Mr2 mk2, idle problem / hunting when applying some acceleration!

[caldridge7]

Hey all,

basically i have a mr2 mk2 1994 (rev 2) UK model.

since having it i have had a fluctuating idle from being low idle to high idle.

basically ill start my car from cold and it will go to about 800 revs then move to about 1100, from there it will sound lumpy and slowely rise to around 1700 revs, after that it will then drop down slowely to 1000 revs - 950 revs, i recently found if i apply some acceleration it will start to hunt (1900 - 2200)

any ideas on what this could be will be much appreciacted.

[Draven]

I would start with ignition components,

check the dizzy, spark plugs, leads etc.. Also check the coilpack they have a habit of splitting and letting water in.

[caldridge7]

done all of that mate all is good, dunno whereelse to go with it tbh, iv had the icv off and thrrotle body off cleaned them all and all working as it should...

[gmac90]

Check all you rubber intake pipes for spilts/ perishing

[caldridge7]

if anyone has anymore ideas please let me know what next to do...

[caldridge7]

iv done that also, i do have a cone filter intake and there a air temp sensor just hanging about what is this sensor and is it okay it just hanging about where the cone filter is??

[chrismit]

I had some issues with a searching idle previously on my turbo, which happened after reinstalling a new downpipe after a week or so a couple of the nuts had come loose and exhaust gasses were escaping out of the side causing it to fluctuate. After tightening these all back up the issue was resolved. Maybe check your exhaust manifold / joins to make sure there are no leaks.

[caldridge7]

i dont beleive that exhaust leaking would cause how my idle is acting but my exhaust is leaking all over though and does need sorting tbh

[caldridge7]

anymore ideas anyone has??

[caldridge7]

just an update i have checked for fault codes, and its a (21) oxygen sign / sensor, does anyone know what to check with this fault code, sorry if that sounds dumb.

[Draven]

I did have a similiar issue but granted mine was a turbo, one of the caps on the ECU had degraded. I replaced it.

Might be worth a check.

[caldridge7]

sorry but what do you mean by degraded cap? what cap? haha any chance for a photo?

[chrismit]

Pretty sure he is referring to an actual capacitor on ecu board

have you tried resetting the ECU by disconnecting the battery to clear the codes and see if the issue comes back right away when you start the vehicle?

[Draven]

Yes sorry, I'm referring to a capacitor on the mainboard of the ECU. Eventually they start to degrade and leak all over the board. This can have interesting results.

[Draven]

My initial issue was some misfiring, I checked all the normal things and couldn't find an issue. As i continued to drive the car over the following weeks different things started happening. It cut out a few times but started fine. Eventually it was running like a dog and wouldn't start at all.

[wenguin]

just an update i have checked for fault codes, and its a (21) oxygen sign / sensor, does anyone know what to check with this fault code, sorry if that sounds dumb.

replaced o2 sensor in exhaust?

[Rob66]

Hi mate

I had the same thing couple of years back, I had a really cheap and nasty exhaust and Cat.

I changed virtually everything, it was only changing the Cat and fitting a decent exhaust (mongoose) that eventually solved it. My symptoms were exactly the same, when accelerating felt like the car was hiccuping or being held back almost like it was being lasooed if that makes sense.

Good luck with it.