Fuel trim bank

Hi, I keep getting EML light on and the code read is fuel trim bank 1 fault? Any common issues to cause this please?

MGTF 2004

Cheers

Chris

This could be one of those quirky ones . I think I remember something like the pre cat oxy sensor being faulty was the cause on my ZR many moons ago . I don't think it has any bearing on the amount of fuel in the tank ie low fuel .

John

This one used to crop up occasionally on ex-wifes TF. I never tracked it down to anything specific, and the fault just went away.

https://www.yourmechanic.com/article/p0170-obd-ii-trouble-code-fuel-trim-malfunction-bank-1-by-andrew-quinn might shed some light. I have a feeling problem on ex-wifes TF was down to some dodgy fuel that clogged the filter for a while and eventually cleared.

Thanks for replies
So is this a case of try a component and see if it current, or is there any better way of checking/elimination?

Cheers

Chris

Yup, possibly so. Essentially it could be something transitory like what I assume was a fuel filter clog on wifeys car, but equally it could be MAP sensor fail or a split hose, or even a lambda problem. Ultimately the error is telling you the fuel mix is wrong, but not off it's too rich or lean.

In the first instance I would clear the fault code, pop a squirt of injector cleaner into the petrol and give it a good run at temperature. This might be enough to clear the problem.

If not, and if no other sensors are showing error or out of range readings, the next simple check is to unscrew the spark plugs. Often a lean / rich problem can be diagnosed simply by the appearance of the plugs.

Once it's established if it's a lean or rich mix it's possible to narrow down problems.

Okay thanks for getting reply, I will try some injector cleaner first

Don't notice any difference of heavy fuel usage

I have changed plugs a while ago , the ones I took out looked normal TBH

Cheers

Chris

Have you changed fuel filter? It's something many people overlook. I forget what the recommended service interval is, but the chances are on a car as old as a TF it's probably due if it's not been done.

Thanks again

Yeah unchanged all filters, plugs and oil at same time
Replaced under floor coolant pipes and anti freeze at same time!!
It's been coming on sincemi bought it coming up 2 years ago, lived with it for long enough, just wanting to sorting now!

Cheers

Chris

If you get an obd2 code reader(either blue tooth or wifi depending on type of smartphone) and download the Torque app(free) you will be able to monitor your fuel trims in real time.
This will tell you whether it is long term or short term fuel trim that is out of whack. Also whether the fuel trim is too high (Most probably)or too low.
From there you can then narrow down where the problem is by googling fuel trim problems. There are a number of good web pages that delve into this issue.

Fuel trim is how much fuel the ecu adds or subtracts from the standard amount to get the air fuel ratio to 14.7 to I. Shows as a percentage on torque. Long term and short term trim are basically what they sound like. Short term is an instantaneous figure. Long term is time average.

You get a fault if the ecu can't get the ratio correct. It attempts to correct the fuel by altering the injector pulse times. So the fault could be as simple as blocked air or fuel filter or injector issues. Or induction leaks or fuel leaks.

Hah! Should have clicked on the link above and saved myself a lot of typing.:doh:

Thanks very much David

I will give this a try

Cheers

Chris

I had this problem with my stepspeed. Missfire reported and fuel trim fault. Changed absolutly everthing nothing cleared it for more than a week. Out of desparation I reverted to a garage. The engine had 2 faults, a slight water leak into pot 1 that caused a really bad tickover when cold but cleared when the engine heated up expanded and sealed the leak. Secondly the camshaft timing belt was one notch out. Someone had removed the cam belt and not checked the timeing marks on replacement. Only 200 miles down the road but it appears to have sorted the problem. OBDs will not find this but they will show wierd fuel trim readings.