[PAULBROM]

Hello all i have looked at previous topics, idle and tickover but none seem to cover my problem so here we go.
From cold the vehicle starts no problem and the rpm climbs to about 800 rpm then as she warms the rpm drops towards it 's idle setting of about 550 rpm,but since the very cold spell the engine struggles in the first few miles of driving to stay at the tickover speed and cuts out when stationary at traffic lights or road juntions.
Once at running temp it runs perfect. 4.0 ltr gems engine
Any help greatly appreciated.

 

[shupack]

mine did this too, intake air temp sensor did it for me (was reading 50F with ice dripping from it...)

 

[PAULBROM]

mine did this too, intake air temp sensor did it for me (was reading 50F with ice dripping from it...)

Cheers Dennis

 

[PAULBROM]

Forgot to ask where is it?

 

[munichp38a]

With GEMS, it's located at the air filter box.

Sigi

 

[PAULBROM]

Thanks Sigi :thumb:

 

[Col]

May not be of any relevance but thought i would just mention it as Rave say's the idle speed should be 700 + or - 20 rpm on a Gem's, so your idle speed would appear low in the first place. As it is controlled by the Engine Ecu just wondered if the Throttle Position Sensor was playing about a bit.

Only a thought.

Cheers

 

[PAULBROM]

Thanks for the info Colin.
The rpm I quote is more of a guesstimation based on a quick glance at the rev counter.
But it's a good point you have made and I will look into it.
Another question that has crossed my mind is after looking at RAVE it says a fault code would be generated if the IAT had failed and the IAT has a default setting of 40 deg.
would the only way of knowing if a fault code had been generated is having the vehicle hooked up to test book system

 

[Keijo]

Paul,

Just coincidentally fixed a very similar problem with my 98 4.0SE only 2 days ago.

Based on the info' in this site, I pulled out the Idle Control Valve to give it a clean.
It was pretty well gummed up and needed some solvent and some good scrubbing to get it clean.

I peered into the hole, and noticed that the valve seat was equally cruddy.
This obvously needed to be cleaned out as well, but was a bit more difficult to get at.

I used a flat bladed, old and rounded screwdriver with a solvent soaked bit of cloth wrapped around the end and inserted it in the hole and around and around and yet around some more.
It finally cleaned up and after putting it all back together again, idle is perfect and problem 100% gone.

May not be your problem of course, but can be a contributing factor, by making the idle control less fault tolerant.

Good luck and cheers,
Keijo

 

[Keijo]

Well Paulbrom, how about some feedback.
How did you go mate?

Keijo

 

[PAULBROM]

Sorry chaps.
Right i moved the air intake off the plenum and cleaned the oil breather pipe inlet which lies just next to the idle sensor as this was virtually blocked.
But when i looked at the sensor the smallest spanner i have is a 6mm and wouldn't fit.
So before i can remove the sensor i need to buy a nut driver of the correct size or a kit.,but i have no doubt it will be oiled up.
But remarkably the vehicle is behaving it's self now things have warmed up a little.
So it's weekend and i will be off to halfords for a nut driver kit,then i will have to replace the drag link (long end) first then see where that leaves me.

 

[PAULBROM]

Update

Fully serviced the vehicle everything done.
New sparks BPR6ES
IAC valve removed fully gunged up with crap cleaned unit and reinstalled, vehicle started but from cold struggled to idle and cut out twice.
once warm all was fine.
So while the vehicle was cooling down i removed the valve and cleaned the valve chamber and the recess where the plunger part of the valve sits.
Vehicle left to go cold and then restarted no problem with starting but slightly hesitant to idle steadily especially when the throttle was quikly pressed and the rpm was allowed to return back to idle.
I will now leave it overnight and see what happens tommorow
A couple of thoughts i have are,
How does the IAC operate.e.g. plunger move in and out of recess?
Can the pins on the valve be checked for values e.g resistance to help identify if the valve is faulty/on it's way out?
Does the Engine ecu need time to readjust after the valve has been removed and cleaned?

 

[shupack]

It's a stepper motor, it moves in little increments in/out.

Yes, the ecu will need to re-learn the "clean" settings, or reset the adaptive values via Faultmate.

 

[PAULBROM]

Cheers Dennis :thumb: don't have faultmate so i will have to be patient

 

[Keijo]

Paulbrom.

My earlier post on this thread said that cleaning out the idle control valve solved my problem 100%.

Well, the problem came back some time later, so my claim to have fixed it was premature.
I finally found the true culprit not that long ago.
It turned out to be a faulty purge valve!!
My earlier work must have disturbed the valve enough to give it a final lease of life.

I posted regarding that, just yesterday on Pegasus's thread "overfuelling when cold"
Read the post and also read up on the prurge valve and see if that might be your problem.

Cheers,
Keijo

 

[PAULBROM]

Hi Keijo thanks for the heads up on the purge valve i have just been reading about it on Rave.
I have just started my vehicle and touch wood everything is ok, blipping the throttle lightly and the idle just drops back to a nice purr so i am going to see how it settles over the coming weeks due to it being an adaptive system it might take time to settle and if the problem does reappear then look at the purge valve as you suggested.
It was deffinately a good find as the valve can cause some real headaches as regards messing up the ECU values for fueling and there is no default settings for the ecu if it fails.
Cheers for now and heres to the next few weeks.
Might have to start looking at a faultmate :think:

 

[HSE]

Hi Keijo thanks for the heads up on the purge valve i have just been reading about it on Rave.
I have just started my vehicle and touch wood everything is ok, blipping the throttle lightly and the idle just drops back to a nice purr so i am going to see how it settles over the coming weeks due to it being an adaptive system it might take time to settle and if the problem does reappear then look at the purge valve as you suggested.
It was deffinately a good find as the valve can cause some real headaches as regards messing up the ECU values for fueling and there is no default settings for the ecu if it fails.
Cheers for now and heres to the next few weeks.
Might have to start looking at a faultmate :think:

Ok, something important to know about the IAC valve cleaning. It really requires a manual/electronic reset as well as the adaptive reset. Right above the IAC valve is a small plug in the throttle body, located in this hole is a allen key bleed screw. A diagnostic system for the engine ecu needs to be connected to see the steps at idle. Each one I've cleaned or replaced has been high in the reading, about 48 steps usually. It needs to be at 22 steps with a working temp engine A/C off. If this is not done the perfect idle will never happen. You may get symptoms like idling too high or low, or stalling at all temps.
Regards Russell.

 

[Col]

Right above the IAC valve is a small plug in the throttle body, located in this hole is a allen key bleed screw. A diagnostic system for the engine ecu needs to be connected to see the steps at idle. Each one I've cleaned or replaced has been high in the reading, about 48 steps usually. It needs to be at 22 steps with a working temp engine A/C off.

Have a look at pages 83 - 85 shows the bleed screw HSE is referring to. Not a P38 but still a Gems engine.

http://www.gomog.com/allmorgan/GEMS/GEMSbyPoole.pdf

Cheers

 

[PAULBROM]

Cheers all.
Some interesting reading there col on the morg site :thumb: