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Discussion Starter · #1 ·
Hey all I an at my whits end! I bought a rolled over Tundra 2005 double cab 4X4 V8. I drove it on the trailer and off. I also drove it around the house and into the shop. I only mention this because it ran great. I bought a new cab and put it on with my original wiring that came with the truck. started it and it runs for a moment then cuts out and dies... I took a short video with my phone and you tubed it, so i can get some help!
After I spent a couple of days searching, I narrowed it down to the alternator... well kinda
With the heavy batt wire connected (on the side connected with a 10mm nut) and the 4wire brown plug that connects to the back both plugged in the engine dies, like in the video.
BUT when the 4wire plug is unplugged it of course doesn't charge....BUT it also runs just fine.
I tracked the wires, one is a blank so really even though its a 4 wire plug there's only 3 in the loom. One goes threw the cab into the cluster, I assume its for the gauge only, one goes to the voltage regulator near the fuse box near the power brake booster, the last one goes to the larger fuse box & charge relays. So maybe you guys can check out the short little video and shoot me some ideas....
There is also one other symptom, there is a small wine or buzz in the transmission when everything is hooked up to factory specs its very faint but Ive tracked it to the trans....
Some things I will say.....
I changed the Alternator
I changed all the interior wire loom, aka dash harness and doors
I changed the batt
I changed the engine bay harness aka outside fuse box and headlight harness, ect
the engine harness never left the engine
the wiring on the frame, suspension,fuel tank, and rear end also never left the frame. All other plugs we simply disconnected.
I only mention the fact all the other wiring was left alone because there really shouldn't be any issues with the rest of the wires. There are no other alterations except exhaust.
 

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First off,,, good luck.. Sending this very odd problem onto an internet forum is like asking a blind man to find a specific needle in a stack of needles.


IMO... and these are just random stabs in the dark.....

Factory security system? When I had security system malfunctions in the past, they would typically run for a few seconds and then trip shutting off the engine.

Have you determined if its cutting spark or fuel?

For kicks and giggles, take the 4 way plug from the alt and remove a single wire at a time to narrow down the circuit, back out just the voltage regulator wire, plug the rest in and test; replace the voltage regulator wire, back out just the fuse/relay wire leaving the other three and test... etc.
 

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im loving the hotel California playing in the video lol.

anyway im pretty sure that the alternator uses a internal regulator which is where that brown harness you are talking about plugs into. so one wire is coming directly from the battery (or fuse box), usually labeled ALT-S on wire diagrams, also known as the exciter wire to let the volt regulator know how much to keep the circuit open or closed to maintain 13-14 volts steady. a second wire is used to run the volt meter in the truck so you know if you running the right current or not and also will illuminate the battery light if something happens to the charging system. the third wire is and ignition wire that lets other electrical system know when the truck is running such as the DRL circuit so it will come on automatically when the truck fires up.

to me it seems like one of the wire connected to the alt is messing with the ECU is causing the ECU to close the throttle flap and the only reason it will stay running with throttle is because you are manually overriding the ECU with a the pedal cable pulling the throttle open.

so tr what was said and narrow down which wire is causing it. you might want to try to find the wiring diagrams and/or the FSM for the 2005 tundra.
 

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Discussion Starter · #4 ·
Well you guys are my last hope! lol I've asked so many people (Toyota guys and professional mechanics) most said the same thing as you, so pat your self on the back.
:cool: BUT I will say
The 2005`s ^ are fly by wire throttle
Im only a SR5 and just have factory keyless entry no factory alarm or immobilizer on mine, that was only available in 2006 up.
I also forgot to mention, I've begun throwing parts at the problem.... I changed the BCM aka body control module, 4x4 brain, and the inside fuse panel.
Tomorrow I'm going to order the main computer and try that. I was going to measure the voltage coming from the wires but I broke the meter some how, so ill come up with that and go from there.

I also went ahead and posted another video showing it with the 4 wire brown hooked up and the batt wire NOT... just to see mayb im missing something....
Toyota Tundra dies when alternator is plugged in VID 2 - YouTube
 

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Well you could use a screwdriver to keep the butterfly cracked open to determine if the closing butterfly is really killing the engine or something else. Have you hooked up a code reader to see if anything is showing or pending?
 

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unhooking the battery wire wont send any power to the battery so the battery has now started the truck multiple times and not been recharged. the gauge will keep dropping and the light is coming on because the voltage drain on the battery. that all seems normal.

the part that it stays running with everything hooked up and you holding the throttle or when you unhook the alt from the circuit it runs fine has got me mind blow lol.

i found the FSM for the 2005 tundra if you dont already have it: https://docs.google.com/file/d/0B-5MhfqaHsHOZXFXWDFEYVd2V0k/edit?pli=1
 

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Discussion Starter · #9 ·
How about 50 Bucks????

I tried some things this weekend and took some reading but lost the throttle control!
I hooked every thing up back to stock started it and as per usual had to feather the engine to keep it running. I had a friend start taking some readings, the three wires in the alternator loom while running they measured the same as the batt 13 volts.
I let the engine die and was getting ready to move the tester and heard a slight wine from the throttle body, I unhooked the throttle body and the sound stopped. I reconnected it and there still wasn't any noise. I wanted to see if it was a fluke so I started it again and let it die, same thing. It was whining/slight buzzing from the throttle body.
I wanted to try to take some readings from the OBDII port with my code reader. I plugged it in and set it up, and it read just fine at 13-14ish volts at around 2300 RPM feathering it to keep it running, as I was checking some of the other parameters ... It died I thought hmnnnn? So I restarted it... about 45 seconds to a minute it died again... One more time I thought... Sure enuff same deal.
Its like it runs out of fuel or some one shut off the key... Remember this truck doesn't have a factory alarm just keyless entry.
When I went to restart it, it wouldn't, well it restarted for a sec then died but no throttle control. When I press the pedal nothing happens it just changes pitch very slightly as it dies.
I had a extra good throttle body so I swapped it out.... Same thing no throttle.
Just for the hell of it I unplugged the brown 4wire harness plug of the alternator.... Guess what, runs fine, well, no charging but throttle works just fine. WTH I`m gonna pull out all my hair!!!
I also tried the ground trick as well I hooked up a pair of jumper cables, one to the frame to the engine then one to the body and batt.... No change.
I also changed the batt.... just to be sure. no change....

As side note I can't seem to post pics, so I put a couple of pics in a video since that`s all I can post.
One more thing..... I really want to get this figured out... I will paypal 50 BUCKS to what ever idea works!! No joke 50 bucks
Next I've got a computer coming from back east so we will see soon. Im at a loss for anything else.....
 

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Have you checked the 140A ALT Fuseable link under the hood? The other fuses for the charging circuit are:

7.5A ALT-S - Underhood Engine Room Junction Block/Fuse Panel.
10A IGN-1 - interior Drivers side Junction block/fuse panel
10A ECU-IG - interior Drivers side Junction block/fuse panel

Also check the 40A AM1 and the 25A AM2 Fuses in the interior Drivers side Junction block/fuse panel.

Also the ignition switch from an AC is different to that of a DC, hopefully that is still from a DC.
 

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Inside of ur alternator are some diodes to convert the AC into DC. Maybe one of them is blown and now ur voltage from the generator has too much ripple on it and ur ECU can't handle this. Check it with an oscilloscope.
If u want, I can give u some reference oscilloscope pictures from my car. (...if we can again upload pictures sometimes...)

Do u hear some noise which is following the engine from ur radio or amplifier, if u have one?

Do u have daytime running light? If yes, could u pls pull the DRL relay and check again?
 

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Discussion Starter · #13 ·
50 BUCKS!! HELP!! Tundra 2005 DC 4X4 Engine dies when the alternator is plugged in?!?

So far the list of parts Ive thrown at this damn thing..... all parts swapped are verified good
  • Dash harness form a 2005 D cab v8 SR5 4x2
  • Outside wire harness (the part that contains the entire fuse box) form a 2005 D cab v8 Limited Edition 4x4
  • all fuses inside and out
  • Inside fuse box, Big tan sucker with all the fuses inside next to the kick panel)
  • Alternator had both tested at two different places
  • BCM body control module
  • Battery.. twice
  • All 4 doors wiring
  • Throttle body
  • The voltage regulator.? The aluminum finned thing bolted next to the fuse box out on the drivers side fuse box.

As a side note.... the 4x4 and 4x2 wire harness are wire for wire the same, I spent 2 hours checking every one..... 2005 DC v8 trucks
I also have a computer comming and ill check the fuses one more time now that the throttle stopped working when its all plugged in back to
stock....
Oh and yes I have DTRlights, so ill check that next! thanks again guys for all the suggestions and yes ive still got a 50$ spot!
 

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Re: 50 BUCKS!! HELP!! Tundra 2005 DC 4X4 Engine dies when the alternator is plugged i

I'm thinking either a bad computer or a shorted wire. You need to inspect the wiring you haven't changed yet.
 

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Let one of the Yoda boys confirm this,,,, but have you exchanged one ECM for another or is the engine running off its own/original ECM?

On an OBDII GM, the PCM (fancy ECM) must be reprogrammed (typically called flashing the computer), even if you pull an exact one from a donor.
 

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Re: 50 BUCKS!! HELP!! Tundra 2005 DC 4X4 Engine dies when the alternator is plugged i

I'm thinking either a bad computer or a shorted wire. You need to inspect the wiring you haven't changed yet.
Short was the first thing that came to my mind.
 

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Discussion Starter · #18 ·
OK finally found it just by chance....! I was actually testing the ohms on some of the wires on the engine and notice there was a shiny spot on a plug on the passenger innerfender... I shined the flash light down to see the plug was pulled out just enuff to NOT make a connections, that is, the wire was slightly pulled out of the socket on the fuel pump resistor! OMG runs perfect now, thanks for all the help guys i dont think i would have ever found it if I hadent have just stumbled on it looking for other things that could have been wrong... Engine Auto part Motor vehicle Vehicle Automotive engine part Compound bow Bow and arrow Bow Archery Auto part
 
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