QR25DE Only Fires on Cyl no 4 after Engine Overhaul.

[Jva]

Hi Guy's

I need some help here.
I own a 2003 QR25 Xtrail 4x4 MT Model.
I just had the engine overhauled and it just cranc's not starting.

First Simptoms before overhaul.
Unfortunately no errors where collected before overhaul in Hindsight it was a mistake. Whent on reliable Mechanics word that it was rings.

What happned.
Day 1
Lack of power / light white smoke.

Day 2
Lots of smoke and / missing on Cylinders / Huge Oil Consumption.


After Overaul simptoms.

Only Cranking.
only firing on Cylinder no 4.
No DTC's(errors) on computer.

We checked the following.
Coils 1,2,3,4 for functionality.
Oil Pressure fine.
Compression fine.
Timing Checked out fine (Mechanics word)
Ignition Signal Opens and closes.
Replaced POS/PHASE (Cam/Cranc) Sensors.
Feul lines working.
Checked Grounds.
Replaced ECU to make sure and the simptoms are the same.


We did do a scope of the Cam and Cranc and can see the difference of one that is running and mine.
On the one that is running You can see the piston no firing order 1,3,4,2 and that signal starts at exactly the same time as the
flat spot starts on the cranc that it pics up from the signal plate.(Ideling)

On mine the Piston firing order signal starts after the flat spot on the cranc has ended.(only crancing)
We suspect the Signal plate is not located properly

Questions
1. So can I go on the scope evidence to take the motor out again and refit or replace
the signal plate which is a big job so I'm out of ideas and need to start at the beginning again and i dont want to do it for nothing.

2. Could this be the Power Transistor that Amplifies the Signal from the ECM for the Coils to Fire that it does not Amplify the signal?
If so does the Power Transistor sit in the ECM or some where else?

3. Would the Computer pic up if the Power Transistor work but not fully?

Any help would be Appreciated.

[boyrs]

sorry man, know how frustrating it is to think you're getting her fixed and then finding out shit just got worse...

not really sure of the terminology you're using so correct me if I'm wrong, your engine is turning over but not cranking... or is it cranking and then immediately stalling(cutting off)? does make a difference.

based of the first assumption I can only point out a couple of things that probably won't have any affect, but might be worth a look at-

~ with my sentra, when the ECU went out, it would turnover but not crank. to make a long story short, I found out that the ECU has to be programmed with my VIN for it to work. not sure if this applies to your model but it'd be worth calling nissan to find out.

~ I've had several problems with the wiring in my sentra, from the headlights to my speaker wires in my trunk... anything you can check would be worth the effort.

other than that I can only point you to this factory service manual link for my sentra- http://www.nicoclub.com/FSM/Sentra/2002/em.pdf would be better if you could find the FSM for your Xtrail

[Jva]

Thanks for the simpathy it's real bummer this.

Yes my engine is just turning but no spark on 3 cylinders.
This is the funny thing and I cant find anybody with this same problem.
I have downloaded the FSM for my car but no mention of this problem.

I have one last thing to try tomorow.
Will keep you informed.