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New (old owner) - self-revving prob
http://www.gt4dc.co.uk/forum/viewtopic.php?f=2&t=7228		 Page 1 of 2
Author:  jon_st205 [ Tue Nov 25, 2014 10:16 am ]
Post subject:  New (old owner) - self-revving prob
Hi all,

Old timer here with a new ST205 bought on a whim. Bit of a shed to be honest! The engine & turbo feel in good health though, and hopefully I can fix the other stuff like the usual dead sillystrut.

One problem I wanted to take advice on is if I clutch from a reasonable amount of revs, the car revs up & down by itself a bit when trying to find an idle. I was thinking of cleaning the ICV out as a reasonable first port of call? I can also see at least one vacuum hose missing (the hard line for the stock BOV on the RHS of the head); although I can't feel any suction with the engine running I'll blank this off post-haste. Anything else?

Cheers all,
Jon
Author:  two_OH_five [ Tue Nov 25, 2014 1:32 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Does it only do it then or is it always a bit hunty?
Author:  jon_st205 [ Tue Nov 25, 2014 3:35 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Nah fine apart from clutching in from, say 3k revs or more. Idle is steady otherwise.
Author:  TrackToyFour [ Tue Nov 25, 2014 11:51 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Any pics of your new Four Jon? Is it pretty much stock or has it been modded in any way?
Author:  Diceman [ Wed Nov 26, 2014 9:49 am ]
Post subject:  Re: New (old owner) - self-revving prob
Don't forget that some of the vacuum ports (in particular the ones connected to the throttle body) are sometimes open sometimes shut depending on throttle position (controlled by valves built into the throttle body)

As such a quick test at idle to see if the loose vac line is blowing, sucking or neither is not representative of all engine conditions.

I would first fix the vac line problem and see if the idle issue will go away.
Author:  two_OH_five [ Wed Nov 26, 2014 11:07 am ]
Post subject:  Re: New (old owner) - self-revving prob
Check obvious things first like sticky throttle cables etc

If it's had a recent ecu reset/flat battery it might simply be relearning how to idle. Mine has occasionally exhibited similar behaviour for a few days after being worked on.
Author:  jon_st205 [ Wed Nov 26, 2014 2:16 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Thanks guys. Okay the symptoms have changed slightly, have blocked all open vac hoses up and no hissing anywhere. However I just struck it up from cold and with no electrics or a/c load and it was fine for about 30 seconds then starting to bounce about every 5 seconds between about 1 & 1.5k revs. It did this for about 40-50 seconds continually until I gave it a little throttle which cleared it. So I think this would be the same problem as when clutching in at speed. Any thoughts?

The car is a storm grey '96 JDM, has a few bits like a (as yet unknown) hybrid, 3" DP & exhaust, filter & bov. Looks very neglected unfortunately and finding more stuff wrong every time I look at it! Looks like it's been broken into at some point too :(

One more question - radiator top mount clamps are knackered - Mr T (part number?) - or has anyone got a cheapy source?

Will chuck some pics up later.

Cheers,
Jon
Author:  Diceman [ Wed Nov 26, 2014 2:51 pm ]
Post subject:  Re: New (old owner) - self-revving prob
A few things spring to mind.
1) reset ECU (you blocking the vac lines may mean the Idle speed control valve/ECU needs to relearn and it will hunt a bit until it re-learns a setting) Also leave it for a few minutes to sort itself out a natural idle, once settled turn on AC - leave a few minutes then turn on electric loads such as rear window heater and main beam simultaneously and leave to settle again.

2) I wonder if it is a dirty or miss-aligned throttle position sensor and hence it is not activating teh throttle closed switch properly at all times??

3) when cold it will not behave normal anyway, I believe the ISC valve will be oipen more to run a higher idle RPM until it warms up. See how it is when warm after doing the above.
Author:  Nibbles [ Wed Nov 26, 2014 3:11 pm ]
Post subject:  Re: New (old owner) - self-revving prob
As above, now you've closed off previous vac leaks, reset the ECU to force it to re-learn the idle. There is a special procedure for the re-learning iirc start it from cold and just leave it idling for about 20 mins without touching the throttle.

A big air leak can cause it to go up to 1500RPM, hit over-run fuel cut and bounce back down again, but this wouldn't cause cut-out on declutch from higher RPM. It does sound more like sticky idle valve, although this is rare in my experience.
Author:  jon_st205 [ Wed Nov 26, 2014 3:44 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Thanks, there has been a recent battery change so if procedures weren't followed you'd all be right in thinking it could be that. I'll have to do it Friday now unfortunately.

Just re-checked everything yet again and found the usual snapped PCV cam cover valve :roll: But don't reckon it would be anything to do with the probs. There goes another 30 quid.

Cheers,
Jon
Author:  TrackToyFour [ Wed Nov 26, 2014 5:20 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Radiator top mount clamps listed on the EPC as:

16533-74260 SUPPORT, RADIATOR, UPPER

Image
Author:  Nibbles [ Wed Nov 26, 2014 8:10 pm ]
Post subject:  Re: New (old owner) - self-revving prob
jon_st205 wrote:

Just re-checked everything yet again and found the usual snapped PCV cam cover valve :roll: But don't reckon it would be anything to do with the probs. There goes another 30 quid.

Cheers,
Jon


My money is on this.
Author:  martinking6 [ Wed Nov 26, 2014 8:52 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Agree with chris although am surprised the revs arnt worse with a leak from the inlet manifold, usually its quite a bit more violent must only be a slight leak

Martin
Author:  jon_st205 [ Wed Nov 26, 2014 9:03 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Cool if it's just that. It's been bodged back together with gaffer tape but isn't anywhere near holding on properly. If you have a spare Martin I'd rather give you my money than Mr T.

Cheers,
Jon
Author:  martinking6 [ Wed Nov 26, 2014 10:30 pm ]
Post subject:  Re: New (old owner) - self-revving prob
Should have one I will check tomorrow, pm me your address please for delivery

Martin
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