Stumble, Surging and the infamous MAF, IAC, ect.

[jwrezz]

I got some pics below, but wait till ya hear this! So this evening was still nasty humid/hot. Still humming like nuts. I started her up after sitting about 1/2 hr. Pulled the wiring off, and the engine died right away. Pluged back in and started up. Pulled the black thingy off, and guess what? The whistle/hum was gone! I put my finger over the tube that the black thingy covers and it sounded like a fog horn! So I figure the black thingy is some type of bypass to let more air in; the black thingy itself is some type of filter. Right now it's partially plugged causing a slight wistle. If it were totally plugged, it'd probably sound like when I plugged the bypass/intake w/ my finger. So the IAC isn't the problem, it's just that black thingy. Any way, here's some pics.

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[fastcougar]

Great detective work! I thought that nob was for something, but never would have figured it was nothing more than a dust cover. I thought at first it was an adjustment nob to perhaps change the spring resistance, thus adjusting the closing rate of the plunger. As a result, I will be buying a new IACV this week so that I can disect this one and see exactly what is going on.

Here is a great shot of the internal workings of the IACV ... notice the plunger on the right and the "overhead" spring on the left.

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[jwrezz]

(quote)
From Ford Parts Network:
From: "Torrie R. McPhail (FPN)" <torrie@fordpartsnetwork.com>
Date: Wed Jun 05, 2002 05:33:44 PM US/Eastern
To: 'John Resciniti' <jwrezz@optonline.net>
Subject: RE: Request Form

That's what I needed :
CX-1758 Genuine Ford IAC valve $ 48.99


Plus $7 freight
To order use our secure order form.

Take Care,
Mr. Torrie R. McPhail
Owner - www.fordpartsnetwork.com
(end quote)

Good luck again, ya'll!

 

[RedBeard]

I'll be getting one of those, too. Or keep the faulty one and put some moose antlers on the hood.

-RB

 

[DonM]

Anyone know how much a new MAF goes for? It would be for a 95 XLT!

Thanks

 

[Jason_25]

Originally posted by DonM
Anyone know how much a new MAF goes for? It would be for a 95 XLT!

Thanks

Hey don, I have changed out my MAF with a reman. one from advance auto parts since talking to you last. It was $100. Make sure they get you the right one. The prefix for the 95-96 is F57F. The performance of my truck increased DRAMATICALLY. It solved almost all my problems except for the rough idle.

 

[DonM]

Thats great to here! $100 is pretty cheap too.


Don

 

[Kenneth Walsworth]

Free Fix contained within!

Up until about 3 hours ago I had this same problem. My explorer has been idling round for months. It had gotten so bad in the last few weeks that I was stalling everytime I came off higher RPMs down to idle (such as cresting a hill).
I replaced the spark plugs and gapped them to .054. I also replaced the wires because I broke one of the old ones taking it off. Well then I start it up and it idles WORSE!

I disconnected the battery.
Took apart the IAC and cleaned it and oiled the shaft with some 3 in 1.
Took apart the MAF and easy outed the security screws. Cleaned the platinum elements and replaced the screws with standard 4MM bolts.
Reconnected the battery.
Started it up again... STILL BAD!

I checked for vacuum leaks and was convinced that there was still some issue with the IAC valve.

I removed the valve again.. This time I shoved my finger in the intake side of the IAC port. I had my girlfriend start the car. I could easily throttle get the engine to idle properly by moving my finger slightly. This confirmed that I wasnt having spark or fuel delivery problems.
What I figure is that the IAC had gotten old and the coil weak or sticky and does not have enough power to close the IAC port enough to fatten the mixture at idle.

I decided to try an experiment.. I took the IAC and placed it flat on the spark plug wire box and cut out a gasket. Then where the port holes are I cut holes that were about 1/3 the area of the port holes.
I installed my new gasket and reinstalled the IAC.

I started it up... VOILA idles like a champ, actually the best it has ever idled since I bought it used 3 years ago.

I was going to buy a new IAC valve from NAPA for $85 but now I think Im just going to see how long this "fix" works.

-Ken

 

[Kenneth Walsworth]

3 Weeks later and explorer still idling great! Comes off of high rpms great also. Im not gonna replace my IAC unless problem comes back.

-Ken

 

[Fischer]

I cleaned my IAC last night, diiiirrrty lil thing. Then I did the MAS and she purrs just a tnige bit smoother than befire. Not that it was bad but I figured it takes all of 2 min to do the IAC so what the hell.

Oiled the KKM up a lil bit, changed oil, cleaned MAS and IAC w/ Gumout carb cleaner and now she is happy.

 

[unabonked]

for those of you who were still wondering, drilling the hols in the black thingy does help. make sure you drill them in between the spines on the inside. i used 5 layers of an old (but unused) paper air filter to make a new filter. works great, costs nothing and houling is gone.

 

[1mustangnut]

engine miss

I have a 94 and have been plagued with the same problem for months. I've tried several things with no luck. The fuel pump went out and the new one didn't cure it. Changing the fuel pres. reg. didn't help. Multiple cleanings of the MAF and generic K&N cone filter was not successful. The wires and plugs have even been replaced with no effect on the miss. The best result was having the fuel injectors cleaned. After 156,000+ miles, it was like a new truck for about a week.

I have the same miss at idle and a stumble around 1700 in neutral. I also get the check engine light on after a few misses at the higher rpms. The miss at idle does not seem to trigger the check engine light. The code is for low egr flow. I've replaced the egr valve and the control valve off the egr back towards the fire wall (IRC???). Ford dealer has reset computer twice and light stays off for a week. No part failure noticed by mechanics. I've reset the computer many times and the light keeps coming back along w/ the miss.

The wife blaims the Superchip but the cheap gas she burns in it doesn't help. The miss is not effected by removing chip or BBK TB.

I'll try regapping the plugs to .050 but if anyone has any other ideas let me know.

 

[duketter]

So can you drive without that black thingy on the IAC? Is that good for the engine? I cleaned mine but it stills howls a bit. I didn't know you could even pull it off.

 

[jwrezz]

This is now my second summer that I've taken it off. It just pulls off the IAC unit. It may take a bit of a tug the first time, but don't worry, you won't break any thing (I hope). As soon as the hot humid weather comes, I just take it off. I'll put it back on if I'm gonna go play in the mud, but other than that, it'll be off till Sept or Nov. good luck,

 

[Hank3rd]

Can someone please note where the MASS AIR Controller is? I am having simular problems and would like to clean it. I hope that the thread is not too old.

Thank you!

 

[1mustangnut]

It is located under the 2 special (star) head screws on the Mass Air Unit. The special bit can be obtained from any local parts store. I'm too cheap for that and was able to loosen mine with needle nose pliers and/or small flat head screw driver.

 

[Hank3rd]

Thank you! After doing some research I found it in other posts as well.

I have seen and palyed with it before, but I did not know that it was the MAF. I thought that my air cleaner was dirty/clogged and I used a rag to act as a filter and the MAF freaked out and threw the infamous check engine light on. I rest the Puter and it turned off.

I am having stalling and hestation issues. I have cleaned the IAC and the stalling is very minimal now, but I still have hesitation.

I am going to clean the IAC again, the MAF and check the spark plug gaps.

Thanks

 

[1mustangnut]

I never got around to checking my plugs, like suggested in this thread. My X has had a hesitation/miss for 2 years. I've replaced so many parts to cure it and had no luck. I've grown to except it. My check engine light comes and goes. I've been to the Ford dealership twice and they tell me nothing is wrong. They reset the computer and a week later the light is back on. Mine has 160,000 + miles and my only complaint was 3 fuel pump swaps to get one that would last.

 

[jwrezz]

Ya know what my miss (foulded plugs) turned out to be? Cracked head. Leaked coolant into cylindar 3, fouled or completely ruined a plug every 2000 miles or so. I just ordered my new heads from Doug at Performance4.0 or 4.0Perfromance or what ever that site is. Sorry. But if you're going thru coolant, check the heads. I wasn't really going thru coolant like crazy. Only putting a quart to 1/2 gallon in every few months, but it was leaking into cyl. #3. I know this is the worst possible news, but I'm already disasembled, renting a car (got a good deal though) and ready for my new heads (and cam too!) to get here!

 

[1mustangnut]

I had a head gasket go out last summer and even replaced the timing chain/gears while it was down. The chain had some slack but still didn't cure my miss problem. The heads checked out fine for no cracks and were reinstalled. I going to run it until Jan. then pass it on to another good owner. I'm going for a Mountaineer or another X with the 5.0.