03 trailblazer cranks but wont start

[Bobbi wells]

Friday i got home from work and had to take my 2 girls to the hospital. Getting ready to leave it wouldnt start. It cranked and cranked but wouldnt fire. I had it towed to a shop and dropped $500.00. Replaced fuel pump and filter and still wouldnt start. I had it towed to a different shop and he unhooked everything from the pcm and hooked it all back up and was able to start it. I drove it never had a problem. The only thing that was different was i smelt plastic burning. Not sure what it was but i pulled over to check under the hood and it wasnt under the hood and went back inside and wasnt in there either. So i just contiued to drive home. Still with no problems at all. I go to leave this am to go to work hoping and praying it was still going to start and nope it dont. Its doing the same thing. Cranking and not starting. I have fuel pressure and spark. It will run off ether also. But it acts like the fuels not getting to the motor but its at all the check points. The only code that comes up is one for the temp sensor and i dont think that would stop it from starting. Everyone is stupmed. We cant figure this out. Can anyone plz help me?

I also just changed the igniton switch, and it has a full tank of gas.

 

[Blckshdw]

That's a tough one. The burning plastic smell is a concern, sounds like a connector somewhere is getting melted. If that's the case, hopefully that's the source of your no start problem, and can be fixed fairly cheaply.

Since it temporarily worked before, I would try re-seating the PCM connectors, and seeing if the truck fires after that. If it does, that gives you a more targeted place to start troubleshooting.

 

[Bobbi wells]

That's a tough one. The burning plastic smell is a concern, sounds like a connector somewhere is getting melted. If that's the case, hopefully that's the source of your no start problem, and can be fixed fairly cheaply.

Since it temporarily worked before, I would try re-seating the PCM connectors, and seeing if the truck fires after that. If it does, that gives you a more targeted place to start troubleshooting.

Well he called me this morning and said when it got dropped off he put the jumpers on it and it almost started kinda like it was flooded. He said so he was thinking plug issue. So he checked the plugs which should of been checked at the first shop it was at cuz thats (spark) they said i had. But all the porclin on everyone was cracked and only 2 outta the 6 were firering. So he replaced them with new and unhooked everything from the pcm again and hooked it all back up. Parjed it outside after he started it. Checked it this morning and fired right up. So all i can do is hope it starts again in the morning so i can go to work.

 

[jsheahawk]

Glad it all worked out. I'd be having a conversation with the shops who didn't fix it.

 

[Torker]

Maybe not be related but when my purge solenoid went out it would not start right after getting fuel. Experts here will have to correct me but there is 2 of them, one is not a solenoid. One is near the tank/charcoal canister and one on the side of the engine. About halfway down on the drivers side. I changed the one on the engine and it took care of it.
When it happened I could floor the truck and get it to start and it would run like crap for a couple minutes. Barely run and not idle, then it would clear up till I got fuel again.. FYI

 

[Torker]

Any luck on your truck?

 

[Reprise]

I have a feeling we're not going to see her again, unless she has another issue with the vehicle disabled (unless she set this thread to post her via e-mail on updates, and she logs in again just to 'prove me wrong')

Nothing wrong with that, of course...to her, the vehicle is transportation, nothing more, and this site happened to exist where she might find an answer to her issue. Good for her that she was able to get the vehicle running again (although maybe the credit should be given to the new mech that she found)

 

[Denalli69]

I have an 03 trailblazer next 4x4 withe the 4.2 and just had the motor replaced because of a rod bearing failure. Since the new used motor was installed the thing won't start, the mechanic said it need a new fuel pump that was the issue. Like an idiot I took his word and put in a new pump. Left the tank down til I knew for sure. Still no start so I checked fuel pressure at the shrader valve at the filter and had 100psi which I thought was high but anyway has pressure. I took the line loose where it goes into the rail and had good fuel pressure there but at the shrader at the back of the drives side of the motor had no fuel there. It seems it's not going through the system meaning through the rail. It has spark will run withe ether sprayed, but wont keep running without the spray. I don't wanna do more, ok actually I'm lost any ideas would help so much.
Thank You,
Denalli

 

[Mooseman]

Which PCM did you use? The one from your truck or the one that came with the engine? If the latter, you may need to do a security relearn or swap it to your original. But then, if it was the security, it wouldn't even crank or turn on the fuel pump. I'd still use the original PCM though.

Did you scan for any codes? Almost sounds like the injectors are unplugged or something is not right with the PCM.

What year motor did you use?

 

[Denalli69]

The original pcm that was in the truck. The new motor is an 05. I'm going to put the original rack /rail on it tonight cause it worked in hoping that the for is bad on the new motor or the rail is clogged, doesn't seem possible but its worth a shot I'm just kind stumped at the cause. Would it show codes even tho it hasn't ran other than with ether?

I knew I should have just bit the bullet and done it myself but really didnt wanna tackle the drive axle going through the pan and all that without a lift. I would have used all the old stuff I knew was working. Plus he was supposed to and didn't thought he knew better lol

 

[Mooseman]

I merged your posts. Please use the edit button if you need to add more info to your last post. Thanks.

Anything is possible. You could get codes if something is unplugged, which reminds me, check the grounds on the block to be sure he didn't forget them. There are two locations with a couple each. They are easy to forget during reassembly.

 

[Denalli69]

I appreciate the help sorry for the posting mistakes. I'll update tomorrow the for didn't make any diff. So I just changed out the rack and gonna try that just a couple things to put back. Oh and no codes

 

[Mooseman]

There's a thing called Noid Lights, basically 12V LEDs, that you stick in the injector connectors and check to see if they are getting a signal while cranking. Can't remember if they are pulsed on the + or - but if + pulsed (check schematics), check the grounds in the connectors. If a ground was left disconnected, that would be it.

 

[Denalli69]

Well couldn't wait til tomorrow it was driving me crazy. So I just got everything all buttoned up and it starts and purrs like a kitten it was the rail with the injectors not sure what was the issue but don't care now it runs again. Good thing I tore into to it there were loose bolts everywhere needless to say Monday mechanics are going to get an earful. Thank you Mooseman for all the help.