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peterpete190
peterpete190, Auto Technician
Category: Nissan
Satisfied Customers: 28251
Experience:  Over 17 years diagnosing and repairing vehicles.
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We have a 2005 nissan frontier that cranks will not start we

Customer Question

we have a 2005 nissan frontier that cranks will not start we replaced the fuel pump and the IPDM we still have no power to fuel pump
Submitted: 1 year ago.
Category: Nissan
Expert:  peterpete190 replied 1 year ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Can you tell me if this is a 4wd model or 2wd and what engine liter size is in the vehicle?

Let me know so we can continue,thanks Pete.

Customer: replied 1 year ago.
Hi and Thanks
This is a 4WD and has a 4.0
Expert:  peterpete190 replied 1 year ago.

Have you had the fault codes checked at all to see if any codes have set with this issue ?(using a scan tool that can read all computers in your vehicle)

Customer: replied 1 year ago.
i plugged my scanner into the truck and it only had 2 pending cat codes ...also whiile i had the scanner hooked up to it and ran live data on it and it DOES have cranking rpm
Expert:  peterpete190 replied 1 year ago.

At the fuel pump relay do you feel or hear it click at all with the key first turned on the first few seconds or when cranking over the engine?(this may take a second person to check this).

Let me know,thanks Pete.

Customer: replied 1 year ago.
i dont feel/hear anything from the relay i already checked fuses and tried swapping that relay with another known good one and still nothing
Expert:  peterpete190 replied 1 year ago.

O.k.,do you have a multi meter to test electrical with at all?

Customer: replied 1 year ago.
i do
Expert:  peterpete190 replied 1 year ago.

O.k.,remove the relay keeping in mind which direction it is installed.You will see four wiring terminals that this relay plugs into.Test the terminals for the signals below and let me know what you come up with so we can continue.

Two of the terminals should have power (at or near 12 volts) with key on or engine cranking

One terminal should only have a ground with the key on first two seconds or engine cranking.

The last terminal is the feed to the fuel pump.Test these above to see if these 3 above have these signals and let me know what you come up with here.

Thanks Pete

Customer: replied 1 year ago.
i have 12.3 volts at 3 or the blades the only one that doesnt have power is the blade that would be directly in the middle of the relay
Customer: replied 1 year ago.
i dont think its the culprit but my boss wanted me to ask anyhow is there anyway it could possibly be the cam or crank sensor even though i have spark and cranking rpm
Expert:  peterpete190 replied 1 year ago.

The fuel pump would normally turn on with the command from the engine computer even if there was an issue with a cam or crank sensor so I dont see these as the cause here.

You should have 12 volts at 2 of the blades and then a commanded ground signal on one of the blades from the engine computer with the key on or when cranking.

Are you sure you have 12 volts on 3 blades and no ground signal from the computer?

Customer: replied 1 year ago.
i just checked it again using a power probe and the only one that doesnt have power shows up as a ground on the power probe
Expert:  peterpete190 replied 1 year ago.

O.k.,the pump feed may show ground but you should also have another terminal out of the 4 that should have a ground only with the key on the first two seconds or when cranking over the engine then no ground after turning off the key.Let me know.

Thanks Pete

Customer: replied 1 year ago.
i have another blade for the relay that goes to ground with the key off ? and when keyed on it goes back to having 12.3v
Expert:  peterpete190 replied 1 year ago.

How many blades do you see that this relay plugs into as my info only shows 4?

Customer: replied 1 year ago.
it only has 4
Expert:  peterpete190 replied 1 year ago.

O.k.,my info shows one blade receives power directly from fused battery voltage.One blade receives power from another battery source.One blade receives a ground signal only when the engine computer is commanding the pump on and one blade feeds the power to the fuel pump when the relay is energized.

If you have 3 blades with power this indicates that either the wiring is shorted/damaged leading from the relay to the engine computer and the wiring needs traced to inspect for any damage needing repaired or that the engine computer itself is shorted internally and needs replaced.

Inspect for any wiring needing repaired and if found o.k. I suspect the engine computer needs replaced.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
is there any way i can test the ecu just to be completely sure after i inspect the wiring
Expert:  peterpete190 replied 1 year ago.

You would need to test the terminal directly out of the ecu to be sure.

You would need to locate the violet wire looks to be at terminal 113 in the connector (below is the connector I apologize as it isnt showing up the greatest).It should have a ground on it according to my info when cranking over the engine.If it has power on it then the ecm is the cause needing replaced.

https://www.dropbox.com/s/mjrmf1nu9pnegzb/113-11-30.gif?dl=0

Thanks Pete

Customer: replied 1 year ago.
i just tested every violet wire that i seen around the ipdm and all carry power wen the key is cycled to the on position so im gonna say its pretty safe to say its gonna be the ecu
Expert:  peterpete190 replied 1 year ago.

I double checked the diagram for this here and this wire should be a ground.This does sound like the ECU is the cause here needing replaced as long as you dont have any shorted wiring.

Thanks Pete

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