Newly Purchased 1986 LX 5.0

Hardwerk

Member
Apr 21, 2022
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This thing still giving me fits. Changed the spark plugs out over the weekend. Little difference.

I put a temperature gun on the exhaust manifold from each cylinder. The passenger side cylinders (1 thru 4) was up to 100 degrees cooler than the drivers side (5 - 8). The temperatures would raise and then drop 50 degrees. Someone said it might be flooding with fuel and cooling off the cylinder. The car is running super rich. This would imply primarily on the left bank. Any thoughts?

I have a OBD1 on the way to check out codes. Just waiting for it to get here.

So, I've replaced the TPS, did a smoke test (didn't see any leaks), did an idle speed reset, checked/adjusted the timing (12 degrees), cleaned out bad fuel/put in fuel injector cleaner, replaced the injectors (mechanic did), checked the fuel pressure (~32 psi), replaced the plugs, running out of ideas...

Anybody got any suggestions?
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Disconnect the battery for about 30 minutes with the headlight switch turned on, turn the light switch off, connect the battery, drive the car around with some stop and go and some steady speed time. Then run the codes.
 

Hardwerk

Member
Apr 21, 2022
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Looks like 63 and 23 were the 2 codes I got for key on engine off test. 63 is TPS voltage too low. I have replaced the TPS so I'm guessing this is meaning some kind of wiring harness issue. Or, based on some research, this can happen with a key on engine off test and maybe I should check with Key On Engine On test.

Does this shed any light for anybody?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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This shows how to check tps setting.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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Code 23 is TPS voltage too high (over 1.25volts)

Code 63 is TPS voltage too low (under 0.5 volts)


Anything in the 0.5-1.25V range is acceptable, no need to chase 0.99 volts. I guess my first question is since you have both a high and low voltage code, did you erase the codes prior to running the test? One of those two could be old.

Sounds like you also did not perform the Key on, Engine running portion of the test. I would reset the codes, start the engine and let it run a few mins and then shut it off and do Key On, Engine OFF codes, and then the Key on Engine Running codes.
 
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Hardwerk

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Apr 21, 2022
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Code 23 is TPS voltage too high (over 1.25volts)

Code 63 is TPS voltage too low (under 0.5 volts)


Anything in the 0.5-1.25V range is acceptable, no need to chase 0.99 volts. I guess my first question is since you have both a high and low voltage code, did you erase the codes prior to running the test? One of those two could be old.

Sounds like you also did not perform the Key on, Engine running portion of the test. I would reset the codes, start the engine and let it run a few mins and then shut it off and do Key On, Engine OFF codes, and then the Key on Engine Running codes.
Yeah, I suspect these are codes from when I swapped out the TPS. I'll be clearing out and running again tonight.
 

Hardwerk

Member
Apr 21, 2022
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Cleared out the codes and received a code 63. The measured voltage on the TPS was 1.24. I turned the idle down to ~500 rpms and that dropped the TPS reading to .997. Ran the codes again and got an 11 (all clear).

Car is still running horribly and now at the lower idle even worse than before.
 

manicmechanic007

5 Year Member
Sep 26, 2017
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During the Key On Engine On tests with the Start tester you are to use
The Latch and Un latch of the toggle switch is hard to do with a test light and a wire
It is possible because they made the Asset students make one and use it in school back in that era
If you own one... Find a star tester
 

manicmechanic007

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Sep 26, 2017
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star2.jpg
 

manicmechanic007

5 Year Member
Sep 26, 2017
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Thank God for ASE
It was them that pushed OBD2 so hard so it is easier for all makes and all independent shops now
Ford and BMW were the worst offenders when it came to special tools that cost a fortune
Nothing has changed
You want to get serious with new Fords as an independent
Its about 10-50k a month for the tools and a satellite link to Detroit last I heard
Thank God for OBD2
Replace the windshield in a BMW, water leaks on the headlight switch. You replace it
You need to go to them to put the miles back in the new headlight switch with their scan tool (new) VAG I believe
The mileage is stored in the headlight switch which has a expensive module attached wtf
Get ready for more of that