I just changed the engine in a 1995 Dakota 4x4. It is 5.2 MPFI. I hooked up the wiring harness and can't figure out where the Black/Pink wire behind the alternator goes. Is it a ground or is it a hot lead from the alternator. Truck won't start. Have spark and fuel pressure in the rails.

HELP!!!

 

I'm assuming the wire your talking about is for the coolant sending unit which is used the coolant gauge.

As for the no start issue my guess since you got spark and fuel, that the distributor or plug wire are incorrectly placed. Possibly a bad crank sensor. Do you have any check engine light codes?

 

It is not a sensor or sending unit wire. It is a pair of Black/Pink wires that come together at a Star shaped ring terminal. comes out of the harness at the same point as the Alternator Battery lead and the other alternator wires. I have all the sensors hooked up.

I tried it to ground, but I am afraid of hooking it to power...don't want to fry any thing.

 

Always add in the details. Yes it sounds like a ground for the alternator.

 

ok, no enine codes...only 12 and 55...normal. Noticed no tach on crank...any ideas?

 

sounds like the dist pickup to me. the cam sensor is (pickup plate) is used for timeing injector pulse. the crank for spark. if there is spark then it's not the crank sensor. check to see if the injectors are being fired off. spray a tad of brake cleaner in the t body and see if it can burn that. that wire is a ground. i have it on my 96. check and make sure that you didn't crack the dis cap if you left it on when you dropped the motor in. did the pcm come from the donor vehicle? what about the pcm grounds. are they ok. also just to save you some time if you have spark or the injector are firing (not just getting ground but power to) then the asd relay is good. the fact is that you are missing fuel or spark. just about any engine that can spin can fire the fuel. maybe not well but something would happen. if you have compression it can burn it. i've seen a parts truck at work (93 ram with 15 trillion miles on it. ok maybe not that many but alot) with 30 psi on several cyls and it runs great. even did a burn out in it.
if it can fire off cleaner then you have spark. if not check for spark. even if the timing was way off you'd have popping or something. some form of combustion. you should also pull one of the plugs and see if it's wet. i've gotton a few junyard motors at work that the plugs were soaked and i had to torch em to clean em up before it would start.

 

Thanks for all the help. Hooked the wire to ground. Replaced the Crank position sensor as well as the Distributor pick up coil. I also reseated the distributor and the darn thing fired up.

Now just need to retard the dist to get rid of the accelerator ping.

Thanks again for the help.