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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 46021
Experience:  16 years experience
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Looking for help with a 2001 ford explorer 4.0 v6 sohc. xlt

Customer Question

looking for help with a 2001 ford explorer 4.0 v6 sohc. xlt 4dr 4wd
Submitted: 6 months ago.
Category: Ford
Expert:  Eric replied 6 months ago.

HI,

What do you need help on with your Explorer? Please keep in mind that I am not there to see, test or inspect your vehicle, so please provide as much detail as possible

Customer: replied 6 months ago.
the truck has 215,000 miles. I recently installed a new remanufactured engine. we replaced all the sensors on the engine with new ford oem sensors. sometimes while driving the engine stalls but the starts right back up on its own without me turning the key. I have replaced the fuel pump and the pressure is good 60psi at ilde with no drop when I do a snap throttle test. I replaced the ign coil also with a ford part. sometimes after driving it a while and you shut it off, it will start up rev to about 2500 rpm the die then it might start right back up and run normaol for a few days with no issues. so far it has not shut off while driving in about 10 days. I was going to replace the fuel pump relay but I have not yet. do know whats going on with it.
Expert:  Eric replied 6 months ago.

HI,

any pending fault codes or current fault codes?

When it does stall, does it happen at a certain speed, or is it random?

How is the idle in drive while stopped?

Customer: replied 6 months ago.
no codes and no pending codes. live data looks good, but IAT seems high to me 135 degrees? seems like random although cant be sure because it is so infreaquent. sometimes will stall at a light with foot on brake at idle. rpm is around 600 to 750. I have a new vac harness on the way cause idle is a little rough not much can barley feel it. have not put a vac gauge on it yet either.
Customer: replied 6 months ago.
I cant explain the high rpm at startup and then the immeadiate stall because it does not do it very often which is puzzling me
Customer: replied 6 months ago.
I am thinking small vacuum leak somewhere but that would not explain the stalling then starting on its own while cruising
Expert:  Eric replied 6 months ago.

HI,

Do you know what the voltage as well as resistance reading on the IAT sensor was when it showed 135 degrees

Customer: replied 6 months ago.
no my scan tool won't show the sensor output voltage. I would have to look at the schematic to figure out which sensor pins to check resistance on though
Customer: replied 6 months ago.
the maf I am using is the oem ford part but it is the original part number one. ford has made newer part revisions but cant tell me why of if it was due to an issue
Customer: replied 6 months ago.
also that was on a 90 degree day and the engine had been running so it might be possible it might be pulling in hot air I guess
Expert:  Eric replied 6 months ago.

HI,

Ok, they dont tell us the reason for the revisions either unless the part was reconfigured or new parameters for it, and nothing showing in this case.

I have uploaded the connector pinout and wiring diagram for you

What I need you to do is to get voltage and resistance readings for the IAT when cold and when warmed up and post the temp reading and corresponding voltage and resistance readings for me

Customer: replied 6 months ago.
ok if I understand correctly that is the view into the connector not into the maf right? and my understanding is I have to unplug the connector to check the resistance on the sensor otherwise the pcm circuit might or will give me a false reading ? could any of that cause cruise stalling?
Customer: replied 6 months ago.
do we leave this case open until I get back to you with the answers eric? my name is ***** ***** and thank you as you can see I have a little more than basic skills lol
Expert:  Eric replied 6 months ago.

HI,

Correct on all counts.

Yes, faulty readings from the IAT can cause stalling

Yes, just leave this open until you can get back to me with the results and we will go from there

Customer: replied 6 months ago.
ok let me go see what the actual temp is out there now
Customer: replied 6 months ago.
hi I just went out and checked a few things. both maf sensors I have show open across the 2 outer pins one was in my center console and the other one I pulled from the plenum. one shows 90 deg on the scan tool and one shows 97 deg with key on eng off. I cant measure volatage right now until i get some wire piercing ends for my leads
Expert:  Chris (aka- Moose) replied 6 months ago.

Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.

The previous tech has opted out. Would you like me to help on this possible wire issue?

This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.

Thanks Moose.

Customer: replied 6 months ago.
Hi moose Have you read up on the issue?
Expert:  Chris (aka- Moose) replied 6 months ago.

I have, were you able to monitor the fuel pressure when this occurred to confirm then the pressure was not dropping?

When you have this issue are you applying throttle, coasting, braking, or stopped?

Can you monitor the vacuum for me at hot idle?

Will your tool show short term fuel trims?

Customer: replied 6 months ago.
Have checked the fuel pressure at idle and snap throttle test 60 psi firm. No not able to see fuel p when the issue occurs. I was going to find out if they have something to hook up an electric gage so I can monitor it. It hasn't done it in a week now. Very random. Happens stopped in gear foot on brake, taking off from stop and at cruising speed. During cruising it will shut off quickly then come right back on. If I am stopped I have to restart it. Yes I can monitor fuel trims. I have 2 oem maf's and they both read open or no resistance across the iat thermistor terminals but they don't set any oat low or high codes. Are they bad?
Customer: replied 6 months ago.
I can check vacuum seemed solid on gage don't remember the reading though I'm not in the shop now
Customer: replied 6 months ago.
I can also see the iat warm up as it runs then cools at cruise seems high though 135 idling in shop
Expert:  Chris (aka- Moose) replied 6 months ago.

As of right now I am not worried about the IAT since its reading right when driving. Stopped at idle it is going to read high from the hot engine compartment. Your latest round of symptoms point more towards the vehicle intermittently losing its cam or crank sensor signal to the PCM.

Customer: replied 6 months ago.
that was my though also but doesnt explain the open condition when I measure the resistance of the iat resistor. If I lose a cam sensor sig or crank sens wouldnt I get a code? ran fine all weekend . puzzling
Expert:  Chris (aka- Moose) replied 6 months ago.

Engine codes set for things that effect the emissions. If you lose a cam signal for example and it just shuts the engine off and does not cause a misfire per say then it would not effect the emissions and store a code.

Customer: replied 6 months ago.
ok I did not know that. yes no misfire. can this be troubleshot if it is happening so infreaquently? this might be beyond what I have the equipment to find unless you have a better idea. I might have to take it somewhere. if you have an idea great if not I will gladly send you payment. thank you again for sticking with me. I wish it would just quit so it can be found lol
Customer: replied 6 months ago.
btw both the crank sens and the cam sen were replaced when the new engine went in 3000 miles ago. they were replaced with genuine motorcraft parts from the dealer
Expert:  Chris (aka- Moose) replied 6 months ago.

It is going to be hard for you and a tech to diagnose this intermittent issue. One of the first things we would try is to make it stall by moving all wiring, and fuse boxes we can get to while running to see if we can make it stall assuming its a wire concern. If that does not find it then you need to try and find if there is a driving scenario that makes it occur.

Expert:  Chris (aka- Moose) replied 6 months ago.

Hello again Chris here,

  • I am following up with you to see if you got everything you needed from my answer.
  • I have not heard back from you, so I assume you were not pleased. We're you pleased with my help?
  • If you were not pleased with my help, please let me know by replying so I can help more.
  • This post is coming up on the 7 day mark where it times out. When a post times out, that means it's no longer on my active list (you reply and I may never know it.)

Thanks Chris

Customer: replied 6 months ago.
Hi ChrisI was happy with your help just want sure if we were done. I still dont know whaat the cause is. it has been fine since our last chat. It has been fine for a few weeks. someone mentioned to me that maybe the pcm is on it's way out. they also said if it does fail there may be some kind of limp mode so it will still drive I have not heard of that one. I stll would like to find out if this MAF IAT circuit is bad. like I said before both MAF IAT's I have read open across the 2 outer terminals. not sure what to do about that.
Expert:  Chris (aka- Moose) replied 6 months ago.

Are you asking for a file from Ford on how to test the IAT and its circuit.

Expert:  Chris (aka- Moose) replied 6 months ago.

Sorry you were not pleased with my help.