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'96 Disco money-pit engine issues....

8K views 33 replies 7 participants last post by  pavel 
#1 ·
Found myself without a running 4x4 for the Nevada winter, not good.
From January to April the weather will be cold and the roads slick.

Found a '96 Disco on the cheap, pretty high miles at around 200K but the price was "too good to pass up".

It sort of runs, but is very low on power.
I've had my Series 2A 88" for decades and will definitely restore it again.
The 88" 2.3 would run circles around this Disco!

Previous owner replaced the upstream 02 sensors, I just replaced the downstream 02's.
Fewer codes now but still getting Early Ignition Coil Activation Fault Coil 3, P1374.
Early Ignition Coil Activation Fault Coil 4, P1375.

I suppose it's nice to have these codes, but they are not well defined.
Early Ignition Coil Activation Fault = WHAT exactly?

"Early" would seem to indicate premature, but really gives no clue to how or why.
This same fault on two of four coils.

Anyone able to clarify what I'm really looking for from here?

In poking around the web I see several Rovers with the coil packs relocated to the front of the engine, any real trick or downside to doing that?

Another issue is that it keeps blowing the 15A fuse for the fuel pump.

Also have the "Service Engine" and Seatbelt system lights on constantly.
Oh, and the tach is pretty erratic too.

Not looking to restore this one, just need to be able to use it for a few months until I can get an OLDER model up and running.

I have some very trick diagnostic equipment I would be able to use if this Disco just had an actual distributor, but no way to connect with this type of ignition.
 
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#3 ·
Did some old fashioned checking tonight.
If the left-most coil is #1 and the far right is #4 as viewed from the front of the engine it is #2 and #4 that are dead.

Now wondering if the coils are truly dead or a signal is bad?

There must be a special hell for the "Engineer" who chose the coil location and mounting.
I tried to test for voltage at the coil pack connector, only one wire had power, a green/white one. (Red on the coil pack side, just lovely to see the color change at the connector!)

So how would I check that each coil is getting a signal?
The connectors appear well sealed and I would prefer NOT to have to puncture the insulation.

#4 barely flickers a spark, it seems #2 may do even less.

I know about moving the coils to see if the problem follows, but what a dire mess with all that has to be pulled apart just to get access.
Then pulled apart again to make the actual repair.

Really need to put my Series back together!
 
#4 ·
The codes for coils 3 and 4 are P1373 and P1374. P1375 doesn't exist.

The fault codes indicate that you have "early activation". What the codes mean is that they are fully charged before they're expected to be. The ECM expects a dwell time (2.5ms) between the initiate signal and the fully charged return signal. If the coils aren't putting out a good spark then it's fair to say they're shot, they're only able to accept so much juice and then they quit accepting any more, not fully charged.
I personally would grab new/used coil pack or individual coils and play swap the coil.....

Blowing a fuse is either pump voltage going to ground or high resistance over 15A. I'd go with bad brushes or the connector to the pump is burned but you need to make sure you don't have a wire going to ground before swapping out the fuel pump otherwise it's moot. Checking is not going to be easy either because when you turn the key you only have about 10 seconds to check the 12V circuit before it quits building prime pressure. Pump is supposed to put out 34/35 psi minimum, the higher the better.

Glad to see your still around Pavel!
 
#5 ·
So it seems I have to rip the intake off to change out the coils, and reassemble to verify the repair.
$20.00 for the upper manifold gasket.
Anyone use Hylomar as a sealant?
When using Hylomar were you able to get it apart again without damaging the gasket?

Anyone have a sealant that makes the gasket unnecessary?
Please do not say RTV silicone, I hate that stuff and know that it does not last for long in contact with fuel.
 
#9 ·
New USED coil pack came today.
$20.00 for original units.

Only need two to be good.
Need to test them.
Thinking of bolting them down, hooking up the connector, putting in some spare plug wires and turning the engine over while looking at what I get for spark.

Or maybe I can just use power and ground at the connector to check for healthy spark.

From my searches ohm meters are not that reliable to test as the standards are not readily available.
But spark is clear, particularly when you get bit. ;-)
 
#10 ·
More ol'fashion testing tonight.

Plugged in the new coil pack, moved the plug wires on to it, grounded with jumper cables.

Fired up the rig, checked spark.
The SAME coils came up dead!

So moved a pair of coils and the problem coils were the same.
Conclusion is that it NOT the coils at all.

So it seems I need to figure out why coil #2 and #4 are not being fired.
#4 has a VERY weak spark.

What actually drives the firing signal?
Where does the other end of the coil pack connector go?
Is this a computer connection of something else?
 
#11 ·
Downloaded RAVE a while ago.
Cannot open most files on my MAC.
Cannot open the tutorial to any useful data, only a few PDF's.

Seems my ignition issue may be fairly simple, if I could only access a schematic of the ignition system to find out where the coils get their firing signal.
Need to trace the dead wires back to their source.
Either the signal is not sent or the wires are defective.
Do not want to cut the harness open so need to know where the junctions are.
 
#12 ·
NOTE TO SELF!
Never, ever, buy another vehicle with OBD II.
Never, ever, buy another "Luxury" vehicle, or any vehicle without a conventional distributor.
Never buy a vehicle who's manual is not complete enough to reveal a simple wiring schematic.
"Electrical" is more than alarm systems, door locks, and sensors!

Sell Disco ASAP, restore Series 88" again!

No, I will NEVER buy a new car, way too much Gov. Org. mandated complication.
If I cannot service it easily I will not own it.
 
#13 ·
Richard, if you look at the world of manufacturing and how it has changed over the last few generations, you'll see trends. One is 'planned obsolescence' - a brilliant idea that has saved countless jobs and economies from stagnation. Another is the idea of 'decreasing durability' in goods and then there's the 'escalation of complexity' in everything (washing machines to religion). The automotive world is no different of course.
Add in the escalating expectation of silent function and your Series 88 just doesn't cut it for the vast majority of new customers.
We were at an automotive "show" two years ago when I was asking some questions about Range Rovers (full size and smaller). The sales rep said with a straight face, "Sir, you are not supposed to keep a Land Rover more than 4 or 5 years".... he was serious.

The Disco I (we have a '96 which we bought new) is relatively uncomplicated compared to the newer vehicles but does have an early OBDII set up. I have been told several times, it wasn't until about 1998 to 1999 that the OBD II systems were fully integrated and worked out in most vehicles, not just Rovers. By the way, one dealership said our vehicle is actually an OBD I vehicle, which I think was their way of scaling back my expections of what the code system could tell me.

Final point: we are in the autumn (early winter?) of the ICE vehicle. I, like you, prefer simplicity and so will inevitably look to older vehicles (and perhaps electric drive sooner than later)

Permit me to suggest that time will heal your frustration and allow yourself the option of buying another Disco I if a good opportunity comes up.

Cheers,

Pavel.
 
#15 ·
Tried to follow the ignition coil pack wires back to the ECU.

SEEMS they go to the black connector.

Wire colors are W/Orn, W/Grn
W/Blk, W/Ylw, W/Blu

Only some of these could be found at the ECU connector.
Several seem to be "Common" as they will ring my tester when I am only trying to find a single connection.

White/Yellow did not appear to be good from the ECU to the coil plug, but it also came up as being common with other wires.
Pretty frustrating, a wire should be just a wire, but "Modern" circuits and relays confuse the issue.

I would still like a schematic!

It seems I either have a bad wire or two despite the wires and connection appearing undamaged, or I have bad output from the ECU.
Crank sensor seems unlikely as two coils DO get their signal just fine.

New ECU is probably more than the Rover is worth (If available), used hard to find at a price I will pay.
So it's up for sale at my current cost.

I will try to dig around some more to see of I can locate the wire positions in the ECU plug.
So far I am disgusted with the dearth of simple information available.
Plug pin-outs are VERY incomplete, apparently in part due to differences in configuration for different markets.

I do have a partial plug pin-out from a manual I downloaded.
Guess I will try to print that page in order to identify the pin numbers.
------------------------
As to the death of the ICE, that's greatly exaggerated!
Gasolene rules for many reasons, only Gov. Org. mandates and a compliant consumer base can change that basic reality.
I've helped build and modify electric cars, even briefly owned a couple antique examples (Now in an Australian museum), owned and driven Propane powered vehicles, and even been a manufacturer of kit cars.
I've seen the "Dale" (Google for a laugh!) and other "Alternative" cars come and GO, I laugh at Tesla, the "Leaf", Prius, and other "Green" nonsense vehicles.
I live in Nevada, where such cute little "Green" aberrations are utterly impractical to the point of being life threatening.

Political manipulations may deprive us of the best vehicles eventually, but not in my remaining life time.
 
#16 ·
As to the death of the ICE, that's greatly exaggerated!
Gasolene rules for many reasons, only Gov. Org. mandates and a compliant consumer base can change that basic reality.

I've seen the "Dale" (Google for a laugh!) and other "Alternative" cars come and GO, I laugh at Tesla, the "Leaf", Prius, and other "Green" nonsense vehicles.
I live in Nevada, where such cute little "Green" aberrations are utterly impractical to the point of being life threatening.
How far away is the closest shop that might be able to diagnose your Disco problems for a few hundred dollars max? I know at least one indie shop in this town that usually does not charge anything (or up to a maximum of 1 hour's shop fee at the most) to sleuth out mysteries. Is there no one who could help you solve your automotive problem(s)?

At the risk of be-labouring this somewhat off-topic discussion, I agree, the "death" of the ICE is sometime in the future, but in big cities, it is becoming much more practical than only 5 years ago to look at alternative transport. One member of my family gets free charging and reduced parking rates because she drives a Leaf. My next daily driver vehicle will be electric - again I live in a very transportation-congested city.
It's very revealing that the two largest Taxi companies in Vancouver have total Prius fleets - the savings in fuel alone (never mind about servicing) is about $1000 per month per vehicle compared to the full-sized Crown Vics they replaced. These (driven 24 hours per day) vehicles are not "green" aberrations in any way.
 
#19 ·
Tried those, even found what should have been the NAS ignition circuit.
Wires do not match the illustration.
Could not get continuity from ANY of the wires at the coil pack to the ECM!
At least three HAVE to be good or I would not have the two working coils that I do.

Really do not want to have to cut open the harness sleeve just to physically trace wires.
At this point I just want it running on all eight so that I can be rid of it.

Silly manuals give more detail to the door locks than the ignition circuit!

I'm going back to building my own cars, and a series Rover with fewer total wires than a Disco has in the light circuits!

Used replacement ECM should be here about Wednesday, hopefully that takes care of it.
 
#18 ·
I have a used ECM on the way.
Will try swapping it and see if the problem is corrected or changes.
At $100.00 it's cheaper than a single hour of local shop labor.
I suppose I will have to get this Rover running fairly well just to get my money back out of it.
The price of letting enthusiasm override a basic life rule, NEVER buy a vehicle that is infected with computers!

I will look at the link above once I'm more rested, long couple of days.
 
#20 ·
I guess this Rover is a Zombie, it's still trying to feed on brains!

Got the "New" used ECM today, installed and it will not start at all.
Put the old brain back and it at least runs on four again.

So I'm on the hunt for another brain.

Go ahead, get the jest out of your system, and if you have a spare GEMS laying about you know works for a fair price please let me know.
 
#21 ·
The wiring is very simple. A white/green wire runs back to fuse 3 in the satellite fuse box and supplies the power to the coil. This white/green wire changes to red just before the coils.
Each wire has a separate wire going back to the ECU. It changes colour along the way. Below are the colours that it leaves the coil and what it changes to by the ECU and what terminal on the ECU it connects to.
Coil 1 starts as a Blue wire, changes to white/black wire and connects to terminal 14 at the ECU
Coli 2 starts as a orange wire, changes to a white/blue and connects to terminal 13.
Coil 3 starts as a purple wire, changes to a white/yellow and connects to terminal 15
Coil 4 starts as a green wire, changes to a white/pink and connects to terminal 1
 
#22 ·
I am going to print out the plug illustration and try to check the wires again.
No apparent damage but I was not getting continuity when I last tried to check them.
As stated at least three HAVE to be good in order to run the two working coils.

Going to a P&P yard in the morning to try to get another ECM.
Getting a warranty this rime.
 
#23 ·
Well NUTS!

Drove 300 miles for another ECM and some other useful parts.
Got back, plugged in the ECM, and it does NOTHING.
At least the old one runs half the cylinders.
Got a warranty this time, have to find another unit at the same self serve wrecking chain.
That's two completely dead and my original.
I may have to stop defending Lucas at this rate, first of their units I have found to be consistently truly junk.
 
#25 ·
??????????
Fob for the ECU?
I've seen nothing to indicate they should not just be plug and play.

All three units I have seen have install dates on them that are later than the manufacture date.
The defective unit I just got was installed by a dealer in 2002.
So I'm thinking these have been an issue from day one.
Maybe why the GEMS system was rather short lived?

Tried to exchange the ECU today but the salvage yard only had a 1994 and 2000 model Disco's.
Neither has a compatible ECU.

I did finally get the wires from the ECU plug to the coil pack checked for continuity.
All checked out as being good, so I'm more convinced than ever that the ECU is faulty.
I do not see how it could be a crank sensor issue since two of four coils work fine.
Swapping the coils around does not move the issue so it's not the coils.

Also did some work on the drivers headlamp area, disgusted with the amount of flimsy plastic in use, does not seem very Rover like.

Got the used drivers side outer door handle installed, nice to be able to open the door normally.

Also removed the damaged rear bumper, will get the strait one on in a day or two.

Several of the petty annoyances are being taken care of, now if I could just get it to run on all eight cylinders!
 
#26 ·
Hmmmmm!

Just found this on an eBay listed ECM unit, is this true?
If so, first I've heard of it.
Also incredibly annoying as "Parts exchange" appears to be new normal diagnostic scheme.
----------------------

"OEM Engine management unit (electronic control unit) for 1995-2002 Range Rovers 4.0 L

Recommend that before buying you first check part numbers carefully against your existing unit and if any doubts arise, that you doublecheck compatibility with a Rover dealer.

Item came from a 2000 Range Rover that had unrelated accident. Cosmetic condition is good, thanks to protective compartment used in this model (as compared with Discovery I).

Terminals are not corroded at all.

Before use it will need to be reprogrammed by a certified LR mechanic or dealer with scanner to clear codes, reset adaptives and put it into security learning mode.

ROVER ECMs ARE NOT PLUG 'N PLAY!".
 
#28 ·
Already spoke to the local LR Dealer this morning.
Sixty miles away.

They confirm that the ECU is "Probably" bad as it seems there are four internal "Drivers" for the coils.

They also state that the replacement ECM has to be initialized TO THE VEHICLE, and that the software for that is unlikely to be available outside a dealership or high volume independent shop.
Apparently none of the readily available "Code reader's" can do this.
Also cannot be done with the ECM off the vehicle.
"Only $150.00", assuming they do not find other issues to insist on being necessary such as spark plugs and or wires at Stealership prices!

So Rover has now gone from the most reliable of user friendly vehicles to just another plastic clad, throw-away, over engineered, write blank checks, lump.
So very sad.

I really &%^#!*'up buying this one, lesson learned.
Now have to decide if I should continue trying to get it running properly or just part it out.
Probably not worth much in parts as they are now common in self-serve scrap yards.
 
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