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View Full Version : X-30 won't restart after engine is warm..


ELB
05-22-2014, 10:02 PM
Please help. 2006 x-30 MCX (excelent condition and low time) will not restart after being shut off once the engine warms up. It turns over and kinda wants to start but will not fire up. Occasionally if I pump the throttle it will start and once it's started it runs great until its shut off again. I thought it was the fuel pump but after I put on a new MC module today (ouch) the same problem occurred. Fuel seems to be getting to the throttle body because I can smell fuel after turning it over several times. If I let it sit for an hour if fires right up. Ignition? Sencor? Any ideas? Thanks for your help in advance.

blackhawk
05-22-2014, 10:19 PM
What is the condition of your plugs, wires, distributor cap, and rotor? Try the simple things first. Also check for vacuum leaks around the intake and valve covers. Check the PCV valve and the hose that runs to it.

mzimme
05-22-2014, 10:20 PM
Vapor lock?

skitilldark
05-23-2014, 12:41 AM
My boat did this (the LTR-earier version of the MCX)—acted just like vapor lock, but being port injected, I couldn't figure out how/why. Believe it or not it was the thermostat. I had a 140 from the factory that was causing a rich issue. Once I switched to a 160, no issues.

CantRepeat
05-23-2014, 03:35 AM
Possibly ECT going bad.

https://www.youtube.com/watch?v=wFHWpgHMAvY

https://www.youtube.com/watch?v=i2Kd0VQWw1o

FourFourty
05-23-2014, 07:37 AM
^ that is what I was thinking as well. That, or the intake air temp sensor.

TeamAllen
05-23-2014, 10:47 AM
Does it have a schrader valve on the fuel rail? if so, check the fuel pressure using a fuel pressure gauge when this occurs.

CantRepeat
05-23-2014, 11:58 AM
Does it have a schrader valve on the fuel rail? if so, check the fuel pressure using a fuel pressure gauge when this occurs.

All the MC MCXs have a schrader valve on the fuel rail.

TeamAllen
05-23-2014, 05:44 PM
Great! If it's vapor lock, it's my understanding when you you are experiencing the non start issue, you can depress the valve and air(vapor) will come out. Use caution since the engine is at temperature and fuel might/will come out. A pressure gauge is still the correct way to check.

swatguy
05-23-2014, 07:59 PM
My boat did this (the LTR-earier version of the MCX)—acted just like vapor lock, but being port injected, I couldn't figure out how/why. Believe it or not it was the thermostat. I had a 140 from the factory that was causing a rich issue. Once I switched to a 160, no issues.

My LTR did same and this fixed my hot start issue as well.

blackhawk
05-23-2014, 09:41 PM
My boat did this (the LTR-earier version of the MCX)—acted just like vapor lock, but being port injected, I couldn't figure out how/why. Believe it or not it was the thermostat. I had a 140 from the factory that was causing a rich issue. Once I switched to a 160, no issues.

Just trying to understand things, but how did the thermostat come into play. Wouldn't the engine coolant temperature sensor still tell the computer the correct temperature to control the fuel/air ratio regardless of the thermostat setpoint?

ELB
05-24-2014, 12:01 AM
I waisted lots of cash in the process but finally figured out it was the cooliant sensor. Well, i figured it out thank to this forum and all the great people that help others.

skitilldark
05-24-2014, 12:12 AM
Just trying to understand things, but how did the thermostat come into play. Wouldn't the engine coolant temperature sensor still tell the computer the correct temperature to control the fuel/air ratio regardless of the thermostat setpoint?

It probably was the coolant sensor in retrospect, but chning the thermostat solved it. Go figure.

sand2snow22
05-30-2018, 01:22 AM
Was engine coolant reading 160 on the gauge?

CantRepeat
05-30-2018, 04:08 AM
I waisted lots of cash in the process but finally figured out it was the cooliant sensor. Well, i figured it out thank to this forum and all the great people that help others.

Was engine coolant reading 160 on the gauge?

There are two engine coolant temp sensors. One for the gauge and one for the ECU. So the gauge could be reading correctly but the ECU is seeing something different.

mzimme
05-30-2018, 10:14 AM
This thread is 4 years old...

sand2snow22
06-01-2018, 12:44 AM
There are two engine coolant temp sensors. One for the gauge and one for the ECU. So the gauge could be reading correctly but the ECU is seeing something different.

Which ECT is near the throttle body on a MCX? Where is the other ECT?