I think we have just sussed it. mine is definatly not a fuel delivery issue, its holding 60psi when it cuts out. I think ill back the boost off a bit. Mine would be even wrorse because i bumped the TPS voltage right up to fuel it up a bi tmore so i would reach that pulse width ceiling sooner. I think ill get a fuel pressure reg and bump the pressure up and back the tps voltage off
The concept that the ECU has reached its limits seems plausable, however, it damn expensive to change to aftermarket managment. I would try swapping the main electrical items to diagnose first, ie ECU AFM CAS etc
just rechipped stock ecu back in Japan, dunno what was done, tuned to 1 bar , speed cut removed is all i can tell. Im going to set up the exhaust gas analyser and take the car for a run to see exactly what is happening. Then i think i will back the TPS voltage off as much as i can and still keep the fueling rich
if the ECU has reached its limit then it is as simple as turning hte boost down. The other items such as AFM and CAS dont fit this scenario
Does this problem happen more when the ambient temp is really low? Cause if it does ur most likley running out of map. Try turning ur fuel pressure down so it is alittle above standard. Also hook up ecu talk/consult or whatever diagnostic progs u have and see if u are hitting max duty cycle . Regards Trev
No, there is a part of the *bin file which has the limits set, stock they are quite low to prevent fatal engine damage if you have a massive boost spike, if tuning the stock ecu you should ideally be put to 255 which is basically no limits. So no, it's not expensive, they just need to burn a new chip for the stock ecu.
Yeah the air-flow limit can be missed by so-called performance chips, do you have the facilities to rip the *bin of the chip and have a look? or rip it and email it to me and I'll see if the stock limit's are still in place.
2nded on internal CAS problem I've seen this before. All perfect then intermittently dead at high RPM. Faulty CAS sending nil feedback to ECU so injectors not getting the fire signal. Would all revive at 1-2K RPM. Check for burnt plugs as supporting clues First and best piece of advice I ever got was to fix the simple causes first before looking for exotic solutions.
sounds very reasonable. I guess the way to decide between the 2 possibles is if it does it when the boost is turned down . that would indicate the CAS
Most likely, try playing with the CAS plug on idle and see if she stumbles. As the engine torques, if you have a dodgy connector or wiring it can loose contact, causing the stumble and as it dies and sits flat again it regains contact. If it's an internal CAS issue then yes, no matter what boost you run the symptoms shoud still persist. But try the plug and see if that sorts it, it could be the female pins are a little loose.
semi fixed it wasnt the cas, ibacked off the boost down to an indicated 14psi. ialso backed off the tps voltage to around 500. the car does not cut out anymore but it doesnt go like a missile either anymore so im happy but sad. next stop is to punt my cheap boost gauge and controller and set this thing up properly.
Yep. Keep it simple ... Many of these ongoing intermittent problems have the owner disregard and only half heartedly try the simple fixes in their haste to look for alternative causes. The end result is someone totally impartial to the problem performs a simple fix (i.e. electrical connector or whatever) and fixes it. The owner swears black and blue that 'I tried that already twice'. The difference is the impartial person hasn't already made their mind up that it won't be 'this or that'. We mechanical types are the worst for this
You have the exact same problem I had matey. It aint the CAS, it's the injectors being maxed out. IMO there is something in the ECU that is causing the issue. Probably just as well seeing it is probably leaning out. It wont do it at 13 PSI so for the moment run it there.. Plan ahead for bigger injectors as I have.
at this stage i just want to run around the 17psi mark so i might just get a fuel reg and set it up on the road with the five gas
You realise if you increase the fuel line pressure to get more out of the injectors. You will have to reset the injector size in the ecu? Increasing the fuel rail pressure essentially makes the injectors bigger and will need the ECU reprogrammed for larger injectors or you will be running hell rich at all times. Even to the point of flooding or it will not run at all. There is no short cut to injectors that are too small.
The gremlin is back. This morning it cut out badly and wouldnt run oiver 2500rpm. Ill be cleaning and resoldering the AFM tonight.
You have two problems, an MAF issue be it connectors etc. Also a fuel cut issue cause you are using too much boost. The 13 PSI probably fixed the second one. They are not the same issue
