Runs rich w/ new fuel pump - get FPR or adjust with nistune

jontgt · Post by **jontgt** » Tue May 06, 2008 9:36 am

I have had a 190lph walbro pump in my 240sx since I put a 1.8 turbo in it. I wanted to be on the safe side for fuel.

I recently put in the LM-1 and Nistune. My AFR goes down to 10.5 during mild throttle and more. I want to lean this out but not sure if I should get an adjustable FPR to do it or the ECU to do it via injectors.

Thanks

Fusion Ed · Post by **Fusion Ed** » Tue May 06, 2008 10:56 am

ECU - simple as that

jontgt · Post by **jontgt** » Tue May 06, 2008 11:31 am

been trying to play around with what to adjust, even though i don't want to play too much. injection multiplier or k value?

datsunboy · Post by **datsunboy** » Tue May 06, 2008 9:49 pm

you should get a FPR.
stock one is crap, and a decent pump will override it.
get a decent one, set it somewhere good.....then adjust with nistune.
much more reliable

injection multiplier is the k value

jontgt · Post by **jontgt** » Wed May 07, 2008 4:03 am

I have heard that this FPR (from CA18DET) is good to far more HP than I am looking for. Let's just assume I keep this FPR, which I probably will in the meantime, where would the adjustments be made?

to my understanding the K value should be changed for new injectors.
This seems like something I could change to correct this high pressure.

I am very beginner and have alot of reading to do but any info to get me started would help. I read about the mixture correction tables with the wideband and will look into this too.

Ferret · Post by **Ferret** » Wed May 07, 2008 7:25 am

Generally speaking, if you're too rich on all (or most) of the sites of the table you should change the K value.

If you're too rich only on some of the sites, you should change the values of these cells in the fuel map.

Avner.

datsunboy · Post by **datsunboy** » Wed May 07, 2008 7:38 am

if the motor is stock except the fuel pump, and its running rich....it will be because the new fuel pump is pushing more fuel past the crap regulator.....and therefore getting more fuel through the injectors.

You could easily adjust the k-value (down) to fix this issue.
although if thats the reason its running rich, you really should get a new FPR

jontgt · Post by **jontgt** » Wed May 07, 2008 3:49 pm

alright touche, very logical point

the only non-bolt on i'd say is an SR20 turbo instead of CA18 turbo. I got a nismo FPR on the way and a gauge to make sure this is my problem.

thanks

Fusion Ed · Post by **Fusion Ed** » Thu May 08, 2008 9:33 am

I agree with the above I didn't see the topic title before I replied. If you change a pump and the AFR's go mad then the regulator or return line cannot cope with the extra rate of flow of fuel.

jontgt · Post by **jontgt** » Thu May 08, 2008 6:45 pm

i agree 100%

i don't think i should try to use the ECU to correct other problems, cause then once they're fixed things will change.

I have a nismo FPR coming in on Friday hopefully I will see better AFR's.

Thanks guys.