I've got a 93 S10 Blazer, 4.3 W. For the last two months or so, it'd been missing off and on while driving. It would run fine for a little bit, then misfire for a while..back and forth. The cap, rotor, plugs and wires are only about a year old. They're still in good shape. I also replaced the ignition module last year. But there's a strong smell of gas...like it's not burning it all. My MPG didn't really suffer but power did. Now..today it started, ran for 15 seconds and died. The starter either turns over twice and stops, or just engages with a bang. Right after it died, I turned it over and it spitfired a couple times until it made a very nasty bang that shook the whole thing. That's when the starter started it's thing. I have no clue where to look. Starter? Coil? Spider injector? Valves? Please help. I love this pain in the rear Blazer.

 

check the spark plugs. i know you said you just changed them but pull out one on each side and take a look, if you have a major internal intake leak you could be filling up a cylinder with antifreeze or oil causing it to missfire.

also it sounds like a timing issue if the starter is cranking and then stops. computer itself maybe since it controls the timing?

 

Yikes! Neither of those sound that nice. Looks like a weekend task!

 

Ok...well, I pulled all my plugs just for the heck of it. Number 1 looked normal. 2 had a small piece of the insulator chipped off. 3 had some carbon build up. 4 had a lot of carbon. 5 had half of it covered in oil. 6 was pretty normal but had a little carbon. I also discovered 5 had a bad wire. But wait... there's more! While the plugs were out, (coil unhooked) I cranked it. I noticed the number 3 wire looked wet. Upon further review, the area below plugs 3 and 5 were gas covered. I turned the key on to make the fuel pump on...no leaks. I put napkins in the 3 and 5 plug holes and cranked it over for about 2 seconds. Both napkins were soaked with 3 being the worse of the two. So I put one plug in, cranked, checked, then pulled it and did the same for the other. 3 is by far spewing more gas than 5. Since I was the only one working on it, I'm not sure how it's coming out, but it appears to be blowing out the plug holes. Any ideas why this would be happening? Bad intake valves? Spider injector not shutting off? Possession by evil Ford spirits? Ok, probably not the last one but at this point I'm not leaving anything to chance! Thanks for any ideas and previous advice!!

 

Sounds like you have a fuel leak inside the intake manifold. I would pop off the upper intake plenum and pressurize the fuel system, inspecting everything for leaks. The 'nut kit' (internal lines) are known for leaking, especially if they are not replaced during service on the CPI spider.

 

The bang you described in the first post sounds like some of that carbon was allowed to heat up, causing pre-ignition. And I agree with swartlkk on checking under the intake.

 

Ugh...I was afraid I'd hear that. As far as I know the spider has never been changed. However the previous owner had no history on it as he got it in a trade and only drove it a few weeks. But with over 204000 miles on it, there's a good chance it has. I've never dealt with CPI systems so this is a little new to me. Looks like I have next weekend planned! Wish me luck!

 

Well swartlkk, again you were correct! I popped off the plenum and charged the fuel system. One of the hoses just spewed gas. I'll replace both since I imagine the other one will probably crack sooner than later. However I did notice motor oil puddled inside the passenger side of the bottom of the plenum? (Where the injector spider is) Not sure where thats from. Thanks!

 

The lines come in a kit. Their about 55 bucks or so from any parts store. Im going through CPI headaches again myself