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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #1 ·
It's been raining for a week and today had a break to take the 96 FWB out for a run.
She started and idled for a few minutes and then off towards I-5.
Climbing a grade with the mechanical fan still roaring (to give an idea of warm-up stage),
the engine bucked and caught several times, so I pressed hard enough to get 2nd gear.
Had to wait at a light and idled fine, but more bucking on the flat straightaway till at speed.
I managed to look down and noticed the 'check engine' light on.
I suspect old fuel and/or dirty fuel filter since she stood with half a tank for at least 2 years.
We have 10% ethanol blend here, so water should not be an issue.
Never had any problem before, in the 1,000 miles I've driven her.
I guess a trip to the mechanic for a scan tomorrow.
I wonder what the OBD II will show...
 

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1976, 1994 Cadillac Fleetwoods, 1996 Lincoln Town Car
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223 Posts
Does your gas gauge work?

Hmm, when I bought my '94 back in October, I drove it back from the auction. It was about a 50 mile drive and the car indicated that it had a quarter tank of gas. I figured, "Eh, it should make it". I was about 8-9 miles away from home when the car started hesitating and bucking on the freeway. The check engine light came on. I pulled her to the shoulder and popped the hood. "Transmission failure? Engine seizing up from lack of oil? Overheating?" were the first things that came to mind. After checking the fluids and finding everything was good, I sat and thought a while about what was up. Funnily enough, my dad decided to call me and ask how the car was running. Heh, I felt like it wouldn't be a good idea to tell him that the car I had just bought had an odd issue which had got me stuck on the side of an interstate. So I kinda left out that part in our conversation.

Anyways, I limped her off a freeway. My roommates came by with some tools and my Town Car and I pulled codes through the HVAC unit. No codes there. After that we planned on taking side streets back, but on the first steep hill in the Oakland hills she stalled and just wouldn't restart. This whole time the car still indicated it had a quarter tank of gas. Anyways, I sent my roommates off in my Town Car to go fetch a gallon of gas. Still didn't start. Called AAA, and they brought 2 more gallons of gas. Still didn't start. Eventually, one of the AAA guys suggested backing the car onto a flat driveway. Sure enough, she cranked right over. The flat gas tank in these cars means that the gas pools at the back anytime the car is on a steep incline. We then took the '94 straight to the gas station and filled her up. 19 gallons.

So on paper, these cars have a 23 gallon fuel tank. 1 gallon from roommates + 2 gallons from AAA + 19 gallons at gas station = 23. It was dead empty. The darn gas gauge wouldn't drop below 1/4 tank.

Moral of the story: Anytime you get a new-to-you-used car, fill it up with gas.


Anyways, I bring up this little anecdote because my car had 81,000 miles on it at the time. In the past 5-6 years, it had averaged about 300-500 miles a year according to smog reports. That was pretty much 1-3 tanks of gas a year. I have a strong feeling that the fuel gummed up the fuel sending unit in the trunk. Your Fleetwood has such low mileage that it probably had gas sitting in it for a long time too.
 

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1996 Fleetwood limo
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32 Posts
So you weren't burning 2 year old fuel today? Ethanol severely degrades with time, not good for fuel injection at all. I think it starts to deteriorate after 3 months in tank.


Sent from my iPhone using Tapatalk
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #6 ·
It had 3/4 tank on delivery in Sept 2014. It sat unused till I decided to take it out of mothballs this winter.
I topped the tank with 12 gallons when the gauge dropped to 1/2, thinking to refresh the old fuel.
The gauge is just now back to 1/2, so it's not likely out of gas. The hill climb might have stirred up the dregs.
The engine light is on, so it will need a scan. A friend lent me a scanner, but I don't have a clue how to use it.
It's an Innova 3030, if anyone can suggest what I should do. I found the manual online:

http://www.innova.com/Content/Support/Manual/Innova/Manual_0303_E.pdf

Thanks!
 

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70 Deville 78 Seville 92 Deville 03 Deville
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1,230 Posts
I also think the rain may have something to do with it; usually the plug wires. I think adding 12 gal of fresh gas is about all you can do and it should be able to burn it. I would burn the rest of it out and see how it works with a tank of fresh gas.
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #9 ·
I got hold of my tech and he said they could clean the MAF sensor and clear the code.
I cleared the dash light with my gauge, but it has to be put through a driving cycle to clear the computer.
I warmed her up and roared up and down the cul de sac a few times and put her to bed till I can take her in.
It could have been a one-off spurious kind of thing, but they can clean the throttle body while they are at it...
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #10 ·
I've read about MAF sensors and still don't understand the working theory.
A hot wire is exposed to a current of air -- and then what? Cooling effect?
I see where the MAF is on the V4P engine, very near the air intake behind the grille.
I wonder if mist from a carwash could have coated the surface and could be cleaned off.
A new part is ~$100, but varies from $50-$500 -- what the heck is up with that disparity?
I can't re-set the computer code, so it has to go visit the tech anyhow...
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #12 ·
Funny thing about the filter -- I can't seem to get to it.
GM put two thumbscrews and a removable hinge on the cover, but then they tied
it down with electrical connectors and plumbing with too little slack!
I've developed unsteady hands of late, so I have to rely on others a lot.
Also, my little scanner can't clear the computer with its 'erase' function.
I just wonder what the MAF element is made of -- if age alone deteriorates it enough
to justify replacement over cleaning. I pay the time for labor either way.
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #13 ·
A note I sent to my mechanic:

Hey, Mike.

I didn't get another error code after I cleared the one.
Reading up, it sounds like maybe a voltage spike from a spark plug wire or something.
This is the only article among dozens I read that addresses HIGH voltage instead of low.
Even if it never happens again, I'll need you to re-set the computer.
Low voltage is the result of a dirty MAF and that is all that the other articles addressed.
Here is the one helpful article:

http://www.troublecodes.net/pcodes/p0103/

"...The P0103 is not a common code. A high frequency or high voltage MAF sensor signal, unlike related code P0102, does not indicate a dirty MAF. The code is also unlikely a PCM problem. The cause can be some sort of wiring issue. You should trace the wiring to the MAF and see if another power source is interfering with the MAF’s signal..."
 

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2014 ELR
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You can't clean the sensors in the MAF manually. They are protected by honeycomb screens. If you remove the screens, touching the wire sensors will ruin them. Spray only. Make sure the MAF is installed correctly, it is possible to install it backwards. Make sure you have a fresh air filter.

Pep Boys or Advance Auto will read and clear the code. They'll also have MAF cleaner spray.
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #15 ·
Voltage or frequency spike?...

http://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/how-to-clean-the-maf-sensor-1

> This article is GM - specific.
> Sounds like a scope would help a lot.
> If the frequency spikes, that would explain the P0103 code and the bucking behavior:
>
> http://easyautodiagnostics.com/gm/3.5L/maf-sensor-tests-1
>
> The MAF sensor's job is to measure the amount of air the engine is breathing at any given RPM. It then converts this measurement into a Hertz frequency reading (as measured by a digital multimeter that can read Hz Frequency) and shoots it to the PCM. Here's what it looks like on a digital multimeter:
>
> At an idle of about 680 RPM's, the MAF sensor outputs about 3.2 K Hertz.
> Let me emphasize the words ‘outputs about’... because every vehicle will output a slightly different value depending on several conditions like: engine temperature, ambient air temperature, etc.
> At about at 1500 RPM;s the MAF signal output is about 4.2 K Hz.
> At 2500 RPM's it hovers around 5.2 K Hz.
>
>
> As you can see, the more air the engine breathes (or the higher the RPM's) the higher the MAF output signal becomes, and of course the less air the engine breathes, the lower the reading on your digital multimeter.
>
> Now, in testing the MAF sensor, you won't be looking for a specific Hertz (Hz) number at a specific RPM... but for crazy fluctuations in the signal that don't correspond to the amount of air entering the engine or NO SIGNAL AT ALL. OK, crash course is over, let's start testing.
 

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1996 Fleetwood Brougham V4P
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Discussion Starter · #16 ·
Rain, rain, rain! Still waiting to take her in for service. P0103 is extremely rare, so a new Delco MAF sensor is probably in order. Probably a new air filter while they are at it. I'm wondering if I should pull the plug on the MAF to prevent a repeat of the bucking behavior on the 2 mile drive to the repair shop? I haven't switched her on since the cul de sac run after clearing the code. No repeat performance on that short run. Not gonna budge till the pavement dries, though...
 

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1996 Fleetwood Brougham V4P
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Discussion Starter · #17 ·
Back at the tech! I took it up the cul de sac before slinging it out into a 3-lane left turn on a blind curve.
A couple of loops and then I punched halfway down from a dead stop. It leapt forward and then KAPOW!
I couldn't tell where the backfire happened, but it was the same as the earlier bucking, only more-so.
The engine light came back on and it was sluggish all the way to the garage, where the tech was glad to have a code.
I didn't hang around for a new scan, but I hope it's only the P0103 MAF sensor defect. Stay tuned...
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #18 ·
Just as I imagined, 21 years of car washes left the MAF sensor soggy and corroded.
Looking for a new Delco with the plasic body -- and a new air filter.
The verdict will come in on Wednesday!
 

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1996 Fleetwood Brougham V4P
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230 Posts
Discussion Starter · #19 ·
The car is running great with the new air filter and new MAF sensor. I'll pick it up tomorrow.
As careful as I've been to never drive in the rain, I have taken it through a car wash a few times and put it away too quickly.
Water got sucked into the intake and corroded the sensor. Maybe I should shut the engine off while in the robo-wash and
definitely should schedule time to dry it out on the road. Lesson learned!
 

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2014 ELR
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Have a look at the intake opening for the air box. There's about a zero percent chance of car wash water getting in there. Not sure how a MAF sensor gets "soggy".

Anyways, the work is done, and I'm glad your car is running well again. Hope it didn't only need a filter, MAFs don't go bad very often. Did your tech return the old MAF to you?
 
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