Continual Idle Problem

smagnotta

smagnotta

SuprSal
Apr 5, 2005
202
0
0
WashPa
i have similar problem. my rpm isnt higher then idle on cold starts and the rpm would flutuate between 500 and 700, i have no codes and the car acclerate great, just the exhaust popping when i let off the gas not stalling. any idea, Dr. J or anybody?
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I hate to give just a generic answer but I believe that problem can be attributed to the wrong air/fuel mixture, timing, spark plugs or plug wires. This kind of thing is tough to figure out but what is needed is a TSRM and a multimeter. Go around and check each system (air, fuel, electrical) until you find things wrong.

I found my CSI switch was bad, along with a VSV and the fuel pump. Who knows I may still have a vacuum leak too.
 
89turbotoy

89turbotoy

2 89 supras 2jzgte/single
Jul 30, 2006
309
0
0
38
cincinnati
89turbotoy said:
could be a sticking egr valve.
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sorry no it couldn't i should have read more carefully before i posted. however i did have this same problem once after i let the car sit for a week in freezing wheater. it would run fine untill it got to operating temp and the start running like shit. it would drive and build boost but sputter alot. so after i checked everything and replaced alot of things it was still there, i even drained the gas tank because i had bad gas. nothing fixed it. finally i said fuck it if it blows the engine i don't care and i drove the piss out of it for 100 miles(i don't condone this really it was a bad idea but i was so pissed i wanted to sell the car) the longer i went the better it got when i got home it was fine (you shouldn't do this ). i still have no idea what it was but it has not returned. i only posted my situation b/c i am hoping someone sees it and know what it is. if not send me a vid of what it's doing and i'll be able to help more.

-Zac
 
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smagnotta

smagnotta

SuprSal
Apr 5, 2005
202
0
0
WashPa
No problem. I appreciate it. It whined like crazy today. I never heard this before. Maybe a bearing in the Walbro motor is bad. Well regardless I won't start the car anymore and I have a new Walbro and fuel pressure regulator coming. In addition the clutch and flywheel need replaced along with the starter and the EGR cooler. Hopefully after all that it will be fine. I definitely feel like an engine rebuilder and car restorer, but hey this is my hobby.

This past winter did a hell of a job on the electronics in my Supra. I had to replace the AFM electronics three times (yes the one on the car went bad along with two more I had as a backup), the CPS, the Igniter, and the 3 coil packs. Oh yea and today I had to change out the CSI switch and a VSV.

In retrospect, I should have just started with a newer MK3 back in 1999, even a 1990 (mine is an 87).
 
smagnotta

smagnotta

SuprSal
Apr 5, 2005
202
0
0
WashPa
The idle problem I was having was caused by a bad fuel pressure regulator. I had an Aeromotive Fuel Pressure Regulator and it was 4 years old (about 15,000 miles). Replacing the fuel pressure regulator took care of the jumpy and erratic idle, the fluctuating idle fuel pressure and the resting pressure issue.

The car also does not stall when accelerating and then coming to a stop. I thought this was caused by the ISC valve but it was also fuel related.
 
smagnotta

smagnotta

SuprSal
Apr 5, 2005
202
0
0
WashPa
So true about the AFM sensor....I was told by Champion Toyota that Toyota does not sell the black electronics box separately; you have to buy the entire AFM assembly to get the electronics ($500+ dollars ouch). I even asked what about Lexus black electronics box from say a Lexus SC400 ans was told the same thing.

I am not sure where to even get just a brand new AFM sensor for the MK3 -- maybe NAPA?
 
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