High idle

[Doulou 3]

Morning all,

I know there has been several posts relating to this topic as recently as the last thread but reading through them all I cannot find any answers or if a procedure recommend has worked!

My car more often than not starts and with in a few seconds is idling around 1600 rpm and there it stays, unless I stop the car and restart then it's fine.

i have checked tps setting, looked for vacuum leaks but not found any, recently replaced the tps, 

Its becoming a bit of worry as I think it's getting worse and not really sure what to look for next.

any advice very welcome.

thanks Paul

[sailorbob 170]

First thing to do is get a datalog and see if the idle rpm is what the ecu is commanding. If it is then check the ECT value to see if that is correct as that influences the idle rpm.

[Doulou 3]

I presume you mean a frees an log ? How will I know if the idle rpm is what the ecu is commanding? And what is the ect value and what is correct?

thanks

[sailorbob 170]

An Espritmon, TunerPro or Freescan datalog (Freescan is least preferable due to the inaccurate values for some parameters). The "Desired Idle RPM" (this is the name in TunerPro, I cannot remember what what the other two call it) indicates what idle rpm the ecu is commanding.

ECT = Engine Coolant Temperature

The ECT will start off at ambient air temperature (assuming the engine is cold at start up) and should rise to about 82 deg C.

[Barrykearley 5,360]

Flog it too me and save yourself a load of hassle 

[Doulou 3]

Thanks Derek, I will do it tomorrow and post the values.

Thanks for your input too Barry!

[Doulou 3]

Gents, I believe I have found the fault! However I want to complete a bit more testing I will then let you know what it was 

 

thanks Paul

[Barrykearley 5,360]

This is in real danger of turning into a how to keep an idiot in suspense thread 

 

come on - what was it ??

[Doulou 3]

Back to square one!

so on Sunday started the car from cold connected to freescan car ran up perfectly, IAC dropped gradually as did the desired idle and actual idle engine temp at 82 degrees. Did the same last evening exactly the same perfect.

tonight came home didn't bother freescaning and bugger me starts fine then slowly the revs go up. I let I run until the engine temp was at 92 degrees with the fans cutting, by now it's revving at about 1800 rpm

knowing that if I stop the car and restart all will be fine I decided to freescan at that point     Findings

desired idle 980  actual around 1800

IAC 135 should have been around 35

TPS sensor showing 1 when should be zero

 

switched off restarted all of the above returned to normal parameters

this is driving me mad...

 

 

[Barrykearley 5,360]

What did you change ?? Thought you'd sussed it.

sell it to meeeeeeee.......

[Sparky 2,072]

Paul - on the phone to me mum, might be a while...

[Doulou 3]

I found a vac pipe that had a really clean slit in it wasn't sure if it had gone through fully but tapped it up. After that it seemed fine

[Sparky 2,072]

Might still be the problem!  If the vac pipe is compromised, it could collapse under load.  Wild stab in the dark.

Which pipe?

[Barrykearley 5,360]

Just change all the vac pipes - they are cheap to do fella

[Doulou 3]

I thought it was a long shot pipe isn't collapsing don't really know what pipe it's one of the ones where the relays and bits are at the back of the engine bay

could my IAC be sticking?

[Barrykearley 5,360]

From memory you can put a vac guage on one of the pipes and see what's going on - it's in the workshop manual what's normal. Remember doing it to mine.

the iac valves ain't great - are you absolutely sure it's the correct one? Does it wobble? Is the o ring seal good on it ??

[Doulou 3]

Yes for sure the correct one proper fit but I don't understand why it was running at 135 when it should have been much lower on the previous runs it was reading fine

also it resets at 170 then goes up to about 230 before dropping is that normal?

[Barrykearley 5,360]

Mine did all sorts of strange stuff to be fair. They seem to get confused where they are and need to be reset and relearn to get the knickers out of a knot.

you need to check you haven't got a vac leak as that does strange things - I'd be doing that as a first check

[Doulou 3]

To be honest Barry don't know where else to look

[Barrykearley 5,360]

I worked through a section in the workshop manual on mine - it gave me a list of things to check. You need a copy of emh I think for yours.

do you get any cel codes flagged or not ??.

[Doulou 3]

No CEL codes or EML light I don't think I have the EML section in my manual I will take a look

[Barrykearley 5,360]

For high idle - there is a section - and it lists what to check - one is run through the code 35 chart.

[Doulou 3]

Evening all,

so here's the latest, took the car for a drive tonight, well it wasn't really a drive it was almost undrivable the car was stalking the moment the car was out of gear and it's running was terrible a bit like running on two but it wasn't I am now thinking either electrics or fuel (pump / filter)

any thoughts?

Paul

 

[Barrykearley 5,360]

Paul,

you need to run through the fault finding charts - there's some very specific instructions and logic as to how to approach this one. I'd be recommending not driving it until you have gone through that.

or - my offer still stands 

[Doulou 3]

I don't have them Barry, well I don't think I do what are you referring too?