1989 7mgte 5 speed no start..

Mk3TargaJames

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Mar 14, 2017
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West Jefferson
DieselScout2;2090781 said:
No codes right now.. The car is teasing me. It runs great for a second or two, then will return to the usual problems. I have tries unplugging the TPS and the lexus AFM(same as maf?). When plugging the afm back in the idle increases for a second, then dies down. Also, My temp gauge is not reading at all. On the thermostat housing the top sender has a wire connected to it, and if I'm not mistaken the sender right below it should have one as well, correct?

Yes. The top sends to the guage, lower to the ECU. ID CHECK TSRM resistances on both too. And if it's just bare wire ran through the loop, please do a favor for all people who care about connections, put a correctly sized connector on there, solder it and heatshrink :)))))


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DieselScout2

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Mar 5, 2017
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Arizona
Mk3TargaJames;2090790 said:
Yes. The top sends to the guage, lower to the ECU. ID CHECK TSRM resistances on both too. And if it's just bare wire ran through the loop, please do a favor for all people who care about connections, put a correctly sized connector on there, solder it and heatshrink :)))))


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Yes, the wire to the top sender is bare and wrapped around the tip of the sending unit.. Will correct that. My next question is that there are two wires (see pic 2 of first gallery) near the CPS that are cut. Any idea which one goes to the sending unit? Or do the both attach to a plug?

ALSO, adjusted CPS timing, no dice. Set timing to 10 degrees and now the car idles even rougher..
 

Mk3TargaJames

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Mar 14, 2017
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West Jefferson
DieselScout2;2090794 said:
Yes, the wire to the top sender is bare and wrapped around the tip of the sending unit.. Will correct that. My next question is that there are two wires (see pic 2 of first gallery) near the CPS that are cut. Any idea which one goes to the sending unit? Or do the both attach to a plug?

ALSO, adjusted CPS timing, no dice. Set timing to 10 degrees and now the car idles even rougher..

Does it IDLE fine? Even for 5+ minutes? If so, let it idle and once warmed up, if it idles fine give it throttle and see what it does. My car bogged down and died when my MAF was unplugged.

The top sends the temp to the cluster guage. New ones are 18$ on Drift motion I believe


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DieselScout2

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Car struggles to start and needs some throttle to keep idling. Once "warm" it idles OK. I will check out the connection at the sender and the sender itself. On the thermostat housing the only part disconnected is the A/C, which makes sense as the A/C does not have a belt on it currently. Everything else is connected, but I will start tracing wires.
 

Mk3TargaJames

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Mar 14, 2017
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DieselScout2;2090812 said:
Car struggles to start and needs some throttle to keep idling. Once "warm" it idles OK. I will check out the connection at the sender and the sender itself. On the thermostat housing the only part disconnected is the A/C, which makes sense as the A/C does not have a belt on it currently. Everything else is connected, but I will start tracing wires.

I don't want to say that it's 100% CPS related but it sounds like it. My car also will crank 10-15 seconds when stone cold before it grabs ahold and starts. When it's warm it'll start up like a normal car. Have been putting it off as I have blowby from the compressor side seals being bad. I'd say keep toying with the CPS, there should be a thread somewhere about how to time and adjust said component.


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DieselScout2

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Mk3TargaJames;2090822 said:
I don't want to say that it's 100% CPS related but it sounds like it. My car also will crank 10-15 seconds when stone cold before it grabs ahold and starts. When it's warm it'll start up like a normal car. Have been putting it off as I have blowby from the compressor side seals being bad. I'd say keep toying with the CPS, there should be a thread somewhere about how to time and adjust said component.


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It starts within 4 seconds of cranking, firing on a few cylinders then it catches up.

UPDATE: Finally got a check engine light, and pulled the codes.
Code 24: intake air temp
Code 31: afm
Code 52: knock sensor

Where should I start first?
 

Mk3TargaJames

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Mar 14, 2017
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DieselScout2;2090841 said:
It starts within 4 seconds of cranking, firing on a few cylinders then it catches up.

UPDATE: Finally got a check engine light, and pulled the codes.
Code 24: intake air temp
Code 31: afm
Code 52: knock sensor

Where should I start first?

A bad knock sensor will put the ECU into safe mode I'm 99.9999% sure.

As for codes 24 and 31, could be a bad AFM, but could also be a good amount of other stuff. I've also read in old threads where people never got their code 24/31 to go away.


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DieselScout2

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Mar 5, 2017
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Mk3TargaJames;2090842 said:
A bad knock sensor will put the ECU into safe mode I'm 99.9999% sure.

As for codes 24 and 31, could be a bad AFM, but could also be a good amount of other stuff. I've also read in old threads where people never got their code 24/31 to go away.


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So looks like I'll be doing the knock sensor rewire, and try swapping AFMs with a friend! We shall see if this fixes my issue.
 

DieselScout2

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Mar 5, 2017
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UPDATE: At idle when warm the air fuel ratio is about 11. When I barely give it any throttle it accelerates slowly but sounds good and air fuel is about 14-15. However when it starts running rough the air fuel ratio is about 17-18. Decided to pull off the afm and inspect some lines. Found that the turbo was leaking a decent amount of oil and some got into the afm. I'm guessing that caused the afm to fail. This is probably why the car ran great for a day, then once the seal failed after being idle for a long time, broke the afm?


Found the build page for the car, with additional information regarding build specs.
http://www.oocities.org/peat_s/
 
Last edited:

supraguy@aol

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Dec 30, 2005
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Yeah, sounds like a bad afm, and I would also suspect that you're not always running on all 6 cylinders.
I would check the connections again.
 

DieselScout2

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Mar 5, 2017
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Alright, new lexus afm came in the mail, no dice. Car is still doing the same thing... I'm going to do the knock sensor rewire and go from there. All of the injectors are firing, I can feel them with a screwdriver. Each plug is getting spark. Pulled one plug and it was extremely black from running rich. Should I pull each plug and clean with carb cleaner?
 

DieselScout2

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Mar 5, 2017
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Decided to pull the entire engine harness. I'm going to test each wire and rewire the knock sensors into the loom. I also pulled off the turbo and rebuilt it Saturday night. I didn't realize how bad the turbo was until I pulled off the hot side of the intercooler piping and found about a half quart of oil in the bottom of it. Due to the shape of the piping, none got into the intercooler itself. After all of this, hopefully I will have a running car. Also found that the coolant lines going to the turbo were filled with gunk and random stuff. So I'm going to be flushing the cooling system and replacing the thermostat as well.
 

DieselScout2

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Mar 5, 2017
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Quick update on the supra.. Got everything back together on the supra. Replaced a few cracked couplers on the intercooler piping. Car did start, but is doing the same thing. Decided to mess around with the TPS connector and I found that if I held it a certain way, the car would run great. I ordered a new connector and TPS and will be replacing/adjusting both.