Well I'm back with another problem. My blazer is having a hard starting issue. I haven't really messed with it too much but I can only get it started by holding the gas pedal all the way down or by pushing and letting go repeatedly. Even then it takes a while to get started. I just replaced the fuel pressure regulator today in hopes of fixing it. Before I changed that i noticed that it smelled like gas and inside the intake on the back drivers side was clean so something was leaking. With the intake off and injectors and fuel lines hooked up i tried to find the leak first with key on then off but didn't see anything leaking. So I figured why not go ahead and replace the FPR while I had it apart. But it didn't fix the hard starting. The only other thing I have done so far is unplugged the MAF while it was running to see what happened and it didn't change anything. Didn't die or change idle or anything. Does that mean the MAF isn't working? Can i put it in a big bowl or something and put rubbing alcohol in it and barely shake it up to clean it? Anything else that would be causing the hard starting?

 

Have you done a fuel pressure test? Can't do a proper diagnosis w/o it. Most parts stores "loan" the testers. With key on engine off minimum is 50PSI and it should hold for 10 minutes with key off.
Check the resistance of you ECT sensor. If it's bad the engine will run way rich because the PCM thinks it's -40°C/F.
They make MAF spray cleaner.
The list is endless.

 

Like oldeerslayer said, a proper fuel pressure test is the only way you're going to diagnose a fuel delivery issue

Your truck not running like crap when you unplug the MAF sensor doesn't mean it's bad. I believe the system goes into speed density mode and uses other sensors to try and "fill in the blanks" basically. It wont run optimally, but it shouldnt run horrible- like it would if a bad maf was plugged in.

 

I took it to have the codes reset so i can start from a fresh set of codes. Cut it off and started it back up so the light would come back on and had it read again. It's only pulling one code and its the crankshaft position sensor. I should have figured that much since the rpm guage kinda jumps instead of a smooth motion. Anyway....... Is that something that i have to take to a dealer after i replace it? Will i even be able to start it up after replacing it? Or should i take it to one of these crooked shops and see how many different things they can come up with about my blazer being hard to start?

 

You'll need to do a ckp variation learn after the replacement. Most any mechanical shop will have a scan tool capable of doing this.

You will be able to start and run the vehicle before the relearn is done(the engine has to be warmed up and get revved up as part of the procedure), though I would not recommend doing so for a prolonged period of time because it controls the timing.

 

Thanks for the info. I'll replace it and find a shop that can do the relearn and see if that fixes the starting issue. Might be a week or two but I'll post the results when done.

 

I changed the crankshaft position sensor. Is it supposed to still be hard to start until i have the relearn done? It runs decent after it starts but it has all the symptoms from everything I have read if the crankshaft position sensor is bad. While trying to start it, it either turns until i let off the key, or backfires or acts like it tries to turn the other way stopping the starter. I'm like 90% sure its not a fuel delivery problem so can we just assume that fuel pressure and leakdown checks out good? I don't care to replace stuff because i don't know the history on it but i do know the previous owner and they would have driven it until it wouldn't move anymore. But back to my question, is it still going to be hard to start until the relearn or should it fire right up like normal?

 

Exactly what code are you getting?

 

i forget but I'll take it and have it checked again if i can get it started after work tomorrow.

 

I've been thinking, i know these distributor caps have issues but could mine still be bad even though it looks like its brand new? The cap and rotor button were the first things i checked after changing the starter and they look brand new. No signs of wear at all so i just ran a rag over the inside incase it had any moisture in it and put it back on. Could that be my problem of it acting like it is out of time?