Patrol 4x4 - Nissan Patrol Forum banner

Misfire on single cylinder TB45E

616 views 11 replies 3 participants last post by  Walter Botswana 
#1 ·
Hi all,

It's been a while since my last contribution or request but alas.

The issue I have is that after servicing the TB45E (unknown mileage as replaced) after I had an issue with airflow contamination after wrong filter element was inserted .

The engine is modified with a aqua tech compressor (South African product) and intercooler and it necessitated the re-arrangement of the engine bay whereas a Toyota air filter (the cylindrical one) off the LC79 was used.

The issue now is that the engine misfires on cylinder #2 (only this one) and we can't find the reason or remedy.

We did valve clearance, injector swap, spark plug replacement, fuel supply check, ignition timing, injector pulsing signal, vacuum leak checks and all electrical wiring and contacts and compression test. All seem okay.

Now, pretty much wits end and still no cure found.

Is there anyone having experienced similar and could give some idea where to look further?

Thanks for any input in this respect.
 
See less See more
#8 ·
I am still searching.

Here a theory as I am running out of options (and now under time pressure as I should start a safari trip in less than 10 days)

My mechanic today mentioned that the misfire started on the test drive first on cyl #4 then moved to cyl #3 and now persists on cyl #2.
He also mentioned that at some stage used compressed air to clean out the inlet manifold in the process before the compressor was remounted after the bolts repair. (on the support where normally the throttle body is mounted)
Bolt's thread was damaged in the aluminium.

Now, me thinking.
If there would be some debris inside in form of a piece of paper label (similar I found 1000 kms ago in the air flow sensor body) and that made its way through the throttle body and the compressor and then moved around in the inlet manifold, depending on air flow turbulence, now finally lodged firmly in the pipe of cyl #2.
We don't have the normal vacuum in the manifold, but compressed air from the compressor at say 0,8 bar.


What would happen.
1st fuel injection timing is given by the computed airflow reported to the ecu from air flow sensor, so the mixture is optimised.
Now based on my assumption of blockage or partial blockage on cyl #2 the fuel - air mixture is rich, it would over fuel by the missing air volume. (all cylinders get the same injector timing hence fuel volume).

The cylinder would fire but with a less efficient mixture thus "limping" or misfiring.
That is what I think I see, maybe not a totally "dead" function but less than optimal.

Now as said, my theory what is your take.

Any consideration welcome.
Thanks
 
#10 ·
It did in a sense.

As it was stuck in the airflow sensor body it compromised the airflow make the ecu think there is less throughput.
In this case the ecu reduced the injection time (fuel volume) which led to loss of power above 2200 revs.
Engine was starved of fuel, similar to a faulty fuel pump not giving the specified pressure.
 
#11 ·
Update and END of ALARM.

Paper debris stuck in inlet manifold sucked or pushed in through airflow sensor - throttle body - compressor and ending up running havoc in turbulence inside the manifold.
Car seems to be running extra smooth now.

Thanks everybody who helped the brainstorming.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top