Muzzsjm

Right folks I had a hesitation problem a while ago which I solved cleaning the MAP sensor. A few days ago it returned but I think it's much worse this time. My friend a Type R owner feels as I do the cars hesitating and down loads of power. His Type R kept up with 3-4 in the car.

I was told by a mechanic it was running really lean so in the next few days I'm planning to put the standard airbox back on. However I'd appreciate some other opinions please, would running lean really knock the power down loads?

I have checked the FAQ and will be going through it AGAIN. I'm hoping it is the air intake or a sensor and nothing serious. Car only has 30K miles on it and is serviced on time and well looked after I never touch above 3.5/4K rpm cold.

MB

You can't really clean the MAP sensor.

Once they are gone, they are gone.

How does the guy know it's running really lean?

If it's running lean, it will feel a lot faster as you get more power!

Is it down on power in VTEC, or just pottering around?

loftust

How does the mechanic know it's running lean??? Has he monitored the AFR? Have you added breathing mods recently?

Sounds like the MAP sensor is kaput to me, and cleaning it was only a temporary measure...

...check out MB's idle thread in my signature if you haven't done so already.

Muzzsjm

He apparently hooked it up to his machine to check fuel air ratios had no engine fault codes but I'm not sure now if he's telling the truth.

It's defo not faster and feels sluggish, down of power and I'd say it misses VTEC every now and then.

MB

He would have had to put a lambda probe up the exhuast - ask him what readings it gave. I would be surprised if it was lean...

New MAP imo though.

If it was misfiring i'd look at injectors / plugs / valve clearances.

Muzzsjm

Would a MAP sensor gone really decrease power greatly?

MB

Can do. MAP sensor is the major governor of the fuelling when on VTEC (the lambda isn't used on VTEC)

You could always arrange to meet up with someone local and borow theirs for half an hour.

ECU reset before hand.

Alas though it could be a lot of things, it's just the MAP is the most likely culprit based on the limited info available.

Muzzsjm

I would say its more in the lower rev range pulling away, low gears, below 50mph etc does miss VTEC occasionally/feels sloppy. Mod wise car has Spoon exhaust, AEMv2, Spoon manifold and custom grille.

MB

Describe "missing vtec"

With your mods it could well be on the lean side. But that's best checked on a dyno with the car under load and full rev range.

Muzzsjm

The rev counter keeps going but without the umph you'd normally hear or feel it's just as if the car carries on going without it kicking in, not the best way to describe I know. Kinda like it's slipping at VTEC...