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Main = 1989 7MGE Ice Blue Pearl, Parts Car 1989 7MGTE Super Red
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6 Posts
Discussion Starter #1
I have a 1989 7MGTE,R154, Yellow Plug ECU parts car that I am going over to see what is swap-able to my NA. Engine cranks and sounds good but will not fire. I do not get CEL with key on. I have been searching the forums and trying different things for 2 weeks and still can not find where the issue is at. Here are some things I have tried. Verified the CEL Bulb is good in the dash ( have swapped with known good bulb ). Jumpered T & E1 and diag connector and did not get CEL.

Have tested EFI Fuse, IGN Fuse, Gauge Fuse, EFI Relay, all test good or show 12 Volts when key is in on position if condition is required for 12v reading.
Have cleaned ECU ground @ bottom side of intake.

Have Tested BATT and E1 ( key off ) at ECU per TSRM and had 12v
E1 + IGSW ( key on ) had 12v
E1 + M-REL ( key on ) had 12v
E1 + +B1 or +B ( key on ) had 12v each.

Checked Spark with Cyl 1 and had spark. Have not checked all holes. Also when turning the key to on the RPM gauge goes slightly above the bottom mark. I have not seen my NA do this so I found that odd... I have assumed my issue was ECU related because of no CEL with key on but now I am not sure. Didn't know if anyone out there had any ideas of what to try next. Thanks,
 

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1987 Toyota Supra
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109 Posts
With an issue like this it's usually the CPS or wiring/connectors.
Weak or no signal.
 

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Main = 1989 7MGE Ice Blue Pearl, Parts Car 1989 7MGTE Super Red
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6 Posts
Discussion Starter #3
With an issue like this it's usually the CPS or wiring/connectors.
Weak or no signal.
Would issues with CPS cause no CEL? I have seen it said that when you have CPS issues you get no RPM reading at all. So I assumed it was ECU related since I was getting no CEL when key on.
 

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1987 Toyota Supra
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109 Posts
Correct.
This crank no start issue does not trigger a CEL.
At least from my experience.

I have had this same problem on my 87.
Makes diagnosing the issue tricky.

Do you have access to an oscilloscope to check the 3 outputs signal quality?
 

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Main = 1989 7MGE Ice Blue Pearl, Parts Car 1989 7MGTE Super Red
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6 Posts
Discussion Starter #5
Well after double checking myself and going back over everything again the issue was either a loose 10 pin connector at ECU (clip is broke) or it was the bulb in the dash. After going back over it again I got the CEL to work. Now shows a Code 51 so looks like its time to diag TPS.
 
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