Hey
I have a 2005 Chevy Blazer that I love so much, I would drive it everyday even if I won the lottery.

It starts fine 80% of the time but 20% of the time it doesn't start at all.
Without fixing or changing anything it will start fine a day later.

It seems to happen more often in the winter.
This has left me stranded all over the place and has resulted in my Blazer getting towed way too often.

So far I've replaced the:
•Fuel Pump
•MAF Sensor

It comes up with a error code P0155 (02 sensor heater bank 2 sensor 1)

I am hoping someone in the history of the Blazer world has had success in this battle before and can share some words of wisdom with me.

Thanks

 

I had an intermittent crank/no-run that turned out to be due to a bad fuel pump relay.

Fortunately, this is an easy thing to test so perhaps worth a try. The fuel pump relay is the same as others in the Fuse/Relay box under the hood. Therefore you can try swapping this relay with another.

When I opened up the original fuel pump relay, I could see that the contacts were fairly erroded. I also opened up the other identical original relays and they looked fine.

I suspect the high current loads for the fuel pump are what damaged it.

 

Cranks but will not run or won’t crank?


George

 

Thanks Christine_208, I will check the fuel pump relay today and see if that fixes it.

And GeorgeLG to answer your question it cranks but won't start.

 

That will help the members help you. I will let Christine continue to support your issue.


George

 

Thank you,

I just went out and changed the fuel pump relay and it is still cranking but not starting.

The fuel pump relay looked good, no corrosion or anything but I swapped it out anyways just to make sure.

 

So now that the easy has been tried, we are now looking at trying to do a thorough diagnosis.

The first reference I have for you is George's excellent "sticky" thread on Crank/No-Start conditions on this forum:
https://blazerforum.com/forum/2nd-ge...rticle-103750/

I highly recommend you go through it.

I have also attached a scan from my 99 service manual for Crank/No-Run conditions that might also help.

Unfortunately, I'll be away from my manuals for a little while so I will defer to others and in particular George_LG for help.

I will leave you with one thought based on what happened to my old 92 Blazer when I had an O2 sensor error too.

At the time, I dutifully changed it out, but then the error came back. Back then I was new to these "new-fangled" OBD vehicles and wasn't thinking in terms of what else could have caused the error besides the component itself failing. What I didn't pick up on at the time was just how dark with carbon the sensors had been, both the first and then the replacement. To make a long story short, what I discovered later was that I had a fuel leak under the intake manifold plenum. One of the hoses that fed the central injector had started leaking spraying fuel directly into the intake passages on only one side. This created an over-rich condition for only the cylinders on that side which was responsible for the extra carbon deposits on the one O2 sensor. When I opened up the top of the intake to do the fuel line repair, I could see where the fresh fuel had dissolved the varnish only one side of the intake. After I made the fuel line repair everything was fine.

 

That's a great thread by George "Crank No Start".I read through that and did a little basic troubleshooting and found that my O2 Sensor Heater Bank 2 Sensor 1 is not reading any ohms across any of the 4 contacts. So I'm thinking the sensor is no good.I'm going to replace it and see if that fixes the intermittent crank/no-run problem.