutely fine. gonna tinker with the idle as you suggested now.

 

[Spendyrx]

Yeah I reckon that would be good! Try the idle screw and maybe adjust the screw closest to alternator! Leave the thermo wax one by the tps alone for now

 

[ascari]

Yeah I reckon that would be good! Try the idle screw and maybe adjust the screw closest to alternator! Leave the thermo wax one by the tps alone for now

I checked the idle screw (under the intake elbow) it was out by nearly 5 turns. i've screwed in in fully, now the idle is 1000rpm which is an improvement in 1200, but still hunts under lite acceleration.

The AWS wax pot extends when warm.

I'll do some fiddling with screws, but get the feeling they're red herrings.

 

[Spendyrx]

Hmm....does the idle come down when the car warms up? I only say because this was my trouble!

 

[ascari]

Hmm....does the idle come down when the car warms up? I only say because this was my trouble!

it does. by all accounts, even with the idle screw a km out, it's never had any trouble idling. the moment i accelerate, it hunts like an ass.

 

[Spendyrx]

Ah I see! Umm.....I feel your pain brother! My brain is now fried

 

[ascari]

Well, the idle is now at factory spec (750rpm) which is a real positive, as it used to be around 1300...

It now ALWAYS hunts past 1750rpm. At least the weather's nice

 

[Spendyrx]

Can you do a you tube vid n post a link of it?

 

[ascari]

Can you do a you tube vid n post a link of it?

I'll do this. New info, if I turn the cabin heater on full, the hunting starts at the higher RPM of 2500!

 

[ascari]

FIXED! It was the TPS after all. I must have knocked it whilst working on the car, but then I had checked it's voltage ranges on a cold engine, therefore the AWS wax pot was engaged... i should learn to read the manual better.

Thanks for the help

 

[Spendyrx]

fucking great news Adam! Good job mate

 

[shaunwil]

Good to her