New owner with an ecu problem

[Rayburn]

Hi everybody
I am new to Beat ownership having bought a type f from e-bay a couple of months ago. Since then I have been preparing it for a Mot. All was going well but now I need some help.

I changed the battery yesterday (the one it came with was too big for the tray). Now the new battery is connected there seems to be a problem with the ecu – the fuel pump doesn’t prime and the engine will not start.
I have checked the following:
• The immobiliser seems to be doing what it should – it blinks the right codes etc.
• The main relay is getting power both direct from the battery and via ‘gauges’ when the ignition is on
• The ‘main relay’ is proving power to the ecu (the yellow and black wire) so one relay is working
• The fuel pump relay works if provided with an earth
• The fuel pump works
• The ecu is getting an earth
• The issue appears to be that the ecu is not providing an earth to the fuel pump relay
I have searched the forum and looked at others for 1990’s Hondas - it appears that problems with the ecu and the main relay are common and there is a lot written about it. All that combined knowledge points to an ecu problem with my car but is there anything else I should check? For example does the ecu expect a certain response from any of the sensors before it primes the fuel system?
Any suggestions will be appreciated!

Sorry to be only posting when I need help.
Tom

[mikei]

hi tom
did your car run ok before battery change ?
if so I would first disconnect and reconnect all fuses in both fuse boxes 1 by battery and 1 under osf of dash then check power going in and out with voltmeter to check all fuses are ok. (I had this once and it was because car had been standing ages and corrosion on a fuse under dash )

when you supply an earth does it start ? if so then you don't need to look any further just trace back the earth
if not and only the pump is running you will be just borewashing the cylinders and making it more difficult to start anyway

I would also make sure you have a spark as if not I would guess the immobiliser is the main culprit as most will cut spark and fuel so by disconnecting the battery completely you in effect turn it on

hopefully 1 of these will give a bit of help if not let us know what you find
mikei

[Rayburn]

hi mikei
Thanks for your quick reply and suggestions. It ran ok before the battery change. It did have the same symptoms when I first got it but the problem righted itself while I was checking the relay - perhaps pointing towards an intermittent poor connection somewhere. I will investigate further along the lines you suggest.
Tom

[bigB]

Is the 7.5 Amp starter signal fuse ok?

[Rayburn]

Still no progress. I have checked the fuses and checked the supply and earths on the ecu connectors - all appear good. The starter signal fuse looks good (though oddly the starter still works with it removed?). The engine doesn't fire even with the fuel pump running via a jump wire. Not sure what to check next. Any suggestions?

Tom

[mikei]

hi tom
so are you saying the car cranks fine but you have no spark and no fuel pump prime ?
if so what immobilizer is on it
is this the blue one that was on ebay

[Rayburn]

Hi mikei
Yes it cranks ok but doesn't start even with the fuel pump running - I haven't directly checked for a spark yet.

It is a Selca immobiliser (3.22?) that appears to act on the gauges and starter circuits (I get no dash lights or starter when it is set). Both circuits work when it is off.

Yes it is the blue one that was on ebay.
Tom

[mikei]

stick to the basics make sure you have a spark first
I may be wrong but that may have been owned by beatproducts on here some time ago
he may know more about the immobiliser
or you could just have no spark

[Rayburn]

Mikei
Thanks for your continuing help.

I have done some more checks. It has a spark and a healthy 5v reference voltage at the engine sensors so the ecu is doing something. It should work with the fuel pump running - but doesn't!

[Rayburn]

I have decided that it is worth ruling out an ecu issue so I have sent it off to be tested.
Tom

[Andrew Fisher]

The best £50 I spent on my Beat was getting the immobiliser/incredibly annoying alarm professionally removed. I even used some of the miles of wiring that resulted for something else.

I hope your ecu's all right.

[Rayburn]

It was the ecu. The ecu doctor tested and rebuilt it in a day, I fitted it this morning and the engine started first try.

Now just need to get an Mot...

Tom

[Andrew Fisher]

ecu doctor rocks they did mine years ago.

Well done good luck with your MOT.

[fxdlidon]

ecu doctor rocks they did mine years ago.

Did mine too - they are really good

[DaBeat]

Any contact info for the ECU Doctor??

[Andrew Fisher]

http://www.the-ecu-doctor.co.uk/

Honda Beat Ecu illustrated far left third of the way down.

It's very sad but I recognised the picture of it before I read the words.