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Discussion Starter · #1 ·
Hi guys!

Hubby's 96 Ranger (4.0, 5 speed, 4x4, 110,000 miles) started to develop a poor idle condition two weeks ago.  A week after that, it started to "almost stall" at intersections and would stall out if left idling in the driveway for any length of time.  It threw a check engine light a few days later.

First thing I did was replace the idle speed motor last Friday.  It's a cheap part, the old one looked like hell inside, and it had already been cleaned a few times over the last five years...probably going to need it soon anyway.

The "almost stall" at intersections stopped, idle improved, and it would actually sit & idle for five minutes or so without stalling.  The truck still didn't sound right to me.  I decided it was a good excuse to finally order that scanner I've been eyeballing.  Now I can pull the codes myself and troubleshoot the idle issue.   ;D

Scanned it today.  The only two codes I got were P0171 (running lean bank 1) and P0174 (running lean bank 2).  The fuel filter & pump were replaced in October, and the truck has no power/missing issues, so I'm not leaning toward an actual fuel delivery issue right now.

Losing two o2 sensors at the same time seems a little unlikely, so I figure that something else is throwing them off.  Some quick googling indicated issues with the temp sensor, a dirty MAF sensor, or a vac leak as the usual culprits.  I haven't opened things up to look into the intake, but I can tell you that the inside of the idle speed motor was full of black soot.

Where would be the best place to start?  Clean the MAF sensor, propane test, check temp sensor voltage?  Any input would be appreciated!

Thanks!
Missy
 

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I would check with propane/starter fluid. may also be the egr systems clogged the intake via partially clogged cat.. only seen this on an 86 buick
 

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i would try the water test,i dont like propane or any flammables.water works well too,have seen a few 4.0L's with leaking intakes,some uppers,some lowers.with the water sprayed around the manifold joints,it will affect idle,sometimes you will hear the vacum leak when it gets wet.
with both banks lean i would guess its an intake issue.
 

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I would start by removing the blue oval.
 

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Discussion Starter · #5 ·
The intake on the truck was replaced 6 years ago when it developed a leak @ 60,000 miles.  That time, the hubby warped it by letting the truck sit & idle next to the barns for up to 30 minutes at a time...several times a day.  It actually ran fine when that happened...just "howled" a lot.  Since then it has been placed on a "no idle" rule and taken out of active farm duty.  I hope it doesn't need it done again already, but I'll cross that bridge when I get to it.  At least I can get the store discount for parts at the Ford garage.  8)

When this started, I did notice that the truck would make a very short, high pitched "fweeep" noise when I punched the gas.  It didn't continue as I accelerated or anything...only if I hit the gas real quick.  When I removed the old idle speed motor, the gasket was missing and there was a slight gap where it bolts on.  After I put the new idle speed motor and gasket in place, that noise stopped.

Just as an FYI...engine temp, distance driven, speed, uphill vs. downhill doesn't make a difference.  I had all three "parts" of the EGR valve setup replaced four years ago.  IIRC, it was a sending unit, then a hose, then the valve itself or something along those lines.  I just remember we did them one at a time hoping the code would clear up with the least expensive part.

Right now I'm kind of hoping that there was an air leak, which threw everything off, made it dump fuel, and gunked up the MAF...after all the recent crap with the Alero, I need this to be simple.  I'll give it the once over on Sunday and go from there.

This is why I love my RC...it's not "bitchy" like my other vehicles.  I told the hubby last night that if  the Ranger & Alero become too big of a PITA, the worst one will be sold and the money will be put into the RC.  It's the only one that seems to appreciate being fixed, and the parts are cheaper.  ;D

Thanks guys!
Missy
 

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Here is the trick to MAF cars. ANY part of the plastic air intake hose between throttle body and MAF must be 100% sealed.

A hole there, is just as bad as a hole in the intake manifold. A professional might fill the intake manifold up with "smoke" and look to see where it is leaking, but I have yet to figure out how to make a cheap homemade smoke machine.

When my ford had done this, I searched and searched. I had a rumble. Since my car was v8, this didn't bother me so much. Had that "cam lope". Eventually found a broken EVAP canister hose. Stupid evap canister was INSIDE the fender. Meaning have to remove the outer fender and it is hidden between the outer and inner fenders. :eek:
 

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those smoke machines are awesome!
i used it often at the ford dealer to find all kinds of leaks.
i thought about building my own too.
i should have opened it up and looked inside to see what made it tick...
i have seen warped air filter housings prevent a ford from running.
dirt accumulates on the maf sensor filaments and throw it out of whack.
i have had a 50 % success rate with a goofy maf by cleaning it with brake cleaner,electronic cleaner or carb cleaner.followed with a gentle blast of compressed air.
 

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offroader_dodge said:
i have seen warped air filter housings prevent a ford from running.
Ford crown victoria amongst other things.

You have to heat some kind of oil, perhaps I could figure out how a "party fog machine" could be plumbed.
 

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if its lean on both banks it needs a new air filter and the MAF cleaned / get the MAF cleaner and NOT just carb cleaner / and yes any air leak past the MAF will cause a lean condition / after you clean the MAF you hafta reset the KAM [ keep alive memory] by disconnecting the BATT for 10 minutes / the way fords are you can FIX the problem but it will still run like it has the problem unless you reset the KAM
 

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Discussion Starter · #10 ·
s ǝoɾ said:
You have to heat some kind of oil, perhaps I could figure out how a "party fog machine" could be plumbed.
Here ya' go!

I was planning to pick up MAF cleaner, Throttle Body cleaner, and an air filter today. With all the dust on the farm, hopefully a good cleaning is what it needs. Thanks again for all the input guys, and thanks for letting me know about clearing the KAM Deano. :)
 

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Discussion Starter · #11 ·
Well, things are looking good!! :)

I unhooked the negative terminal and removed the MAF sensor/intake duct assembly. The air filter is in good shape, so I didn't need to replace it. The rubber duct had a thin layer of black soot on the inside and the butterfly had a thin coating of oil & dirt on it, so I cleaned everything up with some throttle body cleaner.

It seemed odd for his truck to have any kind of oil build-up, so I cleaned the PCV valve & breather tubes. The PCV valve was a little "sticky" inside, but the tubes were pretty clean.

All of the wires on the MAF sensor were black. It took a whole can of cleaner to get them shiny again, but they did come up. After I put everything back together, I started the truck up. It was better, but not quite right. The rough idle had become a rhythmic "lope" that swayed the truck from side to side. Now that it had a quiet low idle, I could hear a loud hissing noise near the intake.

Here was the culprit (this is after I rigged it up, of course)...



There are also a lot of small cracks throughout these lines, so I'll get some new hose at work and replace them next week.



So, it's running a lot better and I am very relieved. All it took was these items and some vac line!



Thanks for the help guys...the hubby is gonna be so happy!

Missy
 

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you can get a can of smoke from your local electric supply company... its for testing smoke detectors but I bet it would work.
 

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smoke needs to hit around 3-4 psi to really find the leaks.
another issue with the rangers is the vent line from the oil filler neck and changing oil-i dont recall what years,but if oil is poured in too fast,it fills the vent hose and when it is first started,the oil contaminates the maf.

glad you found it,missy!
 

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Discussion Starter · #15 ·
offroader_dodge said:
another issue with the rangers is the vent line from the oil filler neck and changing oil-i dont recall what years,but if oil is poured in too fast,it fills the vent hose and when it is first started,the oil contaminates the maf.
Looking at the way the hubby's early 4.0 is setup, I think his is one of them. The vent line off of the filler neck is only an inch above the valve cover, and it connects to the air duct about two inches behind the MAF. It is easy to "overfill" the filler neck on it if I'm not careful.

Hubby gave me the big thumbs up when he started it tonight. 8)

Some wives buy their husbands cards and write notes to show how much they care...I just fix his trucks. ;D
 

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good fix MISSY / it was probly the PCV sticking that coated the MAF and the vacuum leak didnt help either 
 

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Discussion Starter · #17 ·
DODGEBOYS said:
good fix MISSY / it was probly the PCV sticking that coated the MAF and the vacuum leak didnt help either
I don't know what came first on this Deano, the chicken or the egg. ;)

The PCV was good underneath, but had a bunch of black crap in the top, just like everything else connected to the intake. My theory is vac leak, black crap, pcv plug, soot & oil on MAF, rough running truck...definitely a "perfect storm" kind of thing. It's not due, but I will need to get the oil changed next week. That crap made its way into the crankcase and turned the oil black. His oil is usually clean and turns brown around the time it's due, never black...YUCK!!

I'm debating if I should pull a plug or two just to check..... {think}

Thanks again for all the help guys!!
Missy
 
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