Really lean then really rich

[HPF Chrisk]

Hey guys i have a s1 rb25det in a s13, it has a walbro 255, and full ehxuast those are my only mods, i have a wideband, oil pressure, water temp and wideband, i have been having an issue with it running lean before warm up then very rich after being warmed up

Heres whats happening, every time i drive it i let it warm up to operating temp, then i drive, for the first few min it will idle around 16 to 1 to 17 to 1, then when driving it will fluxuate and if you do go wot then it does dip to 11 to 1 and under but when crusing it will go around 15 to 1 and 16 to 1 at about -10 to -20Hg, but after driving for a few minutes it will go extremely rich like 11 to 1 and under, if you go wot then it just dips 10 to 1 and sticks, but depends on situation. so what i am thinking is that my fpr is going out and that it sticks in one spot and it happens to be an extreme, from lean to rich

I have tried replacing the ecu coolant temp sensor and that didnt help at all, its really weird cause right now its like 40 degrees out and the car was completley warmed up and i drove it and it never went rich, so i am thinking that once the fpr it self gets heat soaked then it goes rich, i am open to any ideas, i am trying to get this squared away cause on the 30th i am going for a 6 hour drive round trip and i would like to get decent gas mileage. thanks in advance

Chris

[Yellow4g63]

Did you change the fuel filter? do you have any exhaust leaks that might be fooling the wideband?

[HPF Chrisk]

I have not tried changing the fuel filter but i will do tommrrow after work and let you know what happens, no exhasut leaks that i know,i just had it in and a dump tube put on but it did the same thing before. there is no sound or discolorations like a exhaust leak might leave.

[HPF Chrisk]

After thinking for a while i have rulled out that its not the fuel filter becaue it did this when i got my swap finished, then about a week later i had cleaned the maf and that helped a little bit, but at the same time i put a 300zx fuel filter. Cleaning the maf helped but i didnt notice a difference in the fuel filter, Is there anything else you guys can think of? A bad o2 sensor? bad Fpr? Bad ecu?

I also dont have any tach signal at all, the shop wired it all the way to the cluster but the cluster doesnt see any signal, they said some times it put out signal and some times it doesnt, i have had 2 shops look at it and me and a few buddies and we are all out of ideas, Could it be a bad ecu or just happen to have 2 bad clusters? the weird thing is it puts signal to the female side of the cluster harness that is in the car, then when you plug the actuall cluster harness in that is removable that goes from the cars harness to the cluster there is nothing from there on, i have a 89 with hud if that helps.

[l0nestar]

SOHC tach's wont read the RB signal. My DOHC HUD reads fine, but CarlH modified mine. It is spot on against my AFC Neo.

[89pignose240sx]

Hey chris, this is cody from vip, I was wondering if you plan on going with the nwn convoy to golden gardens?

[HPF Chrisk]

Yea i am going in the convoy, the one that is meeting up at the gas station by pir or whatever. u giong?

[89pignose240sx]

yea ill be there,I just wish it was later getting up at 5 is gonna suck..

and about your car maybe u got a bad fuel pump, how new is it? maybe it is the fpr did we ever do a fuel pressure test? bad maf, bad 02, I dont know your car acts kinda wierd im just guessing

[HPF Chrisk]

well it has a new walbro in it, its really weird cause it just goes from lean to rich and then it will just stay rich as long as the car is warmed up, idk about the maf, i was thinking maybe someone at gg might have one i could bum or somthing, could be a couple of things but i was hoping to narrow it down so i didnt just throw parts at it and hope it fixes it cause that never seems to work