Idle speed cold engine - QP4 3.2 Evo

Arvid

Junior Member
Messages
78
Hi all,

I've got an irritating problem on my engine. When cold it idles too hight,aprox. 1600-1700 rpm. After a few minutes it starts to settle down but will then fluctuate between 1000 and 1400. When warm it settles on 1000 rpm. I've tried to adjust the air flow potmeter on plenum but can't seem to find the sweet spot. I also find that when pivoting the potmeter the Amal valve - boost control valve - is clicking on/off. When revving the engine the Amal valve is clicking rapidly. There is no "check engine" light.

I can't understand that this is normal behavior. Does anyone have any suggestions ?

Regards,
Arvid
 

Ewan

Member
Messages
3,821
Call Myles at Emblem Sportscars in Poole. He is the guru on these engines. Tell him I sent you.
 

dt95aac

Junior Member
Messages
52
Not sure on the V8 3.2 engine, but if it's anything like the V6, then you need to follow the steps in the workshop manual precisely to get it to idle properly.
Moving the throttle pot around and hoping for the best won't work.

From memory first you do the idle stop screw, then the throttle pot sensor using a multimeter, then the idle screw.

Do you have a copy of the workshop manual?
 

Arvid

Junior Member
Messages
78
Sadly the pot is not the same as the pre-Evo cars and can not/should not be tuned with a voltmeter. The idle stop screw is also sealed of and should not be touched. The WSM for Ottocilindri states exactly what you mentioned - adjustment of idle stop screw and volts on the pot. Sadly there is no WSM for the Evo models. This car use a Weber PF09/05 pot - same as Ford Sierra Cosworth and others. Maybe I can fish some info on the Ford forums. I have also contacted Emblem Sportscars but have no high hopes as I'm far from the UK shores.
 

Arvid

Junior Member
Messages
78
I have found some interesting info on the Ford forums. The Sierra Cosworth 4WD uses the same TPS and they have a clear set up for it to function properly. I might try it as it a matter of adjusting to correct volt value. They also mention the Idle Speed Valve as a possible culprit as they are prone to carbon build up. The valve is serviceable and should be cleaned now and then.

This might work and I'll report back the results.
 

dt95aac

Junior Member
Messages
52
In newer cars there is a process where you teach the ecu the limits of the throttle pots movement. It usually involves fully pressing and releasing the gas pedal a few times.

Then if you still can't get decent idle you check your idle air control valve, remove, clean and check operation whilst removed and if that fails then check the inlet side for leaks.
 

Arvid

Junior Member
Messages
78
Thank You. I will try that procedure on the TPS. I have had this idle problem for a couple of years and was sure I solved it when I found a broken seal on one of the intake runners. All seals was replaced but still the idle acts up from cold to warm. I while ago I cleaned the idle air valves but did not dismantle them. The Ford guys is very adamant that they should be taken apart and all parts cleaned thoroughly as they are a bit sensitive to carbon build up and won't function properly after some years.

Fingers crossed :)
 

Gazcw

Member
Messages
1,547
Thank You. I will try that procedure on the TPS. I have had this idle problem for a couple of years and was sure I solved it when I found a broken seal on one of the intake runners. All seals was replaced but still the idle acts up from cold to warm. I while ago I cleaned the idle air valves but did not dismantle them. The Ford guys is very adamant that they should be taken apart and all parts cleaned thoroughly as they are a bit sensitive to carbon build up and won't function properly after some years.

Fingers crossed :)
No need to cross fingers or mess about. Just follow Ewan's advice first.
 

Arvid

Junior Member
Messages
78
No need to cross fingers or mess about. Just follow Ewan's advice first.
It's not that easy,surely. Would you expect a renowned Norwegian mechanic to take time of his schedule and answer your foreign UK call for free ? I have not lost faith in humanity but it seems highly unlikely.

I have sent an email to Emblem asking for Myles to contact me. Would be great if I get an answer - if not I'll completely understand.

Meanwhile I'll take my time and go step by step.
 

Gazcw

Member
Messages
1,547
It's not that easy,surely. Would you expect a renowned Norwegian mechanic to take time of his schedule and answer your foreign UK call for free ? I have not lost faith in humanity but it seems highly unlikely.

I have sent an email to Emblem asking for Myles to contact me. Would be great if I get an answer - if not I'll completely understand.

Meanwhile I'll take my time and go step by step.
I will let all the longterm Emblem customers respond to that question. Their knowledge is well known here.. hope you get it sorted.
 

Ewan

Member
Messages
3,821
I was chatting to Myles yesterday and have just messaged him on your behalf. He’s a top chap so sure to try to help when he gets a spare moment. They are still working through their work backlog during the lock down, but with reduced staff.
 

Arvid

Junior Member
Messages
78
Ewan,that is most appreciated. Thank you mate. The main thing now would be to know how to tune the TPS correctly as that would be my next step. The idle air valves has just been taken apart and cleaned - about time as one was sticking due to residue.
 

mab

New Member
Messages
13
I had the same problem a couple of years ago. 0.5v at idle is what I ended up with using. Got the information from this source, as the Integrale utilizes the same TPS.

 

Arvid

Junior Member
Messages
78
Thanks for the link. Yes,I think 0.5v would be ok. I see Cosworth 4x4 is set in the range of 0.35v-0.5v and they also use the same Weber Marelli system. I was sure I read somewhere that the TPS should not be adjusted with a voltmeter - clearly I was wrong as that is what everyone with same system does.

I have mostly been fiddling with the idle air valves. One of them was not operating well when tested with variable voltage. Notchy and slow movement meant that it needed to be cleaned. I think this could be the main problem regarding the idle issue. Now they both opens nice and evenly from 0-14v. Test in car next.
 
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Arvid

Junior Member
Messages
78
Well,more fiddling going on. The idle air valves are working fine - no more hunting idle during warm up stage so they did like a good clean. But,the engine will not tolerate TPS set at 0.5v - it will start with with a 2000 rpm cold idle and idle unevenly when warm between 1000-1200. I have set it to 0.30-0.35v and that seems to calm things down with 1400-1500 cold idle and rock steady warm idle at 1000 rpm. The cold idle still seems too high - what rpm other members cars have when cold/warm ? I don't know if tacho is reading correct or not but at least it's steady. I think I'll leave it like this for a while and see how things progress.
 
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RMC

New Member
Messages
26
Can I ask you where I can get 225/40/17 front tyres for that very model ?
 

RMC

New Member
Messages
26
Mmm. The handbook says 245/40/17 rear, and 225/40/17 front, and that's what's on it at the moment ?
 

RMC

New Member
Messages
26
No mention of 245/40/17 in the handbook.
Although Kwik Fit say 225/45/17 front and 245/40/17 rear, which is really odd as that would make the fronts 7mm larger than the rears.
Whereas if I had 245/40 rear, 225/40 front as per my book, then the fronts would be 16mm smaller than the rears, which makes some kind of sense to me.