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Wont start

1.9K views 17 replies 3 participants last post by  BamZipPow  
#1 ·
After new alternator, battery light would light up when rpm's got high, then truck would run hot. It blew EFI fuse and would not crank, went through 3-4 fuses until I put a jumper on it and now I have noticed I have no spark nor does my fuel pump kick on. Took the jumper off and now the fuse doesn't blow but still no start, no spark or fuel. Is there another fuse or relay between my battery/fuse box to my ecu i could have blown? I swapped EFI relay out with tail relay n still nothing. 1999 taco 3.4l V6 m/t 4x4

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#2 ·
Welcome to the forums! :)

Putting a jumper on that circuit could've fried the wiring. :(

Have you checked to see where yer not gitting power at? You'll need either a multimeter or a test light to trace yer power on that circuit. Is there 12VDC power at the EFI fuse? After the EFI fuse? At the Circuit Opening Relay? At the fuel pump? Does yer Check Engine indicator light up when you turn the key to the ON position? ;)

How many miles on the truck? Have you replaced the fuel filter at all? Have you been running the fuel too low to the point where the engine died from lack of fuel? If so, you might've damaged the fuel pump as it uses the fuel to lubricate and cool the pump. Disconnect the wire harness and test the pump leads fer resistance. Report back with the reading. ;)
 
#3 ·
Thanks for the reply, im stumped lol all fuses are good and are getting power to them, its somewhere between fuses and ecu or just my ecu being fried. My radio has no power, my power outlets have no power, the clutch cancel button light doesn't come on but clutch cancel still works, and no the CEL doesn't come on when i turn ignition on.

The truck has 270k miles, i have not checked ecu power and ground, im not sure which wires are power n ground. Fuel filter was replaced about 3months prior to all this and i replaced it again when it happened because some forums read that could be the problem and its never been fuel deprived that i know of, it also was overheating n was showin to be puttin out 17v (going by computer reader plugged into the port under steering wheel) the night the truck quit, it also blew out tail light bulbs n headlight bulbs, luckily i had a replacement head light bulb with me and was able to drive on home. I will check for power at the fuel pump asap but im sure there is none.

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#4 · (Edited)
Since the Check Engine light doesn't light up, it's an indication that yer ECU isn't gitting power. When you jumpered the fuse terminals, did you smell any wiring burning up? If so, then the issue will most likely be a wiring issue along with the original issue of the fuse blowing. :(

You can confirm this by turning on the ignition key and testing the B+ test port in the engine bay Diagnostic connector located off of the air plenum. If it doesn't show 12VDC, then there isn't any power on that circuit. That circuit usually sends power to the ECU, fuel pump via the Circuit Opening Relay, MAF, and IAC valve, If that is the case, you'll need to determine what happened to the harness along the way and repair it. ;)

I would still test the resistance of the fuel pump just to make sure it isn't burned up or causing a lot of resistance. The issue I had with my EFI fuse blowing was due to a lot of debris in the fuel filter which caused the fuel pump to draw a ton of amps trying to push fuel through it. After removing my bad fuel filter, I couldn't even blow air through the bad fuel filter! ;)
 
#9 ·
In my last update i mentioned one of the plugs being grounded and fuel pump kicked on, all i done was ground my test light n stuck it into the bottom left port of the plug, test light lit up and fuel pump kicked on, also discovered that i had a blown fuse in my radio, its now working and i have power to my power outlets. There were numerous ports in the ecu plugs that showed to be having power, still thinking i either have a ground problem or ecu is fried, any help is appreciated, thanks!

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#10 ·
Also i was just cleaning grounds and checking them, there is some wires under the the diagnostic port where i checked the B+ for power, the wires are what seem to be grounded to the engine. When i unbolted them n bolted them back up they were sparking, but i tested for power after gettin them bolted back down and they didnt show to have power....

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#11 ·
The brown wires going to the air plenum near the diagnostic port are the ground wires fer the fuel injectors via the ECU. If the ground is weak or bad, yer injectors are not gonna fire. ;)

When the wires were sparking, was the ignition key turned to the ON position? If not, then I would suspect the ECU having serious issues as the ECU controls the ground to fire the injectors. The injectors git 12VDC at the injectors. :(
 
#13 ·
I also feel like i found my problem starter, when i changed out the alternator, the new one came with 2 nuts on the connection u bolt down, i put the wire that goes there between the nuts, maybe shorting out???? Idk, but i took the alternator to autozone to test it and they were hooking their wire directly to the nuts and it was failing, the hooked to the screw and it passed, so i feel like the alternator wasnt grounded right n started all of my problems.... correct me if im wrong plz... lol

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#14 ·
With power on the B+ port and the Check Engine light not on when the key is positioned in the ON position, I would still suspect the ECU. You can see who might have a used one near you if yer inclined to save a little bit of money. Give www.car-part.com a shot and see what's avalable. Most companies will ship. Just make sure it is the exact part number of the ECU that you have now. ;)

The other option would be to have yer ECU inspected and "repaired". I don't have any experience in this arena so it would be hard fer me to point you in that direction. I guess you could always pull yer ECU covers off and inspect the circuit boards inside to see if there was anything obvious. ;)
 
#15 ·
Update: new ecm ordered, could only find 3 in the U.S. that could be sent to me without sendin mine in to be remanufactured.($400)Beats toyota's $2003.00 lol. Took my old ecm apart and found that the part labeled D500 is burnt/melted, any idea what that might go to?

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#17 ·
I didnt have any luck with them, i did contact alot of ppl through them but no luck, i found this one on Ebay, im scared to hook it up cuz of my EFI fuse blowing, that's where I was at prior to the ECU being fried lol im not sure the cause of my EFI fuse blowing, i have traced all of my wires, i feel like it has somethin to do with alternator cuz after puttin the new one on i started having all these issues. Things like, when RPM's get high battery light comes on and it over heats, headlights blowing and dash lights glowing that i never knew i had

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