Idle, cold start and wet issues

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Bungo

Idle, cold start and wet issues

Post by Bungo »

Hi guys, first time posting! Sorry in advanced for the wall of text...

I finally got my MR2 (97 NA 140K miles) on sunday and I'm in love! However, it does have some issues...

So every time i need to cold start the car I have to hold the revs at around 1.5k for 2 mins to avoid revs dropping and stalling out. After which it'll eventually reluctantly seemingly have a stable cool idle of only around 800 RPM until it reaches temperature then the idle sits around 11-1200. Occasionally having a bit of a rough idle when warm.

Also whenever the cars gets close to around 1.2k RPM in any gear other than 1st it doesn't maintain rpm, instead it starts to choke and start jumping around about to stall before I catch it and downshift.

I have already ordered all new ignition components (except coil pack) because it was all original and wanted to change it out anyway.

Anyway, i was fine with the cold start issues and was planning on sorting the ignition and cleaning the throttle body over the weekend and next week when I'm off work.... however...

This morning it was pretty cold but dry the car started up normally, had to hold revs, but was happy after a minute or two, got to work fine. However, starting it back up after work after it had been raining all day I proceeded to hold the revs like normal until it got up to temp at which point I noticed it couldn't maintain it's rpm even when warm. It was sounding really lumpy, don't think all cylinders were firing properly. It would try to stall over and over while I have throttle maxed out trying to stop it from stalling, it would then slowly cough and splutter its way to 3k revs. As soon as it hits 3k its back to sounding like it normally does and running 'fine' without issues. As soon as i drop the revs it splutters its way back to a stall. I tried turning it on and off again multiple times, same issue.

Anyway it 'seemingly' improved so i thought i'd try to drive it and see what happens. Stalled twice as soon as I got below 1.5k. So I pulled over and let the car sit for 5 minutes, i then prayed to the MR2 gods and she fired straight away and started to idle normally, I then drove her home seemingly without issues (did notice some small splutters whenever the rain picked up?).

I was wondering if anyone had any thoughts, especially on what happened earlier in the rain. (Only times i've noticed rough idle its been wet but I've only had the car 3 days so who knows).

Any advice is much appreciated!


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peteV6R5
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Re: Idle, cold start and wet issues

Post by peteV6R5 »

coil is prone to cracking and causing issues like rough running etc. worth checking .
same as HT / dizzy etc. so worth checking and replacing if suspect
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Re: Idle, cold start and wet issues

Post by benckj »

Search on IACV as they cause problems on MR2s and require cleaning.

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Re: Idle, cold start and wet issues

Post by Wheelnut »

Had a problem with my cold start not coming in. Disconnected the battery and left
for a while, connected back up and all good. Don't suppose that's all your problems
but might cure one.
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Re: Idle, cold start and wet issues

Post by abovetherim »

As others have said, coil probably cracked. If you search for coil and my username you will find a post I did on it.

The throttle body will be fine but behind it is the idle air control valve that can get sticky. Sarah-n-tuned on YouTube did an episode on cleaning hers. A turbo but the same part.

Also check the throttle position sensor TPS is set correctly as per the bgb Toyota manual
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oVerboost.
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Re: Idle, cold start and wet issues

Post by oVerboost. »

Also check the throttle stop is actually set correctly and doing it's job and idle control valve/cold start valve and as mentioned check your throttle position sensor is set as it should be.

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Re: Idle, cold start and wet issues

Post by Wheelnut »

Two mentions of cold start, I thought I could be changing that but as previously
mentioned disconnecting the battery for a while sorted my cold tick over out.
Worth a try.
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Re: Idle, cold start and wet issues

Post by benckj »

Unlike earlier models Gen 3’s don’t have a cold start injector. IACV problems are common with these cars. I’d start by checking the air pipe from TB when car is running to see if blocking it makes any diff.
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Re: Idle, cold start and wet issues

Post by TonyleFrog »

Bungo wrote: 18/12/18 21:48 I was wondering if anyone had any thoughts, especially on what happened earlier in the rain. (Only times i've noticed rough idle its been wet but I've only had the car 3 days so who knows).
To me that strongly suggests it's the one ignition component you didn't change: the coil pack/igniter.
Remove it and examine the casing for cracks. It's a common fault on Mk2s.
The result is similar to a cracked dizzy cap. Moisture ingress followed by misfiring.

The one on T2 threw a wobbly in heavy rain and finally decided to quit altogether.
As it happened I was on my way to Patrick in Bexhill but I arrived rather later than planned.
On the back of a recovery truck...
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