blueshift
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| posted on 8/4/04 at 11:32 AM |
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Idle problems with my road car
Hi all, I'm at a bit of a loss with my road car, it's developed a problem where it won't idle; just stalls. Thought I'd see if
any of you had any insight into what it might be..
some background: it's a '95 primera 2.0 slx, SR20DE engine, multipoint fuel injection. just over 100k on it. for a while the idle has been
a bit iffy, seeming to "surge" when I pull up at lights and so on after driving, when the engine is warm. it's as if the idle goes a
little low and the ecu goes "whoah there!" and gives it a quick shot of fuel, then repeats the cycle every second or so, revs going
between about 500 and 1000 (should idle at 800).
recently a fault developed with the lights, after I refilled the washer bottle and spilt some water around the washer filler. not sure if that's
related. The circuit with the front and back sidelights and all the interior lights has developed a short, blows the fuse immediately if I turn the
lights on.
I disconnected the rear light cluster and front sidelights one evening trying to diagnose the short, and afterwards the car started but died
immediately. It is now in the same state, won't idle, I have to keep the throttle slightly open. I have driven it (to detling!) but it wanted to
cut out every time I stopped, I had to monkey around braking and stopping on the handbrake, heel and toe, etc etc - so it happens whether the engine
is warm or cold.
With the throttle held just a little open, it sounds a bit rough idling. at higher revs / driving, it seems normal.
Since the problem occurred I have had it idle once, by coming off the throttle veeeerry slowly I got it to idle at around 500rpm, much lower than it
should do. blip the throttle and come off though and it stalls.
I have checked the plugs, accelerator linkage, air filter and exhaust back box, they all seem fine.
there is a rattle in the exhaust that's developed recently, not sure where it's coming from.. cat heatshield or front box maybe..
wondering if that might be it, blocking the exhaust, my next move was to try disconnecting the exhaust in front of the cat but none of those bolts
have moved since the car was built I think, and I don't want to shear any of the bolts off and wreck it.
so. anyone got any ideas before I tear my hair out and take it to a professional?
thanks,
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flyingkiwi
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| posted on 8/4/04 at 02:16 PM |
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Have you checked the air filter hose? I had a similar problem in my mazda, drove ok but wouldn't idle. Spent hours under the bonnet, eventually
found that the rubber pipe between the air filter and the throttle had developed quite a large tear, allowing in more air than needed when at idle.
The mazda v6 has a filter restrictor that opens up progressively as the speed of the engine increases, opening fully around 4000 rpm. wierd.
Just wrapped a large amount of self amalgamating tape around the whole shebang - worked a treat.
Dunno if this could be the cause of your snag's, but sound's rather familiar
Chris
Oh - my car had just pulled up 100k when the problem started
It Runs!!!!! Bring on the SVA!
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GO
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| posted on 8/4/04 at 02:34 PM |
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check all the vacuum pipes carefully.
guess its got to be kinda difficult to find the problem if you cant leave the car running while you're trying to check it!!
what sort of fast idle mechanism does it use, and does it idle ok at all when cold?
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MikeP
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| posted on 8/4/04 at 02:49 PM |
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Sounds frustrating. Couple of more things you might check:
Any error codes from the ECU?
A stuck EGR valve might cause similar symptoms.
Since there was some connection with the lighting short you've got, I'd try to solve that first. You might find there's a chaffed
part of the loom somewhere that's shorting out a sensor or actuator.
Good luck!
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blueshift
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| posted on 8/4/04 at 02:51 PM |
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Thanks chaps.. I'll have a look when I am back at home, busy helping a friend move house at the moment.
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Mark Allanson
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| posted on 8/4/04 at 06:15 PM |
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A gummed up idle control valve looks favorite, dead cheap to fix too. Pinto's are especially prone to it
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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gjn200
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| posted on 8/4/04 at 10:34 PM |
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Check the acc valve for sludge, the air flow meter for deposits on the wires and the lambda sensor. These guys might help (forum) www.sxoc.com
<- Me!
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blueshift
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| posted on 16/4/04 at 11:18 PM |
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aww bollocks
tried various things, finally a compression test. looks like the engine's fucked.
nominal pressure should be 12.7 bar or something, minimum 10.8 ish.
initial pressures (cold engine)
11 - 5 - 5.5 - 7
put some oil in the bores as per haynes, got
(not re-tested) - 8.5 - 6 - 11
the engine started quite easily with the bores full of oil, and stayed running for the 30s or so until I turned it off.
but.. nackers. looks like worn piston rings / bores / pistons, and maybe head gasket blowing between 2 and 3 (according to haynes).
going shopping for an mx5 tomorrow.
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craig1410
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| posted on 17/4/04 at 12:39 AM |
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Blueshift,
Before I read your last post I was going to point you at the Lambda sensor. This would explain the erratic running, especially the
"hunting" during idling as the mixture will be fluctuating. It might also have explained the rattling in the exhaust if it had broken
completely.
I hate to say this but running it with a dodgy mixture might also have damaged the rest of the engine due to overheating or detonation. The pistons
could be holed due to detonation or it may just be the rings which have siezed. Did you hear any "pinking" when driving it?
Anyway, looks like it's busted as you say, good luck finding an MX5!
Craig.
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pbura
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| posted on 17/4/04 at 12:59 AM |
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I feel your pain
The family van is down with a similar complaint. I'm getting 120 psi compared to the minimum normal of 130. I'm hoping it's caused
by a knackered thread on the most offending cylinder's spark plug hole.
I'm going to try some thread adhesive tomorrow, to try to get a bit more life out of the old girl. Could be the head gasket, though, which went
at similar mileage last time. That was a damned big job with this car (one mechanic wanted $2,500 and others wouldn't touch it, so I did it
myself), not sure it's worth it this time.
[Edited on 17/4/04 by pbura]
Pete
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Noodle
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| posted on 17/4/04 at 10:02 AM |
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quote:
Originally posted by blueshift
for a while the idle has been a bit iffy, seeming to "surge" when I pull up at lights and so on after driving, when the engine is warm.
it's as if the idle goes a little low and the ecu goes "whoah there!" and gives it a quick shot of fuel, then repeats the cycle
every second or so, revs going between about 500 and 1000 (should idle at 800).
I have a similar problem with my 96 eGT, but only when running on LPG. The idle goes completely to t*ts when the car has been started after it's
warm, surging in exactly the manner you describe, but only on gas. If the revs drop and the engine's loaded (by turning the PAS), it stalls. It
doesn't like starting again and needs some quite severe swearing and threats of eternal damnation before it'll fire again.
Settles down nicely again on petrol though.
Cheers,
Neil.
Mine's at 134,000 now
Your sort make me sick
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