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Discussion Starter #1 (Edited)
So I was just idling one night for some time.... and the car just starts to idle are screwy and shuts off. Start it and it is barely staying on with Major Missing. I make it home, barely. Shut the car off and it doesn't want to start again. It just Cranks and stumbles but, no Start. I take the plugs out and they are shot! (black). I put in some fresh ones and still just crank stumble but, no start. I thought i had it fixed with a bad connection i found on the MAPECU2 but, nada. So i swap out the MAPECU2 for my brother's unit and change the factory ECU as well (i had a spare) The car starts! and idles.... I drive it but, it won't go past 5psi?? it just begins to break up BAD. I try putting my ECU back in and it still cranks then I put my MAPECU2 back in and still Starts. Then it gets progressively worse so I'm thinking from all the bad cranking with no spark the plugs must be shot. I decide to change the plugs the next day again but, this time no Start, back to just Cranking and stumble... :/ after several tries and securing more connections that may have not been solid at the MapEcu2 I pull the plugs out again and #2 and 6 are fouled the others are wet with fuel.

I'm going to put another set of plugs in and see if it was those last connections that i Secured but, I doubt it..

I have also changed out the ignitor. The coil packs i purchased new a few years ago and I have an HKS DLI. Does the DLI kill coil packs twice as fast?

I know in this situation there are a number of things it could be:

Crank sensor
crank sensor wire
Cam sensor's
Crank/trigger wheel (as per Speedmaster747)
Coil packs
Ignitor

I'm looking for someone who may have had the similar symptom (Crank stumble with no start) to point me in the right direction. I would like it not to be the last thing I check... :/


*****Edit*****: - So i found the problem in case anyone searches and finds this thread.... it was the damn HKS DLI!.... go figure...... LED light was on and there was no indication it was bad but, it was! I just un plug it and done! problem gone!

thanks in advance! :)
 

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Discussion Starter #3
Check crank trigger wheel. The star piece fell off of my car once and the car wouldnt start.
Yes but, mine started again and wouldn't pass 5 psi?? Then it went back to crank stumble.... with that failure is it possible that the car would start again? Was your car cranking with a stumble or just blank cranking ? I have no spark apparently
 

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mines doing the same thing right now. It will start then stumble and die.if i feather the throttle it will stay alive but then dies. spark plugs are fouled 2,3,5 and6. 1 and 4 are just wet soaked with fuel.
 

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Discussion Starter #5
mines doing the same thing right now. It will start then stumble and die.if i feather the throttle it will stay alive but then dies. spark plugs are fouled 2,3,5 and6. 1 and 4 are just wet soaked with fuel.
Well my car doesn't start.. It just crank stumble, crank stumble, crank stumble,....
Your plug results do sound similar...
If I figure it out I'll post what it was..

Till then... HELP! :/ lol
 

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Discussion Starter #9 (Edited)
sonny12 - No, I haven't made any head way yet. I dropped in some good plugs and still nothing. I will be trying a couple things this week.

Howlermonkey - Not sure if that will keep it from starting all together.
 

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Howlermonkey - Not sure if that will keep it from starting all together.
Car wont start if coolant sensor is bad or the ecu is not getting the signal. New sensor is 45+ shipping from Curt. Its the larger of the two sensors in the upper water neck.
 

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Discussion Starter #11
Car wont start if coolant sensor is bad or the ecu is not getting the signal. New sensor is 45+ shipping from Curt. Its the larger of the two sensors in the upper water neck.
ok, I will swap it out and give it a shot but, I'm pretty sure I changed this out when I put a Fresh short block in..
 

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ok, I will swap it out and give it a shot but, I'm pretty sure I changed this out when I put a Fresh short block in..
Could be the wiring. That plug seems to go bad on a lot of Supras I've seen over the years. If you're getting fire (spark at the plugs) then your crank signal is working. So your cam sensors should be working too. Those are the major things to stop a perfectly healthy car from running out of the blue. GL
 

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Discussion Starter #13
Could be the wiring. That plug seems to go bad on a lot of Supras I've seen over the years. If you're getting fire (spark at the plugs) then your crank signal is working. So your cam sensors should be working too. Those are the major things to stop a perfectly healthy car from running out of the blue. GL
Well thats the thing, as you read above I am not getting good spark.
 

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Try putting jumper cable between engine and body of car and see if symptoms persist.

Another possibility is crank/cam reference waveform being messed for a multitude of reasons one being foreign objects either stuck to sensor or have damaged the tone wheel.

I've seen this from cars when I worked at lexus where a technician removed the crank timing belt pulley to replace a seal and either knocked off a tang on the "wheel" or simply just dented it.

The resultant bad waveform caused really strange running.

As far as the head temp sensor possibility, your car will go extremely rich even with stock injectors that is so rich that the car won't run and quickly wets the plugs.
 

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have you checked the temperature sensor on the upper water neck as described above? I had the same problem with my car yesterday, turns out one of the two wires that go into the plug for the sensor was rotten/cracked/cut from all the heat maybe?? anyways I fixed it and the car starts now

I would get a hard fuel smell when it crank/stumble so I'm pretty sure my plugs are fouled by now .. still starts though
 

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Discussion Starter #17
have you checked the temperature sensor on the upper water neck as described above? I had the same problem with my car yesterday, turns out one of the two wires that go into the plug for the sensor was rotten/cracked/cut from all the heat maybe?? anyways I fixed it and the car starts now

I would get a hard fuel smell when it crank/stumble so I'm pretty sure my plugs are fouled by now .. still starts though
So your car would "Not Start" before at all?
 

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hopefully that solves your problem, I had to check the wiring on my map ecu and even redo some of the connectors and nothing so I know how frustrating it could be
 
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