Alright, this is kind of long and convoluted...but there is a point.

Drove to SLC over the weekendand the Range Rover was running like CRAP. Bucking, jerking, loss of power, then SMOOOOOOTH as silk for oh, about 5 seconds, then more bucking jerking and loss of power.

This went on for about 350 miles until I got to SLC. Got to the dealer in American Fork stopped in to get a rotor, plugs and an alternator belt (it was squeaking).

Looked at the invoice and quickly handed back the rotor when I saw they were going to charge me $45 BUCKS!!!! :eek: Sheeshe, I know that Genuine is good in some cases, but buying from the dealer in this instance certainly had a premium. I declined on the rotor.

Got to my inlaws house, replaced the plugs and it was still running like crap. I called my local Land Rover guru Alan Johnson who lives in SLC to ask his advice. He said 'try this, this and this...', which I did, and it made no difference. Called him back and went up to visit him the next day.

He said that he had seen ignition problems occur from the ignition wires (the ones from the ICM), passing too closely to the alternator and main power lead. He suggested that we re-route those wires away from the alternator and main power lead, so we did. Started running great, so I headed back home satisfied that I had found the cheap bastard solution and my wife would be thrilled. Ran perfectly all the way home, then went out that night to get some food and it was back to it’s old familiar bucking and jerking. Went and re-did the wires, zip-tying them into a slightly better location and tried it again. Same symptoms. Called up Alan again and he said to come up in the morning on Sunday.

Headed up, bucking and jerking the whole way, got to his place and started testing everything. Saw corrosion on the diode that sends power from the computer to the EFI relay, he said that is a common problem, we cleaned things up, seemed to help a little…but not the main problem. Tested the pump, tested fine. Swapped pumps, his replacement pump ran fine, test drove truck, same symptoms. Swapped back to original pump, no change. Checked filter to make sure I had installed it correctly (just had put a new one in on Thursday and a new pre-filter on the same day). Both were installed properly.

Checked the rotor, swapped rotors, nothing changed.

Got out the computer, checked the alternator, looked good on the scope. Checked the coil, looked good, checked the ICM, checked out good, swapped ECU’s, nothing changed, swapped coils, nothing changed, checked Throttle-Position Sensor (TPS), nothing changed, checked dwell, nothing….

Starting to feel really frustrated we thought we’d swap the rotor back to my original, and unhook the alternator to see if anything was different. Swapped out the rotor and undid the alternator belt.

Loosing the squeal from the belt was nice, so we headed up the hill. Ran even worse than before!!!! Alan and I are starting to get VERY frustrated. I was supposed to be leaving back to Vegas that morning, and it’s now pushing 5pm.

We pulled the car over to listen to it run and Alan could hear it missing, so we popped the hood. I had put 3 plug wires in the wrong place so he straightened it out for me. Got back in and headed up the hill.

VOILA! PRESTO CHANGO! The truck ran smooth! Good power, good pickup, good acceleration, good sounding, no alternator. Hmmm….we were finally onto something.

Headed back and swapped out the alternator I had on there which was a Wrangler NW 150 amp alternator for a Delco re-built 100amp he just happened to have laying around. He was planning on returning it, having never been used, but luckily he hadn’t yet. Swapped pullies and installed alternator, went for drive. Still the same great pickup, acceleration and no hiccups.

Alan was skeptical until we’d driven about 15 miles, then he started to look relieved. The tach wasn’t working, so he swapped some wires and got it running properly.

We had achieved success, and only 5 hours after I had arrived (sheeshe).

His thoughts are that the alternator was creating a massive AC field around itself and was causing ignition interference with the ICM and the ignition wires. Once we had re-routed the wires away from the alterntor, and swapped it out for a new one, the field was eliminated and the original components I had in the vehicle worked fine.

The funny thing is I have been running this alternator (a Ford reman) from Wrangler NW for nearly 3 months without any problems. I will call them today to see what they think is going on, or if they have heard of this before.

Got home last night about 1:30 PST after a very non-eventful 7 hours of driving.

HUGE HUGE HUGE kudos to Alan for helping me out in a pinch. Alan came in 4th place in the Top Tech Challenge that Land Rover has for it's technicians. He's a sharp one, and I guess I should just feel lucky that I was the one that got to really put him through his paces and make him scratch his head a bit.

Thanks Alan!!!!!!

Will update as I learn more…

The corrosion around the diode could have made for some curious radio frequency interference. Given the number of wires that lead fromt he engine compartment to the ECU, this RF could have been induced into one of them and caused all manner of fun with the ECU.

My father had a Lincoln that every time we transmitted on the ham radio, the cruise control would shut off and eventually, the engine would shut down if one got long-winded.

So, the old man takes his car to the dealer and they put a new ECU in it... About a month later, he's back for a new ECU again when the mechanic askes him what the round mark on the hood is. When the old man told him it was where the antenna mounted (mag mount, 2 meters), the mechanic opened the hood and showed the old man where the ECU was located, directly beneath the antenna! After they replaced the third ECU, we moved the antenna and never had a problem again...

I was gonna say that you should have started with a voltmeter and then I read where it looked good on the scope and I knew you had someone helping you who knew how to run a voltmeter!:flipoff2:

Glad you got it runnin'.

Did you get the package I sent a few weeks back?

Peace,
Paul

Yeah, got it. Thanks!

You can probably see that I haven't had much time to learn Auto-Cad with Moab, snapped taps and poorly running Range Rovers!

Will it never end?

Originally posted by Serious One


Will it never end?

You're tellin' me. :flipoff2: I have to take the afternoon off from the day job to get Rovers out of the driveway to make room for more!

I have seen this as well. Only my experiences have been with Platinum Plugs in Bosch ignition systems. RF energy creating feedback to the timing control. Very ugly.


j

Michael,
I have had this problem as well. Many people I talk to who convert to higher output alternators run into problems with EMF. I finally relocated the power wire off of the alternator so that it did not pass anywhere near the Fuel Injector circuits. All my problems (Alternator at least) went away after that.

One of the things Alan suggested was to re-do the alternator cable.

The current, and stock setup is to use that cheap brown insulated wire (that cracks BTW...), from the alt. to the starter and then back to the battery.

He suggested to run two seperate cables of higher grade wire, one straight to the starter, and a second straight to the alternator, routing it away from any electrical controls (the EFI stuff would be part of that I presume).

I will be putting a second Optima in the RRC right in front of the air cleaner, so I will have the perfect chance to re-do those cables in the not-too-distant future.

I haven't given up on the super swanky WranglerNW alternator quite yet...just had to get home in a relatively quick manner last night.

Thanks for the confirmations guys.