What would the symtoms be for a bad Maf? Could code 172 result?

1994 302 with 115,000 miles fyi

 

have u tried cleaning it?. usualy bad MAF results in poor fuel milage because its reading less air so it trys to suck more air in makin the engine work hard and use more fuel. but i will ask dad for more input

 

Im guessing a code 172 would indicate a plugged fuel injector or a weak fuel pump.

 

Did you convert this from a SD to a MAFS intake ?

I thought the '94s were SD engines ??

If it is a MAFS, you would get pinging on acceleration is one symptom of a dirty MAFS. I think 98Screamer had a MAFS go bad, you'd have to take a look at his postings to find out what the running symptoms were. I know he also had a CEL set, aside from driving issues.

Try doing a search on P017* to find the postings, and the steps other members took to cure the problem, there are a few from different members.

For ref:
DTC
P0172 - System to Rich ( Bank 1)
Description
The Adaptive Fuel Strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a lean calibrated limit.
Possible Causes
See Possible Causes for DTCP0171
DTC
P0171 - System to Lean ( Bank 1 )
Description
The Adaptive Fuel Strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.
Possible Causes
For lean and rich DTC
1. Fuel system
- Excessive fuel pressure.
- Leaking /contaminated fuel injectors
- Leaking fuel pressure regulator.
- Low fuel pressure or running out of fuel
- Vapor recovery system
2. Induction system:
- Air leaks after the MAF
- Vacuum Leaks.
- PCV system.
- Improperly seated engine oil dipstick
3. EGR system:
- Leaking gasket.
- Leaking diaphragm or EVR
- Stuck EGR valve
4. Base Engine:
- Oil overfill.
- Cam timing.
- Cylinder compression.
- Exhaust leaks before or near the H2OS
Diagnostic Aides
A SHRTFT-1,2 PID value between -25% to +35% and a LONGFT-1,2 PID value between -35% to +35% is acceptable. Reading beyond these values indicate a failure.

 

I am with Scully, a 94 should be SD and not have a MAF unless it is a car or a weird CA model.

172 is a EECIV code for lean condition detected by HEGO

P0172 is a OBDII code for Rich

Fuel pressure check would be a good place to start.

 

Yep, I had a 171, and it was using gas pretty bad. Otherwise I noticed nothing really as far as how it ran. They gave me the old one back, which I quickly gutted, then switched the elements out.,,,,98

 

Jon,

Did you or the previous owner convert this from a Speed Density ( SD ) to a MAFS, or is it an odd ball type like noted in the CA truck area ?

This is a picture of IzzyEddy's engine compartment with his SD engine.

You can see the 2 tube on it, vs a MAFS is the single tube, as I am sure you have seen a million times:


If you can let us know which it is, we can get moving forward on getting this resolved for you. It would be from someone else, as the little amount of EECIV knowledge I had leaked out of the side of my head years ago while I was sleeping I have been working on ODBII based stuff too long now.

 

'94 was the first year Ford used a MAF sensor on the 302 & 300 Engines in the F150. The 351W was still Speed Density that year.

 

Tailgator,

Thanks for the info, I can't keep it straigth myself. I think IzzyEddy has a 5.7, so that would explain it.
Jon started another thread on the same topic, and I thought he said it was SD ??? Does that mean that it is still a EECIV or was it switched to a PCM ? I don't know for sure if the code is a ODBII code of P0172 or a EECIV code of 172 ( different code items ).

Thanks again for the info, I am really grey in the conversion date on SD / MAFS.