Auto electrician in South West

[Pauls SLR]

Can anyone here suggest a decent garage / auto electrician who might be able to help finding a problem with my wiring. Having spent hours trying to work through the loom and then thinking I'd fixed it and having a couple of short blats I was gutted to find the car now won't start again. 
I've barely used the car this year and was hoping to get some miles on it over the Christmas break.

I'm in North Dorset but happy to travel as I really want this sorted properly now.

Thanks in advance

Paul

 

 

 

 

 

[SM25T]

Do you want to try troubleshooting here ? You never know. Tell us all of the symptoms, the engine and year, type of immobiliser, etc.

[Pauls SLR]

The car is a 2002 SLR so k series with Emerald ECU. 
I'm not getting either a spark or any fuel from the injectors. 
I have unwrapped the loom and looked at all the likely connections. I found a couple of connections which looked poor but didn't seem to have failed. I re-did some of these and then put the loom back in just held together with cable ties, not taped up. The car ran fine for a couple of runs out. I then decided it was fixed so took the loom out and taped it all up and re-fitted. Now I'm back to square one and exactly the same issue. 
I'm not sure now whether there is just a faulty connection or plug somewhere but I'm not sure I've got the energy to take it all apart again when I don't really have much expertise in electrical faults!

[7 wonders of the world]

When cranking does the led on side of the Emerald show red or green...?

[Pauls SLR]

It's red switching on the ignition then green on cranking

[ncm]

I'm not getting either a spark or any fuel from the injectors. 

This could indicate a failing crank sensor. I had one on an old Corsa that played up occasionally , then worked perfectly for a few weeks before acting up again.. Unfortunately the car was not OBD compliant so I had to work out what was going wrong the old fashioned way......

Is Emerald OBD compliant? If not it might be worth testing your sensor (or just fit a  new sensor  for what they cost)

Brian.

[7 wonders of the world]

does the fuel pump prime...?

[Pauls SLR]

Brian

The Emerald is not OBD compliant. But thanks for the tip. I'll look at the crank sensor. 

7WW  yes the pump is priming.

 

[rj]

Check the throttle pot (and it's connections) Output depending on throttle position should be between 0.2 and 4.7V ish. The more welly the higher voltage. (Output is pin 2) Across 1 & 3 you should find 5V.

Not throttle pot no spark nor fuel.
 

[Piers300]

Check the electrical multi pin connector under the T/B’s. Mine was green with corrosion and use contact electrical cleaner. It’s not easy to separate. Also clean all main earth connections. Also check earth connection for ECU.

Piers

[Jonathan Kay]

On the original question:

Ivor Terrill in Oxford, but someone must know somewhere nearer...

I've always been pleased with them, but from the fault you're describing I might prefer a Seven specialist to a good electrician.

Jonathan

[Jonathan Kay]

On DIY:

Some good advice above, some of which is repeated here.

Have you got a multimeter and the appropriate wiring diagram? Let me know if you need the latter.

Sounds as if it's cranking well, but what's the battery voltage at rest and minimum during cranking? Have you tried jumping it from another vehicle?

Check immobiliser and inertia switch.

I'm not getting either a spark or any fuel from the injectors. 
... the pump is priming.

How have you tested those? And is that from hearing the pump or detecting pressure in the line?

Check all connections, including the the relevant earths. Inspect, wiggle, disconnect, clean, reconnect.

I have unwrapped the loom and looked at all the likely connections.

Any particular reason for getting to that so early in the process?

Check ECU fuse, and 30A is now recommended for Ks rather than the factory 20A.

Jonathan

 

[SM25T]

 

Fuse rail on my 2002 car 

[Pauls SLR]

Thnks for all the ideas. 
JK

Yes - I have a multimeter. I have an old wiring diagram but some has not corresponded to what I've found. 

It's not the battery. Voltages are good and cranking from both a starter pack or another vehicle has made no difference. 
 

I've tried with the immobiliser deactivated in the Emerald ECU which has made no difference so assume that is OK and have checked the inertia switch. 
 

I tested spark by removing a plug and shorting on the block whilst cranking: no spark visualised. Used a NOID light on the injector loom and no current to that. Also removed an injector and put it in a jam jar and cranked. No fuel coming out. 

When I first got marooned on the side of the road I moved the loom around and got it to start again and managed to get home. However this hasn't been repeatable since. 

Unwrapping the loom wasn't early in the process!! I've been through all the obvious things first! 

Checked the fuses and they are OK. Yes 30A for ECU. 
 

I have a suspicion now that I'm not getting power from the MFRU  as this seems to be shared between injectors and coil. This may be a connection with the grey plug under the TBs so will check that tomorrow. If you have a wiring diagram I'd grateful if you could send that for me to compare the one I have.  BTW I have plugged in a spare MFRU and that also made no difference so that is out!

Can anyone confirm which wires from the grey plug activate the MFRU for the injectors and coil?

Thanks all

 

Paul

 

 

[Jonathan Kay]

Please send me a Private Message with details of the Seven and your email address.

Jonathan

[Pauls SLR]

JK

PM sent (two actually!)

[Pauls SLR]

Right. A quick update for anyone who hasn't given up on me!!!

I've removed the MFRU cover and have found if I manually push the solenoid contact on the bottom right relay (main relay) the car will start perfectly on the key and runs correctly. As soon as I release the solenoid arm the car then stops. 
I happen to have a spare MFRU in the garage, so thinking I'd cracked it I fitted that. Same scenario. So it seems there is an issue in triggering the main relay. I'm slightly struggling with the diagrams I have to trace the wiring. Could anyone here outline the path from the key through I assume the grey plug to the main relay on the MFRU? What colour wires and which pin in the grey plug?

 Thanks all for the help so far.

Paul

 

 

 

[SM25T]

Good progress ....

[Jonathan Kay]

Does this match your car?

Jonathan

[John Vine]

Have you seen these excellent items by Andrew Revill?

LF article on K-click:

http://lowflying.lotus7.club/lowflying/search.jsp?author=40&category=0&tag=0&month=0&year=2013&query=&orderBy=1&strPage=1&doSearch=1

K-series starter solenoid circuit:

https://www.lotus7.club/forum/techtalk/demystifying-k-series-starter-solenoid-circuit

JV

[John Vine]

It does sound as though the starter and pump relays aren't getting power from the ignition switch.  Check whether there are any loose/detached spade connectors on the back of the ignition switch.   If all is OK there, split the big grey plug and check the condition of the connections.

JV

[revilla]

Did somebody say my name?

Right, the Main Relay in the MFRU is usually controlled by the ECU. On EU3 cars its a White/Pink wire from Pin 54 on the smaller of the two ECU connectors. On EU3 cars its a White/Pink from Pin 4. If your car has an Emerald it will have EU2-style connectors (or an adapter).

In both cases it's a switched earth from the ECU. It doesn't rely on anything like a crank sensor signal.

The White/Pink terminates on Pin 3 of the smaller Econoseal connector on the MFRU where it connects to the negative side of the relay coil. The positive side is fed straight from the main power feed to the switch side of the relay on Pin 6 of the larger 8-pin connector.

With your multimeter:

1. Check that you have pretty much full battery voltage on Pin 8 of the large connector. I guess you will or it wouldn't have run when holding the relay in as that terminal feeds the switch circuit too, but check anyway. This should be powered even with the ignition off. If you have then ...
2. Check the voltage at Pin 3 on the smaller connector. With an Econoseal you can slip a fine needle down the side of the rubber seal on the White/Pink wire to contact the terminal beneath it with the connector still in situ. You should still get sensible results disconnecting the connector and measuring the voltage on the connector, but if it's a really high resistance bad connection that could still look OK as it's unloaded, when it would read wrong when connected. So if you can, test it while still connected (if you've still got the lid off the MFRU can you get at the other side of the connector?). You should see battery voltage when the Main Relay isn't powered and a low voltage (maybe 0.1V, less than 1V) when the Main Relay is supposed to be turned on.

• If you don't see battery voltage (this is only valid with the connector still connected) when the MFRU is supposed to be OFF (e.g. ignition off and leave it for 15 minutes to ensure the ECU has timed out and shut down - it can stay alive for a few minutes after switching off as in a Rover it manages the fans) but you do see it at Pin 8 in the previous check, there's a fault inside the MFRU.
• If you don't see it dropping to a low voltage when for example trying to start, there's a fault with the ECU or the wiring from the ECU pin to the MFRU.

EU2/Emerald connectors are just big Econoseals so you can do the same trick of slipping a needle down the side of the seal at the ECU end to see what the ECU end of the White/Pink wire is doing to work out whether it's a wiring fault (probably expect low voltage at the ECU end all the time, the driver in the ECU is just an open collector transistor that switches to ground so nothing to pull the voltage up if there's no connection) or an ECU fault(probably expect high voltage all the time).

There should be bo issue with disconnecting the ECU connector and poking a bit of wire into the appropriate terminal on the connector, then connecting this to the battery positive and seeing if the MFRU relay pulls in (if you've got the lid off you;ll see it, otherwise listen for the click). If not, it sounds like wiring.

[SM25T]

The wiring God awakes ... and has time to post. Thanks Andrew.

[John Vine]

Well done, Andrew!

JV

[7 wonders of the world]

There are planty of places in the loom for poor connections..... my previous car lost power on the rollers at Emerald - a little slicing on the loom by John Dave and ,myself found another dry solder joint...... as looms go the stock item is pretty shocking with so many taped back cables and badly soldered joints, the MFRU is not the perfect solution either merely fitted as a complete hack from Rover.

Also worth looking at the terminals in the ECU plug as depending on who fitted the Emerald will affect the quality..... worked on two now where the crimps and connections were simply shocking and the cables could be dislodged with the lightest pressure.

Also look for partially dislodged pins in the big frey multi connector too, and poorly crimped spades on the main power cable too.