C20Xe Ecu Swap Out

[Guest A.B]

That's where the problem is. It was running before my father switched some relays. Didn't check to see if it would start up before sending it off foolishly. It's now been rewired and everything works as it should except the engine won't start as there's no spark getting to it apparently. They changed the coil pack which they then realised wasn't the issue so put fault with the ecu.

[knights_templar]

Unfortunately you have encountered a common problem with kit cars.

 

Electrics

 

why? because if something starts with some sort of standard, its pretty certain it will be modified, changed, altered or bodged.

 

A techy must then try and make some sort of sense of it, without a wiring diagram, any knowledge of the original base car, no idea what the builder was thinking and no way of plunging in a diagnostic box.

 

not much help I know, but it may in-fact be quite simple.

 

trigger pulse from ECU to coil can be tested with a simple tester from Maplin, standard Avos are no good the pulse is to short. No pulse, we need to go into loom checking, same tool will test live and ground to coil. Pulse, but no spark, coil pack test, there is a simple test of primary and secondary windings. some coil packs use a built in amplifier, which often needs a 5volt positive or negative pulse to trigger so difficult to test without a special tool.

 

Before condemning the ECU, which are actually quite robust things, the wiring need to be checked, especially since we know there has been wire damage, difficult without a wiring diagram but still possible, get the ECU pin outs with a bit of googling or a manual for a car fitted with that engine. check inputs and outputs go where they should, a simple continuity test will do this, and that the ECU has Ignition, live and earth where it should. This is time consuming so therefore costly.

 

There will be some other circuits to check, for example the ECU will switch a power relay to feed coils, it might be switched on by the ECU but may have no power itself

 

Now your garage may have already done this and come to the conclusion the ECU is a problem, A more precise explanation of their reasoning and tests done would be an advantage. But my guess at a £125 labour fee is that they have spent a couple of hours on it, may be wrong but it would be low for above work.

 

Unfortunately too far away to offer help myself, and the only kit place I could think off that may have offered help is about to loose their electrical guy.

[Guest A.B]

I believe the fault diagnostics is in with the £460 bill the £125 is just for the ecu repair itself.

 

I gather they think they've checked the bases and believe the ecu at fault.

 

I'm also far away back at uni so just have to keep faith that it's going down the correct path.

 

I will try and relay the information to the garage, thanks for your help. When you say tester is it a special device or a multimeter?

 

If so I will try and find out the ecu pin layout for my engine.

 

Thanks again

[cb750]

Knights Templar - have you a part number of the simple pulse tester from Maplin? Always looking for new bits of kit to add to my range of tools!

[knights_templar]

Knights Templar - have you a part number of the simple pulse tester from Maplin? Always looking for new bits of kit to add to my range of tools!

yes I will, but I cant find it on the Maplin site now, I will have a look when I get to work.

[knights_templar]

I believe the fault diagnostics is in with the £460 bill the £125 is just for the ecu repair itself.

 

I gather they think they've checked the bases and believe the ecu at fault.

 

I'm also far away back at uni so just have to keep faith that it's going down the correct path.

 

I will try and relay the information to the garage, thanks for your help. When you say tester is it a special device or a multimeter?

 

If so I will try and find out the ecu pin layout for my engine.

 

Thanks again

found this, you will have to check its right for your setup

 

https://dl.dropboxusercontent.com/u/11598108/motronic2.5_pinout.pdf

[Guest A.B]

So today I have received the news that they have tried another ECU but still no good after spending some time on it. So in short even the garage is stumped.

I have gone through everything knights templar has suggested with them to no avail...

 

They are suggesting a full rewire of the car and a new ecu which makes me doubt they know what's truely going on.

 

So I guess there's three options:

 

do as the garage say and pay for a full rewire.

Sent the car to someone else.

Sell the car as is and take the hit.

 

I would really like to have the car back up and running, I'm waiting to hear what the bill currently sits at, I don't know what they'll charge me for if the problem hasn't been fixed.

 

Any advise would be greatly appreciated.

Edited November 28, 2016 by A.B

[Guest mcramsay]

I don't know why they are suggesting a new ecu as they have tried 2 and still have the same issue. And as for a full rewire...you only need to identify the circuits In the wiring that are not working/ have not been wired correctly.

[knights_templar]

Sorry to here that.

 

Must agree with mcramsay, but if no one is able to fathom the wiring, you may be left with those options.

 

We are all good at diagnosing from afar, and we have not actually seen what you have, but anything is usually fixable given time and a little knowledge. The time is the big factor, and if you need to use a professional, the most costly part. And not always the best option, remember you have a one off,a Bespoke setup, no info, no diagrams, and to be fair, no professional will have training for that scenario.

 

It I a case of costing your options, but I would also include, the DIY option, using help from this and other forums, you will just need to be prepared to have a go, research, and ask questions, but you are free, it'd just a case of your time, and how much you cost that.

 

Sorry if not much help.

[Bob Tucker]

I went the KISS priciple with my redtop.

I got a dizzy from a 1.6 carb cavalier, and a coil, matchbox ecu and associated wiring from

a 1.3 MK2 astra.

I know these will be like hens teeth now, but if all else fails, they work very well.

PS trying to post a pic of the dizzy etc.....but struggling at the moment.

This may help

http://westfield-world.com/xeinstall.html#Ignition

http://www.locostbuilders.co.uk/viewthread.php?tid=50307

Edited November 29, 2016 by Bob Tucker

[Guest lotusPaul]

Have you tried your ecu on another car? Potentialy this could prove or disprove a nackered ecu.

 

So assuming yours is working you have the diy fault finding method.

 

I would first check the pins in the multi plug that connects into the ecu,clean them all and ensure none are snapped.

 

Here's the time consuming bit,

 

Trace each wire from ecu end to it's termination point. Check for damages and signs off burning out ect,

If you need to replace the wire like for like.

When you get to an earth or end point, then clean all terminals and cover in Vaseline.

Essentially I'm sure you can see my point so I won't go and on about the task process.

 

At each stage you need to check by starting the car to see if what you have done has cured the fault.

 

I'm not a sparky but I would adopt a very systematically approach to it.and don't rush it.

 

Good luck and if all else fails..im stuck

[Guest mcramsay]

The easiest option may be to go for an emerald ecu, really easy to wire up for the novice. But you are looking at around 800-1000 for that option, I am in Somerset and have a good knowledge of ecu's but I have no experience with the red top engine/ecu. I can't offer any help this side of the year I'm afraid.

[Big Jim]

i run a redtop in mine, and I went for the SBD ignition only mappable set-up, complete with wiring, throttle position sensor, coil pack etc. It's easy to wire up, if I remember correctly, you only need to connect 2 wires to the small loom they sell. It's been ultra reliable and i can recommend it. I've no idea how much it would cost now though.

[Longboarder]

Can you check the relays that Dad replaced? Relays come in various configurations of the terminals. Did he replace like for like? Two common configurations are shown below and are not interchangeable.

 

Nigel

[Guest A.B]

He swapped between the two configurations shown that aren't interchangeable.