Engine Imbalance??
 

If anyone has been following this, I have had a misfire for about 2 months on my 1998 t4r, 166k.

It's been at 5 shops, and nobody has been able to figure this out.

Here is the deal, after a small water crossing I had a misfire develop and a code P1300.

I cleared the code, and it has not come back. It has misfired ever since.

Someone recommended that I take it to an Electrical Expert (P1300=igniter or igniter circuit).

This auto electric expert has concluded, I am not misfiring, I have an Engine Imbalance!?!

He is done for the day, and away tomorrow- so Thursday he is going to work on it. He mentioned the Harmonic Balancer, and also said something about pulling the bell-housing off?? This seems like a bit much, does anyone here think he may be on to something??? I am concerned that he may be doing unnecessary work here.


Some additional facts: since the misfire brand new NGK plugs wires,
3 new coil packs, the circuit has been trouble shot and voltages are correct, compression tested, fuel tested,

However, sometimes in the morning it will run good for a few miles.
I did notice the fan is missing a blade?

That's probably it then right there.

Remove the fan belt and run it for a minute or 2.

Wow, I noticed the fan was broken the day it happened and I never suspected it could make my truck run so rough. I am going to pick up a fan and see what happens.

Assuming this is the issue and I will use it off road again-does anyone know if I could get a fan that wont break as easy?

The new ones don't break as easy as an old one, plastic gets brittle with age. Don't put it off, the carnage from a fan letting loose at high rpms can be expensive.

None of these 5 shops picked up on you have a broken fan!!!!

This would explain why the MIL was not tripping!!

Do you have any other damage you thought was not important to bother with??:helo:

Back on the road and running smoothly!


Thanks to everyone who helped out on this issue. It turned out to be the fan, causing the engine imbalance. I would have never thought one plastic fan blade (out of 7), could interfere with the whole engine.

You learn something new every day, now who wants to hit the trail?

You're very welcome.

But in all honesty, I had a shadow of a doubt. Which is why I said "probably". I'd actually changed my reply before posting it. Initially I was going to say "That's it then right there. Without question." But then I guess I thought a bit too hard about it.

Seemed kinda strange that it would sometimes go away like that. But I reasoned that would be due to the fan clutch being engaged at the time. Which was causing the fan to rotate at higher speeds. And sometimes the faster you can spin something that's out of balance like that, the less it will appear to be. But sometimes that's not the case. So I just wasn't 100% sure if that theory made enough sense.

Anyways, I was going to feel a little bummed for steering you the wrong way again. If it turned out replacing the fan didn't solve the issue. Good thing it did! :bigok:

:yotarock:

Bottom line it was never a engine miss!!!

So after the drying out you never had any electrical issues hence the ECM never tripped the MIL

Because all was good.

Which was driving me nuts .