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Discussion Starter · #1 ·
So about a month ago I replaced the ground wire that runs from the battery to fender because it was reading .01 ohm so I replaced it started it right after and it started beautiful then I shut it off right after starting it to check the fluids and went to restart the 1984 mk2 supra and it would not start with no spark, I checked the timing thinking it jumped timing and timing is spot on and all the grounds are perfect along with the wires running up to the igniter and I replaced the igniter and all checks out fine so I have no idea what else it could be please help
 

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Welcome to the forum. Run down the checklist in the TSRM, available online here: MK2 TSRM On-Line

If you don't come up with a plan of action and test things you're just throwing parts and wild guesses at it. This could be as simple as your coil wire not being shoved in all the way, no power at the coil, etc. That is if you've actually verified this is no spark. The only test you've mentioned so far is confirming the timing, but if you did that with a timing light it would have been sensing spark through the wires to do that. Timing being off wouldn't even stop the spark, you would just be getting it at wildly off times.
 

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Discussion Starter · #6 ·
Update: so I checked all the ground wires and they are the proper ohms and same goes for the wires that run to the and connections are all tight but still no spark my question is did the 1984 model have a pickup coil or does it just run off the ignition control module?
 

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1985 Toyota Celica Supra P-Type
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Check ignition fuse (7.5a)

Check continuity between the ignition fuse and the junction box to the left. Do a wiggle test when checking. There could be a loose connection/corrosion.

Check for b+ at relay, you can jump the relay if need be.



Basically you want to follow the circuit until you have a reading that is incorrect (power where power should be at that time).

RedP85 walked me through my no spark issue and I am thankful I did not go out and buy an ignitor (~$150).
 

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1985 Toyota Celica Supra P-Type
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How did you verify you have no spark? Spark tester? Timing light?

Also the coil and ignitor are separate components that make up the ignitor assembly.
 

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1985 Toyota Celica Supra P-Type
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The pic below is the wire diagram for the ignition system. I highlighted what I knew was good, or checked out to be good. My issue ended up being between the fuse and the JB (9-2I). Corrosion in the connector under the dash.

I would verify that you do not have spark. You can do this by timing light, spark tester or just taking a coil off the plug and looking for spark. After that it is only a matter of walking down the electrical path until you find your issue.

Schematic Rectangle Font Parallel Engineering
 

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1985 Toyota Celica Supra P-Type
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Coil is on top, and by the looks of new yours is that's what you replaced.

Ignitor is directly below it. You will see three different part numbers (oem) stamped between them. Coil, ignitor, ignitor assy.
 

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1985 Toyota Celica Supra P-Type
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Again, refer back to the diag procedure I posted. Check fuse first.


If the fuse is good, check voltage at both the coil and switch side of the relay.
 

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Discussion Starter · #15 ·
Update: I fixed the issue after replacing all 5 circle relays under the hood and under the dash and it's getting spark but now it's struggling to start and was wondering what the recemmended octane fuel is to put in it I feel 87 pump gas is too low of an octane to use
 

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87-octane is best. Higher octane fuels are more difficult to ignite and results in lower power output. You only get more HP from higher octane if you built engine to use higher-octane with high-compression 12:1 pistons, high-lift cams, ported and polished intake, fully-radiused valve-job. This prevents ever using lower octane again.

Most likely problem is non-OEM part. Especially anything electronic. Replace that Duralast part with OEM Denso and car will run perfectly. Same with relays, extremely unlikely all 5 relays died at once. Risk with replacing perfectly-working parts with brand-new perfectly-working parts is you introduce another variable into system. Many auto parts from stores are defective right out of box and needs to be tested and verified good before using.
 

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1989 Toyota Soarer GT Twin Turbo L
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A weak distributor cam signal will cause the ecu to not give spark. Looking at the rust on your igniter body, I suggest you sand off that rust real good, and also sand the bolt head and washer as well as the body where the it bolts to.
 

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Discussion Starter · #18 ·
Update: so I replaced the fuel pump and still nothing I noticed when the car is on on position the fuse for the efi does not light up at all with the test light but when I pull the fuse and plug the test light directly to the efi port on the fuse light it lights up fine
 

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Stop guessing and randomly replacing parts without testing and confirming they're bad before replacing. You're wasting tonne of time and money!!! As well as introducing additional unknown variables into system. Now you've got TWO fuel-pumps to test. Many, many new parts are bad right out of box. I went through FOUR brand-new fuel-pumps for my wife's Lexus before getring good one. Without testing, you have no idea if they're good or bad.

Test fuel-pump circuit.
1. Disconnect fuel-pump connector and attach voltmeter to harness-side of fuel-pump connector
2. Jumper fuel-pump test connector
3. Key ON
4. Is voltage at fuel-pump connector same as battery voltage?

Test replacement fuel-pump - I hope you got Denso pump
1. Disconnect fuel-line from cold-start injector and aim into measuring cup
2. Using long jumper wires, apply +12v and gnd directly from battery to fuel pump
3. Run pump for 15-sec, then disconnect
4. Note volume of petrol collected in measuring cup

Test original fuel-pump - Put original pump back in to reduce unknown variables
1. Disconnect fuel-line from cold-start injector and aim into measuring cup
2. Using long jumper wires, apply +12v and gnd directly from battery to fuel pump
3. Run pump for 15-sec, then disconnect
4. Note volume of petrol collected in measuring cup

Now we have some concrete quantitative tested and measured numbers for troubleshooting:

1. What voltage did you measure being delivered to fuel-pump at harness connector?
2. Compare volume flow of original pump vs. replacement pump


Should also do additional fuel-pump pressure-tests according to manual. Many pumps can flow lots with no pressure, but when pressed to deliver under presssure, they fail.
MK2 TSRM On-Line - fuel-pressure test

Next, troubleshoot EFI system using procedure in manual in order starting with verifying diagnostic system is in order to flash codes. Then displaying any error codes stored in ECU. Then proceed to test EFI system in order of tests given. DO NOT skip any steps, they are all important and vital to proper operation of car!

- EFI system tests
 
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