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P174 and P171 codes

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  #1  
Old 05-06-2017 | 10:02 PM
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Default P174 and P171 codes

I have a 04 D2 with 125,000 miles. Has run perfect for the last 5 years. Last week the truck began to have some starting issues and would crank more than usual. Then, with my tank about 1/4 full, I filled up at the local gas station ( new place with new tanks so gas has been good). About 5 miles down the road the old girl started to lose power. Made it off the Interstate and it seemed to run fine at lower speeds. So drove her about 120 miles at slower (65mph) speeds and made it back home. Only codes off the OBD were P0174 and P 171. I cleared them and per the advice of the Land Rover forum replaced the MAF.

Now nothing is easy these days! Found an overhauled unit at Advance Auto. The Bosch version required a special order. When I arrived at the store the overhauled unit was just a few cm smaller than my original MAF sensor housing. The store removed the sensor and put it on my old housing. Still getting the codes and starting about the same. And when the truck gets hot, will not start. Need to wait about 2 hours to cool down ( It is already hot here in TX!)

Maybe CPS? Should I trust the MAF?
 
  #2  
Old 05-07-2017 | 01:54 AM
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Your suspicions might be correct on both. the codes are MAF related codes but you need to get the premium part to lessen the headache.
 
  #3  
Old 05-07-2017 | 05:18 AM
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Those codes can indicate a failed MAF but there are several cases documented here where a vacuum leak or leaks triggered them. A smoke test can confirm or rule out a vacuum leak.

There's also information online about how to test a MAF.
 
  #4  
Old 05-07-2017 | 04:47 PM
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As I have gone down the route of replacing the MAF, my recommendation is order the Bosch unit from Amazon. For Tricky Dick, that was the only MAF that didn't cause a code.
 
  #5  
Old 05-07-2017 | 07:41 PM
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For lean codes and noticeable reduced power, I would check the fuel pressure.
Especially with the no start when hot and extended crank time.
 
  #6  
Old 05-07-2017 | 08:30 PM
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Originally Posted by disc oh no
For lean codes and noticeable reduced power, I would check the fuel pressure.
Especially with the no start when hot and extended crank time.
I am not going to say you are wrong but, I would start with the MAF first and go from there.
 
  #7  
Old 05-08-2017 | 09:09 AM
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Thanks for all the replies. Started to replace the CPS but all my neighbor's wives are weight lifters (massive arms . Need to drop the exhaust manifold to gain some room at the connector. A few more inches of wiring would have been nice!! Have a Bosch MAF coming. Will update after installed. I will never surrender!
 
  #8  
Old 05-08-2017 | 10:00 AM
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Originally Posted by gulfst
Thanks for all the replies. Started to replace the CPS but all my neighbor's wives are weight lifters (massive arms . Need to drop the exhaust manifold to gain some room at the connector. A few more inches of wiring would have been nice!! Have a Bosch MAF coming. Will update after installed. I will never surrender!

HAHAHAHA! Just have them drop the entire engine for easy access! lol
 
  #9  
Old 05-08-2017 | 10:04 PM
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Lmao you can't make that **** up
 
  #10  
Old 10-26-2017 | 09:59 PM
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Good evening fellow DII rovers, P171 and P174 problems solved! After replacing, plugs, wires, and CPS I finally found time to replace the fuel pump/fuel filter. The DII has NO separate fuel filter but it is built into the fuel pump. Located under the rear baggage carpet. Side panels were pretty easy to remove and after removing the 6 small screws the fuel pump is easily accessible.

There are TWO types of fuel pumps for the DII and your VIN will not help identify the correct one. One has secondary air and one does not. Just look at the top of the unit and buy the correct pump.

The workshop manual shows a special tool to remove the pump, but I found a suitable drift and hammer worked fine to remove the metal locking ring. Then just gently pry out the old pump with two screw drivers so as to lift evenly.

Installation of the new pump is just the reverse of the removal. A few notes:
Install the new O ring in the tank opening and NOT on the pump so the seal fits properly.
The pump has two metal flat springs so the pump needs to be pushed down into the tank opening evenly with a small force. Their is a plastic alignment tab on the pump and tank ring.

The truck started right up and had lots of power. No more codes. Smooth acceleration right up to 80 mph.
 



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