Odd running Chim

[Adnic69]

Hi Guys.
My chim has been running fine and returning about 240 ish miles per tank. All of a sudden its started jerking really bad in any gear at 30mph. It smells rich too and is drinking fuel. My last half tank was gone in just under 70 miles. Both distance i travel has not changed and driving style has not changed.

I have cleaned the stepper, taken the inlet plenum off and cleaned them, checked the leads, dizzy and rotor and its made no changes.

Any ideas?

[ian187]

Does the running get any better when the engine is warmed up? Does it idle OK etc.....

I had some quirky problems with mine which turned out to be the Coolant Temperature sensor (seems a common'ish thing to go) and that caused a rough ride especially at low revs 'cause the ECU was being fed wrong information, but once the engine had warmed up it seemed better!

I've got a knackered Temperature sensor, you can have and if your car is no different, then you know what it is

[stringbag]

Doesn't sound like ignition (that ususally gets worse with higher revs, or under load, I believe), so as mentionad above, probably a sensor. Someone here has an ECU fault code reader for hire for £10 inc postage. That would be my first line of attack. Cheaper than a trial by error sensor change and plenty cheaper than a garage.

[Adnic69]

For the price of them i think that i may just aswell buy one. I did have a feeling that would be an answer.
I have reset the ECU and no difference has come from this. Must indicate the temp sensor.

[parrot of doom]

Tried the lambda sensors on the exhaust?

[martinipaul]

Adnic69, did you sort your problem out? I seem to have similar symptoms on my '98 450

[Ricardo Bertone]

The symtoms suggest that either the ECU thinks the induction charge is cold (temp sensor/AFM input) or has got stuck on Limp Home mode (tune resistor/fuel relays). Get your multimeter out and start checking readings.

Ricardo

[That Daddy]

I would make the coolant temperature sensor for the ECU my first port of call,it may think the engine is cold permantly,causing massive overfueling,as the other guys said the fault code reader may save you time & expense.