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go-west..
go-west.., Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1207
Experience:  Technican with 20 years experience focused on engines and electrical.
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I have 1994 m11 cummins that will crank and run for 30 to 45

Customer Question

I have 1994 m11 cummins that will crank and run for 30 to 45 seconds and cut off. No codes are showing on computer.
Submitted: 10 months ago.
Category: Medium and Heavy Trucks
Expert:  go-west.. replied 10 months ago.
Good evening
When it faults have the computer hooked up and tell me if the engine speed is erratic, I'm wondering if your cam sensor is starting to die
.
Customer: replied 10 months ago.
It had no faults had mechanic chech while it was running then engine shuts off showed no faults or codes. Did this several times with same outcome. Engine will start right back up run 30 or 40 seconds cut off.
Expert:  go-west.. replied 10 months ago.
Go to the can sensor, it's at the front left of engine behind the air compressor, it's a 4 wire sensor, if you unplug it and see any oil in the sensor the sensor is compromised and should be replaced, the sensor is timing reference for the ecm and will cause the engine to stall.
Customer: replied 10 months ago.
The sensor has about three inches of wire and then plug do i need to unscrewthe sensor to inspect for damage?
Customer: replied 10 months ago.
If that sensor was bad would it show up as code or no?
Expert:  go-west.. replied 10 months ago.
Sometimes it doesn't code
Is there oil in the connector -?
Customer: replied 10 months ago.
No oil in the plug is 3 inches away from sensor and it is clean. Where wire inter sensor is made on doesn't detach.
Expert:  go-west.. replied 10 months ago.
Check the outer 2 wires and 2 inner for resistance should be around 1 to 2 k
Customer: replied 10 months ago.
The shop has shut down for night can I get back with you in am?
Expert:  go-west.. replied 10 months ago.
Absolutely
Customer: replied 10 months ago.
Good morning go west. I check the resistance on sensor two outside wires 1419 and two inside wires 1431 ohms.
Expert:  go-west.. replied 10 months ago.
Good morning
Seems ok there
Remove the alternator belt and retest, sometimes a alternator can cause this
..
Customer: replied 10 months ago.
Remove belt and start engine see if stays running?
Customer: replied 10 months ago.
Or remove belt and retest sensor?
Expert:  go-west.. replied 10 months ago.

sorry for the delay

remove sensor and inspect the end of it and make sure not damaged,if good,reinstall,then remove the alternator belt and retest,se if it clears up,if no then remove the fuel line off the inlet of the fuel pump and run a line from there to the fuel line to rule out a flapper in the fuel line..

Customer: replied 10 months ago.
Ok I have tried fuel line out of bucket to bypass the fuel line and block on back off brain box with no luck. Let me look att the sensor and get back to you.
Customer: replied 10 months ago.
Sensor looked fine I tried the belt off alternator does same thing with or without belt. I'm going to try a clear line straight out bucket of fuel just to make sure. The last 2 times it cut off was almost like it was running out of fuel but has plenty in it. Try the straight line to make sure you may catch something I'm missing.
Customer: replied 10 months ago.
Tried line right out of bucket same thing runs for 30 seconds before it stalls it cuts out few times before stalls completly.
Expert:  go-west.. replied 10 months ago.
Ok
Do you see any bubbles in the tank when it faults?
Customer: replied 10 months ago.
Not sure about that will go check and see I still have it running out of bucket do I need to put it back coming from tank?
Customer: replied 10 months ago.
I hook lines back up from tank started engine there is bubbles formed in tank. Iest them clear and done it done it a second time. What does that indicate?
Expert:  go-west.. replied 10 months ago.
I'm wondering if a injector is sucking air into the fuel system, you can pressure test the fuel system to 30 psi and look for leaks at the injectors.
Customer: replied 10 months ago.
you think the fuel pump is ok?
Expert:  go-west.. replied 10 months ago.
May have a issue, what is pressure coming out of it when it faults -?
Customer: replied 10 months ago.
120 psi till engine stalls.
Expert:  go-west.. replied 10 months ago.

https://www.dropbox.com/s/yyoiiqnvd0pu2gg/Untitled.pdf?dl=0

135 is spec,i don't suspect a issue with 120

Have a look at the link i sent you..

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