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Stalling on low revs...

Posted: Sun Oct 25, 2009 9:33 pm
by SimonB
Ok, so here's the situation ...

(Overseas trips always seem to bugger up the works)

Pumba was recently serviced with the main rider on the service that my starter needs an overhaul. Before the service she stalled soon after startup if I didn't keep the revs up for minute or two, almost as if she were behaving like the days of old with manual chokes. They replaced the fuel filter which looked bad and everything ran fine for probably 400 kays.

Now, the situation is:

At startup, if I don't keep the revs high (around 3000 for about 20 seconds), she dies.
Previously, if you turn the aircon on at idle, the revs climbed by about 300rpm - this is the compensator. Now, if I turn the aircon on the revs drop by about 200rpm, almost to the extent that the check engine and battery light might flash (and it confuses the solenoid on the DB system)
If the steering is at full lock when cold, she is prone to stalling.

Any ideas as to what might be causing my woes? Once warm, the car runs fine.

Re: Stalling on low revs...

Posted: Mon Oct 26, 2009 12:28 am
by HBannink
Sounds like the cold start map might be a bit low. Turning the steering to full lock loads the engine as would the aircon. If the cold start map does not give a rich enough mixture this is the time that it will behave at its worst and stall. Take it back to the stealers and ask them to push the cold start map up slightly

Re: Stalling on low revs...

Posted: Mon Oct 26, 2009 7:30 am
by 4ePikanini
maybe it's old fuel. just a wild guess. otherwise I agree with the cold start map.

Re: Stalling on low revs...

Posted: Mon Oct 26, 2009 7:55 am
by SimonB
What concerns me more is the fact that whereas previously the revs picked up when the aircon kicks in, they don't anymore so I'm wondering if I also have an electrical problem.

Re: Stalling on low revs...

Posted: Mon Oct 26, 2009 3:43 pm
by HBannink
It could be electrical but my guess is that they accidently tweaked a wrong parameter when they serviced the baby. If the revs pick up when at operating temp they almost definitely have done so.

Re: Stalling on low revs...

Posted: Thu Nov 19, 2009 3:50 pm
by SimonB
Ok, so I have phoned and booked my vehicle back in to have the starter motor overhauled (I know if I had the time I should do it myself).

I discuss with the mechanic the problem at low revs below:

Symptoms:
Revs barely over 600 at idle (although not always), and prone to stalling, especially when cold. Idle levels do not change when the the engine is warm.
When one switches the aircon on the revs drop, whereas they are supposed to increase. Engine more prone to stalling.
When revs drop too low, to around 400, even if it doesn't stall, it fools my dual battery solenoid into switching back.

Tentative Diagnosis Note emphasis :roll: :
Faulty idle stepper motor, or stepper motor not receiving any signals from the ECU

Your thoughts. What Alan explained to me certainly seems to make sense....

Hopefully not to expensive.

Re: Stalling on low revs...

Posted: Thu Nov 19, 2009 4:03 pm
by CATS
Sounds right on the diagnosis. Did they not just forget to plug something back, like a vacuum advance or something like that?

CATS

Re: Stalling on low revs...

Posted: Thu Nov 19, 2009 4:12 pm
by SimonB
CATS wrote:Sounds right on the diagnosis. Did they not just forget to plug something back, like a vacuum advance or something like that?

CATS
I don't think so - it was happening before I sent it in the first time, and we thought it was fuel related because the FF was really bad... which was replaced and is still clean. It "seemed" to be better afterwards but it's not.

I have now done some reading on the other paj forums and almost all of them point to a faulty stepper... usually resolved with a good clean with carb cleaner. Perhaps this is something I can just try look at this weekend. Anyone done this?

Re: Stalling on low revs...

Posted: Thu Nov 19, 2009 5:33 pm
by 4ePikanini
my throtlle body was stripped and I let it soak in prepsol for a week and then let it dry for 2 days.

You won't believe the amount of junk that came out - due to the egr ( which is now blanked off )

Re: Stalling on low revs...

Posted: Fri Nov 20, 2009 9:54 am
by SimonB
Hell, the stepper motor from the stealers is R2445.37 ex vat! I hope it just needs a good clean!