Supra stalling in neutral

epsilon · 12-10-2009, 10:31 AM

Hey guys,

My friend very recently bought a 1989 Supra with Turbo. It seemed like it was working fine when he got it but now some problems are coming up.

When you give the engine gas and rev it up to about 1500-2500 RPM it will suddenly dip back down by 500-1000 rpm and then back up repeatedly. The engine has been stalling randomly when being driven. It also stalls out after coming down from being revved up to 3000-5000 rpm. Sometimes (maybe 1/2 or 1/3 of the time but more often since purchase) giving it a little bit of gas (enough to get to 1500 rpm normally) will cause the engine to stall out.

On purchase the idle speed was set around 1200 rpm though after "research" my friend lowered it to 600 rpm. I originally thought that the idle speed was just too low and was going to raise it, but the other problems above have got me wondering if there might be another problem

I saw someone else here had a problem where their air intake to the turbo correctly and that was causing theirs to stall out. How can I tell if this is happening to us?

cre · 12-10-2009, 10:58 PM

You really shouldn't have screwed with trying to manually adjust the idle.... it's computer controlled and unless you know exactly what you're doing you can make the diagnosis of the REAL problem even harder.

Start with checking for diagnostic codes: http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx

Then check for vacuum leaks.

Is the stock blow off valve still installed and correctly routed?

You haven't tried to clean the air flow meter I hope.

12-10-2009, 10:31 AM	#1
epsilon Stock Join Date: Dec 2009 Location: Mendocino, CA Posts: 1	Supra stalling in neutral Hey guys, My friend very recently bought a 1989 Supra with Turbo. It seemed like it was working fine when he got it but now some problems are coming up. When you give the engine gas and rev it up to about 1500-2500 RPM it will suddenly dip back down by 500-1000 rpm and then back up repeatedly. The engine has been stalling randomly when being driven. It also stalls out after coming down from being revved up to 3000-5000 rpm. Sometimes (maybe 1/2 or 1/3 of the time but more often since purchase) giving it a little bit of gas (enough to get to 1500 rpm normally) will cause the engine to stall out. On purchase the idle speed was set around 1200 rpm though after "research" my friend lowered it to 600 rpm. I originally thought that the idle speed was just too low and was going to raise it, but the other problems above have got me wondering if there might be another problem I saw someone else here had a problem where their air intake to the turbo correctly and that was causing theirs to stall out. How can I tell if this is happening to us?

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12-10-2009, 10:58 PM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	You really shouldn't have screwed with trying to manually adjust the idle.... it's computer controlled and unless you know exactly what you're doing you can make the diagnosis of the REAL problem even harder. Start with checking for diagnostic codes: http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx Then check for vacuum leaks. Is the stock blow off valve still installed and correctly routed? You haven't tried to clean the air flow meter I hope.