7mgte cutting out stalling. idle fluctuation

[ssjmikeg]

i have a 89 turbo supra. it has been cutting out in boost and breaking up out of boost and idle fluctuation and it will stall it had one vacumm leak but i have since ran the lines down and found nothing. i have also checked the spark plugs and cleaned the valley from oil. i also replaced the coil pack with an exsiting working one i had. i think it may be the AFM but im not sure and dont want to throw parts at it. here a better discription. i will start it up and it will idle normal then die down to like 600 and jump up and down. (normal idle 1000). i take off and it will cutt out at like 3000 when boost comes in and some times when it doesnt. if i try to boost on it the car cutts out then dies down. Could a knock sensor cause this?

here are my mods:
2mm head gasket
arp head studs n bolts
APEXI SAFC II
Greddy Prefect B
gt42 turbo i just put this on month ago?
fuel pressure regulator
lexus AFM
550 cc RC
3 1/2 in exhuast.

 

[bountykilla0118]

have u pulled the engine codes?

 

[ssjmikeg]

have u pulled the engine codes?

yes i have some old codes a 34 turbo pressure and 42 i just havent deleted them. i had a 52 but i swaped a knock sensor that i think was bad. the code never came with the other one though so im going to swap back. it still does the same thing though.

 

[bountykilla0118]

Are sure they are old codes and not codes that are still present? Are you using the factory pipes? Also how much vac/hg's are you pulling at idle on your boost gauge?

 

[ssjmikeg]

thats a goo question. im not 100 percent sure but neather code would cause this definily not 34 thats fuel cut. but i have aftermarket 2.5 piping. ill check the vac and get back to you. i know it was like 60 on the greddy i dotn know what that amounts to on the other gauge. ill look at it closer.

 

[bountykilla0118]

It could ..... How much boost are you running? If you have a boost leak your gauge would read lower than the actual air thats being pulled in by the turbo thus throwing that fuel cut code. You could look at the SAFC and watch the KARM signal and that could give you an idea whats going with the amount of air being pulled through the AFM vs the actual readings on the boost gauge .... at idle want to be pulling 19-21 vac/hg's if not you have a vac leak or other issues but start with the simple and work up to the complex things

 

[noel]

It could ..... How much boost are you running? If you have a boost leak your gauge would read lower than the actual air thats being pulled in by the turbo thus throwing that fuel cut code. You could look at the SAFC and watch the KARM signal and that could give you an idea whats going with the amount of air being pulled through the AFM vs the actual readings on the boost gauge .... at idle want to be pulling 19-21 vac/hg's if not you have a vac leak or other issues but start with the simple and work up to the complex things

i have the same problem idle moves up/down alil and i have 19-20 Vac..i think my O2 Sensor is bad but i have no check engine lights

 

[ssjmikeg]

yeah i willl check some stuff this week and get back to you guys

 

[jdub]

i have the same problem idle moves up/down alil and i have 19-20 Vac..i think my O2 Sensor is bad but i have no check engine lights

I can tell you with 100% accuracy, it's not the O2 sensor. The O2 sensor may be bad, but it will not cause idle fluctuation.

To the OP - suggest you clear codes, run the car, recheck codes.
It does sound like a big vac leak. I would look at the ISVC for proper operation as well.

 

[noel]

I can tell you with 100% accuracy, it's not the O2 sensor. The O2 sensor may be bad, but it will not cause idle fluctuation.

To the OP - suggest you clear codes, run the car, recheck codes.
It does sound like a big vac leak. I would look at the ISVC for proper operation as well.

Really o damm hmmm i better go check something else lol

 

[MKIIISupraGuy]

It could be a vac leak, but personally I think your AFM is bad. Think about this, if your AFM is sending bad/incorrect signals to the ECU, and not metering the passing air correctly.. then how in the world could your Supra possibly run correctly ?...or hold a steady idle? Your ecu is wondering what's going on as soon as you turn the key. I could be wrong, but I wanted to share in case I might be right and it helps you out. Keep us posted.

 

[BOOSTEDSUPRA]

a vac leak will cause small idle fluctuations. and i def agree with jdub, you have a boostleak somewhere. and you stated that 1k was normal idle... this is incorrect. i believe it is 750? anyone clarify this as i am at work, lol. all my notes are at home.

 

[MKIIISupraGuy]

a vac leak will cause small idle fluctuations. and i def agree with jdub, you have a boostleak somewhere. and you stated that 1k was normal idle... this is incorrect. i believe it is 750? anyone clarify this as i am at work, lol. all my notes are at home.

I got your back on this one:

7MGE - 700 rpm
7MGTE - 650 rpm

Info pulled from TSRM :icon_bigg correct idle's from TSRM

 

[BOOSTEDSUPRA]

650... thats right... thanks bro. :biglaugh:

 

[suprajztwenty]

do the idle control valves (or whatever toyota calls em) throw fault codes on these cars? whats the best way to test it? im fairly certain its the problem with my stalling and sometimes higher idle, ive cleaned the carbon off of it and it seemed to get a lot better but it still drops way low and barely catches (once in awhile anyways)

 

[ssjmikeg]

i was stating that is where i have my idle set at because with aftermarket blov the car will die once the air is released from the blov. what is a iSVC

 

[noel]

i was stating that is where i have my idle set at because with aftermarket blov the car will die once the air is released from the blov. what is a iSVC

is ur BOV Recurlated ? or Blowing to atmosphere?

 

[ssjmikeg]

is ur BOV Recurlated ? or Blowing to atmosphere?

atmosphere. recirculating doent make the awsome sound lol anyway wahts isvc stand for

 

[Hmong_1G]

atmosphere. recirculating doent make the awsome sound lol anyway wahts isvc stand for

That is a possible leak. Without assuming, venting in the aptmosphere is not a proper way of running with karmen vortex maf. Reroute it back into the intake for proper readings. As for ISCV.. its Idle Speed Control Valve, right on the front side of the intake manifold... Close to the Fuel pressure regulator.

link to picture on google. http://tinypic.com/view.php?pic=105bqxf&s=5

 

[suprajztwenty]

i was stating that is where i have my idle set at because with aftermarket blov the car will die once the air is released from the blov. what is a iSVC

idle speed valve control?....wait, my bad he beat me to it