electrical problem

Short Bus

New member
Joined
May 18, 2011
Messages
1,131
Reaction score
0
Location
kansas
Ive got a truck in the shop thats turned into a real mess. It came in needing an injector. However after the injector swap, it now has another gremlin that has come out. When you turn the key on the injectors buzz, wts light comes on just as it should but when you try and crank the truck over the starter grinds, relays click and buzz.... symptoms you'd usually see if your batteries were too dead. Now, if you go over to the passenger side fender and take teh start wire apart and jump it to the battery the truck fires right off and runs fine. However when you drive it the trans acts like its not starting in 1st, it doesnt shift right, tow haul wont engage, and the converter wont lock. I can run a buzz and balance test, pull codes, but i cant do koeo or koer tests because it has egr ****** and no tune. I tried to dump a tune on to it and the tuner comes back with a communication error.

Things ive checked- battery cable connections, all harness connections on drivers side inner fender, pcm connectors, FICM connectors, all under hood grounds, under dash fuses. Im about to start tearing stuff apart in the cab so i can check the grounds inside. Basically im working down the ground side of the wiring diagrams, next will be the power side. anyone have any other ideas? Its gotta be something stupid simple, it wasnt doing this before i changed the injector.
 

Derek@Vision Diesel

New member
Joined
May 18, 2011
Messages
5,054
Reaction score
0
Location
Canby, OR
Unplug the fan clutch and try starting it with the key. If that doesn't work try unplugging the EBP sensor and starting it.

The transmission goes into limp mode when you jump start it, I wouldn't recommend driving it much in that state.
 

Short Bus

New member
Joined
May 18, 2011
Messages
1,131
Reaction score
0
Location
kansas
unplugging those did not do anything. Also have to communication to the transmission with teh scanner.
 
Last edited:

Short Bus

New member
Joined
May 18, 2011
Messages
1,131
Reaction score
0
Location
kansas
my scanner will not pull up any data or diagnostics for the transmission. I hooked the scanner on to my truck and it would, just wanted to make sure the scanner didnt have an issue.
 

Short Bus

New member
Joined
May 18, 2011
Messages
1,131
Reaction score
0
Location
kansas
I think ive got it figured out. After reviewing the engine data on the scanner, i noticed that the vref was only 3.5, yet the map, baro and ebp readings were correct as was the EOT and ECT readings. I checked the Vref at the map sensor and it was 5v. Call me stupid, but the only thing i havent done was nail down the start circuit, i swapped relays but didnt jumper the relay or check out the coil pwr/ ground.... I spend too many days out of the year in a combine i guess. Anyway, today i jumpered terminal 30 to 87 bam it cranked over like it should. checked coil volts between 85 and 86, 12.5vdc. terminal 86 to ground, 12.5 vdc. ohmed 85 to ground while cranking and the ohms were all over the place, i think it was anywhere from 200-900. Ive already checked the pcm grounds to the battery so that pretty well points towards the pcm itself being bad unless im missing something else.
 

Latest posts

Members online

Top