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Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8535
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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Was driving up the highway and vehicle lost power and

Customer Question

was driving up the highway and vehicle lost power and stopped. it just cranked but acted like it wasn't getting gas. I couldn't hear fuel pump run when turning on key so I came back the next day with new fuel pump relay. I put it in and the car started immediately. I drove it down the highway 11 miles and it cut out just like before but started again and ran for a few more seconds and then cut out not to come back again. I towed it to family members house and worked on it. I replaced the fuel pump, fuel filter, cleaned maf, replaced air filter, and it won't start.
JA: So many things can cause fuel pump issues. Some simple, some complicated. Fortunately, the mechanics we work with have tons of experience dealing with them. Are you hoping to fix this yourself?
Customer: I have been trying but have to go back to my home town tonight and no place is open to talk to and see if they can look at it. If there is a fix i can do that would be great. I have checked all fuses that I know of and I don't know where else to look except for other relays.
JA: Is there anything else important you think the Mitsubishi Mechanic should know about your Mitsubishi?
Customer: Is there a fuse or something that runs the fuel pump or something else to look at for this.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Mitsubishi Mechanic about your situation and then connect you two.
Submitted: 5 months ago.
Category: Mitsubishi
Expert:  Doug replied 5 months ago.


What sort of vehicle is this?

Customer: replied 5 months ago.
2001 Mitsubishi montero sport
Customer: replied 5 months ago.
This cranks over but just won't start. I'm wondering if there is some other relay or fuse or fusable link keeping this car from starting.
I've read online about camshaft relays/sensors and crankshaft relays/sensors that can be at play in this? Is there a way to check these if they are
Expert:  Doug replied 5 months ago.


Lets do some basic inspections so to avoid any more unnecessary parts replacements.

Please turn the key on and watch the dash, does the Service Engine Soon light still do its bulb-test at key on?

If yes, please check to see if there is spark while cranking the engine.

Customer: replied 5 months ago.
what is the bulb test at key on?
Expert:  Doug replied 5 months ago.

The service engine soon light.... when you turn the key on, it should test the bulb by turning the light on.

Customer: replied 5 months ago.
The service engine soon light comes on when the key is turned on. I pulled the only spark plug that I could get to and tried to confirm spark and I could not see any. It's a bright day and all i could do was place it near the nuts on the throttle housing to see if I could see spark. I couldnt see any spark.
Customer: replied 5 months ago.
I know it had spark yesterday because i drove it for 11 miles until it died.
Expert:  Doug replied 5 months ago.


We are only worried about what it has now... yesterday it was running so having spark yesterday doesn't mean anything about today. We need to start with spark to facilitate the fastest diagnosis and minimum amount of parts purchased.

Please locate the crank position sensor harness. It is the three wire triangular shaped connector sticking up behind the water neck area.

Unplug the sensor and use a volt meter to measure voltage between battery negative and each pin of the connector on the harness with the key ON. Tell me what the voltages are on each wire.

Customer: replied 5 months ago.
3 top of triangle. 12.55v bottom right of triangle 5.01 v bottom left of the triangle harness .01
Expert:  Doug replied 5 months ago.


Please plug the sensor back in and now back-probe on the 5V wire.

In this state use a 22mm socket and ratchet to rotate the engine by hand and monitor the voltage. What does the meter read as you rotate the engine by hand?

Customer: replied 5 months ago.
did you get my voltages? This was at the harness with the key on, but not cranking.
Expert:  Doug replied 5 months ago.

Yes, those were good voltages which is why we need to do as I described above... plug it back in and back probe the 5V wire, then rotate the engine by hand with a socket/ratchet on the crank shaft bolt.

Customer: replied 5 months ago.
voltage didn't change on the 5.01 as i turned the engine over
Expert:  Doug replied 5 months ago.

Thanks, ***** ***** definitely do it.

The crank sensor is going to need replacement. You should have seen 5v-0v-5v-0v as the engine rotated indicating revolution of the crank shaft. Without that signal, no spark and no fuel pump operation.

I strongly recommend only using a genuine Mitsubishi crank shaft sensor in this vehicle... it does not get along well with aftermarket sensors. And because you have to take the majority of the front end apart to change it, this is not a job you want to be doing twice.

If you have further questions on this just let me know; I am stepping out on my 6PM break right now, but will be back shortly and we can discuss this further if needed.

Customer: replied 5 months ago.
would this keep the new fuel pump from coming on. I don't hear it start up at all? Do you have instructions on how to change this item or a place where i can get these. Please let me know.
Expert:  Doug replied 5 months ago.

Yes, Mitsubishis use the crank sensor as a fail safe for the fuel pump. Unlike other vehicles (American cars in particular), Mitsubishis (as well as Toyotas) use the crank sensor as the fuel pump trigger. The reason for this is that if you were to get into an accident and a fuel line ruptured, this system automatically quits pumping fuel all over the ground. Since the line ruptures and the engine can no longer run, the crank sensor stops getting signal and so the fuel pump is stopped. On a key-on system like General Motors was known for using among others, if this were to happen you would pump fuel for minutes after the engine shut off (They used the oil pressure switch to trigger the pump).

So yes.... no crank sensor signal definitely would mean no fuel pump operation on this and all Mitsubishis... its the leading cause for mistaken pump replacements :)

To change it... this is a large job I do not normally recommend for DIY's unless you are really comfortable with this sort of work. You will need to do the following:

Unhook the battery

Drain the coolant

Remove the radiator hoses

Remove the fan shroud

Remove the fan clutch

Remove all belts and tensioners

Remove alternator

Unbolt power steering pump

Remove bolts from accessory plate (The big aluminum plate) and remove

Remove lower timing cover and upper driver timing cover

Remove crank bolt (~137 ft lbs spec torque... anticipate much tighter though if it has been on there a while) and crank pulley

You can then unbolt the crank sensor (two 10mm bolts) and pull it out... however it is very tight behind the timing belt. It is usually recommended to just change the timing belt at the same time anyway though since you are several hours of work invested at that point. If the belt is not due for replacement you can slip the sensor past it though... again it is just very tight clearance.

Expert:  Doug replied 4 months ago.

Did you still need help with this or can we close out this ticket?

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