What will make a 4g63t run lean?

[BudmannG]

Hello, I had posted before about broken studs in my head. The guy I have fixing it says that it has been running lean. I was wanting to know what will make it run lean? I have no mods other than my exhaust. I have a mbc but it's not on the car yet as to the prior posts. I fixed all my boost leaks. And thats how I found my exhaust manifold bolts. Thought it was a gasket that blew. It would hold 20 psi at intake for a while. Thanks!

 

[ddavisaf]

lack of fuel. Clogged injectors, clogged fuel filter are the first thing to check.

 

[BudmannG]

Thanks, I will start there. I will post back with what I find.

 

[Spoolin4Ever]

I agree with the above.

In addition, running seafoam can help clean up some of the carbon build up which could lead to hot spots, making you run lean. Or at least cause detonation.

Well see, I just had the same isssue with a non turbo car (which could be different reason naturally).

It was pinging when runnning regular fuel. So we just decided to run premium fuel. That worked for a few thousand miles, then I noticed it was pinging even with premium! That sucks!

So I ran some seafoam. Also, I cleaned the plugs afterwards, and noticed 2 of them had too small of gap (like i gapped them for my turbo car by accident).

Anyway, I can't say whether it was the gap or the seafoam, or a combo, but after that it stopped pinging.

I then went and paid the guys at grease monkey $40 to change my fuel filter

It looked like it had been there since the car was sold back in 90

No more pinging. Correct me if I am mistaken, but pinging in an NA car is kind of the equivalent of running lean (the plugs had white on them, which is unusual for this car as it normally gets them oily, bad rings but with Lucas Oil Stabilizer keeps it under control). The NA car has no knock sensor, so it can't correct the issue by retarding timing, thus causing the pinging (?).

Would that mean that a turbo car never really pings, because it's able to retard timing? Sorry to turn this answer into a question, just trying to clarify.

This car has 200K on it.

To recap:
plugs
seafoam
fuel filter

All got done today, and helped quite a bit. Hopefully MPG will go up too.