'02 suddenly running like crap

[BLINGMW]

My 2002 was restored in '99 and I've been daily driving it for almost 2 years. Runs great every day. It's got a Weber 32/36, Pertronix ignition, larger alternator, headers, (all really common upgrades) but other than that the engine is stock, it was new in '99, compression is good, and my time with it has led me to believe it is in good tune.

Today after a drive to Richmond, stopping in Charlottesville on the way back, I got off the highway and suddenly it was barely idling, running really rough. I've never seen it do this. Quick inspection over beers with John and Brian led me to believe more beer would solve it. :dunno: It didn't. I got it back to Roanoke under pretty normal highway speeds, oil pressure and temp were fine, but it flutters badly on low-speed acceleration, idle is low and engine shakes violently, but under load and at medium revs... it seems nearly normal. Strong fuel smell. Backfiring a lot. Sounds like a tractor coming up the neighborhood streets.

I thought I was down a cylinder, maybe ignition.
Pulled the plugs figuring one would appear fouled, and they all are identical. Fairly white though. Inspected cap, rotor, wires, they aren't perfect, but seem ok. Vacuum leak? Couldn't find a loose or even brittle hose. Pulled off air filter, carb butterflies and choke plates appear to be functioning normally... though I'm no carb expert.

I figured for it to suddenly turn to crap, I'd find something obvious. What am I missing? Tomorrow I'm going to check the timing, possibly the tensioner failed and it jumped a few teeth? Other ideas? :|

[CaptainHenreh]

It desperately wanted to be hoisted in the air like a triumphant conqueror returning to Rome.

And you crushed its dream.

[JustinG]

Don't white spark plugs = a lean condition?

Check your fuel pump? Clogged Jet(s)?

[BLINGMW]

i'll be a little less lazy tonight, get out the timing light and rule out the ignition before i get too crazy

[.RJ]

Bad gas.

[JohnC]

Chan - where did you get gas in Charlottesville?

[D_Eclipse9916]

Bad gas.

Euro cars dont run well on that hippy crap out of charlottesville :lol:

[.RJ]

Either that or something happened to your ignition - distributor out of whack, ignition coil dying, etc.

[ViPER1313]

I'm thinking timing or ignition. The back firing really points to the timing being way off. Is the distributor vacuum or electric advance? Making sure the base timing is correct and that the ignition advance are working would be where I looked first.

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[SlimKlim]

It could be the timing or ignition but to me it sounds like it might just be some shit that got lodged in the carb. Have you taken the bowls off it? I'd check the floats and clean the jets out just to rule that out.

Do you have a timing light?

[ScottyB]

if its smelling like gas i'd think super rich exhaust due to bad spark or ignition.

check grounds, timing? what Adam said about the dizzy advance makes sense

[PDenbigh]

It ran out of beer!

[ViPER1313]

It could also be a clogged low jet in the carb.. that would also explain why it runs well while under throttle but like crap at idle.

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[SlimKlim]

It could also be a clogged low jet in the carb.. that would also explain why it runs well while under throttle but like crap at idle.

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[.RJ]

It could also be a clogged low jet in the carb.. that would also explain why it runs well while under throttle but like crap at idle.

Very unlikely to happen if its daily driven. It would need to sit for 3-4 weeks or more, unless the fuel filter is not working or failed.

[ScottyB]

pour RB+V in the tank, drive in anger

[Jake]

pour RB+V in the tank, drive in anger

Popov > Seafoam? :dunno:

[BLINGMW]

Well now I'm really confused. :|
It IS running on 3 cylinders. When I pull plug #1 with engine running at fast idle, it doesn't change a thing. The other ones clearly do.
But the timing light says spark is going through wire #1.
And when I use my little spark tester, one of these:

The spark is very much there when cranking, appears just as hot as the others.
Bad plug you say?
I swapped plug 1 and 2 and it's still cyl 1 that's dead per the "pull the wires test while running". And 2 is working. So plugs are fine.
Compression test on cyl 1 is also fine, pulled valve cover and there's no broken rocker arm or something like that.
And since it's a carb, If 2,3,4 are getting fuel, 1 probably is too.

Now what. :dunno:

[Apoc]

And since it's a carb...

Well there's your problem.

[BLINGMW]

I had to double check my results, so I tried pulling wires while running again, swapped plugs with #3 this time... and you know what, cyl 1 wasn't totally dead. I thought it made no difference when I would pull that wire, but it does, just so much less than the others. And the engine runs smoother without it, and backfire goes away completely! I swapped wires, cap, rotor, none of that helped.

Guy on the 2002 forum was suspect of the Pertronix, and it made some sense. Maybe it was triggering late on cyl 1 and not the rest? What do I know?

So I found a bag with points and capacitors... I don't know anything about these, I've never messed with points, car came with the Pertronix. Pulled out the pertronix, swapped in the points system and adjusted per manual. Fired right up. Runs like crap. Cyl 1 still barely helping and now the ignition timing is messed up. 2AM so I came up here to post my double failure and go to bed with the intention of checking ignition and cam timing tomorrow and valve lash.

Then I see on the 2002 forum:

... Loose a vacuum cap?

A vacuum cap eh? Ran back downstairs. Like the ONE ON THE INTAKE RUNNER TO CYLINDER ONE? Where I see a tiny little test port with no cap on it? Found something to cover it and THAT WAS IT!

That was it all along.

Well that was "fun", I learned a lot at least. Maybe I'll even leave the points on in case of nuclear blast and EMP on Dec 21st.