one for the boffins

[deathrider311271]

i was getting random misfire code and codes for misfire on every cylinder and also P0172 which is long term fuel trim lower limit, so i changed both lambdas gen bosch items MAF sensor gen Bosch, all vac lines changed, spark plugs gen Volvo, coil pack changed for mega blaster, magnecor leads, gen Volvo cap and rotor arm and finally injectors cleaned.

Now i have got rid of the misfire code however i still have the P0172 code and also anything above 4500rpm @ wot the lambda light comes on but doesnt stay on.

Just for reference i have 3" intake system including MAF, 3" exhaust with decat and its been custom mapped by Tim Williams, i have tried a Rica ECU and standard ECU and problem persists. Also has RIP kit fitted and forge actuator with 19psi spring (red). it pulls like a train and fuel consumption is normal, no leaks i can find. Compression test also done all cylinders between 160psi and 165psi so nothing wrong there.

[JamesT5]

Also replied on FB mate, but for the benefit of this thread I'm thinking it may be a blocked Catalytic Converter causing the rear O2 sensor to throw a fit?

[deathrider311271]

no cat fitted James

[JamesT5]

no cat fitted James

Ok, that rules that out then.

[stribo]

Have you changed the fuel pump since you've done all your mods Simon, maybe it can't keep up.

[oblark]

i was getting random misfire code and codes for misfire on every cylinder and also P0172 which is long term fuel trim lower limit, so i changed both lambdas gen bosch items MAF sensor gen Bosch, all vac lines changed, spark plugs gen Volvo, coil pack changed for mega blaster, magnecor leads, gen Volvo cap and rotor arm and finally injectors cleaned.

Now i have got rid of the misfire code however i still have the P0172 code and also anything above 4500rpm @ wot the lambda light comes on but doesnt stay on.

Just for reference i have 3" intake system including MAF, 3" exhaust with decat and its been custom mapped by Tim Williams, i have tried a Rica ECU and standard ECU and problem persists. Also has RIP kit fitted and forge actuator with 19psi spring (red). it pulls like a train and fuel consumption is normal, no leaks i can find. Compression test also done all cylinders between 160psi and 165psi so nothing wrong there.

From my experience on remapping M4.4 ecu`s, I had a code on my about the LTFT. This was caused by the upper and lower banks for the MAF table being the same.

As for the MIL light coming on my did the same and it is being caused by the "sum of retards" going above the set level.

Sum of retard is to do with phantom knock (pinking in other words) The engine thinks it is pinking so it adjusts the timimg.

I refitted the standard the cat and this has stopped the phantom knock.

[deathrider311271]

Have you changed the fuel pump since you've done all your mods Simon, maybe it can't keep up.

no i havent changed pump but assumed for its present power (approx 300bhp) should be fine i was thinking as some have said maybe needs mapping for 3" intake

[deathrider311271]

From my experience on remapping M4.4 ecu`s, I had a code on my about the LTFT. This was caused by the upper and lower banks for the MAF table being the same.

As for the MIL light coming on my did the same and it is being caused by the "sum of retards" going above the set level.

Sum of retard is to do with phantom knock (pinking in other words) The engine thinks it is pinking so it adjusts the timimg.

I refitted the standard the cat and this has stopped the phantom knock.

so if thats the case surely it can be mapped to suite?

[Ettienne]

i was getting random misfire code and codes for misfire on every cylinder and also P0172 which is long term fuel trim lower limit, so i changed both lambdas gen bosch items MAF sensor gen Bosch, all vac lines changed, spark plugs gen Volvo, coil pack changed for mega blaster, magnecor leads, gen Volvo cap and rotor arm and finally injectors cleaned.

Now i have got rid of the misfire code however i still have the P0172 code and also anything above 4500rpm @ wot the lambda light comes on but doesnt stay on.

Just for reference i have 3" intake system including MAF, 3" exhaust with decat and its been custom mapped by Tim Williams, i have tried a Rica ECU and standard ECU and problem persists. Also has RIP kit fitted and forge actuator with 19psi spring (red). it pulls like a train and fuel consumption is normal, no leaks i can find. Compression test also done all cylinders between 160psi and 165psi so nothing wrong there.

I had incredibly similar, random maf or lambda codes, turned out to be the fuel I was using.

[M-R-P]

Sum of retards....

Currently 650.