Runs rich on warm startup
Submitted: Wednesday, Dec 01, 2010 at 15:39
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Member - Tour Boy ( Bundy QLD)
Hi guys,
Talking about a 1FZ
I know that the coolant sensor sends info to the ecu to make the mixture rich when cold. The cruiser starts cold fine.
The problem is that after it has been driven and is warm, the next time it is started, it runs rich (black smoke) and floods making it miss for a few secs. Then it is Ok.
The injectors have been flow tested and are balanced to within 1% of each other and have been leakdown tested to double the normal operating pressure.
Leads, plugs etc are new and didn't help.
Fuel pump relay is new.
new fuel pressure relief valve,
Not throwing any codes
Any ideas? Would it be the sensor?
Have asked on mud and lcool no response yet.
Maybe one of our EO auto sparky's would know exactly how it works.
Reply By: Rangiephil - Wednesday, Dec 01, 2010 at 16:27
Wednesday, Dec 01, 2010 at 16:27
Well it wouldn't hurt to renew the sensor, which is probably cheaper than any of the other stuff.
Usually they have a high resistance when cold( say 3k ohms) and go down to a low resistance when hot (say 300Ohms)
.
It doesn't take too much of a bad connection to increase the resistance.
If a single wire check the threads have not corroded, or if double wire check the connections back to the ECU.
One check would be to check the resistance cold and hot at the ECU plug, and then when it goes rich check it.
Regards Philip A
AnswerID:
437492
Reply By: Member - Christopher P (NSW) - Wednesday, Dec 01, 2010 at 20:31
Wednesday, Dec 01, 2010 at 20:31
mate, pull your multimeter out and have a look at your O2 sensor and coolant sensor. whilst there check your MAP/ airflow meter aswell????
IH8MUD has a couple of tech articles, marlincrawler as
well.
AnswerID:
437527
Follow Up By: Member - Tour Boy ( Bundy QLD) - Thursday, Dec 02, 2010 at 16:14
Thursday, Dec 02, 2010 at 16:14
Hi Christopher,
How do you take the readings for the coolant sensor?. Would I have to take it out and heat it up like a thermostat test and keep checking the ohms or does it need power to test?
Has an AFM and gets really cranky if I unplug it so it must be ok
96 mod so no 02 sensor.
FollowupID:
709182
Follow Up By: Member - Christopher P (NSW) - Thursday, Dec 02, 2010 at 20:51
Thursday, Dec 02, 2010 at 20:51
i think you need to do a ohm test, check the resistance, get vehicle hot, go for a drive then retest, it may give you a clue.
the other thing is to pull off one of your battery teerminals to reset the computer, leave it off for at least 10 mins to an hour then plug it back in!
If you haven't unplugged the battery before it might still be registering a fault!!!
hope this helps?
FollowupID:
709224
Reply By: Member - Tour Boy ( Bundy QLD) - Thursday, Dec 02, 2010 at 21:37
Thursday, Dec 02, 2010 at 21:37
Thanks guys, I'll have a look tomorrow.
AnswerID:
437656