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350matt
350matt, Engineer
Category: Mitsubishi
Satisfied Customers: 21496
Experience:  Mechanical Engineer BEng Hons 22 years experience in car engine industry, 10 years in formula 1
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I have a 203mitsubishi Montero sport 3.0 v6 I have a po335

Customer Question

I have a 203mitsubishi Montero sport 3.0 v6 I have a po335 code engine will start then die
Submitted: 9 months ago.
Category: Mitsubishi
Expert:  350matt replied 9 months ago.

Hello

that code points to a faulty crank sensor, which can prevent starting and the engine running at all

So I'd 1st check the condition of the wiring and connector plug for damage and corrosion, if this is OK then I'd replace the sensor with a new part

see the attached image for the sensor location

Customer: replied 9 months ago.
I already have replaced the crank sensor wiring looks good
Customer: replied 9 months ago.
car will start and then die
Customer: replied 9 months ago.
could the icm module cause this issue
Expert:  350matt replied 9 months ago.

OK

in that case I'd trace the sensor wiring back into the engine loom as if there's a poor connection between the sensor and ECU then it will have the same effect as a faulty sensor

follow the engine wirign loom back to the ECU, checking for loom damage and corroded connections as you go

Expert:  350matt replied 9 months ago.

and yes a faulty ICM can give this fault

but you have a crank sensor code so I wouldn't proceed with another fix until thats bottomed out

Customer: replied 9 months ago.
ive already checked power and ground wires to sensor I'm getting good voltage on both of them the only one I havnt checked is the signal wire
Customer: replied 9 months ago.
not sure what I should have there
Customer: replied 9 months ago.
or even how to test it
Customer: replied 9 months ago.
I know it is a blue wire
Customer: replied 9 months ago.
could it be the rulactor ring on the crank
Customer: replied 9 months ago.
that is what generates the signal to pulse the coils right
Expert:  350matt replied 9 months ago.

hello

thats all correct

the signal wire is pushed by the reluctor ring to generate a pulsed 0-5V signal that is then fed back to the ECU

if this signal is corrupted back to the ECU then the engine won't start

Customer: replied 9 months ago.
I have 13 volts on the power wire and the ground the signal wire I have 4.9 volts when I turn the crank by hand should I change the icm
Expert:  350matt replied 9 months ago.

hello

where are you measuring the signal voltage?

If its back at the ECM plug then yes I'd move onto checking the ICM

however just measuring at the sensor plug won't help as this only proves your new sensor is OK

Whereas I suspect that the signal isn't reaching the ECU so there's nothing to fire the injectors

so I'd be tracing the wire back at the ECM plug to confirm its getting to the right place

Customer: replied 9 months ago.
I also have changed the icm module still no luck
Expert:  350matt replied 9 months ago.

Ok can you measure the signal voltage at the ecm plug?

Customer: replied 9 months ago.
I got a soulation to this if I knew what pin the crangshaft signal came to the ecm was I would re wire the whole thing is there any way you can tell me
Expert:  350matt replied 9 months ago.

Hello

OK there's this, which is a few years too early but may match up, if I find the exact diagram I'll post it up

http://www.4x4extremesports.com/Docs/ECM_PCM/1999_Montero_Sport_3.0L-3.5L_automatic_PCM_to_1997_Montero_Sport_3.0L_5-speed_ECM_harness_pin-out.pdf

Customer: replied 9 months ago.
I have 4.9 volts there but when I am cranking it over the voltage drops to 2 . something then when I stop cranking it goes back to 4.9 does that need to be steady voltage if so what could be causing it could it be the rulactor ring
Customer: replied 9 months ago.
I have ran my own wire to the ecm from the crank sensor
Expert:  350matt replied 9 months ago.

great !

has this helped at all?

Customer: replied 9 months ago.
still having the same issue and the same code could it be the rulactor ring on the crank
Expert:  350matt replied 9 months ago.

Hello

yes thats entirely possible

I'd suggest the way to confirm this is to use a oscilloscope to look at the shape of the signal as it should be sharp edged square wave like the attached image

Customer: replied 9 months ago.
I don't have one here I'm thinkin that is about all it could be ive replaced or checked everything else
Expert:  350matt replied 9 months ago.

well if you remove the sensor and peer through the hole at the wheel to check the condition of the wheel edges and to confirm that the missing teeth are not there

Customer: replied 9 months ago.
it all looks good I'm thinking it could be bent tho causing voltage to drop off while cranking
Expert:  350matt replied 9 months ago.

thats true

do you have a dial depth gauge? so you can measure the run out on the wheel?

Customer: replied 9 months ago.
I do what should the run out be
Expert:  350matt replied 9 months ago.

Hello

it needs to be under 0.1 of a 1mm

Expert:  350matt replied 9 months ago.

Hi

do you still need help?

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