Not likely in my case anyway - as after you get through the flat spot around 5k rpm it revs out ok to the red line
u checked your ecu .. it may have a jap spec rom in it.. open her up and have a look. mine did and it meant tons of low down power but ping ping up high
If I was dealing with a trusty old holden I'd say either a blockage in the carby or the points / condensor are stuffed, or a couple of the leads are either shorting out or not connected properly Its trying ever so hard to pull but it just cant quite make it through cleanly. If I ease the throttle on sloooooowly its 90% right.... if a slip the moccosin to the mat its not happy at all, definately far more noticable if ya heavy on the throttle. Kingy
The zorst sound is normal right through the rev range, the cats Im running arent that old and they are big cats so I doubt that is the issue
Tried 2 differant ones..... the spare I have and the one from the other zx..... made no differance at all. Its not pinging at revs at all, its just breaking down under load once that 4500 mark is passed. If I 'nurse' the throttle on its nowhere near as bad as simply punching the throttle to the mat. Kingy EDIT: spelling mistakes
I think it's the PTU. I've said it before in cases like this and no-one will probably believe me this time either but I had similar symptoms in my car. From experience I can tell you that the series 1 PTU does not only just die completely or stop working when hot. Mine ,and I suspect yours, had stopped producing a strong spark; so at 4000+ rpm when you are producing full boost and lots of airflow the spark can't keep up and is blown out. I tried a lot of things before getting a series 2 PTU and the difference was amazing. My symptoms were just as you describe, I could rev out to the redline if I didn't use full throttle but anything over 90% (and less as time went on) and the engine would pretty much cut out for a second at around 4500. I thought it was a fuel issue for quite a while.
Coil paks swapped...... no diferance New plugs fitted .... even tho the 'old ones' were sweet CAS ... cleaned .... no change PTU.... its a series 1 so its next, the other Zed has a series 2 Back to the shed
PTU's swapped .... differance .... none what so ever I even re-cleaned all the connectors just to be 100% positive I had them right... One thing that has caught my eye and has been a problem in the past is the injectors, I was thrown in the deep end 4 days after I bought the car by having to do an intake pull to replace a blown injector 'O'ring, the injectors had been removed for a 'service' prior to the sale of the car and the stupid mechanic did a lousy job of it, many of the vacume hoses wernt re-connected and occasionally there was a slight miss @ idle. The miss has been back and the cars been great up to now, but one thing I did notice was the sparkplugs when I exchanged them...... Although their age wasnt known @ a guess they appear not to be that old as they were spotlessly clean ! The black carbon buildup on the metal outer was minimal, The core rod was only slightly "greyed off" & The porcelen centre.... one side was white while the other had darkened off somewhat. To me that says a lean mix, so my thoughts now are maybe the mechanicle dude didnt 'clean em' so great if at all or perhaps they are due for replacement??? thoughts ???? Kingy p/s email has been sent/received to CAZ re-programs. I think this step is now the critical one. Datascan or Conzult ?
im also leaning towards injectors. ill be doing a compression test on wednesday and if that comes back ok ill do a plenum pull and check out the injectors. now...if that doesn't fix it...ill be out of ideas.
Is there anything that switches at around those revs like the EGR valve? A faulty EGR can cause pinging so maybe the knock sensor is kicking in, although it is said it doesn't operate at higher revs as it can sense regular engine noise as knock. Do you still have an EGR?
Made some progress today Had a very long chat with a "Fuel Injection Guru".... learnt a few things to try or check. Injectors either work or dont work... @ no stage do they work up to any stage of the throttle then breakdown once the throttle is matted. If an injector is clogged it will missfire at idle aswell as at revs.... my car is idleing fine although there has been a miss there in the recent past ... this was directly related to a coil pak's electrial connector ( now fixed ) The guru said that fuel pressure is the issue with what he's read in this thread so far. Two places can cause the problems we are experiancing. 1/ the actual fuel pump. it 'may' be getting tired and not keeping the flow up @ higher revs thus the fuel supply/pressure is low and therefore the engine hesitates @ higher revs. makes sence.... 2/ Fuel pressure regulator. Now apparently All fuel injected engines have a regulator that is sposed to make sure that the fuel pressure remains @ the desired level. This 'regulator' lives somewhere between the last injector and the tank ( usually near the last injector ). If it fails then the fuel pressure in the injector rail may drop slightly although it wont be that noticable @ idle or in the lower rev range. At higher revs however the pressure may not be near enough to cope with the additional RPM, therefore the engine hesitates. So...... I did do a fuel pressure test early on & guess what, ..... it was fine BUT..... I never laid on the revs to see if it maintained that pressure, better still, if I had of taken the car for a drive with a pressure guage fitted it certainly would have shown up if this was the problem. On Wednesday ( ANZAC Day ) I'm going to install a pressure guage and go for a drive..... Till then ..... fingers crossed Kingy
Looking forward to the results. I also did a fuel pressure test and idle and it was fine. I didn't have access to a proper in-cabin fuel gauge so I couldn't go for a drive with the gauge attached. I can't wait to see what you come up with. Hopefully thats the problem!!
It makes sence..... even the other sensors would respond to a leaner mix, ECU would also detect a change..... Compounding a small drop thats barely noticable. Come on Wednesday is it wednesday yet ?
keep searching guys!! mine started doing the same thing and i just ignored it and drove it lightly but then it started doing it at lower and lower revs until now it is parked in the driveway and i cant drive it changed all the stuff that you have tried already with no result... my fuel pressure regulator was making clicking noises before this all happened, so i swapped it with another one but it still made the noises, then after a few months all the problems started. make sure you keep us all posted!!
A reply I got on another nissan forum....... I'd suspect a fuel pressure issue, it's easy to test rpessure at idle while running is a different story, I had a similar problem, it kept coming lower in the power band before I figured otu it was the fuel pump, if you can get a remote fuel pressure gauge and verify fuel pressure under those conditions you might find it drops, at least worth looking into
yep.... thats the tricky bit....... which one is playing up ? I've got spare regulators so thats a straight and easy swap & test. if its the pump...... guess I'm up for some dollars ! if it turns out to be neither ..... I'll need a beanie to keep my head warm after I finish pulling out whats left of my hair !
