Engine guru near Marlow?

[JossElan]

Anyone know of a M100 engine guru near Marlow/Henley - I’ve had a recurring problem with what I thought was a MAP sensor issue, but it’s still occurring despite two new sensors. I could really do with someone who knows what they are doing to have a look at it. Tearing my hair out!

[rip]

Hi.

Two thoughts, neither of which are really answers..

What issues are you having? It is very possible that someone will recognise the fault from your description of the symptoms.

Have you managed to get somebody to capture some data with Elanscan? If you have not seen it in action, it is so much more than a fault code reader. It actually logs the information being sent by the ECU.
There may be another sensor which is giving a false reading but still 'within range' so the ECU accepts it as genuine.

[JossElan]

Thanks. It’s an intermittent engine fault, which usually starts after a couple of minutes driving with a small judder* followed by the engine light coming on. The judders will then become more frequent and then the engine will start running rough and then cutting out completely. It will sometimes clear up and allow me to limp home - very steadily. The CEL only comes on when the juddering is actually happening and it is not registering a fault code with the paperclip test when I stop. I’ve taken it to a nearby ‘lotus specialist’ garage who struggled to get anything on an ElanScan, but finally got code 34, MAP sensor fault, and replaced the MAP sensor (£400!!!). This didn’t solve the issue and I got 20 miles out of it before it happened again. I replaced the MAP sensor again with one of eBay (£20!) and made it 40 miles (but then the bloody immobiliser stuck on!!! and had to get it recovered). It’s not been driven for a while but just got a new alarm/immobiliser fitted and made it 0.7 miles in heavy traffic before the engine fault returned. Left it until after rush hour and drove it steadily home later that even (7 miles) with a bit of juddering after 0.2 miles, but then it settled.

*the initial judders feel like a half-second loss of power and a corresponding lurch forward.

[HJ2]

I would start with the basics:
- Adjust Base timing
- Wastegate wiggle
- Check adjustment of spark plug gap
- reproduce the problem whilst logging with elanscan.

All at zero or very low cost

[JossElan]

I’ll get on it this weekend and report back!

[Rambo]

Have you checked your coil packs ?

[alan e]

Also check for any loose earth wires onto the engine.

[Simon_P]

As HJ2 says start with the basics, then move on to the cheap things. Work methodically.
Also reset the Ecu by disconnecting the battery.
And force it into limp mode by disconnecting something - does it still happen?

When it happens does switching the engine off for 5 minutes give you another 7 minutes running?
. When was the fuel filter last changed?