Running lean?

Beadybc · Sep 1st, 2023, 23:20

Car is a 1997 945 b230fk with an Owens 19t running at 1.3 bar on 450cc injectors.

Recently the car has decided to start running lean when off throttle.

Normally on the AFR gauge I'd get around 15 at idle however the other day I hot started the car and it idled very low at around 500 rpm with an AFR reading of between 17 and 18, after a few little blips of the throttle it went back to where it should be.

When driving if I apply throttle - then lift off, first the reading will drop to around 10-11 for a second, then up to 20-23 for upwards of 5 seconds, then back to 15.

Under throttle the readings are where they should be from 1-100% throttle.

The fuel pumps are the original ones and are on 175k miles. There is an audible whir from them when the ignition is turned on.

The fpr and injectors have only done 2k miles from new.

My best guess is that the fuel pumps are knackered and/or too weak but I have a melon for a brain so could someone help identify the problem please?

Sep 1st, 2023, 23:20	#1
Beadybc Member Last Online: Apr 8th, 2024 21:52 Join Date: Nov 2020 Location: Epping	Running lean? Car is a 1997 945 b230fk with an Owens 19t running at 1.3 bar on 450cc injectors. Recently the car has decided to start running lean when off throttle. Normally on the AFR gauge I'd get around 15 at idle however the other day I hot started the car and it idled very low at around 500 rpm with an AFR reading of between 17 and 18, after a few little blips of the throttle it went back to where it should be. When driving if I apply throttle - then lift off, first the reading will drop to around 10-11 for a second, then up to 20-23 for upwards of 5 seconds, then back to 15. Under throttle the readings are where they should be from 1-100% throttle. The fuel pumps are the original ones and are on 175k miles. There is an audible whir from them when the ignition is turned on. The fpr and injectors have only done 2k miles from new. My best guess is that the fuel pumps are knackered and/or too weak but I have a melon for a brain so could someone help identify the problem please?

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