Hi all, I have a 96 blazer that wont start and backfire through throttle body.Changed crank positioning sensor, timing chain,cap,wires,plugs. What else should I check? 127,000 miles, seems odd.Any help would be appreciated.

 

Was all that changed before or after you had the issues? Sounds like its 180 out.

 

sounded like that from the beginning

 

So you did the work and its still behaving the same way correct?

Did you also change the rotor, I assume you did.

One of two things is happening. one or more plugs are firing at the wrong time, or you have a mechanical problem where valve timing is off or valves not closing. I would start with a good foundation. Have you performed a compression test?

How did this begin? all of the sudden? Gradually? Did it die?

Please tell us a story, it might have some clues in it.

 

I just bought this blazer, always liked this style, thought it a good fixerupper, sounded as if the timing chain was out like the old chevys. Did not run, just backfired, so I pulled no 1 plug brought it to tdc, rotor on distributor was not on 1 and theres no adjustment for timing.Proceeded to change timing chain,cap,rotor,plugs.Tried to start, same thing.So I changed crank positioning sensor still nothing.I just found another thread says maybe its the intake gasket.Also I threw some fuel down the tbi and there was no effect, crank for 30 secs backfire, nothing.This is a new one on me any ideas?
please help thanks.

 

Pardon me for interrupting..
"replaced the timing chain....." in the context of the problem seems loaded with assumptions.
Especially when combined with 'rotor was not on #1'. Well, where was it, then?
Throw in a CPS and you've got all sorts of possibilities for simple error.

Did you check cam timing before you replaced the chain? You have done it before.. are you sure the shop manual agrees with your procedure on THAT engine?

Sounds like, recheck the basics time... been there, wasted hours because of that.

 

Thanks petty I used the shop manual to re-set cam&crank, chain was really loose & cam timing was off, rechecked all that plus compression today so maybe its fuel, dunno. Thanks. I see others have had this problem but I have yet to see a reply with a solution.

 

My blazer was doing the same thing this past Thursday night after changing my intake gasket, but it's a 2000 model. It took me about 3 hours to finally get it timed. Now that I know what I'm doing it should have taken about 30 minutes or less.

The symptoms: Not starting, Backfiring through the throttle body.

The cause: It was a timing issue caused by my distributor being out of position in regards to the number 1 cylinder.

The fix: I posted the procedures I used to fix it in the following links.

Step 1: First you will need to know how to change your distributor position to the number 1 plug when the number 1 piston is top dead center.
I'm not sure if this link will work on your model, but the distributor on mine could be adusted using a a large screw driver @ 12 inches in length as demonstrated in this video:


‪How to Install Distributor Video-Engine Building Repair DVD‬‏ - YouTube

Step 2: Once you know how to adjust the distributor postion now you can use the following link which will give you easy to follow step by step instructions on how to adjust the timing:

https://blazerforum.com/forum/tech-a...-timing-24373/

The picture in the above link is a little misleading and it threw me off for about an hour. The position for a 6 cylinder is labeled 1. In the picture firing arm (?) looks to be pointing just left of the screw hole on the distributor, when in reality this position was designated by a small triangle with a 6 in it, which was also exactly 180 degrees from the number 1 cylinder.





I hope this helps.

 

good stuff man my 02 blazer is doing the same thing but sunday i had it started and driving and i let it sit over night and it started but then it sat for 24 hours and wont start again but i have the same symptoms as you guys did. so is this my problem?

 

have the icm checked