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  #1  
Old 10-15-2017, 05:30 PM
Grubb44 Grubb44 is offline
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Default P0401 this is KILLING ME!!

Ok, 1997 ford ranger 2.3 with a 5 speed. New motor. Got most of my codes cleared up but this one is pissing me off.

When the truck is COLD and I start it, idle comes up then down as normal. Then it sounds like it's missing for a min or 2 then it goes away and runs fine. Code popped is P0401. Pretty vague. Any ideas why the truck sounds like it's missing only when it's cold? I'm tired of racking my head over this. Anyone ever had these symptoms before? Thanks in advance!!
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1997 Ford Ranger. 2.3ltr 5speed. Ext cab. 2 wheel drive
1998 Ford Ranger 3.0 V6 5speed Ext cab. 2 wheel drive
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  #2  
Old 10-16-2017, 02:59 AM
EaOutlaw1969 EaOutlaw1969 is offline
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Default Re: P0401 this is KILLING ME!!

Do you have a new motor or used engine or rebuilt engine?

Your choices are to get a factory service manual and diagnose the trouble code with the appropriate pin point test for the trouble code, or you can play games with your truck and toss parts at it and hope for the best.

Many problems like this may have a easy to accomplish magic part that fixes a high percentage of vehicles with the same code and you may get lucky and have a member here provide you with the exact part you need to cure your problem.

Yet to avoid further delays, frustration and wasted money I highly suggest performing the pin point test.

here is some generic information on the code

http://www.myautorepairadvice.com/p0401.html
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  #3  
Old 10-16-2017, 04:44 AM
Grubb44 Grubb44 is offline
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Rebuilt motor. All new insides and new head. Block and intake are pretty much the only original parts besides a lot of the sensors.

What is a pin point test? I don't believe I've heard of it or heard of a test called that? Thanks.
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1997 Ford Ranger. 2.3ltr 5speed. Ext cab. 2 wheel drive
1998 Ford Ranger 3.0 V6 5speed Ext cab. 2 wheel drive
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  #4  
Old 10-16-2017, 06:38 AM
RoberticusMaximus RoberticusMaximus is offline
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Default Re: P0401 this is KILLING ME!!

have you inspected the egr components? assumming so, sounds like you were involved in the rebuild?
and have you reset the code? i'm curious as to when exactly the code is popping up.
seems like two separate issues to me. but yeah, don't throw parts at it, it could get very very expensive

Last edited by RoberticusMaximus; 10-16-2017 at 06:40 AM.
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  #5  
Old 10-17-2017, 04:56 AM
EaOutlaw1969 EaOutlaw1969 is offline
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Default Re: P0401 this is KILLING ME!!

Quote:
Originally Posted by Grubb44 View Post
Rebuilt motor. All new insides and new head. Block and intake are pretty much the only original parts besides a lot of the sensors.

What is a pin point test? I don't believe I've heard of it or heard of a test called that? Thanks.
A pin point test is a series of test that are completed because of a symptom or stored trouble code or both.

It is a series of diagnostic test done in order that lead you down a diagnostic flow path.

As you perform each test you get closer and closer to the exact cause of the problem.

For example if you had a no start problem you would check compression, fuel pressure , spark etc.

Once you know what is missing you use the appropriate pin point test to help you diagnose the problem.

Without these important test procedures you may as well buy a magic wand and start chanting at the truck. LOL

Since your not a mechanic or technician by trade you my find yourself getting lost with some of the terminology or wiring diagrams etc in these pin point test, but this is where we can help effectively by guiding you through each test as you need help.

Sure I could say test this or test that or even just replace a part yet we would not be doing you any favors even if it fixed the problem.

I think to help you we will need more information.

First off the problem with the way the engine runs I think has nothing to do with your current trouble code.

I think you have more than one problem and perhaps you have not driven the truck far enough to trigger other codes that may be pending.

I would start by double checking all the work that has been done, especially if the current issues you are having did not exist before the engine was replaced.

Also it would help if you wrote everything you can about your truck and what has been done to it so far.
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  #6  
Old 10-18-2017, 06:30 AM
Grubb44 Grubb44 is offline
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I have reset the code, roughly 2 days it pops again. 1,300 miles on new motor. During reassembling the motor I called the intake where the EGR feeds to. Was clogged up BAD. In my previous experience with this motor if it was truly missing it would throw a misfire code. Not a P0401. And it literally idles like that for only a min or 2 then goes away. And only when it's cold. I've even let the code sit for almost 2 weeks and no other code gets popped.
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  #7  
Old 10-18-2017, 07:16 AM
RoberticusMaximus RoberticusMaximus is offline
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Default Re: P0401 this is KILLING ME!!

hmmmm if the intake (post egr valve) was caked up, then there's a chance that either the valve is no opening because of build-up or the DPFE hoses are clogged. Either case, the DPFE will send an unexpected voltage back to the computer. hence the p0401.
just thinking out loud. you would have to verify if this fits your situation of course

----------

and insufficient egr flow will by no means cause a rough idle ... excessive flow would though lol! i'm still thinking that its a separate issue. really hoping to see the resolution on this!
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  #8  
Old 10-18-2017, 11:33 AM
Grubb44 Grubb44 is offline
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I have a family friend who works at ford ask someone. He's a mechanic for ford but is gunna ask one of the tech guys.

----------

Also I have already replaced the DPFE. Rough idle at startup started when I got the motor put back in if I recall. I'll try and get time soon to check over the DPFE hoses though. I believe they run to the egr tube.
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  #9  
Old 10-18-2017, 12:01 PM
RoberticusMaximus RoberticusMaximus is offline
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Default Re: P0401 this is KILLING ME!!

yeah, the hoses run strait to the egr tube. take some thick weedeater line and see if you can push anything out of the hoses as well as the ports on the egr tube while your down there
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  #10  
Old 10-18-2017, 06:08 PM
stateranger stateranger is offline
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Default Re: P0401 this is KILLING ME!!

Quote:
Originally Posted by RoberticusMaximus View Post
hmmmm if the intake (post egr valve) was caked up, then there's a chance that either the valve is no opening because of build-up or the DPFE hoses are clogged. Either case, the DPFE will send an unexpected voltage back to the computer. hence the p0401.
just thinking out loud. you would have to verify if this fits your situation of course

----------

and insufficient egr flow will by no means cause a rough idle ... excessive flow would though lol! i'm still thinking that its a separate issue. really hoping to see the resolution on this!
You can have insufficient flow at opening rpm but some flowing at idle without setting the excessive flow code off if the egr is caked with junk. The 0401 code could also be a bad dpfe plug like me and you had.
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  #11  
Old 10-19-2017, 06:26 AM
RoberticusMaximus RoberticusMaximus is offline
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Default Re: P0401 this is KILLING ME!!

Quote:
Originally Posted by stateranger View Post
You can have insufficient flow at opening rpm but some flowing at idle without setting the excessive flow code off if the egr is caked with junk. The 0401 code could also be a bad dpfe plug like me and you had.
i've been thinking about that, if the plug had a short or burnout between different leads...several possibilities on that alone!
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  #12  
Old 10-19-2017, 06:38 PM
Grubb44 Grubb44 is offline
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Thank you guys! I'll check the hoses this weekend. How would I check for a short in the plug?
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  #13  
Old 10-19-2017, 06:51 PM
RoberticusMaximus RoberticusMaximus is offline
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Default Re: P0401 this is KILLING ME!!

Probing the leads for continuity is probably the best. I'll try to find the expected voltages for you. One is ground, one is 5volt ref, the other is signal back.
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  #14  
Old 10-30-2017, 09:26 AM
Grubb44 Grubb44 is offline
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Ok hoses check out. Took to a local shop who I trust. Hooked computer to the truck, the "rough" idle on startup is the truck starving for air. So he tested the IAC. IAC was clean and appeared to be working fine. Could open and close with his computer. Cleaned throttle body and tried again. Same "rough" idle. It's NOT a misfire all electronic firing components are working as they should. I went ahead and replaced the IAC. Ya $40 but completely ruled out the rough idle even being an issue with the IAC now. Just dropped her back off the the shop so he can test and monitor it more. Any leads would be helpful. Thank you.
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  #15  
Old 10-30-2017, 10:14 AM
RoberticusMaximus RoberticusMaximus is offline
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Default Re: P0401 this is KILLING ME!!

seems consistent with a funky MAF signal. might try cleaning the elements. and checking the pins on the connector. but i's have your mech do more testing before buying a new maf - last i checked those were still expensive
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