Misfire at idle. - newb here

cygnus58 · 06-18-2008, 11:43 PM

Hi all.
I am the the proud Dad of a Metro 1992 1.0.
My son's first car.
We bought it knowing it had major exhaust probs and an idle ocsillation at closed throttle when warm. I've replaced the entire exhaust, and aligned TPS to fix oscillation at closed throttle.
EGR valve and ports were clogged and I opened them as much as possible from outside the manifold.
New plugs, cap, and rotor. Much better, yet still seems to have a misfire at idle.
Are there other areas re: EGR that could be clogged requiring disassembly with carbon deposits unseeable from outside in this engine?
And another question - IS the 1.0 interference or not?
I have read different opinions to that.

thank to all in advance.

CapnCrunch · 06-19-2008, 06:05 AM

If it's just at idle, I'd look more at EGR. One of my Metros was having similar issues a while back and thoroughly cleaning the the internals of the EGR valve with carb cleaner seemed to take care of it. You might also check the vacuum line going to it for cracks/leaks.

Does the plunger on the EGR valve actuate freely by hand?

It may still be something else (perhaps throttle body?), but an idling problem as a result of EGR should be fairly easy to fix if you possibly weren't thorough enough.

Also, check to see if your idle might be set too low or too high. I'm not sure about the Metro's computer, but years ago I had an idle oscillation problem on my Toyota pickup and it turned out to be the idle being set too high and the computer kept kicking it down repetitively to compensate.

Johnny Mullet · 06-19-2008, 06:53 AM

Quote:

Originally Posted by cygnus58

And another question - IS the 1.0 interference or not?
I have read different opinions to that.

Non-interference engine.

cygnus58 · 06-19-2008, 07:25 PM

Thanks for the input guys.
Am removing EGR again to check ports in and out.
It seems stuck closed which would be much better than open yes?

There is a device attached via hose to the Idle controller that has a 4 inch hose open at the opposite end. There is much vacuum there and it seems to modulate. Can't be right to be open I would think. If I block it, idle increases but still misses same. The car works very well anywhere from 0 - 60 otherwise.

cygnus58 · 06-20-2008, 08:01 PM

Update - the miss/shake goes away pretty much if idle is at around the 800 RPM specified.
Problem is, it drops quite a bit when I put it in gear. I don't think the diode bank is working on electrical load either. Hell I forget, didn't try that today.

Now, Sunday, it's all together and running quite nicely.
We are thinking 40 plus MPG and the idle under load is so sweet.