3SGTE really rich cold start and idle

[Lee H]

Rev 3 3SGTE with 3" downpipe and boost controller. Stock ecu.

Only just started doing this in the last few months. If I start the car from cold wideband instantly drops below 10 (doesn't read any lower). If I turn car off immediately and restart a few minutes later it's missing and pumps out clouds of black smoke when revved lightly, once that clears it's ok again.

If I turn the car off warm it's a pain to start sometimes, turns over several times before catching.

Also noticed today that at hot idle my AFR's are 13.2 ish, used to oscillate between 14.7 and 15.2.

No fault codes.

Any ideas please?

[Nails]

Coolant temp sensor? Only just over a tenner and a 5 minute job to try.

[Lee H]

Started with a few more fuelling issues.....

http://www.imoc.co.uk/forums/viewtopic. ... 04#1623604

Coolant temp sensor was replaced about a year ago but guess trying another wouldn't hurt. Used an aftermarket part so quality might be suspect.

[2mad]

10:1 afr's crazy rich, might need to look a bit deeper into this than a coolant temp sensor.

Whats it like afr wise when warmed up.

[Lee H]

13.8ish, know it should be more 14.8 so still rich even when warmed up. Managed a longer run the other day though and got afr's behaving normal at idle, however I then had lean issue and holding back.

Suspected faulty wideband at first but its definitely rich by the smoke and definitely holding back so need to sort that issue initially. Wideband is standalone.

[2mad]

You running a stock ecu .. I had an ecu fail a afr's went a bit sideways .. might be worth having it checked out .. it would be nice to rule it out.

[Lee H]

Yes. Shame I don't know anyone local with an ecu I can borrow to test.

[rev3turbo]

did you manage to sort this out?

[Lee H]

Nah, bought a new lambda and no difference so another £80 down the drain.

Given up and bought an S2000 for summer instead as I'm sick of it now.

[rev3turbo]

Nah, bought a new lambda and no difference so another £80 down the drain.

Given up and bought an S2000 for summer instead as I'm sick of it now.

thats a shame

what did/didn't you replace?

did you swap over the map sensor?

[Peter Gidden]

Nah, bought a new lambda and no difference so another £80 down the drain.

ECU doesn't go into closed loop when cold, so O2 sensor not being used til engine at normal temp.

[Lee H]

Nah, bought a new lambda and no difference so another £80 down the drain.

Given up and bought an S2000 for summer instead as I'm sick of it now.

thats a shame

what did/didn't you replace?

did you swap over the map sensor?

Changed coolant temp sensor, lambda sensor and map sensor so far. Have reset ecu and been for a pretty decent drive to ensure lambda was being used and voltage on sensor just remains static at 0.9ish implying something else is causing the rich situation.

[Peter Gidden]

Check MAP sensor against BGB. And cam and ignition timing.

[Lee H]

Check MAP sensor against BGB. And cam and ignition timing.

Will check map sensor again. Cam timing and ignition timing both checked recently.