JeffRX7

I just got back from a roadrace lapping event at Gingerman in Michigan, and on the way home i noticed that my air/fuel guage was almost off the scale on the lean side, opposed to sitting where it usually does, right on the border of stoich and rich... this also was accompanied by a strong hesitation when i accelerated from any crusing speed below 3000rpm... but then the power felt fine while accelerating hard, but still was very lean. I made it back to wisconsin and let it all cool down, then took it for a drive later, and the a/f guage was reading just like normal again... this lasted for a little less than 10 minutes, then i watched the guage quickly go towards the lean side again, and the hesitation came back. Ive repeated this a few times and everytime, its fine right when i fire it up and start driving, but after a little bit, the problem comes back... I'm guessing its gotta be a fuel issue, possibly the fuelfilter or an injector clogging up? I know the filter is reallly old, all the injectors are stock with 124K on them. Is there anything else which could cause this? and why is it happening after a bit of driving? If anyone has had this happen or has any advice it would be much appreciated... I know running these things lean isnt good, and i really don't wanna blow it up.... I did run this motor about as hard as it can be run for the day at the track, and my biggest worry is i heated up a seal to bad and thats causing some issues.
thanks

Jeff

j200pruf

iTrader: (4)

Is your AF gauge hooked up to a wideband sensor, or just the stock 02 gauge?

slvr7

iTrader: (1)

Here's a stab in the dark -
the in - tank fuel filter is clogging up with rust/crud shaken loose from the track day. When you shut down, the stuff falls off as the suction ceases.

adamlewis

I dont think it matters what its hooked up to. Theres obviously a more serious issue than "is your A/F gauge accurate"

However, I dont know what the solution to your problem would be. Im sure someone else will come along and help you though.

j200pruf

iTrader: (4)

Yeah Adam is right, I do think that starting off by replacing the fuel filters would be a good idea.
Did you overheat it at the track? Or notice any thing that was kinda weird before you left the track?
Its kind of a far pull but it might be electrical, beating a RX7 at the track and brake loose the crappy electrics.

JeffRX7

so theres a filter in the tank as well? do you have to pull the tank to get at it? and no, i didn't overheat at the track, my fluidyne and e-fan kept the temp guage right in the middle no matter how hard i beat it... I don't think i was ever below 5500 rpm . as far as it being electircal, i see this as a possibility because when it does freak out, it does it rather suddenly, and isn't cured until you shut the car off and restart it. any ideas of what to check?

pillage6

Try new grounds, my air/ fuel didn't work until I put new grounds all over the car.

JeffRX7

well, its not really a matter of the air/fuel working or not, because its worked just great for months... there also is a change in the vehicles performance which would have nothing to do with a bad guage... also, I have made some new grounds at different points.

adamlewis

Yes. Theres a little net filter over the end of the fuel pump in the tank. Sometimes it will get clogged but I dont think thats your problem. Couldnt hurt to change it though. Its been known to clog up and run the engine dangerously lean around turns sometimes.

NoPistns

Cleaning or replacing the fuel filters is a good place to start. Usually a clogged fuel filter shows up as a progressive loss of power, very much like a bad fuel pump. This feels like you're running out of gas.

Something told your ECU that you're running rich after the engine warms up, so it compensates by decreasing the amount of fuel in each injector shot. It isn't really obvious during steady rpm running, but when you put a quick extra load on the engine, it's supposed to give you more gas. (Think accelerator pump on a carbureted engine.)

Best bet is to get it to a shop that pull the code, if one was set. You didn't say whether or not the check engine light came on, but it's possible the bulb doesn't work after 124k. Check your plugs for signs of lean running. They will look very light brown, almost whitish.

JeffRX7

alright, update.... On my way home from work last night, the same problem occured.... but on my drive to work this morning(on opposite side of town) there was no problem at all, and the car ran borderline rich as it used to. The only differences in the drive were that i was on bumpier roads today, and its cooler this morning cuz it rained... I cant see it being a problem with running too hot, because before i put the e-fan on, the temperature went twice as far up the temp guage. I still haven't figured this issue out... any ideas? ( will do filters as soon as i get paid...) thanks