mass air meter sizes and how to determine them?

Topic: mass air meter sizes and how to determine them? (Read 1752 times) previous topic - next topic

mass air meter sizes and how to determine them?

July 03, 2011, 03:16:49 PM

Scenario: a buddy just bought a car, but it's not running right, won't idle, has no power.

We're troubleshooting it, and I thought I'd find out if there was a chart or a list that told what the numbers on the meter meant in regards to meter size, etc.

It's an '89 5.0 from a Mustang, has a Cobra upper and lower, he has no idea what size the mass air meter and the throttle body are.

It DOES have 19 pound injectors and the '89 eec...at first he thought it was a genuine Cobra engine, but the 19# injectors denied that..

Anyway, I've looked at 11 or 12 sites, and can't find a list of the numbers to cross check to determine the meter size.

Anyone know where I could find what I'm seeking?

mass air meter sizes and how to determine them?

Reply #1 – July 03, 2011, 05:39:45 PM

Any codes before you change the MAF?

There are only two stock MAF meters that work with the stock Mustang MAF. Either the stock 55mm unit or the 70mm unit from a 94-95 5.0 Mustang, or 92-95 Crown Vic, Grand Marquis, or Town Car (part number on the top starts with F2VF). Any other factory MAF will not work with the stock computer. The computer is programed to a certain transfer function from the MAF, i.e. stock MAF meters are NOT calibrated for a certain injector size, the computer is programed with a certain injector size. Swapping around stock MAF meters will not allow you to run bigger injectors. Aftermarket MAF meters either change the amount of air traveling over the MAF wires (C&L like I use) or change the voltage signal sent to the EEC (Pro-M) to trick the computer into running larger injectors.

mass air meter sizes and how to determine them?

Reply #2 – July 03, 2011, 05:43:54 PM

I'll ask the fella if he's got any codes, but I'd wager he does. I'll pass along this to him as well, maybe I'll go over in a bit and look the car over, and see what brand it is...he says it doesn't have any numbers/letters on it though.

mass air meter sizes and how to determine them?

Reply #3 – July 03, 2011, 06:53:49 PM

I could be a Cobra motor but the GT40 cast iron heads would be a dead give away. Otherwise the short blocks were pretty much the same between the GT and Cobra of that year. Have you done a Google search on the part number on the MAF and TB? That may give you some hits and help detemine what you have.

Darren

mass air meter sizes and how to determine them?

Reply #4 – July 03, 2011, 06:56:54 PM

No, but he said he would send me a pic of the meter so I could look it up for him. He's 25 miles away, and not so keen on the newer efi stuff, despite being a Ford mechanic years ago.

mass air meter sizes and how to determine them?

Reply #5 – July 03, 2011, 08:15:20 PM

OK, according to Ford Fuel Injection.com, the meter he has is for an '89 Stang, which is what the car is. Apparently a previous owner swapped on the Cobra upper/lower. He's timed it twice, and still no change in the way it runs.

Has a high idle, runs rough, and no power. I'm going to go over in a bit with my code reader and see what comes up.

mass air meter sizes and how to determine them?

Reply #6 – July 03, 2011, 09:57:26 PM

Pull the MAF element and make sure it is not dirty. I bet it will be loaded with codes.

Darren

mass air meter sizes and how to determine them?

Reply #7 – July 04, 2011, 01:01:43 PM

Strangely enough, I couldn't get any codes...the tester said it was "getting" code(s), but none ever showed. His fuel pressure reg wasn't hooked up to a vacuum line, so I fixed that, but still no change. Cleaned the MAF, nada. Has good fuel pressure, 40 psi. Timing is set to 14btdc. Pulled the SPOUT first. This one has me stumped.

It smells like it's way out of time, but he set the timing to both standard 5.0, and HO, neither of which made any change. I also set the timing to no avail.
He's got another shortblock he's going to swap the heads and upper/lower onto, and tear this one apart to see what's the issue...i wonder if the cam isn't installed correctly...I'll post up about when he tears it out.

mass air meter sizes and how to determine them?

Reply #8 – July 04, 2011, 01:04:29 PM

Are the plug wires in the right order?

mass air meter sizes and how to determine them?

Reply #9 – July 04, 2011, 01:11:59 PM

Vacuum leak is my bet.

mass air meter sizes and how to determine them?

Reply #10 – July 04, 2011, 02:13:10 PM

Did you make sure that the dizzy was installed correctly? Are the plugs actually getting spark? Basics then electronics.

Darren

mass air meter sizes and how to determine them?

Reply #11 – July 04, 2011, 02:39:39 PM

Yeah, plug wires in the right places.

I found the one vacuum line that wasn't correctly installed..actually, it was a line going from the egr to the fuel pressure regulator...I found a vac line that wasn't connected to anything, put it first on the egr, with no change, then the fpr with a tiny change, so left it there.

Steve (owner of the car) said he got the dist. installed correctly...however, my gut feeling is that it's mis-timed still. He's out of town today or i'd go back over and fight it some more.
We set the timing every way we could think of, but I'd swear that the way the exhaust smells, the way it idles (or doesn't idle, to be fair) and the lack of power to me indicates being out of time.

He told me he made sure that it was at TDC, but I'm wondering if he didn't misunderstand my meaning...tdc on cylinder #1 is a pretty infallible way to set basic timing....unless the cam is horribly off.

Sucks that the car is a 40 mile round trip away...I know well there's nothing wrong with that engine, but he's convinced it's junk, and is gonna pull it...just trying to keep him from wasting his time and a good block that is (i'm rather certain) only in need of being timed...

mass air meter sizes and how to determine them?

Reply #12 – July 04, 2011, 02:41:08 PM

And thanks for the tips guys