11 replies to this topic

[sirweste]

Hi, I'm hoping for some help here as my MPi is dead and come thursday I'll be needing to do a 250mile trip in it - home for christmas!!

I have been chasing a electrical fault thats causing a few problems mainly associated with lighting (however when the rad fan is supposed to kick in, it only spins abt about 5rpm and the centre spots light up instead). This is my third weekend on it and last night things got a wee bit more serious. This electrical mainly lighting problem is Problem 2.

The original problem was when i turned off the ignition the rad fan would suddlenly turn on. This was caused by the speedo cable cutting through and fusing together some wiresn in the loom that runs behind the inlet. This i corrected but it didn't fix the light problem.

Back to the serious problem: Last night when i got the loom back in place after a serious fault finding session had turned up shag all, i cranked her over and she only ran on 3 cylinders. Pulled No.1 lead off and it was this cylinder that wasn't firing.
I've had another go today and it would seem that the coil pack has power but is only firing 3 points. I swapped leads and such, to confirm its just No.1 thats not working - only to discover that the others have now stopped working.
Cranking her over and she does try to catch but only very occasionally.


SO massive story over, do these coil packs fail? It has power, for sure, but there deffinately are other electrical problems going off - but i didnt think they'd effect the ignition.
Though that said the coil pack is in two banks co I'd only expect it to fail on 2 cylinders not all four or just one....

Cheers veyr much for any help
Ryan

[Sprocket]

if the coil pack fails its two cylinders at a time, not just one.

Sounds like the engine may now be flooded.

Have you inspected the plugs? are they wet? Have you done a compression test?

How do you know the plugs are not sparking? what visual method have you used to determine no spark?

As for the electrical issues, i would check ALL the grounding points. The negative battery terminal, the engine to body ground underneath the engine steady, the ground on the boot floor, the main body ground behind the radiator expansion tank, and the main engine loom ground behind the ECU.

[Cooper1999]

sirweste, did you get to the bottom of this? What was the problem? (I've got an interest in ignition problems )
Hope you've got it sorted in time!

Edited by Cooper1999, 23 December 2009 - 06:05 PM.

[sirweste]

Hey

Cheers for the replys, aplogies for not getting abck sooner.
The issue is on hold as I've manage to wangle a company car for over christmas. So I'll no doubt be back on in January.

Grounding has been checked.
Main ECU loom has been redone.
Main body earth was inspected and was slightly rustly but i considered it fine - think i'll redo it though.
Engine to body strap is slightly frayed - but last year I put a second one from the alternator bracket to slam pannel.
Boot earth is rusty but the car cranks over perfectly so i dont think its that - again I'll redo it in january.

The pluigs were wet yes - I need to recheck the sparking - as i made a embarrising mistake when checking (blaming it on being out in -2c for 6 hours!)

Have a good christmas and cheers for the help again
Ryan

[sirweste]

Hi

I've just been out making the most of the good weather.

I have just check the plugs for spark, earthing on the rocker bots and on the slam panel. I tried 3 different leads, 3 different plugs and 3 different coil points.
There is no spark.
I have checked the coils connections, its receiving 12V supply on the NK (brownpink) as it should.
The other two wires WB (whiteblack) and WS (whitegray) are both 0V, checked in ignition II as well as III (during cranking).
I have check both these wires WB and WK for continuity to the ECU plug.

I attempted a compression test but it appears my tester is faulty. But obviously it appears the problem isn't with compression.


Any advice on what to check next?

[sirweste]

"MEMS ECM
The ignition sense of the ECM receives battery voltage from fuse A4 in the
passenger compartment fuse box on a W wire provided the starter switch is in
position II. As a result the ECM supplies an earth from the main relay control on
a WK wire to one side of the main relay coil (within the MEMS relay module).
Since the other side of the main relay receives battery voltage on an N wire from
link 4 in the engine compartment fuse box, the relay will energise switching
battery voltage via the relay contacts on an NK wire to the injector(s), purge
valve, stepper motor, ignition coil, manifold heater (Japan only) and positive feed
to the ECM. "

So perhaps its a problem with the Main Relay in the Relay Pack - or a break in that wire or something.???

[Ethel]

The coil will still work in essentially the same way as an old clockwork setup - tapping the ground wires to earth should create sparks at the plugs.

[sirweste]

Ok bit of a update,

I sat for a couple of hours infront of the hateful car this morning trying to look like I knew what I was doing with all those wires. From this session i concluded that the coil pack is definitely not getting the signals it desires from the magic box, and so is not sending any magic out to the plugs.

In ignition pos II
There is a 12V feed on the BrownPink wire.
There is also 12V to the other two wires, WhiteBlack and WhiteGrey.

From the Rover electrics guide the ecu should switch one of the white wires to earth to make the coil pack spark.
So....

In ign pos III (cranking)
12V feed brownpink
~4V to the other two wires. This voltage is fluctuating with cranking.
No sparking is apparrent - i.e. the car doesnt try to start.

the Rover manual says that the ECU gets it's earth from the Main Relay in the Relay Pack, on a whitepink wire. The whitepink wire on mine is to the relay coil, and is engergised when in the Ign II position. Giving a reading of 1V.

The rover manual also mentions something about the alarm having something to do with things, so i checked what the voltage of the WhiteGrey wire that runs from the alarm to the ECU.
This was giving a flicking 5V to 5.2V.


A suggestion as to tap either of the two white wires from the coil pack to earth to check its function. I wasn't able to do this on my own.


I'm lost with all this, any advice on what to do next would be greatly appreciated.

Many thanks
Ryan

[Sprocket]

Have you VISUALY checked that there is no spark.

The ground on white pink is from the alarm box and is used as the first stage imobilisation, the second stage imobilisation uses a digital code sent from the alarm box to the ECU and it is this that prevents the ECU firing the injectors or the coil Edit** The white red is the first stage imobilisation. The white pink is the main relay. The ECU energises the main relay only when it recieves the digital code from the alarm box, this is part of the second stage imobilisation.

If the main relay os energised the ECU is in an operationals state

so, there is one of two problems

The ECU is not recieving a signal from the crank sensor

Or, the ECU is faulty

Its all going to be down to getting a diagnostics computer on there and or sending the ECU away for testing.



The 12v feed to the coil will saturate the coil with voltage and the two wires back to the ECU. It is not until the ECU grounds that wire will there be a spark. The time scale we are talking about that the ECU holds the outputs for the coil to ground is in milliseconds.

Is there any fuel in the cylinders? have you considered that the engine may be flooded, in which case the engine will not fire until it is cleared. Like I said before, have you used any visual method of determining if there is a spark.

At the end of it all, considering you had a mine field of wiring issues, I put my money of the ECU outputs being shot.

Yhe fring on three cylinders if it was something to do with the ignition, would not be down to a faulty ECU or coil. Perhaps this is a red herring

Edited by Sprocket, 24 January 2010 - 11:11 PM.

[sirweste]

Yes i've visually checked for spark - though not in this last session as I struggle with just the three hands to crank the engine and use the multimeter.

At some point the LED for the alarm appears to have died too. I have re-soldered it on but it's still refusing to work, I may have it the wrong way round... I have also noticed the alarm didnt work this evening - but the immobiliser definitely made its tell tail click off.

I must point out that the car was firing on 3 or less cylinders. I only removed cylinder 1's lead and it didnt effect it so i figured it was that one. There is obvioulsy the chance that it was actually running on 2.

Since then the car has slowly got worse and worse i.e:
the engine was at first struggling to start but did and ran on 3 or less,
Then the engine really struggled to start, finally did but on 3 or less,
The next day, the engine would not start but was spluttering and trying
The next session it was occasionally trying
The next session it virtually didnt bother trying
Now it's given up completely and just cranks.


When hunting for the original earth problem I was having. I found the earth connections at the ecu plug i.e. the separate earths that are all crimped together and then run upto the earth point near the brake servo.
I soldered up this crimp, encase for some reason it had poor conductivity,
I also inspected the "shield" wires that were crimped and run to earth. These fell to bits in my hands, so i attempted to rejoin them but if i recall dint make a very good job of it - SO the lack of shielding could be effecting the crank signal.
The nature of the engine getting worse and worse could be due to the battery getting flatter and flatter, meaning that the crank signal is weaker and weaker and so the poor shielding may be having a greater effect.......

The engine may be flooded, but when checking for sparks and whatnot i have the fuel pump disconnected to try to prevent this. And I've been removing the spark plugs on most session to reduce battery drain when cranking.

Cheers very very very much for the help

[sirweste]

ITS ALIVE!!!!!

I'm not entirely sure which thing has fixed it, but either way it ran tonight.
I got tip of Andy at MLMotorsport in Kent who said that repeated disconnecting of the ecu could open up the female pin conenctors in the ecu plugs. So i went through them the other night and squeezed aload up. Though non were noticably wide.

The battery was removed from the car yesterday night and had been on charge for about 24hrs, til i refitted it this evening and she started up on the dot as she always used to - since the 19th of decemeber.

So now i just need to find the original earth problem so she can get her ticket.


Cheers for the help, thanks very very much.
Fingers crossed it was as simple as the pins......

Ryan

[sirweste]

Just to conclude this all up for any one referencing it.

The initial problem was a earthing fault caused by the terminal connector that earths the lighting circuits. Is referred to as earth point 2, and is located under and behind the coolant reservoir. Happy moment when i found that one.

The engine not running was due to poor connections between the ECU and it's plugs. I have sat for a good while at work (after taking the engine loom out of the car last night) removing each of the female connectors from the lugs and closing up the gaps i.e. bending the spring up.

I seriously hope this concludes it anyway...will see tomorrow...


Cheers for everyones help again.
Ryan