canuck0199@hotmail.com

It goes back toward the coolant reservoir then straight down to the bottom of the engine and into a heavier protector, looks to go under the engine. Maybe to the starter.
I'll investigate further tomorrow.

Anyone know why I would have an extra wire attached to the jump post?

canuck0199@hotmail.com

Scott,

The injectors would be a more consistent problem.
This only happens when the rad fans are running. With the fuses pulled or fans unplugged the car pulls like a school boy!

canuck0199@hotmail.com

The extra black wire on the jump post runs to the starter and then the alternator. I thought the stock wires did this also for jump starting?? I looks like they do underneath.

When I disconnected this wire the car hesitated much worse - fans on or off (but still worse with fans).
Even having the jump post unscrewed and dangling (wires still connected of course) the car hesitated worse.

I did isolate the 3 wire clusters at GPII and ground them directly to the battery, although when I grounded the fan wire it seemed to send a little pulse every second or so to the fan motor, I heard a muted tick and saw the fan lurching about 2mm or so every second. This only happened though with the battery master switch off, once the car was powered it stopped, (I have a main battery switch to disconnect the battery between the battery neg and ground).... and I have already disconnected it and it is not causing any issues.

Thanks all!!!!

Lizard928

I think we are going to need to fully inspect every lead in the front of engine harness

Bill Ball

Hmmm...

That black wire would be duplicating the function of the red (battery power) wire that runs from the starter to the alternator and then to the jump post. If that red wire had a break inside the engine harness, I can see jumping that break, but not both sections. Also, I gather they left the original "defective" wire attached. This seems odd. And if there were a break in the original wire, then when you disconnect the black wire, the alternator should stop charging. Did you notice that? You did notice the hesitation was much worse. The fans make it much worse. This sure sounds like a low voltage problem which will affect the EZK and LH.

Are all the original red wires still attached to the alternator and starter and jump post, as well as the new black wire? On the starter, there are 2 red wires together with the large black battery cable. One of the red wires goes to the ABS junction block up near the PS reservoir. With the battery disconnected, you could identify that by continuity testing, and then remove the other red wire. At the alternator disconnect both red wires on the B+ post, as the new black wire is duplicating it.

borland

Your alternator might be excessively noisy with increased demand of the radiator cooling fans running. Have you tried installing a bypass relay in place of the exhaust monitoring relay?

Lizard928

Bypass relay is installed already with no change.

hb4

If the second wire makes it better, add a third!
What happens if the stock wire is disconnected (both ends).

The pulse sounds like a component in the the fan controller or a control input to the controller shorting to ground and creating a noise spike that affects the EZK or LH. When the ground disconnect is 'on', there is now a second ground path to the controller or its input electronics that divides the ground current and decreases its impedance, changing the strength of the pulse below the point where it triggers the fan.

It sounds like someone's been chasing this before, and adding the second wire and soldering the controller were attempts that alleviated the symptom at the time, but not the underlying problem that got worse.

andy-gts

what about just changing out the fans to see if a known working system wont cause the same presumed spike and ensuing issues, I feel your pain knowing how difficult this chasing of symptoms can be!

Lizard928

I gave Steve a set of fans that I know had no issues, problem remained!

oups59

Colin,

What about the ignition amplifiers? Do you have HuCo's amplifiers ? I had the same kind of hesitation problem and swapping the HuCo with Bosch amplifiers cure the problem.

Luc

Lizard928

Luc,

Known good factory amplifiers have no change.
It is looking more and more like something in the front engine harness.

Lizard928

I am dredging this thread back up as I got the car back to complete further testing on this problem.

To cut a very long story short to a much shorter story, the problem is caused by a problem somewhere deep within the digital dash, specifically to do with the tachometer.

I do want to thank Jim Coreman, and Louie Ott for taking the time to talk to me about the symptoms and problems with this car.

Mrmerlin

doesnt the tach also take a feed from the computer,
we had a car that wouldnt run because the dash feed to the tach was broken,
it was a digital dash fixed the feed and all was well

Lizard928

The Tach is tagged into the line that comes from the EZK to the LH.
There is something in the cluster that is corrupting this line.
I'm going to try an inline diode to see if it stops the reverse signal. If not out comes the cluster to try and figure out which chipset controls that. :S