Electrical Problem following manual tranny swap.

Japedo · Post by **Japedo** » 30 Mar 2010, 10:02

Hey folks, I finished swapping my manual transmission into my 94 850 turbo lastnight. And it seems I have an electrical issue.

When I first started the car it immediatley fired up but my buddy told me to shut it off quickly. The braided ground wire going from the back passenger side of the cylinder head to the passenger inner fender was smoking. And very hot to the touch. I disconnected the ground and cleaned it up a bit and reinstalled, now the car will not crank over at all!!!

When the key is put in position 2 the fuel pump keeps kicking on and off and there is alot of buzzing. Also the large grey relay above the radiator is clicking like crazy. When I turn the key to try to start it at this point the solenoid on the starter just clicks and then all the dash lights go off, like i'm stalling the battery.

After doing a bit of reading I believe I may have a ground issue between the battery and the starter, and that the starter is trying to ground through the engine grounds. To much current things getting hot. Im at work today and trying to figure things out a bit, any advice would be grealty appreciated.

Thanks Curtis

Post by **phils94850** » 30 Mar 2010, 17:43

curtis,

if everything was ok before the swap then more than likely its something youve done afterwards. As you stated id say you have something grounding causing all the electrical gremlens..take the time and meticulously go over your hot and ground leads.

Japedo · Post by **Japedo** » 31 Mar 2010, 06:43

I did a resistance check between the negative battery wire to metal bolts on the engine head, I got 980 ohms. I believe I read somewhere that a properly grounded engine should have 0 resistance in such a test. Haowever I cannot find that bit of info anymore and am wondering if anybody could confirm this method.

I am really looking forward to trying the manual transmission. I am going to start taking things apart for a further inspection this afternoon regardless, just hoping that that high resistance reading is a good indication.

Thanks

Curtis

Japedo · Post by **Japedo** » 31 Mar 2010, 09:08

I did find that there is a small black ground wire that comes out of the wireing harness below the starter and it is to be attached to the block at this point.
It was attached just above this point with the starter bracket bolt. I moved it down to it's proper location but this didn't improve anything.
Could this improperly placed ground have fried my starter solenoid,? I don't believe it could have but maybe...

I removed the blue negative wire from the transmission "large negative wire from battery" and reinstalled. Could this transmission not be grounding properly, as the engine is essentially grounding through the transmissio. The transmission did have alot of corrosion on it.

After messing around this is what it does when I try to start it. Key in position 2. everything lights up , fuel pump runs like normal.
At this point when turning the key further to engage the starter, the car just clicks and all dash lights go out.

Now with the key still in position 2 "dash lights out" if I wiggle the braided ground wire from engine head to passenger inner fender"the one that got hot" The car will come to life again, fuel pump kicks in dash lights on etc.

This leads me to believe it is still using an alternate route to ground, that isn't adequate. As this ground will still smoke a bit while doing this.
Did I mention I hate electrical problems?
Any insight as always is appreciated. Curtis

Post by **BEJinFbk** » 31 Mar 2010, 12:01

It sounds to me like your negative cable from the battery to the block is bad.
You said 980 ohms? That sound pretty high. If it's the original, just replace it.
Also, have you made sure that the battery still has a good charge on it?

Japedo · Post by **Japedo** » 31 Mar 2010, 14:20

the 980 ohms reading i got was when I put one end one probe on the negative battery terminal, and one probe on one of the head bolts. When I had the cable off from the battery to the block it had a reading of 3ohms I believe.
I have been charging the battery on and off while testing and it seems to be staying charged.

I removed the ground from engine to inner fender and then tried starting again, it still wouldn't start but now the other small ground "engine to firewall uptop" got hot and smoked. So the car is deffinently taking the path of least resistance in trying to find engine ground.

Maybe the ground wire from the battery to the block has got damaged by the engine coming in and out.

I am trying not to pull my hair out over this, but with the manual transmission installed I really want to get this thing going. Not to mention the wife is taking the kids up north tomorrow with the cross country so i need wheels!

And the battle goes on.

Japedo · Post by **Japedo** » 01 Apr 2010, 07:29

I messed around with the car lastnight untill 11:30 without any success. Although I do have a bit of further information.

I replaced the large negative battery cable from the battery to the engine with a new cable. In attempt to ground the motor better, no improvement.

I tested the small green wire that attaches to the starter solenoid, its the one that recieves signal from the PNP switch and allows the starter to engage. This wire had 0V with the key in position 2 and 12V witht the key in the start position. So it's safe to say that my PNP is sending appropriate signal "even though it isn't attached to a transmission".

The large red positive battery cable that attaches to the starter has 12v of power all the time.

I am able to short the solenoid out with a screw driver and the solenoid will click very loudly, but will not engage starter. No matter how I attempt to short the starter terminals I cannot get it to engage.

And while attempting to start the car, the solenod doesn't click all the time. Probably about a third of the time.

However, when the solenoid does click and you keep the key held in the start position, this is when the engine/fender ground at the back of the engine will smoke a bit and get warm.

Could a damaged starter motor be causing all my problems? I know it sounds odd as it worked fine before, but I did have it in the vice and had to use a hammer and punch to remove the dowl pin, as there was allready one in the manual tranny. I also started the car "initially when it started twice" in gear the first time, car lurched ahead and stalled. Maybe put to much load on the starter?

I am going to remove the starter and bench test it today.

Wish me luck. Curtis

Post by **jblackburn** » 01 Apr 2010, 07:37

I think a seized-up starter could well be the root of all your issues. It draws what, 200 amps or so of current, probably more, and even more than that if the thing can't turn, probably overloading all the grounds it has. Bench testing's probably a good idea. Have you tried hitting it?

Let us know how it goes!

Japedo · Post by **Japedo** » 01 Apr 2010, 18:55

Progress has been made! I replaced the ground from the engine to the fire wall, and the ground from engine to fender " the one that kept smoking" and the starter now cranks the engine.
The wire that was smoking had a resistance of .003ohms, the new grounds both had 0.0ohms.

So now I have a cranking engine, but no fire from coil or power to injectors. The coil pack is getting battery voltage while cranking on the red wire "closest to firewall" and the blue wire "closest to front get 2.3 volts while cranking the engine. Is this blue a ground or signal?
I have a spare coil pack which worked when I removed it, and swapping it in didn't help. Im a little unsure of waht is going on now as it fired up prior to the starter quitting, now it's cranking and no fire.

I did try reversing the polarity of the crank sensor , as I now have a different flywheel "didn't help". I understand that this is sometimes required when donig a manual tranny swap, but since it started twice before and the manual tranny flywheel is from a 1994 I don;t think I need to do it.

Maybe my cam sensor or something has died but I really would find it hard to believe as everything was working great engine wise when I pulled the drivetrain to swap the transmission.

This I find interesting, I am not able to read codes from a2 socket. I could always read a2 before.... it stays lite dimmly with the jumper wire in place, unable to flash codes.

Hopefully Iget this thing to life soon, for my own sanity.

Curtis

Japedo · Post by **Japedo** » 02 Apr 2010, 08:16

Have noticed this morning that although the fuel pump makes a buzzing noise, the IAC valve doest buzz like it's supposed to with key in position 2.

Have tried another fuel system relay "large grey elay on top of fan shroud" with no success.

I need to lacate a schematic for these systems and do some testing of the circuits I guess.

Does anyone know if that grey relay can withhold fuel injector power, and spark? As I am not getting either.

THanks