economy, dead spot, sparkplugs

[RRv8]

Just thought I would share my recent experience with my P38

For a while I have been having bad economy when towing my 21ft caravan
and when under load such as towing uphill had a massive dead spot as in no power between 3500-4500 rpms

I also recently had my P38 on a 4WD dyno and saw that not only was I missing a third of the
horses that I should have but a bloody v6 Toyota had more than me

so it was time for me to play bush mechanic

As well as dead spot my P38 also had slight hesitation at 4000rpm
at times when accelerating from 100kmph I would hear pinging and I felt economy
was to good at 14.5 avg/l per 100km
I suspected that it was sucking air after the MAF sensor, needed spark plugs
or had a faulty MAF sensor

Air system looked Ok so I pulled my plugs and found that the best plug had a 2mm gap some were closer to 3mm

standard plugs on the p38 are champion platinum I wanted the same as they are a known
quantity and the ones I had lasted well past that expected 100,000
but no one had champion
bosh info kept leading to old school type plugs (clearly wrong)
so I went NGK

thus far I am very happy the massive dead spot from 3500-3500 revs has gone and my highway economy is unbelievable
@100kmph can hit 10.1 avg/l per 100km with average of 12.4
@80kmph average 10.4

I have regained missing horses then some but
I occasionally still hear pinging and a barely noticeable slight hesitation @4000 rpm
so In considering this with economy I suspect a new MAF may be in order they are meant to be replaced at 60,000
my car as done twice that and as plugs were factory I'm sure the MAF is factory to

regards Peter

[adm333]

Try cleaning your MAF before you replace it.

You might be surprised.

[Keithy P38]

Any hints on cleaning the MAF? I purchased mine from Sydney in September last year and drove it up the entire way through that big dust storm, mine has fine dust on the clean side of the air filter and I haven't touched it for fear of disloging something and causing minute engine damage...

Is water and kerosene fine to clean it up or is it more sensitive than that?

Cheers
Keithy

[adm333]

No, no, no.

Either buy some of the electronic circuit board cleaner from Jaycar or I think you can get actual MAF cleaner ( both aerosol spray cans) from Supercheap.

Remove the MAF housing from the air intake.

You will see a small tube inside the centre of the main housing and inside that, you will see a very small copper electrode, that looks sort of like a diode or resistor.

Gently spray in through that tube to clean the copper resistor.

Only spray a little at a time and let any surplus drain out or dry up. The right cleaners will have a super quick drying property.

I use the little extension tube on the aerosol can to get closer in, but be extremely careful not to make contact with the resistor.

A few good squirts is usually enough and then let it sit to dry out properly before putting the air intake back together.

Dave

[PaulP38a]

Dave's suggestion works well... I use Isopropyl Alcohol in a pump bottle, available from JayCar to clean the MAF bits, and a can of compressed air, also from JayCar to dry it off.

Cheers, Paul.

[Keithy P38]

Thanks fellas! I might give that a shot!

Keithy

[DT-P38]

YEP cleaning works... as per what the other guys have said, but I bought MAF cleaner from dick smith. About $15 a can and I give mine a (gentle) blast at every service 5-10,000 km's.