27 Mar 12 20:55, Mark Hofmann wrote to Roy Witt:



 RW>> Once you get those plugs/wires changed, you might want to take a
 RW>> look at having the MAF and O2 sensors tested. The MAF gets
 RW>> contaminated by all of the particles in the air and oil (if you use
 RW>> an oil impregnated filter) and looses it's ability to accurately
 RW>> report to the ECM. At the same time, O2 sensors get carbon build up
 RW>> and when the two are out of spec, the A/F ratio gets screwed up and
 RW>> the ECM can't control how much time to leave the injector's open.

 MH> Right, I do plan to load the ECM software on my tablet/netbook
 MH> computer, connect it to the Durango and take it for a drive.  It is a
 MH> delicate operation when cleaning the MAF sensor.

 MH> Normally, the O2 sensor will throw some type of code - especially if
 MH> you have more than one of them.  I have seen a dirty MAF causing low
 MH> readings and throwing everything off.  They are not hard to clean -
 MH> just have to be careful.

An O2 sensor won't give you much of a warning. It just loses its ability
to perform as intended, messing up the MAF/O2 loop reading. i.e. my Z28
used to give me fits with O2 sensor codes (check engine soon), but that
stopped after changing the 'brand' of fuel used.

 RW>> All of those sensors have sealed connections on them, so you won't
 RW>> bother them very much unless you use the power washer to directly
 RW>> clean them off. Any overspray won't hurt them at all. Since you
 RW>> don't have a distributor anymore, there's no chance of getting it
 RW>> wet.

 MH> You never had a problem with the power washer ripping through a wire?

Insulation? No. Sealed connectors, no. Cars with non-sealed distributors,
yes. Cars with old frayed wiring (no insulation left on them) no. At least
not as long as they weren't hot wires touching ground.

 MH> That is my other fear.  There are so many wires and things in the
 MH> engine compartment these days.

Don't aim at them...

 RW>> If there is a MAF in the hose from the air cleaner to the throttle
 RW>> body, check it too. It may have a clogged screen, which will also
 RW>> give you fits if it's dirty. Be very careful when handling that
 RW>> thing, as it's a very sensative device. Replacement costs are around
 RW>> $200...

 MH> Yes, they are expensive.  I had to replace one years ago in my 85
 MH> Camaro. They are not cheap.  The good thing is, they normally only
 MH> need cleaning vs. replacing unless you damage the wire(s).

I put a high performance Granateli MAF in my Z28 back in 2001/02...it's
still going and I also kept the original, stored in the Granateli box...


                R\%/itt


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