Re: RNN14 injectors change issues
Posted: Tue Jun 15, 2010 12:30 pm
I'm not sure if this will be any help but your comment about it being very touchy when adjusting latency caught my eye.
I recently did an RB26 tune for a mate of mine. He'd fitted bigger turbos and 550cc injectors. That's it. I had no end of trouble trying to do exactly what you are - just get it running nicely across the range with solid idle, cruise and half decent full load AFR's.
The only way I could get a decent idle was to play with latency and even then a very small change would radically affect idle mixtures.
In the end the problem came down to two things. Firstly it had blown out the gasket between inlet manifold and the head. His new turbos had 1 bar actuators and so boost was much higher than stock. I suspect the first time he gave it a burst it would have spat the gaskets out. Resulting in it sucking extra air in at idle. I was obviously trying to compensate for this with injector latency.
Secondly his throttles were not closing properly (it had an uncontrollably high idle once we got mixtures correct). Apparently this is a common thing on the RB26. He did some hot mod where you paint something on the edges of the throttle butterflies to seal them properly into the throttle bores. He reckons it's now a completely different car.
Probably a long shot but I just thought I'd run this by you seeing symptoms were so similar to what you're seeing...
PL
PS: You tried raising and lowering TTPmin? This can sometimes yield unexpected results.
I recently did an RB26 tune for a mate of mine. He'd fitted bigger turbos and 550cc injectors. That's it. I had no end of trouble trying to do exactly what you are - just get it running nicely across the range with solid idle, cruise and half decent full load AFR's.
The only way I could get a decent idle was to play with latency and even then a very small change would radically affect idle mixtures.
In the end the problem came down to two things. Firstly it had blown out the gasket between inlet manifold and the head. His new turbos had 1 bar actuators and so boost was much higher than stock. I suspect the first time he gave it a burst it would have spat the gaskets out. Resulting in it sucking extra air in at idle. I was obviously trying to compensate for this with injector latency.
Secondly his throttles were not closing properly (it had an uncontrollably high idle once we got mixtures correct). Apparently this is a common thing on the RB26. He did some hot mod where you paint something on the edges of the throttle butterflies to seal them properly into the throttle bores. He reckons it's now a completely different car.
Probably a long shot but I just thought I'd run this by you seeing symptoms were so similar to what you're seeing...
PL
PS: You tried raising and lowering TTPmin? This can sometimes yield unexpected results.