MBE - ECU replacement

[samnorthy]

I have been having a missifre at 6k rpm under full throttle. I have replaced all the usual suspects (Ht leads, Coil pack, Throttle pots, EPROM chip etc) and the car has had a service. And still the misfire.

I had the ECU checked by MBE via TVRpower and they returned the ECU with no faults. I have recently ran the car with another ECU and it ran flawlessly. I sent the ECU back MBE via TVRpower, I am now being told that MBE still can’t find the fault and that I need a new ECU!

I am reluctant to fork out over 1k for a new ECU, when MBE can’t find a problem with mine.

Does anyone have any suggestions, any one know of a second hand ECU?

For got to mention, the car is a 2004 T350, with a 4.0L

Thanks

[330p4]

Sam does it misfire when cold or only when warmed up. I suspect the coil driver in the ecu is breaking down a mosfet i guess?
Ian

[samnorthy]

Ian,
I wouldn’t know if it misfires when cold (I like to get it nice and warm before giving it any beans)
it only does it under full throttle, full load at high RPMs.

If a Mosfet was breaking down, would MBE be able to diagnose the problem? They would be able to swap them out for new? (they are surface mounted right?)

Thanks

Sam

[BGB autosport]

Interesting as i have had a similar problem. After doing bits and bobs (coil, leads,fuel filter) it seemed to cure it, then it went, then it was back and finally after doing the throttles it seems to have gone again.

I spoke to Dom at Power and he suggested that the ecu could be on its way out and to try to get a spare to put in to see if it cures it but i have not yet had chance. From my experience with ecu's is they either work or they dont so this is new to be that they can break down.

Can anyone identify the specific component?

[nelly1]

Before you go to the expense of a new ECU, may I suggest you check the condition of the pins in the ECU connector.

If any are corroded or bent out slightly they could give an intermittent poor connection.

This could explain why a different ECU appeared to solve the problem, as the act of removing / replacing it could have given a temporary better connection.

Worth a look?

[330p4]

Sam they will be SM i guess not had mine apart that is not a particular problem they can sometimes breakdown with temperature also on the car they are subject to electrical noise,heat,condensation & vibration it could be when on the car for 10 mins the problem occurs when a quick bench test would not show the fault. Check the connector as someone else suggested but if you can slip the ecu out of the case & check the solder joints very closely for poor joints & hairline cracks around any of the pins. It may not be the problem but worth spending half an hour having a look. Where are you located
Ian

[BGB autosport]

Here is a pic of the inside of my ecu.

[330p4]

BGB send me a PM with your email if you can send a JPEG image maybe we can zoom in
Ian

[samnorthy]

I have taken the hit and ordered another ECU via TVRpower, I am apparently getting a discount price
I will try and re-pair my old ECU and keep as a spare.

I am working abroad (Peru), and want the car to be flawless for the short time I am home in August (I have not driven the car in 6 months ). I need the car drivable asap as it is getting the front end re-sprayed and some other work carried out, all to be completed before I return.

Ian, I will let you know how I get on when I get round to opening my old ECU. Thanks for your help.

[yzf1070]

Have a look at the condition of the pins in the cannon plugs as well. The engine harness terminates at the drivers side (right hand drive) with 2 cannon plugs. The plugs are pretty good and should not allow dampness ingress, however worth checking out. Also check the plug connectors under the dash. Some Tuscans leak rain water into the cabin and it can run along the under dash wiring causing corrosion at these connectors. Worth checking all this before you fork out on an ECU you may not need, especially if MBE have tested it to be ok. Have you made sure the flywheel trigger pick up lead is not routed too close to the HT leads? Have you even considered that this sensor or its lead may be breaking down? It's a Ford item and very cheap to replace.