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Discussion Starter · #1 ·
My 2000 Tundra started dying at random intervals over the last 5 years. Has gotten progressively worse as time goes on. Only occurs in the heat of the summer here in Texas. When the outside temp exceeds 90 degrees the engine will not start when it gets hot. After it cools down (2-4 hours) it starts right up like it did day one. Does not throw any codes. Checked spark on all eight. Have fuel pressure on the rail and return. When the temp gets over 100 degree the engine can just stall out and die at random just going down the road. Again once something cools down it starts no problem. I have taken it to 3 dealerships and 4 Toyota specialty shops and none have found the problem. Most tell me the truck is fine because it starts and does not present any codes. One did see the problem but by the time the mechanic got to it there was nothing found. I have had it towed to a dealership and then it started up and drove without a problem by the time the truck delivered it. I have replaced all the coils ($125 each) and all the fuel injectors ($75 each). I have replaced the throttle position sensor, Idle air sensor, O2 sensors, MAS and the problem persists. I have been told that the ECM is the next choice but at over $1200 (@ dealer), I'm a bit reluctant. I can drive it all winter without ever encountering the problem. I have been hoping that it would just die one day and never start but that has not happened. So I cannot drive this over 7-8 months out of the year as is. Has anyone here heard of this issue. There are been similar issues with other Toyota products (Corolla, Camry, and others) All involve the ECM in the recall.

Oh another symptom is that it can blow the ECM fuse 1 but on replacing the fuse and letting it cool down it starts right up.
 

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In the olden days (late 1960s) my buddy had a Mercury Cougar with a huge engine stuffed into the car; came that way from the factory. He had the same issue you are writing of here in this forum. Bottom line: The starter motor was heat sinking (absorbing all sorts of heat from under the hood while the engine was still hot) and loosing efficiency because of this phenonimum. The engine would always start up just as soon as the starter cooled down enough to regain proper strength and efficiency. This could be what's happening to your vehicle although I would think the major manufacturers would have this all figured out by now. Good luck with your fix and keep us posted when you find out what's causing this problem.
 

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I think boneyard ecm's are dirt cheap (like 50 to 100 bucks) on ebay. Might be worth a shot, if only to rule it out. Sounds like you've tried most everything else.
 

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I'm guessing it still cranks since he says the truck dies while driving. The starter has nothing to do with his symptoms. Try pulling codes anyway and see if it shows anything.
 

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Discussion Starter · #6 ·
Cranks like a bat out of hell. I have an yellow optima battery in it and turns over easily. I have not found a ECM for $50-100 bucks yet. I have looked ebay for years and only seen them for $500-600. I'll start looking again. I had the starter problem with my 429SCJ in my 69 mustang after I added the headers. Fixed it by putting an asbestos welding blanket around the starter and header. I have an engine monitor for my laptop and I can watch all the engine status and performance sensors in real time. Nothing shows up when it wont start and the few times that it has died when I had the laptop connected looked like I turned off the ignition.
 

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Cranks like a bat out of hell. I have an yellow optima battery in it and turns over easily. I have not found a ECM for $50-100 bucks yet. I have looked ebay for years and only seen them for $500-600. I'll start looking again. I had the starter problem with my 429SCJ in my 69 mustang after I added the headers. Fixed it by putting an asbestos welding blanket around the starter and header. I have an engine monitor for my laptop and I can watch all the engine status and performance sensors in real time. Nothing shows up when it wont start and the few times that it has died when I had the laptop connected looked like I turned off the ignition.
You need to contact member "Rhinosarge". He's got access to a toyota wrecking yard in Los Angeles. Plenty of Tundras being parted out at decent prices. It sound like you've got a faulty ECM, maybe a cold solder joint inside. Have you tried cooling the ECM down when the no start condition exists? You could cool the ECM with electronics "chiller" spray when the problem reoccurs to diagnose a faulty ECM.

Just my .02:)
 

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Discussion Starter · #9 ·
cooling the ECM has not been tried yet. I was told that it sits behind the glove box so I never thought it possible to get to to try it. Is the ECM accessible?
 

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Discussion Starter · #10 ·
Sounds like a vapor lock....
I don't think vapor lock is possible in a high pressure fuel injected system. Back in the old mechanical fuel pump on the engine block days with a carburetor this was a common problem.
 

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cooling the ECM has not been tried yet. I was told that it sits behind the glove box so I never thought it possible to get to to try it. Is the ECM accessible?
It may take a bit of doing to access it, but it would be worth the effort to be able to test it. All you need is enough access to "chill it" when the no start or stall occurs. If the engine restarts after cooling the ECM, you'll have your answer.
I know it can be tough to condemn an ECM, because of the cost and the fact that all repair/diagnosis info stops short of the actual internals of said "magic box". They do fail- albeit rarely as I've only replaced 10 or so in the last 20 years as a professional tech.
 

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I don't think vapor lock is possible in a high pressure fuel injected system. Back in the old mechanical fuel pump on the engine block days with a carburetor this was a common problem.
Yep. Fuel is under too much pressure in these newer rides to be able to sit long enough to vaporize or boil.
 

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I've had other brand of vehicles die in traffic when the engine is hot & by the time I get there they restart like nothing is wrong, no codes, replaced cam sensor & never stalled again, until about 5 years later, new cam sensor again.
 

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I've had other brand of vehicles die in traffic when the engine is hot & by the time I get there they restart like nothing is wrong, no codes, replaced cam sensor & never stalled again, until about 5 years later, new cam sensor again.
Yep, I used to replace Crank Position sensors on GM vehicles all the time.
IIRC faulty Crank position sensors do not throw a code, because the engine management software is written in such a way that the ECM just "assumes" that you've turned off the ignition when the RPM signal is "lost" from the Crank Angle sensor.

To the OP- Checkout your Crank angle sensor. There should be an RPM PID showing at least a few hundred rpm during start up. No RPM reading on the scan tool during engine turnover may point to a faulty crank sensor.
 

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I would start with the ECM fuse issue. AVOID the salvage yard ECM. I would look at the CKP sensor. Does it die at a steady speed? 60mph, then nothing? All of the first gens die at stops because of the throttle body buildup. When it dies, does the tach flatline first, or as the RPM drops. Any moisture accumulation on or near ECM/PCM? Good luck.
 
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