random idle fluctuation and engine stall

Ariamius · 08-07-2011, 04:40 AM

My 7m gte in 88 supra turbo has a strange habit of idle fluctuation at red lights and just idling. idle sometimes ranges from 500 to 1200 rpm and occasional will completely stall at idle. Check engine light is on also. I know I have a small hole in the turndown pipe behind the turbo. compression test shows 165 to 170 on all cylinders. no misfiring or hesitation really while driving. Hopefully someone can shed some light on how to solve my issues. Any help would be great.

El Supracabras · 08-07-2011, 02:17 PM

Check codes first. (in the faq section)

Ariamius · 08-07-2011, 05:52 PM

Don't know how to get the codes. know you can jumper a wire in the diagnostic box, just not sure which ones to jumper.

El Supracabras · 08-07-2011, 06:25 PM

Couldn't find it in the faq section eh?

http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx

Ariamius · 08-11-2011, 08:00 PM

I now have the codes for the engine light code 31 air flow meter , and 52 knock sensor. what next???? Anyone

supraheelfan · 08-11-2011, 09:21 PM

You can just rewire the knock sensor, it's more than likely just the wire going to the knock sensor that is toast, hardly ever the sensor itself.
That is what I did and it worked like a charm.

Ariamius · 08-11-2011, 11:32 PM

removed cold air induction which is an apex bolt on and ran car with no air filter and it stopped throwing the air flow meter code 31... any ideas?

Ariamius · 08-12-2011, 02:36 AM

also discovered have a BHG never done one about to learn any tips or suggestions would be great planning on going back with a metal HG, unless someone gives me a reason not to. Several people have told me to torque to 75lbs. Hope that is right.

Green7mgte · 08-12-2011, 02:48 AM

lets take it from the top.
you have a knock sensor code and a afm code.
As suggested re-wire your knock sensor, that will solve that problem.
Running your car w/o an air filter isn't doing anything to solve your AFM problem. You're not getting the code because you erased it after you checked it. It will come back, air filter or no. Could be one of 2 issues. 1 your afm itself broken (possible) or 2, one or more wires running to the afm are giving crap signals (more possible). You can try to wire in a new clip or replace the wires some other way. Or purchase a new afm for about 80 bucks at a scrap yard. (Ls 400 use the same electronics) I would suggest checking the voltage at the wires and see which one is giving you the issue before spending the money on a new to you afm.

Now to hit on your BHG.. are you sure you have one? if you answered yes ok. a mhg is all well and good. But the machining it takes to have one installed correctly is not able to be done by you alone. (*unless your technically savvy.*) A cosmetic HG is completely fine, unless your trying to run say 20+ psi of boost. The amount of torque needed for the bolts are dictated by what type of oil, fastener you use. stranded stock bolts yes, 75. studs are like 90 or something idk check up on it. Tons of information out there and here on the required fastener/torque recommendations.

good luck
(edit, sorry for the crap punctuation, im tired and don't care..)

Ariamius · 09-01-2011, 02:38 PM

I need to know where the knock sensor is and how to rewire it to get rid of the knock senosr code.

08-07-2011, 04:40 AM	#1
Ariamius Stock Join Date: Aug 2011 Location: Louisiana Posts: 10	random idle fluctuation and engine stall My 7m gte in 88 supra turbo has a strange habit of idle fluctuation at red lights and just idling. idle sometimes ranges from 500 to 1200 rpm and occasional will completely stall at idle. Check engine light is on also. I know I have a small hole in the turndown pipe behind the turbo. compression test shows 165 to 170 on all cylinders. no misfiring or hesitation really while driving. Hopefully someone can shed some light on how to solve my issues. Any help would be great.

08-11-2011, 08:00 PM	#5
Ariamius Stock Join Date: Aug 2011 Location: Louisiana Posts: 10	engine codes I now have the codes for the engine light code 31 air flow meter , and 52 knock sensor. what next???? Anyone

08-11-2011, 11:32 PM	#7
Ariamius Stock Join Date: Aug 2011 Location: Louisiana Posts: 10	cold air induction removed cold air induction which is an apex bolt on and ran car with no air filter and it stopped throwing the air flow meter code 31... any ideas?

08-12-2011, 02:36 AM	#8
Ariamius Stock Join Date: Aug 2011 Location: Louisiana Posts: 10	Bhg also discovered have a BHG never done one about to learn any tips or suggestions would be great planning on going back with a metal HG, unless someone gives me a reason not to. Several people have told me to torque to 75lbs. Hope that is right.

08-12-2011, 02:48 AM	#9
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	lets take it from the top. you have a knock sensor code and a afm code. As suggested re-wire your knock sensor, that will solve that problem. Running your car w/o an air filter isn't doing anything to solve your AFM problem. You're not getting the code because you erased it after you checked it. It will come back, air filter or no. Could be one of 2 issues. 1 your afm itself broken (possible) or 2, one or more wires running to the afm are giving crap signals (more possible). You can try to wire in a new clip or replace the wires some other way. Or purchase a new afm for about 80 bucks at a scrap yard. (Ls 400 use the same electronics) I would suggest checking the voltage at the wires and see which one is giving you the issue before spending the money on a new to you afm. Now to hit on your BHG.. are you sure you have one? if you answered yes ok. a mhg is all well and good. But the machining it takes to have one installed correctly is not able to be done by you alone. (unless your technically savvy.) A cosmetic HG is completely fine, unless your trying to run say 20+ psi of boost. The amount of torque needed for the bolts are dictated by what type of oil, fastener you use. stranded stock bolts yes, 75. studs are like 90 or something idk check up on it. Tons of information out there and here on the required fastener/torque recommendations. good luck (edit, sorry for the crap punctuation, im tired and don't care..) __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines : Last edited by Green7mgte; 08-12-2011 at 02:50 AM.

08-07-2011, 02:17 PM	#2
El Supracabras 3" Exhaust Join Date: Feb 2010 Location: Chicago Posts: 240	Check codes first. (in the faq section)

08-07-2011, 05:52 PM	#3
Ariamius Stock Join Date: Aug 2011 Location: Louisiana Posts: 10	Don't know how to get the codes. know you can jumper a wire in the diagnostic box, just not sure which ones to jumper.

08-07-2011, 06:25 PM	#4
El Supracabras 3" Exhaust Join Date: Feb 2010 Location: Chicago Posts: 240	Couldn't find it in the faq section eh? http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx

08-11-2011, 09:21 PM	#6
supraheelfan 3" Exhaust Join Date: Feb 2011 Location: Wilmington, NC Posts: 178	You can just rewire the knock sensor, it's more than likely just the wire going to the knock sensor that is toast, hardly ever the sensor itself. That is what I did and it worked like a charm.

09-01-2011, 02:38 PM	#10
Ariamius Stock Join Date: Aug 2011 Location: Louisiana Posts: 10	help with knock sensor I need to know where the knock sensor is and how to rewire it to get rid of the knock senosr code.