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HELP Engine won't start, it has spark & is getting gas

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olblu55

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Hi everyone, I am new to the forum and I really need some help. I have just finished rebuilding my engine in my 78 blazer and I can't get the thing to start. It cranks fine I have verify spark and it is blue; it is getting fuel; and I have even pulled everything to get to the timing chain to make sure all timing marks lined up, they do. I have gotten a few backfires out of the carb but other then that it does not even try to start. I am running out of ideas, so anything would be helpful. :confused: Thanks
 
I'm guessing that the timming is off. Pull the distributor out and reintall it with #1 at TDC on the compression stroke, or around 8* advanced (looking at the timing pointer).
 
That’s what I thought originally, that the timing was 180 out or I had some thing off when I rebuilt it. That’s when I decided to put it apart again to check the timing marks and to verify that when at tdc the distributer was pointing to the number one cylinder. Everything checks out, it was how it should be. But even as you said it the timing was out 180 degrees it would still try to run, it is not even trying.
 
have you checked cranking compression? Are you sure the valves are adjusted right....do you have new lifters, and did you purge them in oil?
 
Sounds either 180 out or it has a huge vacuum leak. When the dots on the gears are aligned, that is exhaust tdc for the #1 cylinder and compression tdc for the #6 cylinder.
 
The distributor is 180* out. With the timing cover off the dot on the cam gear should be at the 12 O-clock position and so should the crank gear dot be at the 12 O-clock position and the distributor rotor should be pointing to where ever you have the number one plug wire. Make sure you have the wires run correctly in the 1-8-4-3-6-5-7-2 orientation in a clockwise rotation.
 
Thanks Guys, this is the first motor I have completely rebuilt so I guess this could be a rookie mistake I currently have the timing dots on the crank and cam facing each other and the distributor facing number one. But if I am understanding you right, at this point if I turn the motor so the rotor is pointing at the number 6 location, pull the distributor and reinstall it so that it is facing number 1, I should have then corrected the 180 issue, and it should start? I will try this later when I get off of work, thanks again.
 
olblu55 said:
Thanks Guys, this is the first motor I have completely rebuilt so I guess this could be a rookie mistake I currently have the timing dots on the crank and cam facing each other and the distributor facing number one. But if I am understanding you right, at this point if I turn the motor so the rotor is pointing at the number 6 location, pull the distributor and reinstall it so that it is facing number 1, I should have then corrected the 180 issue, and it should start? I will try this later when I get off of work, thanks again.
Click to expand...

You've got it. People make the mistake of thinking that when they install the timing chain and gears Dot to Dot that that is TDC for the #1 cylinder (it's actually TDC #6 cylinder but easier for you to get the timing hooke up correctly). Once the timing is all hooked up then the engine needs to be rotated until the Dots are both at 12 O-clock then it's on TDC #1 cylinder.
 
Ok I tried what I mentioned in the last post and still no luck. It won't start. I had one loud pop/backfire from the carb, then nothing. Is there anything else I can try?
 
I still don't think you've got the distributor lined up right. What method are you using to determine if the no. 1 cylinder is at TDC?
 
Originally I aligned the timing marks and pointed the rotor to number 1. When I was told that was incorrect I turned the engine over until the rotor was close to number 6. I then turned it over by hand checking to make sure that the number one piston reached it full upward stroke by allowing it to go all the why up and then just barley back down again.
 
olblu55 said:
Originally I aligned the timing marks and pointed the rotor to number 1. When I was told that was incorrect I turned the engine over until the rotor was close to number 6. I then turned it over by hand checking to make sure that the number one piston reached it full upward stroke by allowing it to go all the why up and then just barley back down again.
Click to expand...

At that point is when you should have pulled the distributor and aimed the rotor to the #1 wire and dropped it back in (i'm assuming you didn't do that since you did not say so)? Either that or you should have moved all the plug wires on the distributor cap with #1 wire where the #6 wire used to be and then ran the firing order (that is not a wise thing to do though in case anyone other than yourself ever has to work on the truck).
 
At this point I did pull the distrubuter and aim it at number 1, still no dice. The blazer will not start.
 
Check your firing order on your plug wires. I bet ya got them all backwards. If not your timing is still way off. Yes these are your choices.
 
Thanks for your help

I have got it to start. It ended up that the valves were adjusted to tight, not allowing the cylinder to build compression. Opps, I must have miss-interrupted the Chilton manual, because after I readjusted them it fired right up. Thanks again to everyone that give a suggestion it at least gave me something to think about.
 
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