as some may remember, i've posted about this fuel cut/hesitation at 0psi a couple of times. at first i thought it was the ML letting boost through just a little bit during the transition. i talked to the guys at synapse(manufact. of the ML) and they sent me a new unit. the same thing happens w/ the new one. i doubt that i got 2 bad units. so the guys there decided to try and custom make me a ML w/ a stiffer spring and send it over. i know have that one on the car, and the fuel cut at 0psi is gone, however because of the stiffer spring my car runs extremely rich to the point where i can no longer turn down the fp's and i get constant backfire while decelerating. so, i'm going to go back to the normal unit, but i need to figure out why i'm getting fuel cut at 0psi. it has to be something w/ my car.

on my pocketlogger, when i get the fuel cut/hesitation, my map is at most 103kpa which should not cause cut. i know there is some amount of overlap that the ecu is aloud to see, and 103 should be well in that area. could it be possible that my map sensor is too sensitive? i doubt the ecu programming is any different than everyone elses. i am sure that it's fuel cut, b/c every once in a while, when it happens i'll get a cel for "map circuit too high". i recently changed my o2 sensor also, and for the day that i had the normal ML on the car w/ the new o2, although i still got the cut at 0psi, it was much more like a little hiccup as apposed to the pretty harsh fuel cut that i was getting. i can't see how a new o2 would affect this any though. i'm going to try and get map sensor froma junkyard and test it out, but does anyone have any ideas, thoughts, ANYTHING on what could possibly be the problem here?? i'm at my wits end w/ this. the only other case like this is on nate's car(ner). nate, are you still having the same problems? i really don't want to through on the black box, b/c that's just avoiding the problem. any ideas from you all knowing vets are appreciated. thanks.

i still get a hickup every now and then. it's such a weird problem, i swear to god my car gets PMS for about a week every month when the drivability goes to shit for no reason whatsoever. then it goes back to normal, without me changing anything, and it runs great - pulls like a raped ape at 1 bar (when i'm able to get traction with my 1 wheel drive open differental)

on monday, i was getting very high MAP sensor voltages. lots of fuel cut around 0 psi, not above, and not below. high voltages as in like 4.67+ volts according to my AFC. the weather on monday was very good... i had a flying lesson that afternoon and while calibrating the altimiter during preflight i had to turn it up pretty high to compensate for unusally high barometric pressure.

maybe the atmospheric air pressure has something to do with it. today, it's rainy, and i haven't gotten ANY weird fuel cut/misfiring/drunkenness/PMS yet.

it's a mystery to me.

exactly... it seems to totally depend on the weather and temperature. however, with me, i seems to get it all of the time, just some days it's much less than others.

any ideas on our problem fellas?

I would try both the regular ML and the HRC blackbox (if you have one) at the same time. I think the blackbox could compensate for the extra map voltage. This should help you track the problem down, but I wouldn't recommend leaving it like that if it works. i hate the hrc blackbox! mine worked for 2 days and died!!!

well like you said, i really don't want to have to throw on both. i hate voltage clamps, and it's just avoiding the problem. i'm sure that would stop it from happening because i've gotten cels for the map circuit too high. it just seems as though the map sensor, or ecu, is really sensitive, but is there such a thing as a too sensitive ecu?? why would our 2 ecu's be different than all the other 97's. there's gotta be something else wrong.

i just got my hands on a map sensor off of a 95 today, so i'm gonna try it and see what happens. logically though, i just don't see it being the map at fault. it just reads the pressure, it doesn't make decisions based on it.

I have the fuel cut problem too, and I agree, it seems to have more to do with the weather than anything else that might be logical. In all seriousness, I believe my problem stems more from the fuel and fuel regulation itself, not the Map sensor. This may be dumb question for you at this point, but are you sure your fuel system is set up properly and your getting the right pressures at idle, boost, etc? Hope this at least a little bit man :thumbsup


Yes officer, the windows are mirrored!

HRC Stage II w/FMIC