Have a follow up question.
If I disconnect the wire going to the IAC, what should the idle be? I noticed it dropped to about 840 rpm.
There is also an idle adjustment. I read on a forum, one must start the engine, remove the wiring to the IAC, then adjust the idle until 400-500 rpm is reached.
Can you comment on this also?
Could use your help again.
I looked all over and can not find the pvc tube. I also sprayed carb cleaner and did not notice any idle change.
The fan on the motor, I noticed it increased and decrease in speed. Is this normal or also related to my vacuum issue?
I recently purchased the vehicle. I removed the air cleaner element, looked fairly cleaned, but I blew it out with compressed air. Do you think this is related?
Also, I recently changed the transmission fluid. Drained anf filled via the fill tube. Just tought it's worth mentioning.
I see one tube from each valve cover.
One tube goes to a large black tube, that goes to air filter.
The other tube connects close to the IAC.
I do not see a PCV valve. Is this vehicle suppose to have one?
I have a service tachometer.
Want to make sure I have it on the correct setting
Which one is the correct setting?
1 Spark plug fires twice per revolution
2 Spare plug fires once per revolution
3 Spark plug fires every other revolution
Ok, I believe I know what tube this is. Has a bunch of foam/insullation around it.
I took a look at the PCV tube, removed it and thoroughly check it for cracks or breaks. Looks fine.
Thank you for the bulletin. I did spray and did not notice and idle change.
How can I accurately measure the RPM?
I have an inductive type of that wraps around one of the spark plug wires.
Here is the VIN, 1FTRF17203NB31651
Since I purchased the vehicle used, is there a way to find out if the service bulletin you sent me has been performed?
I could be mistaken here, but, prior to cleaning air filter, I do not recall having this issue, but I am not completely sure as I recently purchased this vehicle.
Couple more questions.
The IAC, if I turn on the ignition, engine not running, should I see the IAC pluger move?
Where is the OBD port located? Do OBD devices measure RPM?
Have a few more questions.
When the vehile is running, I reach into the engine compartment and manually pull on the accelerator. By doing this, I notice the engine runs high for a few seconds, then the idle drops back down. Is this normal or should it drop down immediately?
So, back to original issue. I noticed tonight, the vibration only occurs when the engine is warmed up (normal operating temperature), brake is applied and the vehicle is in drive.
Is does not occur when the vehicle is first started or within the first 5 minutes.
With this new information, do you have any other thoughts?
Thank you for all your updates.
It does not vibrate in neutral or park.
Ok, think I am going to order th gasket and replace it.
Where you located out of?
I will most likely replace the gasket and bolts sometime next week.
Last night, I cleaned the EGR. Did not look bad.
I also removed the throttle body and cleaned it again. Wanted to clean the flap and check the insides again. It is not thoroughly clean.
Did not have any change with the vibration in drive.
Good suggestion on the comparison. Hopefully I can find one to take a look at.
I am thinking about replacing the spark plugs and air filter today, since I really do not know the history. Anything else you recommend since it has 75k on it?
Do you have a service/maintenance interval guide that you can send me?
Thank you for all your help. I will soon have this all figured out.
Would like to send you some more money since you have been most helpful.
What do you thnk is a fair price?
The truck did not come with any manuals.
I found an electronic copy of a 2003 owners manual, but did not have any service guide.
Do you think I should replace the spark plug wires and cap?
I did not see anything for this in the schedule. Only the spark plugs.
Here is an update.
I have replaced the spark plugs, gapped them to .054".
Replaced the air filter
Cleaned the MAF
Since I really have not driven the car much, I decided to take it out for an hour today. I noticed after about 10-15 miles, it did not happen.
I also noticed that if I turn off the vehicle after driving it for a while, then wait for a few mins, then start and drive vehicle, it would not happen.
I will eventually change the intake gasket, but wanted to privde you more information.
I have some vacuum gauges, any idea on what the vaccum should be at idle? Where would I plug the gauge into?
Hope to replace it this week then. I have been learing much about this vehicle, it has been a fun project.
While I have the manifold apart, anything else worth replacing or inspecting?
For the rear differential, they call for a 75w140 gear oil. Do you suggest I replace it?
Will pick up gasket and bolts this evening.
Any other gaskets worth replacing sine I have it apart?
Wanted to provide you an update.
Purchased 6 intake port gaskets, 8 bolts (green) and the upper intake gasket.
Removed the intake last night and replaced the 6 intake gaskets and 8 green bolts. The lower intake was dirty, especially by the front 2 ports. All the gaskets were dirty on both sides. I cleaned the entire housing and the ports.
I need to install the intake cover with the 10 (or 12) bolts. Do you know what the correct torque setting should be?
I also used a wooden skewer stick and cleaned out the 6 EGR ports.
Really hope this fixes the issue.
Put it all back together, same issue.
What should I do next?
Back to the IAC. I checked and there is 11.79 volts at the connector, engine off, ignition ON.
I removed the IAC and did not see the plunger move when I plugged in power. Is it suppose to?
Battery was disconnected when I replaced the manifold gaskets.
I tried another new IAC and it had the same behavior.
I removed the IAC to see if the plunger moves when I turn on the ignition, and it does. It has the same behavior as the old and new. It moves about 1/8" open for 2-3 seconds, then closes. I hear a "click" noise in the IAC when this happens.
I did unplug it as the engine was running, the RPM stayed the same, no change.
Also, keep in mind, I am not driving the vehicle, I start it, wait for it get to normal temperature, then place the vehicle in drive or reverse.
Replacing the gaskets I believe did help, but the vibration still persists.
I believe it is idling fine. But, I can not be sure what it is idling at? My gauge shows 620. But, not sure how accurate it is. Any idea on what I can use to accurately measure the idle?
Ok, I will try the idle screw this evening.
Back to the transmission fluid change. It was removed from the dipstick, filled, then engine was run and gears where changed. Then fluid was removed again, then filled.
My memory could be wrong, but I believe I noticed it after the fluid was changed.
Does the new fluid have to "break in" or something like that? I have read something to the affect, that trans fluid changes could cause issues. Maybe by putting the vehicle in drive, the torque converter is not engaging properly at low idle?
Do you think replacing the fuel filter would help?
Could this be a possible cause?
Could it be a bad fuel injector?
How can I check them?
Got a good injector cleaner, maybe this will fix it.
I played around with the throttle plate screw. Backed it all the way out, very slight change in RPM. Took it for a test drive, actually vibrated worse, so I put it back to where it was.
Question. I disconnected the tube going into the PCV valve. It has very good suction. By doing this, I noticed there was no change in RPM.
Another question. I noticed I get some water out of the exhaust. A few drop or more. Is this normal? I notice to collects at the end of the tail pipe.
I disconnected the MAF. Started the engine, inital RPM is 850, then over the course of 1 minute, dropped to 620, car was in park.
I reconnected the MAF, started engine, inital RPM is 850, then over 1 minute, it dropped to 620 again, car was in park.
For both tests above, I disconnected and connected the MAF when engine was off, did not disconnect battery.
Any thoughts on this?
I assume I do this with the engine running?
Could it be a problem with the PCM?
Is there a way to reset the ACM?
Here is the latest. I turned up the throttle about 1 full turn. Idle is now 700.
When placing it in drive, it idles is now 550. Much better, vibration is pretty much gone. I do hear a ticking noise though, when I press the accelerator slightly, it goes away.
So, how can I be sure the idle screw is set correctly?
I am going to compare the vehicle idle to another one this weekend. In speaking with the person, sounds like the behavior is common.
If you don't mind, I have a steering question.
When driving I noticed I have to make slight adjustments, left and right, with the steering wheel to keep it driving staight. I have replaced the tires and the alignment is dead on.
I did not see any play in the tie rods or ball joints.
Any ideas on what it could be? Does the steering box have a worm gear that can be tighetened up?
Still playing with the vehicle.
I noticed I am getting water and black soot from the tail pipe and from other parts of the exhaust, cat converter and where some of the pipes join.
Is this normal? What causes this?
Also, I measured the TPS, at idle, it is 1.0 Volts at 700 RPM.
If I disconnect the IAC, there is no change in the RPM. I did the ohm test and it looks fine based on what Chiltons tell me it should be.
Ok. I will take a look at the TP voltage. To adjust this, do I need to disconnect the IAC or it does not matter?
I think if I adjust this, the RPM may be too low, it is current at 700 RPM at idle.
Hi Juan, Ok, here is the latest.
I set the TP sensor to exactly 0.95 volts.
I decided to look at the IAC again.
(Ignition on, engine not running) I removed the IAC with the harness still attached and back probed the connector. I noticed there is no voltage. I do get volatage if I disconnect the IAC, it is around 11.8 volts.
I then did the following:
Removed negative battery connector
IAC with harness attached and back probed into harness, volt meter attached
Attached negative battery connector
Checked voltage, jumped to 12 volts and I see the IAC plunger moved 1/8" for 2 seconds
Then voltage dropped to 0 volts and plunger closed
Is this information helpful?
Next I will check voltage with engine running.
Here is another update.
After changing the TPS to 0.95 volts, the idle in park is 600 RPM.
With the engine running, I removed the IAC wiring harness, it showed 14.4 volts. When I unplugged the wiring harness, there was no drop in RPM. When I plugged the harness back in, there also was no change in RPM.
I then backprobed the wiring harness for the IAC. At 600 RPM, it showed 2.8 volts.
If I increased the idle to 2000-3000 RPM, the IAC voltage dropped to 1.8 volts.
Any of the information helpful?
Brought truck to shop today. They could not find anything wrong. Turns out, my tachometer was not correct.
At idle, based on the OBD port, it is 800. In drive, it is 620.
All the sensors checked out fine.
The noise may be coming for the exhaust or the engine mount.
I spent some time under vehicle, engine running and in drive (had to trust the wife with this one). I did not see any broken engine mounts or broken exhaust hangers.
I did see the exhast muffler vibrate some. I could pull the exhaust either left or right, and it did make the vibration less.
Also, I noticed a pinging noise just below the right side exhaust manifold, near where the catalytic converter. Could I have a bad oxygen sensor?
Ok, hope to look in the next day or 2.
Any idea on why this would happen when vehicle is at normal temperature?
I purchased a AutoLink OBDII reader. See below results, I am curious what you think.
TP (Absolute Throttle Position) % is 19.2
O2B1S1 (Oxygen Sensor, Bank 1, Sensor 1) fluctuates between .10 thru .745 volts
O2B1S2 (Oxygen Sensor, Bank 1, Sensor 2) .785 volts
O2B2S1 (Oxygen Sensor, Bank 2, Sensor 1) fluctuates between .08 thru .750 volts
O2B2S2 (Oxygen Sensor, Bank 2, Sensor 2) .675 volts
SHRTF1B1S1 (Short Term Fuel Trim Bank 1, Sensor 1) % fluctuates between -3.1 thru 2.3
SHRTF1B2S1 (Short Term Fuel Trim Bank 2, Sensor 1) % fluctuates between -3.9 thru 2.3
Took a break from the F150. Will get back to it this week. I will "neutralize" the exhaust, probably tomorrow night.
Just to confirm, do you believe 620-640 RPM in drive is correct?
Took a look at a 2003 F150, V6, 4.2L, 118k miles today.
Have some updates for you. All the measurements I gave you match the vehicle I checked out today (throttle position sensor, O2 sensors, engine RPM in park and in drive are identical).
The vehicle with 118k, did not have any vibration that I am experiencing.
Here is the only difference.
If I unplug the IAC on the vehicle with 118k miles, the engine drops to 520-550 RPM.
If I unplug the IAC on my vehicle, there is no RPM droppage.
I am going to swap IAC and see how the truck reacts.
I took my IAC and placed it into the vehicle with 118k miles. Appears my IAC is working fine. If I unplug it, then the idle dropped to 550 RPM in the vehicle with 118k miles.
I have peace of mind that my IAC is fine.
So, wondering why when I unpug the IAC on my vehicle, the engine RPM does not drop.
Have another question, could it be something with the transmission/torque converter at this point? Maybe the torque converter is engage at a lot RPM when it should not be?
Anyway to check this?
Ok, I will take a look this evening. I do not believe I have a read out for IAC duty cycle.
Also, when checking, should I have the vehicle in park or drive?
Both Long Term Fuel Trim Bank 1 and Bank 2 had the same readings. It started out at 0.0 and stayed there for about 5 minutes, then moved to 1.6, then to 3.1 at operating temp. If I press on the accelerator, it would decrease to 1.6 then 0.0, then back up to 3.1. I did this in both park and drive, same results.
I do not have a reading for IAC duty cycle.
I did unplug the IAC again, no drop in RPM at all. I thought about removing the IAC and blocking both ports in the manifold and see if it makes a difference. Any thoughts?
Inside the engine compartment, if I press the accelerator with my hand, I hear a big sucking sound, I think this is normal since the engine RPM is increasing and it demands more air. Although, the engine tends to "run-on" for a few seconds.
I decided to measure the vacuum. It is 19 in HG, dead on, no fluctuation. According to Hayes manual, should be between 17-22 in HG.
I snapped the throttle open and closed quickly, vacuum dropped to 0, the jumped to 23, then after 4 seconds, back to 19. So, I think the vacuum should be fine.
Here is something interesting though. When I placed the vehicle in drive, the vacuum dropped to 17. Is this correct?
Thanks, XXXXX XXXXX a nice Thanksgiving.
I blocked the IAC port, started the vehicle and it idled at 800-830 rpm. I did not press on the accelerator.
Hope this information is helpful.
I am at a complete loss on what to do next.
Thanks Juan, will check it out on Friday and post my findings.
Sorry this is taking soo long to resolve.
Do you have a cell phone? If so, who is your service with? I work for AT&T, let me know if you need anything.
Here is the latest.
I plugged the PCV (PCV still attached as there is a coolant that runs thru it), plugged the brake port and the port in front of the brake port, IAC wire disconected, still ran at 800 RPM.
While running, I removed the air filter snorkel going to the throttle body, it ran rough for a second then died.
Here is what I also noticed, with the IAC wire attached, I would start the vehicle, then immediately removed the IAC wire, the idle would drop. If I attached the wire, it would ramp up. After about 2 mins, unplugging or plugging in the wire for the IAC has no affect. This is the same regardless if the vechile is warm or cold.
Any of this information helpful?
I took the day off today. Anything else I can check today on the vehicle?
I have a voltmeter and can pin probe the TP harness. Will this work? It is currently set to .95 volts.
The ODBII device can read absolute throttle position as a %, currently set to 19.2.
Here is the latest
Engine off, I loosened the screw where it did not touch plate, lowest reading is 0.89 volts, would not go any lower. I then turned in screw until I reached 0.90 volts.
I then removed negative battery terminal for 15 minutes.
Intalled battery terminal and started vehicle, once warm, idled at 830, same as before.
I then removed the IAC harness, idle dropped 100 RPM, approximately 700-730. I then installed wiring harness and it jumped to 1000+ RPM, then settled back to 800-830 RPM.
I then placed vehicle in Drive, got a lot of vibration.
Where do I go from here?
Have another update. I think we are close to getting this figured out.
Took vehicle for test drive, once it warmed up, there was much vibration in the engine, where I felt it in the vehicle, the original problem I am trying to solve.
I then turned off igntion, started it immediately back up, placed it in drive (break applied, vehicle not moving), no vibration until 60 seconds later. I have done this 3 times and the pattern is the same.
Does this information help?
Here is an update. So, I bumped up the throttle just enough where the vibration goes away and reset computer.
Huge difference. In park, idle is 880-830, in drive idle is 680-730.
The absolute throttle position is 19.8 %. The throttle position voltage is 0.98
Any thoughts based on these readings?
Want to spend you some more money for all the time you spent on this.
Have another question. I believe I have a slight oil leak on the oil pan rear seal. Is this a common problem? I have the 2WD, do I need to remove the support to remove the oil pan?
Just sent you a few more bucks. Please take a look at my questions from the other day.
Here is the procedure. It tells you to pull the motor, but if you have a soft rubber gasket. Then you can just drop the pan and cut the old gasket out and kinda stretch the new gasket around the oil pan to get it where you need it.
Oil pan procedure<-----click
I will send you all the reading I get off the OBDII device in the next day. Can you take a look and let me know what you think?
For the readings, should I give them to you while vehicle is in Park or Drive?
If you have an email, I can send you the spreadsheet I am putting together.
Ok, here are the readings with vehicle in Drive, vehicle not moving.
Let me know what you think or have any concern.
Ok, I will keep it as is and just keep an eye on it.
Thanks for all your help.
I will be in Orlando next week.
Thought about bringing vehicle to you to check out if you have an interest.
Ok, that would be great.
Do I need to setup an appt with you?
Pls send me address or dealership name to I can map it out.
I will be driving to Orlando on Monday to see my parents. I would be willing to stop by your dealership if you have time to do some further troubleshooting. You mentioned there are other tests that could be run, like duty cycle for IAC. I am sure your dealership has more advanced diagnostics tools than I?
I would drive down to Tampa on Tuesday morning, Dec 15th if that would work for you. Let me know as I would make this trip if you are available.
That would be great.
Send me a time and I will plan accordingly.
Hope you had a nice weekend.
I am still on schedule for tomorrow. Should be there around 9:30 or 10.
Just spoke with the dealership. So far, they claim that the vibration is from the motor mounts. They are still investigating.
But, if I turn off the vehicle, start it right up, no vibration until 2 minutes later, so, do not think this is the motor mounts.
They also claim they are not seeing a high duty cycle. Any thoughts on this? Anything specifically I need to tell them to look for?
Here is the latest. They could not definitely determine what the issue is, PCM or not. The are keeping the vehicle over night and will take another look tomorrow morning. They want their foreman to take a look tomorrow as he is off on Mondays.
They also said, Ford will not let them replace the PCM unless they have hard evidence that this is what the issue is.
Hate being caught in the middle.
Anything else you can suggest I could push forward with? This is why I hate bringing vehicles to the dealership.
Well, picked up vehicle, they could not determine the cause and stated a engine mount and something else causing the vibration, they felt still not enough info to determine it is a PCM issue. I did not speak to the service tech or foreman as they were out on lunch. May give them a call. I do not believe they spent much time on this.
I am going to take it to another Ford dealership next week.
Hope you had a nice Holiday.
I am taking truck over to Gwinnett Place Ford in Duluth today.
I have been speaking with the service manager about the vehicle.
Lets see what hapens.
Johnson Jackson is the service manager at Gwinnett Place Ford, just in case he calls you, but I do not hink he will. Spoke to him a couple of times. He is ordering a PCM. Will probably be installed early next week. So, I picked up vehicle until they have the PCM.
He made a couple of comments and felt it may not resolved the issue, but he is willing to give it a try. He said he would carefully unwrap the PCM and install it, worst case he would send it back.
So, my question is, if this does not fix the issue, any thoughts where I go from here? Sell it? Junk yard? :)
Probably a good idea, not sure I will have time next week to do this.
Can I mark the PCM or do something to ensure the old was removed? Maybe mark a cable or screw/nut with paint or chalk to ensure they removed it?
Hope you had a nice New Years.
Ford called and the PCM has arrived. Will be dropping off vehicle to have them install it. Unfortunately, I do not have the time to spend with them.
Hope this fixes the issue.
Here is the latest. Dropped off vehicle last night just before they closed.
They called me the morning, said they installed new PCM and it is all fixed. Will pick it up this evening and let you know.
Sounds too good to be true.
Looks like it is all fixed.
Would like to send you a copy of the invoice and see what you think.
One items states:
78775 P1506 INTERNAL PCM MALFUNCTION EEC TEST DCL MONITOR INJ FLOW FUEL PRESSURE LK DN POWER BAL RELATIVE COMPRESSION & PIN POINT TEST REPLACED PCM RETEST OK
Does the above statement indicate a fuel injector problem? Not really sure how to read the invoice.
Here is what I copied from the invoice.
CAUSE: 78775 P1506 INTERNAL PCM MALFUNCTION EEC TEST DCL MONITOR INJ FLOW FUEL PRESSURE LK DN POWER BAL RELATIVE COMPRESSION & PIN POINT TESTS RE
12650D EEC (QUICK TEST) - DIAGNOSIS - L 97241 WF 1 2L3Z*12A650*ADC MODULE - ENGINE CONTROL - EEC CORE CHARGE W -1 2L3Z*12A650*ADC CORE RETURN
12650D6 POWERTRAIN CONTROL MODULE (PCM) - REPLACE (12A650/12B565) - L 97241 WF
12650D45 EEC SYSTEM - DIAGNOSTIC PIN POIN TEST - L 97241 WF
12650D47 RELATIVE COMPRESSION/POWER BALANCE - TEST - L 97241 WF
12650D84 PCM REPORGRAMMING - TEST (RECAL) - L 97241 WF
12650DX1 EEC (QUICK TEST) - DIAGNOSIS - L EXTRA TIME TO REPEAT FINAL QUICK TEST 97241 WF
FC: E29 42PART#: 2L3Z*12A650*ADC
78775 P1506 INTERNAL PCM MALFUNCTION EEC TEST DCL MONITOR INJ FLOW FUEL PRESSURE LK DN POWER BAL RELATIVE COMPRESSION & PIN POINT TESTSREPLACED PCM RETEST OK
B MULTI POINT INSPECTION 99P MULTIP POINT INSPECTION 97241 WF
Well, I guess I am done with this project for now.
I want to thank you again for all your help and sticking with me on this one.
How can I post a recommendation for you?
Give me a shout if you are ever in the Atlanta area.
It has been a week, and have 250 miles since the new PCM has been installed. The issued has surfaced again as of last night.