Technical Punto 55s Erratic Idle

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Technical Punto 55s Erratic Idle

badboy4life05

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Hi, all

I have a problem with a (P reg 1996) Punto 55s 1.1 Petrol. Wondering if you any of you could help me out?

I bought the car about 3 months ago with an idling problem, I got told off the guy it was a simple problem to fix, all it needed was the idle stepper motor replacing/cleaning. First of all following the Haynes manual i cleaned the Idle Stepper Motor.

Still no effect on the idle it still surges between 1500 - 2000 rpm and then after about 30 secs the revs build up on there own to about 5500 rpm till i push on the throttle to bring it back down again then it continues to surge.

so i went and bought a full Throttle body i took the old one off put the new one on still the same.

Tried all the sensors with new ones, reset the ECU, checked all the vacum pipes for splits, oh and stripped the engine to check all the gaskets which they are all fine, but because i stripped the engine i have to replace all the gaskets with new ones,

so pretty much ruled out its not a gasket. im going to buy a gasket set today and rebuild the bugger.

Could this problem be electrical (bad earth) ????, Faulty ECU. the car has only done 64k the head gasket looked in really good codition.

If anyone has had the same problem and solved it i would love to hear from you :) as its really doing my head in now.

Cheers All

Adam
 
Hi Matt,

I have not checked the Alternator as yet, would that cause a problem, and how would i go about checking it.

Well i think by the time ive finished i would have replaced all the car lol

Thanks for the reply Adam
 
Give it to an auto electrician. I once put a crap alternator on a car and my revs went up and down more than a tarts knickers:D . In fact it did exactly what youre describing. Sounds like youve tried most things so it'd be worth giving it a go.
 
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Well once ive rebuilt it, will try a new alternator see if that fixes the problem, then if still no. Will need some C4 lol,

na will give the auto electrician a call see how much he will charge to have a look,

Another Quick Q - Do you always have to have the head skimmed when you take it off even if the head gasket was not blown in the first place ??

Cheers Adam
 
Regarding head skim, if it was alright before you removed it, providing it was loosened 1/4 turn each bolt in sequence then probably ok. New stretch bolts are a must though in my opinion. Skimming is only about £15, so do you really want to do it twice?. I have read somewhere that stepper driver in ECU can give trouble. Take a voltmeter to TPS and check that sensor voltage sits at zero volts on tickover, if so then too much air is getting into manifold, you have ruled out leaks, so it must be getting past the idle valve, you have replaced that, so it must be the idle valve is being opened by wrong stepper control. If the ECU is not the fault then maybe it thinks the temperature is low ie a cold morning and is winding up the revs to compensate. What ECU have you got there?.
Tony
 
yeah i know it was a stupid mistake now,:bang: but when i bought the car it seemed like such a small thing. We asked him why he hadnt fixed it but he said he hadnt had time to look at it....hmmm. lol.

cheers for the advice reddy(y) deffinately gonna get the head skimmed if its only that cheap, then once its back up and running again, i will check the volts. but will get back to ya for more advice lol.

keep checking back cause i really need some help. hopefully wont be too long till the engine has been re-built.

cheers v.much.

adam
 
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