Cascade Crew

[85 T/A WS6]

1998 Yukon 5.7. 144k miles

Having a bad time starting, It cranks over then it acts like it wants to start then it kind of backfires, like the timing is off because it quits turning over for a sec like something is fighting it from turning.

I thought it was bad gas or water because on freeze days it would not start. I added water remover and filled it up wehn I got it running. Once it runs it runs fine. I had to put 2 portable propane heaters under it to start it last time it did this.

Now I think it may be an ignition problem. No codes come up and even when I put start fluid in there it wont fire.

Im at a loss now, any ideas appreciated.

[Sellmanb]

sounds like your battery may have a low charge (not neccessarily bad yet), which makes the starter not crank as strong (not neccessarily slower), which means it takes more effort to crank.


Just my thoughts?

[chevymad]

That should be a vortec motor. Kind of an offbreed hybrid system. There's a crank trigger behind the harmonic balancer and a cam sensor inside the distributor. There is no timing settings for these motors only a cam sensor setting that you need a scan tool to set. If that was wrong you'd get a code though. The actual ignition module should be on a bracket next to the pass side valve cover. Chevy finally got start and moved it out of the distributor. That said I've never changed one at the shop. These flat distributor caps have a bad habit of corroding real fast, just like the small cap hei's. Take a look inside make sure thats not your trouble. Also these are a re-ordered cap with each bank coming out on their respective sides. I've had many that have shorted out internally and caused crossfiring.

The thing that usually happens when a vortec is hard starting is a fuel pump issue. These motors usually use a single injector(some californian and recalled rigs got individual injectors) and a fuel distributor. The fuel is sprayed out of poppet valves connected to this. These poppet valves require 60psi to make the engine start. If you have 55psi, guess what.. it won't start. I've actually had this problem. Once the motor is running your battery voltage goes up and the pump works better, so once you get it started sometimes they'll run fine.

Other than that I change lots of caps/rotors/ and plug wires on these. Everything else seems to be pretty dependable. GM has had a known issue with coolant temp sensors but I havent run into it on these particular motors. Still a possibility.

[85 T/A WS6]

Thanks Brandon.