proud 1st time owner of 87 supra turbo

btwilson86 · 03-29-2012, 01:16 PM

I don't have an answer for your hg question, but running a blow off valve (vented to atmosphere, not recirculated) can cause your engine to stumble and/or die when shifting. This happens because all of that air passed through the AFM, so the ecu expects the air that was just dumped to still be in the intake. The ecu then provides the amount of fuel to the engine needed for the volume of air it thinks is still there, causing it to run excessively rich.

You can eliminate this problem by running a bypass valve instead of a blow off valve (easy) or by running a system like MATT-PRO 2 (?) in speed-density mode (not exactly sure if that's correct; in any case this would be a better setup because you can eliminate the AFM, but my understanding is that it's incredibly difficult to set up). A search on the forum or Google should bring up several results for this particular problem, as it's very common

03-29-2012, 01:16 PM	#3
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	I don't have an answer for your hg question, but running a blow off valve (vented to atmosphere, not recirculated) can cause your engine to stumble and/or die when shifting. This happens because all of that air passed through the AFM, so the ecu expects the air that was just dumped to still be in the intake. The ecu then provides the amount of fuel to the engine needed for the volume of air it thinks is still there, causing it to run excessively rich. You can eliminate this problem by running a bypass valve instead of a blow off valve (easy) or by running a system like MATT-PRO 2 (?) in speed-density mode (not exactly sure if that's correct; in any case this would be a better setup because you can eliminate the AFM, but my understanding is that it's incredibly difficult to set up). A search on the forum or Google should bring up several results for this particular problem, as it's very common __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

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