Carb cleaner in MAF elecronics...ugh!

[jaded93atx]

My 93 has been getting a stored 172/176 combo with no other codes. So assuming it was a dirty MAF I sprayed it down really well with Berryman's. After re-installing it I was optimistic about clearing the codes. Unfortunately now not only do I still have the 176/172, but I've also added a 157-maf signal low and a 177 system rich. I'm getting super low mileage and an erratic idle and stalling.
I'm assming that I must have soaked it too much and got cleaner in the electronics and fried them...doh!
I'm super tight on cash right now and cant spare the change for new MAF electronics. I need to drive the car to and from work. If I unplug it and run in limp mode until I can get a new MAF will it be better or worse than leaving it plugged in and reading air incorrectly.
I know neither option is necessarily good but I'm looking for the lesser of two evils. It kills me to let it go but for now I have no choice.

Big Thanks for any offered insight.

 

[sdpatt]

Cleaning the exposed MAF filiments will neither cause nor correct the error codes you have identified. It will allow the MAF to read the air mass more accurately. If there is an error code regarding the MAF sensor, it affects only the electrcal circuitry to the sensor or within the sensor.

The problem identified with the 172/176 both O2 sensor lean codes was probably a vacuum leak in the manifold. You have changed something with your manipulation of the MAF electronics. The electronics are sealed so I doubt you affected them with the solvent.

You should check the electrical connector and perform the wiggle test on it to determine if the wiring harness has a discontinuity (broken pin or conductor).

You should clear the error codes by running the KOEO test and unplugging the jumper after the codes have started flashing. The re-run the test and see what condition still exists. If you really have a lean and rich condition happening, there is a real problem.

If you unplug the sensor, the system will run in open loop mode and run acceptably, but since this is an over rich mixture, you should attend to it as soon as possible so as not to create other problems such as burned catalytic converters and limited cylinder wall lubrication. These will cost much more than a replacement MAF.

 

[Mr Anonymous]

It usually takes less than an instantaneous squirt to clean the MAF filamets, chances are you damaged or broke one or both. Used MAF's are like $10 on eBay most of the time.

The 172 & 176 codes have nothing to do with the MAF, I'm curious where you got the idea that it was, because if it was from this forum I want to delete the offending thread.

The 172 & 176 codes indicate a lean condition, which is usually caused by unmetered air (air that enters the intake tract AFTER the MAF). Typically, this is the result of a vacuum leak somewhere. Try searching the forum for "vacuum leak" to find some methods and locations for tracking down a leak. In the meanwhile, running with the MAF disconnected will actually enrichen the mixture, so it might actually eliminate the lean codes temporarily, but your gas mileage will probably get worse than it already is.

Some people might suggest that the lean codes are due to bad O2 sensors, however when you get the same condition indicated from both sensors, it's usually indicating a true condition and the sensors are doing their job.

 

[jaded93atx]

Thanks for the replies fellas,
I'll check the maf connections again, although I screened it pretty well after the new codes popped up. If the filaments were somehow damaged by the spray of the cleaner then it cant be seen by the ***** eye because they appeared fine before I dropped it back in.
I found well over a dozen posts that pointed to a dirty maf as well as a vacuum leak being the cause of a 172 and 176 combo lean condition in my searches. I also read on an independent site a service bulletin about Ford maf's incorrectly metering air and causing the PCM to incorrectly lean out the A/F mixture resulting in simultaneus 172 and 176 codes.
Believe me my first strategy was to find a vacuum leak, I have tried everything short of a scanning it in real time, I have checked and double checked all of the intake couplers, the throttle body, egr hoses, and the hose going to the cannister purge solenoid. Even when I give it wot and let off I can find no evidence of unmetered suction anywhere around the intake.
The light comes on intermittently only when heated and driving and seems to occasionally coincide with letting off the throttle, but there is no way to recreate those conditions while parked with the hood up. Maybe a real time scan is the only way to go in order to find the source of it getting leaned out?

 

[Rockledge]

I hate to disagree with two of the most knowledgeable SHO guys on the board, but as far as I know, a dirty MAF can indeed cause the codes being complained about:

http://www.diesel-central.com/Tech/ford/Docs/98-23-10.doc

I'm not sure if that's the problem here, though.

 

[Slo-Sho]

Look to the B/R hose on the main underhood vacuum distribution junction. This hose goes to the brake release switch in the shifter console. Since it is a mechanical switch, they do fail. It may be a long shot but try plugging the B/R port and see if that's your problem.

 

[sdpatt]

I would also try removing and plugging the CANP inlet to the TB with a finger. It's an easy check of a hard to view vacuum line.

Regarding the MAF, I was stating that dirty MAF elements are not detectable by the EEC. The EEC can only detect electrical signals. Dirty MAF elements do not change the resistance of the MAF elements. The MAF may send an inaccurate signal that reduces performance and fuel metering accuracy, but it won't be out of range. Damaged or failed MAF electronics or wiring harness, however, can create a low or grounded signal to the EEC. Of course, I can be wrong, just like any other human creature.

 

[SHO Dude]

Scott (and Chris),

A dirty MAF can and will give this type of code. It can be lean or rich depending on what the computer is seeing. You're correct in saying that the PCM can't determine if the wires are dirty, but the dirt on the wires can and does effect the signal coming out of the sensor. Since the PCM relys heavily on this info, a dirty signal (punny) will have a grave effect on engine operation.

Cleaning the MAF is the first thing to do when you have a lean or rich code set in the computer and the answer isn't obvious (vacuum leak [lean] or FPR [rich]. Looking at commonality for an engine that's divided into two banks and proper diagnostic routines points to a component that's common to both sides of the engine. So, if the same code is set for both banks, the problem is going to be common to both sides of the engine.

 

[jaded93atx]

I performed the wiggle test and checked the connector, all four pins are ok and corrosion free. (the whole maf unit was replaced a few years ago)
I prematurely pulled the jumper, went for a drive and the same codes came back. It seems like for whatever reason the MAF electronics are shot, is there any chance anyone in Shocago has a working spare one laying around that I could try swapping out?

When pulling the Cannister purge hose from the T/B what am I looking for? It has suction at the inlet. I pulled out the hose that runs from the inlet to the solenoid and checked it and it held a vacuum. Should I also check the hose that runs from the other side of the solenoid and under the radiator too? It's kind of buried under there and I'm not sure if that side of the C/P solenoid could be a contributing factor.

 

[TimZ]

I'm wondering abut the Berryman's itself. Is it specified as "carb cleaner", or were you paraphrasing? Some carb cleaners leave an oily residue, which might have made your problem worse.

I use brake cleaner instead for this reason - it leaves no residue, and seems to work well for me.

 

[jaded93atx]

Berryman's doesnt leave a residue like Gumout- it dries out just like brake cleaner, It sure would be nice if that was the problem though.
Thanks for the thought,