Subarutex Posted January 15, 2004 Share Posted January 15, 2004 Ok guys, I'm looking for some information on how the car goes about cutting the fuel. If we can figure this out we can much more easily determine a way to bypass it. Thanks! Quote Link to comment Share on other sites More sharing options...
Dr. RX Posted January 15, 2004 Share Posted January 15, 2004 Hey Sexy Texy, are you talking about the cut out related to engine speed?? Are you trying to blow up your engine?? By the way, it didn't sound right the other day when you were over at my place. It sounded very tinny, like it is really worn out and lots of things rattling. Quote Link to comment Share on other sites More sharing options...
Subarutex Posted January 15, 2004 Author Share Posted January 15, 2004 Well, my thoughts are the fuel cut is related to the amount of airflow. It senses to much airflow and cuts the fuel. I've hit the fuel cut at as low as 5psi of boost. Going over the pass, with my cold air intake, and the spider intake, and the boost controller. Yeah, my car was sounding pretty bad. Changed the oil, got rid of the lifter clack. The last trip to pullman really did it in for some reason. Also, i have a small exhaust leak where the EGR use to be. Quote Link to comment Share on other sites More sharing options...
Mike W Posted January 15, 2004 Share Posted January 15, 2004 I thought Sean had it figured out and an electronic cure he could supply. Did that turn out to not be the case? Quote Link to comment Share on other sites More sharing options...
rallyruss Posted January 15, 2004 Share Posted January 15, 2004 skip has a good grip on how the fuel cut works and a possible way to get around it with the stock system but it seems a bit dangerous to me. you wolud have to fool the computer into thinking that there was less air flow than there really was and then set up a way to enrich the mixture to compensate for fooing the ecm into letting you flow more air. seems to me if you really wanted to build a high power turbo system you would need a stand alone fuel system. these have been discused in the past. I installed one on my toy. 4x4 when I converted it to EFI with mixed results. power was great but drivability was a pain to dial in. I ended up installing a ECM and related parts from a Celica and it runs great now. Quote Link to comment Share on other sites More sharing options...
Subarutex Posted January 15, 2004 Author Share Posted January 15, 2004 Rally: Yes, i agree that the only way to get any power out of these engines is to put in an aftermarket fuel control system. Right now, i'm running whats called and Apexi SAFC. It interrupts the MAF signal goign to the ECU. It has points you can program...that either increase the % of air the ecu is seeing or decreasing it. By doing this, the ECU injects more... or less fuel as desired. Fairly crude I spose. But I got it used for $125 and its done just fine thus so far. I've investigated several aftermarket ECU's. One being the Megasquirt, one you build yourself for like $200 in parts. Another is the ProECM M-1 which is piggyback type computer that actually controls the injectors. I'm not sure on price for this one yet. They market it as a cheaper alternative to a full blown standalone engine management system. I haven't done anything thus far to control the fuel cut. I purchased an HKS FCD that is supposed to interrupt either the MAF or the MAP signal to move the fuel cut higher. Since I already have the SAFC interrupting the MAF signal, and we don't have a MAP I guess it was a waste of $60. But i'll play around with it and see. I'm now going to downtune the upper limits on my SAFC to try and make the ECU see less air than its actually getting. THis of course seems sort of backward... because its up there that potentially needs the most fuel under boost. Quote Link to comment Share on other sites More sharing options...
rallyruss Posted January 16, 2004 Share Posted January 16, 2004 hey tex just rember if it thinks it is seeing less air it will add less fuel. this will cause a lean condition under boost most likely at high RPM. and you know what hapens to lean turbo cars. I have a dead 2002 jetta 1.8Turbo (not mine) in my garage. one of the contributing factors to its demise was a lean condition caused by a dirty MAF due to a crappy aftermarket foam air filter. sorry to go off here a bit but this job is such a pain. I would like to stress this point LEAN BAD. Quote Link to comment Share on other sites More sharing options...
Subarutex Posted January 16, 2004 Author Share Posted January 16, 2004 Yes, I am well aware of what a lean condition can do. Thats why I have an A/F gauge. Quote Link to comment Share on other sites More sharing options...
beauregaardhooligan Posted January 16, 2004 Share Posted January 16, 2004 My brother put a colder thermostat in his 5.0 stang which fooled the ecu into thinking it was still cold. This made it think it was still warming up and enriched the mixture. Best bang-for-buck, according to him. Quote Link to comment Share on other sites More sharing options...
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