MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: mr2race on November 7, 2016, 17:04

Title: 2ZZ Stalling when coming off throttle
Post by: mr2race on November 7, 2016, 17:04
Hi, 2zz in a roadster. The car wasn't idling well so I replaced the MAF and all good, now a constant idle at stand still.

But, when reving the engine and coming off throttle the revs fall and the car cuts out everytime?

Doing a search my results brought up a number of similar traits with the 1zz including: a sticking IACV, MAF (already replaced with a known good one). Is there anything else or is there a more likley culprit for the 2zz?
Title: Re: 2ZZ Stalling when coming off throttle
Post by: cabbydave on November 7, 2016, 19:53
Did you do the conversion?
Title: Re: 2ZZ Stalling when coming off throttle
Post by: gazza1286 on November 7, 2016, 20:11
Gummed up idle control valve.

 m https://www.celicahobby.com/forums/ubbt ... clean.html (https://www.celicahobby.com/forums/ubbthreads.php/topics/364046/idle-air-control-valve-how-to-properly-clean.html) m


The gasket may have failed?
Title: Re: 2ZZ Stalling when coming off throttle
Post by: mr2race on November 7, 2016, 20:37
Quote from: "cabbydave"Did you do the conversion?

Yes, was working fine. Then left unused for about 5 months. Started up today and have this issue.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: 1979scotte on November 7, 2016, 21:00
5 month!
Condensation in the fuel or some other contamination?
Title: 2ZZ Stalling when coming off throttle
Post by: jonbill on November 7, 2016, 23:08
I'd 2nd that - I'd drain that fuel and try some fresh.
I don't understand the chemistry but I'm pretty sure petrol doesn't burn so well when it's been stood for a few months.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: beavisrules on November 8, 2016, 00:37
Got a good battery on it and not just jumping a flat one?.
I'd bet on icv too. The fuel systems should easily adapt for partly stale petrol , might just run poor.
could also be tps.
would be worth having a code reader in case any errors are happening.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: mr2race on November 8, 2016, 09:55
Code reader would be great, but as it's a Jap spec ECU it won't work with my reader which is a shame.

Thanks for the suggestions.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: shnazzle on November 8, 2016, 12:14
Quote from: "mr2race"Code reader would be great, but as it's a Jap spec ECU it won't work with my reader which is a shame.

Thanks for the suggestions.

HFB is in Gatwick and has a jap spec OBD reader.

 l viewtopic.php?f=11&t=16017&start=240#p700129 (http://www.mr2roc.org/phpBB3/viewtopic.php?f=11&t=16017&start=240#p700129) l

Does that help?
Title: Re: 2ZZ Stalling when coming off throttle
Post by: mr2race on November 8, 2016, 16:27
Quote from: "shnazzle"
Quote from: "mr2race"Code reader would be great, but as it's a Jap spec ECU it won't work with my reader which is a shame.

Thanks for the suggestions.

HFB is in Gatwick and has a jap spec OBD reader.

 l viewtopic.php?f=11&t=16017&start=240#p700129 (http://www.mr2roc.org/phpBB3/viewtopic.php?f=11&t=16017&start=240#p700129) l

Does that help?

Thanks, bit of a distance for me. However, I just spoke to another forum member local to me who said he is getting a reader from someone, so I will hopefully be able to use that.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: Fin on November 8, 2016, 21:41
Quote from: "gazza1286"Gummed up idle control valve.

 m https://www.celicahobby.com/forums/ubbt ... clean.html (https://www.celicahobby.com/forums/ubbthreads.php/topics/364046/idle-air-control-valve-how-to-properly-clean.html) m


The gasket may have failed?

Not wanting to hijack a thread, but.... I take it this will be the same problem I am having. Occasionally, when coming off the throttle, it feels like the engine has shut right down. No stall, just like the engine has stopped until I go back onto the throttle. Most noticeable when cold. I had always wondered if there was a throttle damper screw or similar. Not enough of an issue for me to go digging around down there.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: gazza1286 on November 8, 2016, 22:46
The link shows the full disassembly but you may be lucky with just spraying carb cleaner into the throttle body - particularly into the bleed hole which leads to the idle control gubbins. Running the engine on idle afterwards draws all of the cleaner through the galleries which should clear much of the crud. You only need to remove the air intake hose to do this. Obviously cleaning the MAF may also help.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: stupink on November 9, 2016, 09:08
if its not IAC then you can get similar symptoms if you change the pipework to the maf and theres not enough pipe before the intake.
Title: Re: 2ZZ Stalling when coming off throttle
Post by: Fin on November 9, 2016, 09:42
Pipework and MAF are standard, so I'll dig out the carb cleaner. Cam chain tensioner and oil change on the list today, as well as working out why my lights are popping fuses...