1long term trim +78/+100

[FFMan]

On the way to classic le-mans, monitoring fuel trim with my android app and I notice long term trim is long term high at +78/+100. Confirmed with Rovergauge.

are these normal figures or does it suggest a problem. car seems fine, the odd hiccough but idle issues of a few days ago seem to have gone. maybe an occasional high speed mis-fire but not repeatable generally.

Beauty of having the top down - excellent 3g connection !

thanks

[blitzracing]

100% is too high, you are out of trim. This is set at idle, so a sensor, or the map is not quite right for your set up at idle.

[FFMan]

I have a tornado chip but I don't suppose that accounts for the continuous 100 does it ?

[blitzracing]

Difficult to say- Tornados are best guess across a range of similar engines unless MA has rolling road tested your car, but Id be surprised if it was that far out unless you have tweaked the motor? Try putting the TVR chip back if you still have it.

[FFMan]

i'll try the original map this weekend and see how it behaves.

what I did notice was...I reset the ecu and we went down the motorway steady 70-80 for approx. 15 mins and long term trim was 0/0, then we slowed down got some traffic and the figures rose to like 90/75 (I have a log from RG on the other laptop). I wasn't able to monitor again after a stop as we swapped drivers, but I think the long trim has remained high but i'll run some more tests this weekend.

apart from a persistant single or double hiccough under hard acceleration it runs ok, but see my post about the speed sensor, which is reported as way too low by RG.

[blitzracing]

The speed sensor does not refect the speed on cars fitted with the ford gearbox- TVR frigg the signal with a box of electronics under the dash.

[FFMan]

out of interest - is there a linear relationship between reported speed an actual speed ? I expect there would be, and I could determine it with a gps and RG

I could in the android app have a tick box for a correction.

[spitfire4v8]

If the engine wasn't at idle for any length of time during your motorway drive then the ecu wouldn't learn a long term trim, it only learns when the idle speed is steady and engine hot.

[FFMan]

ah ok - thanks - that explains that observed behaviour.

Is the trim only applied at idle & hot then or only learnt then and applied generally ?

I need to track down why I have high long trim numbers. what are the possibilities to check through:-

• air leak ?
• under performing injector (but as both banks are high seems unlikely)
• bad lamda (again, seems unlikely)
• fault MAF ?

what sort of numbers might be expected on long term trim ?

[FFMan]

Decided to contact Mark Adams as it has one of his chips. I got it off ebay and without the instructions.

Mark recommends an increase in fuel pressure on the 500 with a tornado chip, so I've booked it in for an RR session and we'll check out injector performance and AFM etc

Super helpful chap - looking forward to getting it sorted.

[blitzracing]

If that Tornado came off a mapped car with boosted fuel pressure that would make a lot of sense its now wrong with stock pressure.

[FFMan]

suspect that is the case - came off ebay so you live and learn !

Anyhow, decent RR session will check the other bits through and hopefully nail down the full bore hiccough its had both before and after the tornado chip - should have done it along time ago really.