Has fuel, has spark, cranks, won't start
 

Hi All,

While driving down the highway, the engine abruptly shut down, almost as if the ignition was shut off.

I checked for spark, good.

The fuel pump has been acting up... so I tried starter fluid and gas down the throttle body.

She cranks and almost wants to start.... but just can't get over that 'hump'.

The truck has nearly 200,000 miles.. bought it used at 180,000 so we don't know much of it's history. We are replacing cap, rotor and fuel filter for now... we will eventually replace the fuel pump.

I'd like to at least get this thing firing on the basics before replacing expensive parts.

Any advice appreciated. Thanks in advance.

2000 Blazer 2DR/2WD 4.3

If the problem is fuel related, adding fuel should make it start right up. The spark needs to jump a half inch gap, and it needs to be a nice blue, not orange, spark at each plug. AC Delco distributor cap & rotor would be the first step. Don't waste time and money on aftermarket stuff, it doesn't make the grade on this engine.

Thank you for your reply Captain Hook.

Yeah, the spark was orange (using a screwdriver method), and combined with the information of how the engine abruptly shut down initially, I was thinking the problem is probably spark related.

Haven't had a chance to change out the cap and rotor yet. We picked up Duralast from Autozone. Should we take it back and get ACDelco?

Thanks again..

Before you return the Durlast, take the ignition module with you....they may be able to test it. Reads like the spark is low which could be coil, ignition module, cap, rotor, wires.

Since the engine shut down abruptly, I think ignition module.

Good luck.

The ignition module is basically a relay. The PCM commands the module to fire the ignition coil, and if the coil is producing spark, it's probably not the module. The module testers in the auto parts stores are there to look impressive and sell parts, don't trust them for their accuracy. Return the Duralast stuff ASAP and do a quantum leap up to AC Delco.

Thanks for the replies, AC Delco it is....

I'll keep you posted.

Quick update...

Changed out the cap, rotor and Coil wire, it now fires but runs rough... with a smell of gas. Obviously some of the cylinders aren't firing. Next we are changing out a full wire set and plugs... after that... the coil.

Ignition module seems to be fine... in fact, it has no dust on it (nor does the heat sink).. so I'm thinking it was changed recently.

I also noticed some idiot who owned the truck previously completely cut out the access flap inside the passenger wheel-well, probably because it was too much of a pain to hold the flap up while changing the plugs (rolleyes). The drivers side flap is still intact. They probably only replaced the plugs on the passenger side.. found out the drivers side is more of a pain-in-the a**... got the truck running.. and then sold it.

Will be back to update after the plug/wire change-out.


Edit: by the way... we picked up AC Delco plugs 41-979. The default gap on the plugs is 0.062". The specs on the truck call for 0.06". 0.002" is less than the diameter of a human hair. I think I already know the answer to this question... but just want to make sure, we don't have to gap the plugs for a .002 difference... right? :)

AC Delco 41-993 plugs, .060 gap. Plug #3 is the worst one. Unbolt the steering shaft from the gear box, and move the shaft aside, takes 5 minutes. DON'T turn the steering shaft or wheels when the shaft is disconnected. The rest of the plugs are easily accessible through the wheel wells, with the front wheels off the ground. Use good quality wires, not the cheapie store brand.


https://blazerforum.com/forum/attach...ine=1451789013

Wow.. .that was fast... Thanks CH!

Yeah... we are only getting AC Delco parts from now on... I've read quite a bit on this forum and elsewhere of the nightmares people have gone through getting aftermarket parts for this truck, prompted by your post above...

Ok then.... 41-993 it is. Back to Advanced Auto tomorrow.. :-)

Thanks for the diagram as well...

Edit - I also found this video helpful...

Viewed quite a few of his videos... good stuff.

Good video, but as I mentioned in post #8, for plug #3, unbolt the steering shaft, waaaay easier than fighting with a universal or a wrench on the socket. You can see it, and get your hand on it at the same time!