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2008 chevy colorado 3.7 I-5 wont run

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old fireman
New User

Nov 22, 2015, 10:07 PM

Post #1 of 2 (872 views)
2008 chevy colorado 3.7 I-5 wont run Sign In

2008 Chevy Colorado 4x4 Z71 Lt, 3.7 (inline 5) engine with 75937 miles. Issue: engine will not fire up.... Description, Second week of November 2015 the engine started to idle rough, along the lines of having some bad gas, nothing major. Service engine light comes on with code P0443 ( purge control valve circuit malfunction) & PO449, (vent valve solenoid circuit malfunction) emission's stuff. Nov. 16, (5 days ago) I try to start the truck (early morning with 32 degree temperature) the engine fired up and immediately shut off and would not restart, It had a real rough idle at that time. My mechanic checked a few things out and came to the conclusion the fuel pump went bad. I changed the fuel pump with a GM brand fuel module. I replaced the gas with 15 gallons of fresh new (87 octane) gas. The engine will not start and run, it will turn over fine. I do not have a fuel pressure gage to check pressure but when I relieve the pressure at the pressure relief valve on the fuel rail, fuel shoots out a good distance. There are no other active codes than what is already mentioned. any ideas of problems I can check for would greatly be appreciated. I do not have the finances for the mechanic (who's booked up for a while) let along the dealership to trouble shoot this. Thank you for your time, Rob.

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 23, 2015, 3:23 AM

Post #2 of 2 (857 views)
Re: 2008 chevy colorado 3.7 I-5 wont run Sign In

Don't blow off those EVAP codes so quickly. A stuck open purge valve can cause flooding, especially after filling the gas tank.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

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