Explorer is sick

[travish_1]

Hey guys, well I started my x up today and the idle was all over the place, then the ce light came on. I took it to the guys at autozone and they told me it was the MAS. I cleaned it twice and it didn't help. I cleaned and oiled my KNN filter about a month ago. Could this have lead to the problem? I can't just leave it dirty! Well... it's 80 bucks for a new sensor, but I'm thinking of just getting the performance MAS from explorer express. Will it happen again if I get a new MAS? What do you guys think about anything I said? Please, I need some input, I'm very frustrated with my X lately.

 

[jimbo74]

getting a new one would potentially solve the problem... however, with te symptoms you mentioned, there are actually a lot of otehr things i would look into as well... it could be the mas.... it could also be several other things... try to pinpoint it first

 

[Alec]

If you already cleaned it and checked for any air leaks in the system, I'd actually replace the TPS before the MAS. MAS codes can mask a TPS problem and actually O2 sensor problems as well.

A new TPS is only about $30 and is returnable if it doesn't fix the problem (if it looks clean and you might need to say it wasn't installed).

 

[travish_1]

Yeah, I just put in a new TPS to fix the hesitation that occured during acceleration. Would the computer read it if it was an O2 sensor? Also, if I bought a new MAS would the problem come back again? I don't want to spend 230 bucks and then have to replace it again

 

[travish_1]

oh yeah, how much are the 02 sensors?

 

[Alec]

About $70 each.

How long after you replaced the TPS did this problem occur?

 

[travish_1]

I put the new TPS sensor in about 2 days ago. I put the old one back in just to be sure that it wasn't defective, and it still acted up. how many 02 sensors are there?

 

[Alec]

Did you reset the computer when you put your old TPS back in? If not, try it again.

It still could be your MAS, I'm just trying to point out other things that may be wrong.

I believe your 94 has either 2 or 3 O2 sensors, but could be wrong.

 

[travish_1]

Yeah, I unplugged it for about 10min to reset the computer. Do you think the oil from the knn filter got into the MAS? That was just a thought. Well.. I was planning on getting that new performance MAS soon anyways. If that doesn't fix the problem than it's probably the 02 sensors you think? I didn't check the system for any air leaks. Where do I look for that? Do you mean the the vacum tubes? I'm 19 and just starting to find my way around in the engine compartment.

 

[travish_1]

Alright, I got a remanufactured MAS from autozone today and it did not fix the problem. The codes from my computer are 157, 158 which indicate that the MAS is defective. Yes, I did unplug my battery, yes I did replace the TPS, and I did clean the IAC. I don't think it's the O2 sensors because they don't even start helping the computer until the exhast temp reaches 600 degrees (looked in haynes manual). Any ideas?

 

[travish_1]

Oh yeah, the exhast smells like fuel when I start it up.

 

[travish_1]

Just an update:
got a new MAS today and put it in... didn't work. Reinstalled my old spark plugs and plug wires that I just put in to see if they were defective... didn't help. I'm taking it to the dealership tomorrow. I'm just too frustrated to even look at it anymore.

 

[Alec]

It's bad O2s or a failed FPR. Didn't tell us before that the exhaust smelled rich. Sorry the new MAS didn't work.

 

[AspenX]

sick

That happened on mine 2 years ago. Codes said mas and O2, replaced all and no change, codes still read same. It was the fuel pressure regulator,and never a problem since. at least with that.

 

[Glacier991]

I think the fact it's a cold startup problem eliminates O2 sensors. Short term fuel trim is only closed loop. You can simply unplug a bad MAF and let the computer use onboard tabular data to "make up" maf input. THAT can sometimes show up a bad MAF. (It will also set a MAF code however). I agree a MAF code can mask other items, but the parameters for a MAF are pretty specific. Check the cabling to the MAF - has it worn through or grounded out somewhere ? How does it run with the MAF unplugged ? I'm thinking you may have a short in the MAF wiring.

Happy exploring

CHRIS

 

[Glacier991]

I missed your codes above. (157 and 158) 157 is MAF output voltage low (some books say shorted to ground) and 158 is MAF voltage is high (some say shorted to power). That you get both is curious... are you SURE you don't have a melted cable somewhere? I'd love to know the actual voltages being read out during cold operation.


Happy Exploring

Chris

 

[travish_1]

Alright, today I took the remanufactured air filter back in to autozone and got a different one. I put it in and tried again (with my fingers crossed). Started up fine and ran fine, except my stupid hesitation is back. The guy at autozone also said that I should look into getting a performance MAS because they are designed to be used with intake kits like my KNN, this could be part of my problem. What do you guys think? Thanks for all the help.

 

[travish_1]

What does FPR stand for?

 

[Alec]

fuel pressure regulator

A 70 mm pro-m MAS from Explorer Express would help performance, but it's not necessary.