Need Help With P1506 troubleshooting - Taurus Car Club of America : Ford Taurus Forum
 
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post #1 of 5 (permalink) Old 03-20-2017, 09:29 PM Thread Starter
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Need Help With P1506 troubleshooting

Hello! Also having trouble pinpointing trouble with this code..

New to me 2003 125 mile Sable Duratec OHC idle high in general [1050 to 1100 – can vary to 1125 to 1175 after driving a while]and on rare occasion will go way up as stay up 2500+ [P1507 code]. This 1050+ seems high to me as expect 1k or below in neutral. Will go to 1000 down to 850 or so in gear no always same.

Initially, I replaced TPS (motorcraft) and IAC (aftermarket). TPS seemed to help a bit but had to return aftermarket IAC (crazy high rpm) and decided to clean old IAC and it works smoothly by hand [pics]. Researched threads and am now focusing on PVC valve, vacuum leak, or cleaning throttle body.

PVC - PVC seems like headache to get to and mine was replaced at 93k tune up by PO. Hoses look OK and from other threads may even be better aftermarket elbow at intake end. [See pics].

Intake leak - I hear no vacuum leak and inspected lines/hoses OK. I am puzzled by what appears to be slow oil leak by one of intake bolts [pic]. Could this be sign of vacuum leak issue?

Throttle body [TB} – I got ELM 327 reader and torque app and got error P1507 (engine light) and have been tracking idle and decided to turn down idle screw (initially showed 18% at closed) and got it to 17.8% only and but idle RPM still high per above. When I first checked TB seemed to snap down sharply and not stick. I decided to turn screw out way further (not running) and detect a bit of sticking at very bottom (previously had and fixed this issue with cleaning carbon on my Caravan). Could this be the idle problem ?? Seems not with rare running way up. ALSO - WHAT IS THAT OPEN HOLE AT TOP OF TB? Initially thought missing bolt but see channel inside of hole - air for IAC or just blank hole?? [pic]

ADVICE?
Throttle Body - Based on above looking for some advice before next move. I am thinking I could remove the ducting to throttle body and clean carbon from there to see if I can get lower stop point without any sticking. Could this alone be causing the idle problem (torque app shows 17.8% throttle position at idle now)??

At that point I would have some access to replace the PVC valve but that still looks hard to get to. Will a socket actually reach that PVC valve. Have seen some utube using needle nose or just hose end for remove and replace but would that work (do not want to remove intake)? If I do decide to replace WILL only get Motorcraft for a new PVC valve but am even confused on the various maker plumbing parts available and not sure of correct Motorcraft part.

Lastly – should I be concerned about that minor oil that I see by intake bolt as sign of potential vacuum leak [pic]. Not a lot of oil but dampness returns and I also saw some oil down further on inner side of manifold when looking for PVC - hard to say on source. No vacuum leak sounds.

Thanks for any advice!
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post #2 of 5 (permalink) Old 03-21-2017, 07:29 AM
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17% to 18% is typical for closed throttle TPS%. NEVER EVER mess with the idle stop screw!!!! It is correctly set at the factory.

P1506 is IAC overspeed error, meaning the IAC cant control idle speed. PCV could be worn and letting in excess air, or you have a vacuum leak. What are LTFT values at idle for each bank?

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post #3 of 5 (permalink) Old 03-21-2017, 07:50 AM
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Quote:
Originally Posted by Jeff K View Post
17% to 18% is typical for closed throttle TPS%. NEVER EVER mess with the idle stop screw!!!! It is correctly set at the factory.

P1506 is IAC overspeed error, meaning the IAC cant control idle speed. PCV could be worn and letting in excess air, or you have a vacuum leak. What are LTFT values at idle for each bank?
Might I add?

Possible causes
  • Faulty Idle Air Control (IAC) valve
  • IAC valve harness is open or shorted
  • IAC valve circuit poor electrical connection
  • Intake leaks
  • Stuck PCV Valve
From the search engine, first one at the top. You can put any code in a search engine and get lots of discussion.

To idle too fast, it MUST have too much air. Anything that could let too much air enter the intake. My experience, PCV aftermarket brand really bad. Old one stuck closed and very slow idle. New one from Autozone had idle way too fast. On DOHC, the pcv is a pain but it can be done with some effort.

And then, anything that can let too much air in. Cruise cable or throttle cable not letting the throttle plate close all the way. Vacuum leaks. Start with the visible, any hose loose, off, leaking that goes to the intake.

Best of luck.

-chart-
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post #4 of 5 (permalink) Old 03-21-2017, 02:55 PM Thread Starter
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Thanks for replies. Having rain most of week here so may not be able to work on car to get readings or look further.

Unfortunately, my bad, I already did monkey with idle stop screw. I've already done the visual and ear checks for vacuum leak and have not found any. I may carefully try some spray in area near that oil seepage on manifold to detect leak, and probably need to think about replacing that PVC just to rule that out even if a pain to get to. Car new to me and only thing I can see on records is at 85k shop did checks on "rough idle" and did checks that indicated to them vacuum leak "P0171 P0174 system lean codes" at that time. They found "damaged hose - replace "pvc assembly" 68.45 part and 90 labor. Even if replaced could be bad and not sure if Ford or what brand. I did also notice complete inspection dealer work done at 93k including tuneup, IMAP sensor cleaning, ect.. I am going to stick with Motorcraft parts for PVC, IAC or any other.

I will see about getting readings when weather permits work under hood. Thanks!
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post #5 of 5 (permalink) Old 03-21-2017, 05:45 PM
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Quote:
Originally Posted by MARKU View Post
Thanks for replies. Having rain most of week here so may not be able to work on car to get readings or look further.

Unfortunately, my bad, I already did monkey with idle stop screw. I've already done the visual and ear checks for vacuum leak and have not found any. I may carefully try some spray in area near that oil seepage on manifold to detect leak, and probably need to think about replacing that PVC just to rule that out even if a pain to get to. Car new to me and only thing I can see on records is at 85k shop did checks on "rough idle" and did checks that indicated to them vacuum leak "P0171 P0174 system lean codes" at that time. They found "damaged hose - replace "pvc assembly" 68.45 part and 90 labor. Even if replaced could be bad and not sure if Ford or what brand. I did also notice complete inspection dealer work done at 93k including tuneup, IMAP sensor cleaning, ect.. I am going to stick with Motorcraft parts for PVC, IAC or any other.

I will see about getting readings when weather permits work under hood. Thanks!
The throttle stop is to be set, as closed as you can get without it not sticking when closed. The PCV can be removed with the method shown in my pic, this is a '01. It also looks like you can remove the air cleaner main box and the throttle plate and reach it through that way. I had to remove the air cleaner box to do a hose and it looked like you could reach in that way. Pic of the tool I used. The PCV turns half turn CCW to unlatch and then pull out. Hose from PCV to the hard plastic line is just friction fit.

-chart-
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