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New MAF Sensor

Yahoo Message Number: 9679
It did the trick. 1,000 miles and everything is fine.

I am the proud owner of the specialized diagnostic tool the dealer says in unobtainable....


Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

Re: New MAF Sensor

Reply #1 –
Yahoo Message Number: 9680
That would be the signal generator that mimics various sensors on the engine and chassis. From GM they were $1600 and apparently no dealer even has one in San Diego County - which could be the 5th largest city on the USA. The Stealers simply start selling you parts until your problem goes away instead of actually doing the proper diagnostics with the correct tools that they are too cheap to purchase, however they feel "OK" charging you $125 per hour labor rate.

Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

From: Victor Burns
To: Kodiak Kodiak
Sent: Monday, August 20, 2012 7:31 PM
Subject: [KodiakChassisClassC] New MAF Sensor



It did the trick. 1,000 miles and everything is fine.

I am the proud owner of the specialized diagnostic tool the dealer says in unobtainable....


Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

Re: New MAF Sensor

Reply #2 –
Yahoo Message Number: 9686
Victor,
Glad you are up and running. Sorry I am late chiming in here but Simpson Chevrolet in Garden Grove CA seems to have a truck center. I see Kodiak MH's out there all the time as well as other big trucks.

Not sure if you ever tried there.

http://www.simpsonchevroletgardengrove.com

Ramon

Re: New MAF Sensor

Reply #3 –
Yahoo Message Number: 9687
Victor,

What exactly is this diagnostic tool, Brand, Model, that you are talking about.

Regards,

David

Re: New MAF Sensor

Reply #4 –
Yahoo Message Number: 9688
SPX J-38522-A Variable Signal Generator
J-38522-A is used in diagnosis of the transmission auxiliary pump controller and speed sensor. The tool is capable of generating pulse width modulated signals of a known frequency that simulate output of the pump controller or speed sensor. Through the process of elimination, the source of the DTC can be easily isolated for repair or component replacement.

The GM Part number referrred to in the diagnostic manual is a J38522 its made by Kent Moore.

Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

From: winkvzn
To: KodiakChassisClassC@yahoogroups.com
Sent: Tuesday, August 21, 2012 8:01 PM
Subject: [KodiakChassisClassC] Re: New MAF Sensor


Victor,

What exactly is this diagnostic tool, Brand, Model, that you are talking about.

Regards,

David

Re: New MAF Sensor

Reply #5 –
Yahoo Message Number: 9689
It also is used for mimicking a variety of sensors too.

Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

From: Victor Burns
To: "KodiakChassisClassC@yahoogroups.com"
Sent: Tuesday, August 21, 2012 8:46 PM
Subject: Re: [KodiakChassisClassC] Re: New MAF Sensor


SPX J-38522-A Variable Signal Generator
J-38522-A is used in diagnosis of the transmission auxiliary pump controller and speed sensor. The tool is capable of generating pulse width modulated signals of a known frequency that simulate output of the pump controller or speed sensor. Through the process of elimination, the source of the DTC can be easily isolated for repair or component replacement.

The GM Part number referrred to in the diagnostic manual is a J38522 its made by Kent Moore.

Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

From: winkvzn
To: KodiakChassisClassC@yahoogroups.com
Sent: Tuesday, August 21, 2012 8:01 PM
Subject: [KodiakChassisClassC] Re: New MAF Sensor


Victor,

What exactly is this diagnostic tool, Brand, Model, that you are talking about.

Regards,

David

Re: New MAF Sensor

Reply #6 –
Yahoo Message Number: 9690
Was the one you replaced checked with this tool and how did it check?
Best
Ron Hall

Re: New MAF Sensor

Reply #7 –
Yahoo Message Number: 9692
You use the tool (signal generator) to mimic the various sensor(s) that need to be validated - so there is not a "testing" of the sensor you can really do as you would need to change the air temp / flow / water content etc. to test the sensor and look for correct changes in the output.

We swapped out the sensor the day my test instrument arrived. It would have been used to mimic the sensor and see if the CEL / Code continued to show up.

The main regular car/pick-up truck dealer in Escondido indicated if all the air connections check out (and you can test for them in the diagnostics) that the only two items left are the MAF or the main computer. The MAF being the easier and cheaper and most likely failure point. When consulted on the issue by the Mid-Duty Truck Depot they just replaced it.

By the way the MAF sensor was UNAVAILABLE FROM GM!!!!! OUT OF STOCK, ON BACK ORDER WITH NO TIME-FRAME GIVEN FOR DELIVERY. It appeared you might be able to source the same sensor from a regular GM dealership as the part is used in some of the other Duramax trucks? They are actually restricted from selling it to you for use in a mid-duty truck. If you just give them the part number that is OK.

THE SOLUTION: ORDER THE FUCKING PART FROM ISUZU!!!!! Yes boyz and girls parts are easier to acquire from Isuzu than GM for this engine as they still support their mid-duty truck line which includes the same engine that was developed under a Joint Venture between GM and Isuzu.

Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

From: ronjhallsr
To: KodiakChassisClassC@yahoogroups.com
Sent: Wednesday, August 22, 2012 8:34 AM
Subject: [KodiakChassisClassC] Re: New MAF Sensor


Was the one you replaced checked with this tool and how did it check?
Best
Ron Hall

Re: New MAF Sensor

Reply #8 –
Yahoo Message Number: 9693
Victor,

I understand the tool, as I built something similar to play with back in the day when vehicle's started having computers. As for diagnosing computer and sensor problems I don't really see much benefit to having the tool if you have a digital storage oscilloscope to see the signal and what the signal is doing, which just about every technician working on electronic problems has a oscilloscope in their toolbox.

Let's say for example that your MAF sensor was not sending the correct signal, or any signal, to the computer causing the problem. Yes, you could put in the signal generator to simulate the signal and wait to see if the problem occurs, just as long as you have the correct frequency, timing, and voltage. This would not help much if you had to drive the vehicle for the problem to happen as the generator would only provide a constant signal and the signal would have to fluctuate under those conditions. But with a digital storage oscilloscope you will be able to capture and see the problem instantly when the glitch occurs; even be able to drive the vehicle with the oscilloscope connected.

Regards,

David

Re: New MAF Sensor

Reply #9 –
Yahoo Message Number: 9694
You are way smarter than most techs - and I am not sure every tech has an oscilloscope. Anyway its not part of the diagnostic tree either. And yes with our cool little 1 pound 200mhz portable battery operated oscopes make these diagnostics much easier that old 100+ pound ones of yesteryear.

What exactly would be you looking for in pulse width, amplitude and frequency which are all used in the sensor? Even if I hooked by Oscope up I would not have a clue unless there was total failure of the sensor. What I think happens is the data signal moves slightly out of range (intermittently) which throws the CEL and error code.

You mileage may vary or you are way smarter that I or GM.

Be well,

~
Victor - KI6IM
Kodiak Diesel Dutchmen 34H Bunkhouse

From: winkvzn
To: KodiakChassisClassC@yahoogroups.com
Sent: Wednesday, August 22, 2012 9:09 AM
Subject: [KodiakChassisClassC] Re: New MAF Sensor


Victor,

I understand the tool, as I built something similar to play with back in the day when vehicle's started having computers. As for diagnosing computer and sensor problems I don't really see much benefit to having the tool if you have a digital storage oscilloscope to see the signal and what the signal is doing, which just about every technician working on electronic problems has a oscilloscope in their toolbox.

Let's say for example that your MAF sensor was not sending the correct signal, or any signal, to the computer causing the problem. Yes, you could put in the signal generator to simulate the signal and wait to see if the problem occurs, just as long as you have the correct frequency, timing, and voltage. This would not help much if you had to drive the vehicle for the problem to happen as the generator would only provide a constant signal and the signal would have to fluctuate under those conditions. But with a digital storage oscilloscope you will be able to capture and see the problem instantly when the glitch occurs; even be able to drive the vehicle with the oscilloscope connected.

Regards,

David

Re: New MAF Sensor

Reply #10 –
Yahoo Message Number: 9696
Not every tech would have an oscilloscope, but just about every tech that diagnoses electronic problems would. Some borrow, but that really doesn't last too long. Yes, you don't find the use of the oscilloscope in diagnostic trees. The tree then wouldn't help those without a scope! Yes, they specify needing tools sometimes that can be purchased through the dealership, usually stating with Part # JXXXXX. Sure, why not, more money for them. Tricks of the trade and things you learn by reading the diagnostic tree, reviewing the wiring schematic, and good old common sense would take you to the o'scope. There are places that technicians can go (usually for a fee / membership) where they can view what a good sensor signal looks like, and what a bad one looks like. Some of the newer o'scopes has these incorporated into the tool. I still have my old o'scope, still sitting on the rolling cart needed to move it around; still works too. I don't use it because my handheld Fluke o'scope is just too smart that can do what the old tool did, plus a whole lot more. I will admit, depending on the MAF sensor, it could be one of the hardest sensors to detect a problem. I have seen a perfect signal, but the P-Code would set, the wiring was good, and the problem moved with the sensor (I put it in a similar vehicle on the fleet). I cleaned the MAF sensor and the problem went away. You being the dealership / technician that do not want comebacks, what do you do? If you clean it and it comes back, the customer is not happy either. The safe thing is to replace the part. More than likely the part has been improved since the original part was installed at the factory when they built your vehicle. I will bet they even reprogrammed the vehicle's computer while it was at the dealership too. Why? Improvements over the previous versions of software. Their goal is to make you a happy camper so others buy their product. Obviously, you were not a happy camper.

Regards,

David

 

Re: New MAF Sensor

Reply #11 –
Yahoo Message Number: 9701

David,

You bring back memories of using my Fluke scope. I can't even remember how to set it up for most test anymore. I do remember being taught to slap the top of a GM maf sensor. If the engine reacted to it, the maf was bad. Next step would be to clean it and test drive. Then use the scope, if you could back probe a connector. Most of the time the wave form could be figure out by the type of sensor you were testing or you could look it up in books that were available to techs through the after market.
I remember working on a Mercedes that had the O2 sensor replaced 3 times at a dealer before I got the car in my bay, only to find out a bad relay in the cabin heating system was no longer supplying power to the O2 sensor heating element. Doing the homework to find that problem was very time consuming and I was being paid by the hour.
These test take a lot of time and dealership techs are not taught to work that way. If they did they would go broke, so they wind up swapping parts to make a living. It is not their fault. It is the cost effective position the dealership puts them in to keep the work bay making money. They only want to pay the tech to turn cars. Customer satisfaction is not as important as cash flow.