A friends car is acting really weird and we cannot find the fueling issue, we have tried everything that comes to mind and nothing.


The car with the stock injectors everything is fine, but since they aren't big enough for the FP Green it has, we need bigger injectors.

So we tried some Precision 1250cc injectors that were used but we had them serviced and were OK. Idle was really high at first, but we managed that, rpm is fine now but it is way too lean (--- on the wideband) nothing we did changed afr, open loop, closed loop, add fuel on the fuel tables, injector size etc. Engine turns on and stalls and turns off, etc. He can't drive it. We used many latency values and no difference, cylinder 3 and 4 are not working at all on idle, no fuel. After 3k rpm if at WOT car pulls fine! no problems at all. but from idle to 3k rpm or anything that is not WOT there is hesitation, lean condition, car sputters. etc.

We have tested and replaced almost every sensor the car has, Tested fuel pressure regulator, boost leak, fuel lines, etc everything ok

So we borrowed some precision 1000cc to try, and same problem, idle lean and stalls.

Today we tried some precision 1200cc, and same thing, we adjusted some speed density tables, and no change.

Can't figure out what the problem is, why the car doesn't likes big injectors.


We switched back to stock injectors and car runs perfect, no problem at all, runs and half throttle is fine, WOT is fine.

What can we do? what's the problem?


Why can't we run bigger injectors?

Any idea would help! similar roblem? how you solve it?


Thanks for your help

 

Spend some money on a vetted tuner on this forum.

 

LOL.

Would agree that it is a tuning issue. Take some more time and scale your injectors properly.

 

Thanks for your replies.

I already sent some emails for tuning help vía email, since I'm not in The USA, so I'm Waiting for a response

Just wanted to see if someone had more ideas or info

It seems to be a tuning issue but we have tried all The latency values and nothing

And it could be q mechanical issue but stock injectors work fine

 

When you say you tried all the latency values what do you mean? Have you actually tried tuning for the injectors, i.e. watching fuel trims and adjusting injector scaling and latency values based on the feedback or do you mean you have just been trying random scaling and latency values people have posted up?

 

We tried values from the supermerge and merlins guide; and also tried tuning from fuel trims, and nothing same thing. Nothings changes at all