Seriously doing my head in....Can alternator cause misfire?

what about the MAF? have you looked at that? and the wiring aswell.

coilpacks or signals to coilpacks?

 

are you running a selin kit?

 

As per my first post, I've replaced all coil packs S2 PTU and tried 3 different MAF's (now back to OEM MAF). Also repalced ECU

 

Its good that you have replaced the coilpacks but what about the signal to them? have you checked that? could be a fault in the wiring somewhere along the line.

if you have replaced everything else then i think it must be your old wiring harness. the only way you can gaurentee the wiring is be using a multimeter and checking every pin individually.

 

I say get a New Wiring loom, Thats what Im doing and just to be safe check the Compression, even in a New Engine just to get it out the way, But I think a new Loom would fix the problem.
Even with a lite short the ECU and consalt won't pick it up.
had a Injector wire just touching and earthing out, No error's on conslt but would sound like a WRX every now and then.

 

I didn't think you could buy a new loom any more?

 

Left hand drive one fit the same just an extra foot or so were it comes out of fire wall, ask Eric about it?

 

http://www.ebay.com.au/itm/ENGINE-E...Accessories&hash=item256abcd609#ht_899wt_1163

LHD but apparently still fits?

 

Thats the one.

 

So $450 delivered. How much do you think it would cost to get it fitted?

 

Engine half way out for that

 

Well to see if it was the issue, all you would have to do is wire it up and leave the ecu tucked close to the battery, ( rather than try feed it through the firewall) wire all the gear up and see how it goes. If it was the harness causing the issue, you could always look at installing the new one when its more suitable.

Engine out isnt 100% necessary, but pulling the dash kinda is.

Plenum off should give u enough room.

Maybe keep an eye out for a good harness? I'll have one which is fine coming out of my zed soon...

 

Cheers. I'll keep it all in mind while I first test all of these other diagnostic ideas (fuel pressure etc). I guess once all other possibilities have been exhausted I may have to go down that track.

 

Have your injectors cleaned

Having read through your post a few times I'm guessing you have an injector playing up. Have them cleaned and flow tested. If you pull them out should only cost about a 100 bucks. Regards Ivan

 

Already has had them done!

 

Fuel Pressure test update

Well I fitted a gauge inline (just after the filter) today with the hope of finally seeing what is causing my problem.........but it wasn't to be. It appears to be doing everything it's supposed to. The gauge could have been better with clearer increments, but it was about where it should be and jumped up about 10psi when I unplugged the fuel reg - plenum vacuum hose.
So next I'm going to try unplugging the O2s, it's a quick easy test. I don't know what I'll do with the information if it improves it . After that I'm going to peel back the loom near the ECU to see if there has been any issues where they spliced the immobiliser in.

 

Bits like a rattle snack? Don't ask me why but I'm picturing a GILF with loose dentures...

 

While you're at it, check for this -

http://www.aus300zx.com/forum/showthread.php?p=908028

Old but very good post from Rollin.

 

This issue is fairly consisten with MAF issues. However, you say youve swapped out MAF's.
MAF signal voltage are low. Sall changes in signal voltages result in quite large fuelling changes and it crucial that the ECU is seeing correct MAF signal voltages.
Youve changed out everything in there so far with no/little change. So MAF wiring is my feeling.

Now, have you had a WBo2 guage up its bum yet?
If not, why not? One pull up the road may point to either fuelling issues or ignition issues.
Im thinking that the (WB) O2 readings will be almost off the (high) scale and then pull back into something useful when the engine "clears its throat".
Just ignore the NB o2 datascan readouts. They are functionally useless.

Off you go Kimosabi!

L8r
E

 

LOL......thanks for your thoughts, now I'm going to look up what a WB02 gauge is . I'm guessing this will be something a typical workshop will carry?
I'll have a closer look at the MAF wiring as well. It appears in good condition at the MAF, I assume that the wires then make their way to the ECU so I'll be digging around in there as well.

Edit: OK.....wide band O2 sensor....