Another problem :sad:

 

Car was working fine yesterday morning when I drove to work. After work when I started her up I could already hear her running rough, sounded a bit like running on 5 cylinders, and when you accelerate she chugs like a tractor.

 

 

So far I have:

 

1: Checked all the spark plugs ( they have only done about 8000 Km - NGK PFR6B- 11C) They all look perfect, no signs of anything unusual.

 

2: I´ve checked the coil packs and the resistance is spot on on all of them.

 

3: The coil pack connectors are all brand new and the wiring etc is ok.

 

4: The Injectors seem to all be clicking- from what I can tell with the screwdriver

Test.

 

5: Fuel pressure appears to be okay too.

 

6: MAF & Filter seem Okay too

 

What I did notice is that the car idles very roughly and when you pull either of the front

Two coil pack connectors there is no change in the way she idles, only when you pull any

Of the 4 other connectors the revs drop.

 

I have a series 2 PTU

 

Does anyone have any ideas what I should check next ? :confused1:

 

:helpsmilie:

When my had a funny 5 minutes along time ago, it was the ECU at fault, i got another ECU and tired it and it ran on 6 again.

stupid answer,you say you have new coil pack connectors, are they all pushed home.? has the maf got wet, or has the series 2 ptu become dislodged??

Had the same problem. A little fiddle with the PTU connectors quickly resolved the issue.

Checked all the coil pack connectors and they are all on right, The MAF is dry and I took the connectors off the PTU and checked them...all seem fine.

 

The front 2 injectors are clicking a little less than the other 4 , took the injector connector off and cleaned it plus cleaned the injector contacts....still no change :(

 

Also. either I am doing something wrong or something isn´t right in that I am unable to measure the resistance of the injectors through the ECU harness

 

:confused1:

ohm test the injectors, should be around 12.

yep, that´s what was next on the list mate, I was just a little apprehensious to try and remove the injector connectors as they are really old and brittle, but then again they could be the cause too.

 

Injector connectors need renewing, that´s for sure. But unfortunately I also have 0 ohm reading on both front injectors. I guess that means I have to change them ?

 

Anyone know if that´s an easy or difficult job , and the best way to go about it ?

 

Any help as always greatly appreciated.

looks like a plenium pull ...or a dodgy looking "dremel and file the plenium" method

 

Not done a plenium pull yet..any pointers or things to look out for ?

All I can offer is to suggest you double recheck everything again before diving in pulling the plenum.

Especially your injector testing as I find it odd that 2 would fail together and also read 0 (zero) ohms. Normal failure is open circuit?

I am not expert, but would hate for you do go through all the trouble to find it be something else.

Sounds like you on to something though.

I just double rechecked as you suggested and found that in fact only one injector is showing 0 ohms..the one on the front right hand side when looking into the engine bay.

 

wouldn´t a 0 ohm reading from the injector itself idicate that it is "dead" ?

Yes a 0 ohm reading indicates a short circuit as opposed to an open circuit and does indicate a cream crackered injector!

So the other 5 definately read around 12??

If so and you are confident its a definate 0 ohm reading you have found your problem.

Its perfectly plausable that the injector coil as failed when you started it after work.

 

As for a guide to changing an injector using the dremel method......

 

http://www.300zx.co.uk/forums/showthread.php?t=117654&highlight=dreme

Edited June 13, 201016 yr by turbocraigy

I haven´t tested all 6 I have to admitt, have to take the balance bar off for the back two, but they were clicking away happily, but will test them before going ahead with anything.

 

Cheers for the link mate, That´s spot on....I think I´ll take that route as it does appear alot easier than pulling the plenium.

 

Now to buy a dremel :)

Had to "dremel" the plenium to get to No2 and No6 Injector as both of them were dodgey. The job was ALOT easier than I aticipated though, and personally I would recommend this method as opposed to pulling a 20 year old plenium.

 

Car is running nice and smoothly again on all 6 cylinders :yes:

 

Thanks again to dannzx, Injectors were spot on mate :thumbup1:

 

and Thanks to everyone for their input, always greatly appreciated.

 

Maz

Nice to hear mate, glad its back on all 6.