Leaning out up top
 

Im not sure why but my car seems to be getting leaner up top every so often and i have to retune, then its fine for a little while and again starts leaning out a few weeks later.

I thought i might be loosing fuel pressure so i changed my filter, no luck.

Ive put some thought into the possibility that maybe my injectors are getting clogged, but i have the stock 550 primarys, the secondarys 1680's are only 13000ish miles old. I run premix but i dont think that should effect it.

i have a aeromotive rising rate fpr, seems to be in ok shape but i guess i could be gunked up in the boost line.

anyone have any idea why this could be happening? my car is leaning out to like 12.1:1 at 17psi 7000 rpms. I used to be able to hold a steady 11:1 throughout.

would it be possible for my wideband to be giving me an incorrect reading at wot but read accuratly for cruising and idle. The sensor has got to have about 13000 miles on it. (i dont think this is the case)

any ideas would be appreciated.

Mike

base fuel pressure?

could the pump be walking out the door?

voltage on pump? if its stock wiring, any change in electrical load could change its output

my base fuel pressure is 45psi

I would be hesitant to say the pump is walking since its only got about 13000 miles on it as well. Its whatever denso pump rx7store uses in their fuel upgrade kit.

What should the voltage be on the pump at idle? I am still using the stock wiring, but unless its just going south i dont think the load is changing every 3-4 weeks or so.

45psi seems a little high for a denso pump, just my opinion (of course at 17psi your pump is pushing 62psi)

voltage at idle is 9V or so...with the stock wiring. There are a few posts around about how to rewire it.

I believe you are running a E6K, correct? you should wire the pump directly to battery and have the haltech fuel pump relay ground it...solid GND. Or vice versa. If you didn't rewire the pump, and used the haltech supplied relay...you now have 3 relays and resistor in the circuit, when only one relay is needed.

i am running the e6k, but i used the magnus adapter harness to the stock harness to utilize the stock system since i was still tt at the time. Ive been meaning to rewire the whole car with the haltech flying lead kit but just havent gotten around to it.

Ill look into rewiring the pump, but it should be on the same stock wiring and relay setup.

Are you still using the fuel pressure regulator solenoid? It is another useless part that is not needed and is a posible soucre of failure. All the owners of very modded cars I know , have removed it. If it sticks partially engaged, fuel pressure will be lower.

You have checked the external fuel filter, but how about the internal one attached to the bottom (inlet) of the fuel pump. Maybe your tank has trash in it.

Why are you using a rising rate FPR? Since you have a stand-alone, you shouldn't need it. A standard 1:1 FPR should be much more reliable and consistent.

well i was under the impression i needed one. Either way it has alwasy been stable until a couple of months ago.

I've never used one, I just haven't heard good things about their reliability.

yeah, im getting the same problem. not quite as high AFRs as your seeing, but 11.7-11.8 up top none the less. BDC tuned me to 11.1 highest AFR. then i noticed it raise to 11.5 at high rpms one day, so i tuned it back down with the PFC. Then yesterday I noticed 11.8 for a peak quick second up top. only for about less than 1000 rpms. i too am wondering about my sensor. i use the bosch 5 wire in the aem eugo kit.

by any chance have you run the sensor in the on position a long time while the motor is off? or run the car with the sensor off? those 2 situations can end them early. I havent done either situations though.

Sometimes the rubber "O" ring and nylon coupler from the FP to the outlet pipe will have a cracked nylon piece and it will not seal good. It happened to mine and a few other people. Just cut of the adapter and run a FI fuel hose in place of it for a non failure fix.

thanks for the idea, ill check that tomorrow.