check engine light help needed
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More Turbo
Joined: Sep 2007
Posts: 552
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check engine light help needed
Hi all.. ive been working on my 97 f150 4x4. im trying to get the bugs worked out. i recently bought the truck so its new to me. she has 170k on the clock, and really runs nice, but the check engine light is determined to be on. ive reset (unhooked ground wire at battery) several times. I took the truck to auto zone and they were kind enough to run the codes. as follows.
p1131
p1151
p0401
this is what ive done so far,
removed egr and upper throttle body cleaned thoroughly (small ports were plugged with carbon) reinstalled.
I installed new plugs and wires(motorcraft)
truck runs better now, used to idle lopy in gear @ 4-5hundred rpm
now it idles smoothly @700rpm steady.
but the check engine light came back again!
i took it back in and she ran the codes again. I lost the p0401 code! so the throttle body/egr cleaning must have worked.
the girl at auto zone tends to think my other codes are from intake leaking
she said the 4.6 is prone to lower intake leaks??? I was thinking maybe the 02 sensor on driver side. Im open to suggestion
what do you all think? thanks
p1131
p1151
p0401
this is what ive done so far,
removed egr and upper throttle body cleaned thoroughly (small ports were plugged with carbon) reinstalled.
I installed new plugs and wires(motorcraft)
truck runs better now, used to idle lopy in gear @ 4-5hundred rpm
now it idles smoothly @700rpm steady.
but the check engine light came back again!
i took it back in and she ran the codes again. I lost the p0401 code! so the throttle body/egr cleaning must have worked.
the girl at auto zone tends to think my other codes are from intake leaking
she said the 4.6 is prone to lower intake leaks??? I was thinking maybe the 02 sensor on driver side. Im open to suggestion
what do you all think? thanks
Hotshot
Joined: Feb 2003
Posts: 11,537
Likes: 27
From: Long Beach, Ms.
Code definitions available here; Ford OBDII Diagnostic Trouble Codes - Overview .: Articles
Reads like an intake leak.
Reads like an intake leak.
Thread Starter
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More Turbo
Joined: Sep 2007
Posts: 552
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when i changed the plugs (autolites) they were all burning the same, very light chalky white all over the electrode area. would you think that was indicating intake trouble? would bad vacuum lines be the problem i really havent looked them over real hard some are really tough seeing in the back under the fire wall. wonder how big of job replacing the intake gaskets are? ive done my share of intakes on 289 and 302 but this is a whole new animal here. thanks for sharing!
Elder User
Joined: Mar 2010
Posts: 601
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So what is the engine vacuum ? I've never seen or heard of a tendency towards intake gasket leaks ( more than any other). The PCV line at the base of the throttle body housing, in the rear, is notorious for cracking and leaking, intake air duct work must be tight fitting, nylon vac lines/rubber end connectors split or loose. All will cause a lean code, and a lean O2 signal.
Dave
Dave
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More Turbo
Joined: Sep 2007
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Thanks Dave thats good news! I would much rather replace air/vacuum lines than have to deal with the intake removal. I will check that out tomorrow. I unfortunately dont have vacuum gauge in my arsenal, I need to get one for sure. thanks again
Hotshot
Joined: Feb 2003
Posts: 11,537
Likes: 27
From: Long Beach, Ms.
Boots; Before you buy a tool that you will use maybe once or twice a year, see if you can loan it out from a local parts store.
Balance the cost of driving to the store to pick up and return the tool against the cost of buying it.
For me it's an easy choice as the parts stores are only a mile away.
Balance the cost of driving to the store to pick up and return the tool against the cost of buying it.
For me it's an easy choice as the parts stores are only a mile away.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
The1131 and 1151 are codes for detection of excess richness in each bank.
This makes the fault common to both banks.
ANYTHING that results in the OX sensors detecting a rich condition in the exhaust gas will result in the fuel tables shifting to their extreme leans setting and generates the codes.
May seem impossible but both an excessive air leak into the intake and excessive fuel conditon can result in the same end result with the OX sensors detecting the fault in another part of the system.
Look at all the rubber parts around the intake for cracks etc.
Look for excess or lack of fuel by testing the fuel pressure.
Remember it's how the OX sensors detect the attempt by the PCM to correct the fault by shifing the tables until the codes are set ending the attempt to correct a fault it cannot correct.
Then it's time for intervention (repair).
This makes the fault common to both banks.
ANYTHING that results in the OX sensors detecting a rich condition in the exhaust gas will result in the fuel tables shifting to their extreme leans setting and generates the codes.
May seem impossible but both an excessive air leak into the intake and excessive fuel conditon can result in the same end result with the OX sensors detecting the fault in another part of the system.
Look at all the rubber parts around the intake for cracks etc.
Look for excess or lack of fuel by testing the fuel pressure.
Remember it's how the OX sensors detect the attempt by the PCM to correct the fault by shifing the tables until the codes are set ending the attempt to correct a fault it cannot correct.
Then it's time for intervention (repair).
