97 K1500 5.7 Vortec Ruff Idle after replacing Spider

[OlDave]

97 K1500 5.7 Vortec Ruff Idle after replacing Spider....

So this all started when the intake manifold started leaking like most do after a while.

So i replaced the gasket, as well as the Spider, plugs and wires, all four O2 sensor's, the distributor, rotor and cap.

oh and all the seals on the Plenum. I have checked the vac lines and the spider seal.

 

So here is whats going on. The truck starts but has a ruff idle like a miss firing. When i drive it, I get to about 40MPH and it starts really jumping and chugging.

It misses really bad. When i get back down to about 30MPH it runs ok but ruff like a miss.

I pull the Mass Flow connector off and no change.

 

???.... can the distributor be off one tooth and cause this. Or am i looking for something else...??

 

Thank You all for helping an old guy here...

Dave Davis

[Flash2004]

What's a spider? That's a new one to me, I had a girlfriend once who described the distributor as an octopus, but never a spider. 

[Flash2004]

But best guess from 12,000mi away is you're at least a tooth out in your timing - or that would be what you'd want to rule out first. I don't know about the modern engines, never have to look at them much and I'm a diesel tech anyway, but it was pretty easy in the old days to set the crankshaft pulley so the timing marks aligned, then have a look to see if the rotor was touching or even close to touching the relevant contact. Since you've had the distributor out that's the most likely cause.  

[Justin101714]

Best way to verify timing easily would be a scan tool that shows “CMP Retard” it should be between -2 degrees to +2 degrees, with zero being optimum. You check for this reading at 1,100 RPM. Im sure you’ll find what’s wrong after that.


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[Jsdirt]

Sounds like you've got a dead miss. I would make sure that spider has all 8 "legs" working - one, or a couple might be dead.

 

Remember, new means Never Ever Worked.

 

I would get in there again and make sure everything is good - no pinched wires, or unplugged injectors.

 

Before you do that though, verify that you have spark to the affected cylinder(s).

[OlDave]

I"m very old school as well. And the Spider is the fuel injection until..

Any thank you all for the help... Looks like i start over.. was hoping i just missed something..

 

Again..

Than You

[Jsdirt]

Gordon, here's a couple pics of a new spider assembly, going into a '96 Tahoe, 5.7L - you can see where it gets it's name from, with its 8 "legs" :

 

 

 

Dave, if you're going back in there, press down on each injector electrical connection - one or more may not be fully seated.