Chrysler to continue using MAP sensors

[StevieC]

Interesting read...

http://www.sae.org/mags/AEI/8539

Japanese seem to have success with MAF sensors for long mileages and I have seen lots of MAP sensors go bad because of condensation, broken/cracked pressure lines.

Your thoughts?

 

[daves87rs]

Interesting read....knock on wood, I've had good luck with my MAPs in the past...

 

[StevieC]

That's interesting because here they always seem to fail in the spring/fall when the moisture is at its worst.

The condensation gets into the sensor and mucks it up.

The only MAF's I have seen go bad are on GM, other vehicles either last the life of the car or it goes bad when someone mucks with it with cleaner or a screw-driver.

 

[Quattro Pete]

Originally Posted By: StevieC
The only MAF's I have seen go bad are on GM,

And some VAG vehicles... previous generation of Golf/Jetta suffered from frequent MAF failures.

 

[StevieC]

Ah, yes I forgot those... I remember replacing some.

 

[pidster]

My old Tercel went to the yard with a 15 yo 350k km MAP sensor working fine.

Not saying they're necessarily a better system but they aren't a flawed design IMO.

 

[StevieC]

Lucky you!

Never saw one last that long...

 

[beast3300]

Speed density are much easier to calibrate/tune. There are a few custom MAP OS (OS = operating system a term used by GM that specifies a specific calibration to that engine/car combo) for the LSx application made by HP Tuners. I agree with the reliability factor. I have never had a GM MAF go bad personally (knock on wood). However they do come in from time to time.

From what I have seen, the speed density systems are not as adaptive as MAF systems (out of the box.) Obviously with a way to tune fuel and spark either system can be accommodated for changes to the engine.

 

[Chris142]

Detroit has been using one that looks just like a GM one on the Series60 forever. They seem to last ok n a truck

 

[StevieC]

Maybe they would give us a calibration POT that we could turn.

I would buy a Chrysler for sure!

 

[Steve S]

Chrysler products aren't the highest quality vehicles on the road. A quality part is a quality part .

 

[brianl703]

Originally Posted By: StevieC

The only MAF's I have seen go bad are on GM, other vehicles either last the life of the car or it goes bad when someone mucks with it with cleaner or a screw-driver.

I had a Ford MAF go bad. It had a piece of hair on the sensor element. I have no idea how that got there.

 

[JetStar]

Thanks for posting. Interesting read. My FI bikes all use the speed density system. Not aware of any that use MAF.

 

[SteveSRT8]

speed density can indeed adapt, it just takes longer to do so.

MAF is a restriction in the intake which can be an issue for some big breathers. And Speed/density is very easy to tinker with the tables and custom tune.

There are LOTS of bikes that use MAF systems.

 

[mechanicx]

That article pretty much explained it. MAF actually measures the air mass and compensates somewhat for temperature and humidity. MAF is easier to tune and is to a degree self tuning since it actually measures the air mass. I think a MAP sensor requires the engine to develop a certain level of vaccuum. MAF is a slight restriction, a part to fail, and not as quick responding to changes (but that's compensated for by the TPS). Most cars have both MAF and MAP.

I'm not sure how a motorcycle with individual runners and low vacuum could use a MAP. Maybe a barometric absolute pressure or maybe they have some special vacuum system. Not sure about cycles. The hotwire MAF that GM always used is supposedly more reliable than the air door type that Imports used.

 

[mechanicx]

Originally Posted By: JetStar
Thanks for posting. Interesting read. My FI bikes all use the speed density system. Not aware of any that use MAF.


Not sure about bikes but there is also the N-alpha system, where you have TPS and baro sensor. I don't think bikes hold the A/F nearly as tightly contolled as cars.

 

[JTK]

I'd think down the road your typical MAP sensor would be a lot cheaper to replace than a MAF. MAFs are ridiculously expensive and can be integrated with the air cleaner box on most models. I say go speed/density!

Joel

 

[JTK]

Originally Posted By: mechanicx
.. I don't think bikes hold the A/F nearly as tightly contolled as cars.


I wonder if they err on the rich side? You'd think even a few seconds of a lean condition when those bike engines are SCREAMING would turn them into molten metal madness.

Joel

 

[mechanicx]

Originally Posted By: JTK
Originally Posted By: mechanicx
.. I don't think bikes hold the A/F nearly as tightly contolled as cars.


I wonder if they err on the rich side? You'd think even a few seconds of a lean condition when those bike engines are SCREAMING would turn them into molten metal madness.

Joel


That'd be my guess. Honestly I'm not familar with FI bikes and their emissions requirements. they can't have much of any emission requirements because they still sell new carbureted bikes with no emission controls. The FI bikes don't have an o2 sensor? They don't have a CAT either so there's no need for them to cruise at at around 14.7:1. They could cruise safely leaner than that for gas mileage, if allowed, but would need to go richer like all engines at load. Without as many sensors they'd probably go rich quickly on throttle transition and load.

 

[IndyIan]

My 16.5 year old Neon still has its original MAP sensor. In my family's cars we've never had a MAF go bad either so both systems seem OK to me.