ECU chip swap

[The Red Baron]

Had the car mapped about a year ago and since then it has always run very rich - fuel consumption was shocking - 150 miles per tank!!

I have an old ECU chip that the new chip replaced.

Can I just swap it back in to the ECU to solve the over rich fuelling, or is there more to it than that?

I suspect because of the rich fuelling it is making the main cat break up (pre-cats removed) as I suffered some misfiring, and sparks and stuff coming out of the exhaust (impressive to see, but not great on the state of the undies when on the motorway!) The engine eventually cut out, but 5 mins later started fine and ran without missing a beat 100 miles to home!

All I really want to do is swap the chip to enable me to drive 80 miles to a service centre for them to investigate and sort the cat issue out. Then I will take it back to the guys who mapped it last year and get them to sort the fuelling correctly. I'm trying to avoid the cost of a flatbed but I'm only worried that the cat might still break away and some might get back into the engine, which would be nasty and probably cost more than the flatbed!

If I can just swap the chips, is there a way of telling which way round it should go, or doesn't it matter?

Thanks in anticipation of your expertise.

And happy new year to all.

[blitzracing]

Who chipped it??? There are very few places that can really do it with the correct software (WinOls)and hardware (eprom emulator) , although plenty of Charlatans who can plug the wrong chip in and claim its an upgrade. IT should NEVER run that rich if you have lambda probes fitted unless something is very wrong. As long as your motor has not been radically modified the original chip will be fine, the ECU can make huge fueling corrections even when the map is wrong if the lambda feedback is working, but it can introduce shunting as the ECU hits its correction limits. A non cat car can be made to run very rich at low speed with the wrong CO trim set up on the AFM. You simply plug the chip back in so the notch in the end lines up with the other chips on the board. Get it round the wrong way and its bye bye chip. If the fuel pump primes as normal when you have swapped it back, its plugged in OK. If the pump runs all the time its damaged. As for cat damage this happens when excess fuel ignites in the cat, and it overheats and melts, but there is no reason for it to go back in the engine. Mind you a red hot cat could cause a fire, plus a highly rich mixture washes all the oil off the cylinder walls (bore wash) and knackers the engine over time due to lack of piston / bore lubrication.

Edited by blitzracing on Thursday 29th December 16:59