# 2007 pathfinder won't start - IPDM?



## jaguilar (Aug 17, 2016)

Hello. Purchased pathfinder in 2007, manufactured in 2007. Engine will crank but will not start. Mechanic said it was the fuel pump. Bought a new one, installed it, no luck. Now he says "computer is not turning on fuel pump, its the IPDM", I would like to trust him and order one for $300 but I have already spent $300 with him replacing the fuel pump and that didn't work. Could it be the IPDM or is there something else I should try first? Everything else battery related works. cigarette lighter chargers, radio, A/C, interior lights, headlights. I need to fix this soon, my daughter will come home to me this weekend and I need a car to drive her around in! Thank you


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## algoma (Dec 3, 2016)

Jaguilar
It could be as simple as the engine coolant temperature sensor. I had a similar issue with my 07. When the outside temperature began to get cooler I began to have a hard time to start the engine. I replaced the 4 year old battery. I replaced the spark plugs. No improvement. I took it to a mechanic that I know and trust. 
The fuel pressure readings were low. The fuel pump was replaced. Vehicle has 200000 kms on it so this seemed feasible. No improvement.
The ect sensor was replaced. It starts like new. 
Ect sensor relays the engine temp to the ecu/ipdm. The old sensor was relaying a warm engine message resulting in a lean engine start condition.
Hopefully you have already solved your problem but this may help someone else.


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## quadraria10 (Jul 6, 2010)

Did you not get an engine check light and a stored fault code? Did your mechanic explain how a bad coolant temperature sensor could cause low fuel pressure? Or did you have multiple problems?

https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-coolant-temperature-switch


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## rogoman (Dec 16, 2004)

One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores. Post the actual codes here on the forum so that we may be able to help you further. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM sections from the Nico Club web site; here's the URL: http://www.********.com/FSM/ (replace the asterisks with "nico club" spelled as one word). The section EC.PDF is the one you need to read.

At this point you'll have to determine if there's an ignition or fuel delivery problem:

* Testing fuel delivery:
An easy way to test the fuel pump and filter is to disconnect the fuel hose from the fuel tube and insert a long length of spare hose into the top of the fuel hose with the other end draped over the fender going into a catch can placed on the ground. Now turn the ignition key to the run position but DO NOT START THE ENGINE. You should see fuel going into the can at a good rate for several seconds.

Tee-in a temporary fuel pressure gauge between the fuel hose and the fuel tube; you will need a special adapter for the snap-in hose connector. If the engine is unable to start, turn the ignition key to the run position but DO NOT TRY TO START THE ENGINE. The fuel pressure reading should be around 51 psi which would be a static reading.

The fuel injectors may not be firing. This can be tested with a "noid" light probe for each injector harness connector. If this is the case, the crankshaft position sensor (CKP) or the camshaft position sensor (CMP) may be bad.

* Testing ignition:
Pull several coil packs to test; use a spare spark plug into any coil pack to test; ground the plug base with a jumper wire to the engine block; see if you're getting a spark while trying to start the engine. Again if there's no spark, the crankshaft position sensor (CKP) or the camshaft position sensor (CMP) may be bad.

* The cam timing may be incorrect:
Check for a broken chain guide or broken chain tensioner which could cause the chain(s) to jump several teeth.


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## quadraria10 (Jul 6, 2010)

What I was trying to understand Rogoman was why the fuel pump was replaced in the first place? There should have been a code for the coolant temp sensor, or at least it seems to me there should have been.


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## rogoman (Dec 16, 2004)

Replacing the fuel pump without telling the customer why, sounds like the caliber of the mechanic is in question. There are many mechanics or maybe think they are mechanics, who throw in parts hoping for a fix.


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## algoma (Dec 3, 2016)

quadraria 10
I have a code scanner so the first thing I did, when the problem began as the weather cooled, was check for a code. No fault codes were set.
So I started with a new battery to replace the 4-5 year old. I then replaced the spark plugs. I checked for codes again. No codes.
The mechanic explained to me that the fuel pressure readings were low. With 200,000 kms on vehicle, I agreed that replacement of the fuel pump seemed reasonable. Again, no codes.
He did more research and found that the ect sensor was sending a warm engine message to the ecu. Hence the lean start condition which became a problem when the weather cooled. I agreed to this and the ect sensor was replaced. Again, no codes.
Starts like new.
To note: The engine started well when it was warm and ran well after starting. Over spin was only with a cold engine.
Agreed that this would have been an easier fix with codes. I likely would have done the repair myself in that case.
Best wishes to all.


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