I think my ignition took a dump

[Scooter311]

Hello folks, happy monday!
Sooooooo, here I am, on a second date with a girl, and we're buzzing along the x-way with the top off yesterday, having a blast, when mah baby starts to lose a little power and backfires - followed by a bunch of strange sounds, sort of like it was really out of tune and the timing was off horribly!
I dropped the rpms from 3500 to about 2500, and it seemed to go away - so we got off at the next exit at a burger joint and let it cool down (my head temp was steady at 350-ish, but it had held that temp and seemed to run well until the backfiring.)
I took back roads back home, and when I got to my street I throttled it a couple times - it would rev nicely up to 4 grand, and then break up and backfire horribly. I pulled the dist (stupid 009, I know, I haven't put the 050 in yet - I'm waiting for my buddy to come over with his timing light) but I could find nothing obviously wrong. SO I put it back in, got around the block, and it quit altogether. Man, it bucked, sputtered, and backfired so bad - it died and I had to PUSH the darn thing back!
Some neighbor kids saw me and said "Hey mister that's a really cool car! Oh snap, it's a Porsche, cool!"
Oh 'snap'? What the heck is 'snap'? Help me push the car you little butt nuggets.....
ANYWAYS, what do ya'll think happened? I have a CDI with pointless ignition - could my CDI have burned out, or the sensor, or the dist finally gave up the ghost????
Besides all that, my date went great, she had a blast - she loves the car, and insisted I mess with it and she help!
Ciao,
Jeff

[robinaube]

Congrat's on the date. Did you test if you have a spark at the coil? This will tell you where the problem may be. Pull the coil wire off and hold it close to the engine case, then have someone crank the engine. You should see a solid spark jump to ground. If the you don't have a spark, check to see if you have 12v at the coil.

If you do have a spark, then there is something wrong between the coil and the spark plugs. It could be the timing, cap, rotor or distributor itself.

[Scooter311]

Heya
Thanks for the reply Rob
Well, so far I figured out why it died on me, and you can go ahead and laugh - I didn't have the dizzy all the way down the second time and the shaft wasn't seated - hawhawhaw
HOWEVER, it still breaks up at high rpm, and I noticed that when I rev it there's a bit of grayish smoke from the exhaust. It just doesn't 'feel' right, like it's missing something. There' sno knocking, no ticking, no shaking, it's still very smooth and sounds pretty normal - but I can notice there's something slightly different from before, when I hit the throttle.
Could I have dropped (I shudder to even ask this) a valve seat, and what are the symptoms anyway? Or does it still sound electrical? I took the CDI box apart, and there's nothing burned or shorted out, so is there something in the distributor itself that could go bad - like the advance system under the top plate?
I'm thinking:
loss of power/breaking up/backfiring = distributor advance

smoke when whacking throttle = poorly burned mixture as a result of dist problem

If it were a valve/mechanical problem, would it even run at all? She still starts and putts around nicely, which has me questioning a major mechanical problem....

Tonite I was going to pull the intakes to check my sparkplugs, whick would afford me an easy look-see at the intake valves.
Any more ideas, has this happened to anyone here?

Cheers

Jeff

[Jason Porter]

If you dropped a seat, you wouldn't even have to ask, it's nothing short of catastrophic! First you hear a clatter, followed usually by a crunchy sorta snapping sound, followed by a helicopter sounding lack of compression. It's very depressing, I remember the day mine dropped.

You're points may be gapped incorrectly, or you may have a mixture problem. What size jets are you running? Maybe they are clogged. A lean mixture could cause backfiring and a loss of power.

[robinaube]

Can you replicate the misfire if you just rev the engine in the garage or does the misfire only happen when the engine is under load?

I don't remember if you have carbs or FI. High speed misfires can be caused by lean mixture (low fuel pressure or dirty injectors) or ignition problems (bad plug wires, dirty plugs).

If you have carbs, the main jet size could be too small or the same ignition problems above.

[Scooter311]

It's carbed (dual 40idfs) - now that you mention it, I can crank the revs up in the garage (and see a little smoke from the exhaust from both cyl banks as well), but when driving it under load, at higher rpms (if I hold my shifts until 4000 or so) it breaks up.
The other thing is my intakes are really short an' stubby, and I can't check my plugs without pulling them off - tonite's project A friend said maybe the plugs are shot - after 1700 miles? I suppose so, but it still seems that there are other sinister forces at work here.
Sigh............

[SGB]

Have you slapped on a new rotor and dizzy cap? What about fuel filter? Actually, I think it sounds fuel related. At 4k you should be off the "idle circuit" and pulling gas through the main jets in the middle of the carb, on top between the barrels. I think you should replace those distrib parts and replace fuel filter. Then pull the needle valves, idle jets and main jets and blow 'em out with compressed air- also blow into the holes where you pull the needle air-bypass valve. When mine did similarly (also 40 idf), it was because of crud in the circuit somewhere. If you do pull the intake manifolds you should take the tops off yer carbs and look for junk in the bowls.

[robinaube]

I agree with Scott's comments of checking the basics. I think the white smoke and the misfire are two unrelated problems. I suggest working to eliminate the misfire and then focus on the white smoke. When was the engine running right? And what changed since then?

[Scooter311]

Last night I pulled the intakes to get to the plugs - 3 looked a little rich but OK (the porcelain had a dark chocolate color along with being dark around the rest of the plug), however #3 looked strange; very sooty, and there was a lot of white around the outside (from where the socket attaches, down past the threads, and the tip had green splotches on it. I even showed it to someone else and asked what color it looked, and she said "GREEN". What the heck is that ? No evidence of an air leak or blowby past the sealing ring either.
I don't know why I forget the simple things lately, what a doofus! I have the carbs off, and I'll thoroughly go through the fuel system tonite - I have a large inline filter as well that I'm certain could stand a look.
I also couldn't see into the intakes like I thought I could, but the sparkplug holes looked fine .
Noone nearby had a rotor or cap in stock, so I have wait a bit for that one - I bought new plugs last night, but they were out of stock for the other stuff. The rotor has a small burned plastic section under the tip, and the cap looks new. It was getting dark and I don't have lights in my garage where I keep the car, so I had to quit.
I started it to pull it out of the garage and it sounded bad, it even knocked a little this time, but it just doesn't sound like a mechanical problem.......
Fuel and carbs tonite, we'll see......
I appreciate the help so far, many thank-you's

JEFF

[Scooter311]

Happy Monday everyone, and a little update......

Thanks for the help so far, it turns out a couple things happened at the same time, but it's still messed up The main fuel filter was clogged, and it appears that the #3 spark plug may have been loose. I had feared that I might have cracks around the plug hole, but I squooshed my head, upside down, into the compartment and looked at the plug hole, and it looked PERFECT..... I couldn't see anything obviously wrong - so I put in 4 new plugs, and started 'er up. It doesn't smoke, and I can drive it and overrev it and it runs smooth and clean with no smoke, and you'd think that was fine, but it's just not right, it's missing its 'thump' - I don't know quite how to describe it. It has trouble idling, and even backfires a bit too, I've tried redjusting the carbs, turning the dizzy, EVERYTHING, and it just doesn't seem to run right. I've gone over everything external, and I fear that it sould be something camshaft related, maybe a worn lobe/lifter?? There is a slight knock that seems to come and co when I turn the distributor or adjust the air screw on the #3 carb barrel as well I have noticed.
I did drive it, and it lacks the pull and the gnarly hit that it had before this all happened, it lost it's oomph. Crap.
What do you think, could it be cam/lifter related? PLEASE tell me there's a way to check it without pulling the motor!!!!!

Crap....




Is there a positive side to this? Why yes, my fellow Pelicanites ---the chick I had the date with REALLY likes me, and SHE REALLY LIKES THE CAR - And wants to help me with it - and even said it would be cool if she had one herself to work on! Oh yeah, and is she ever cute.....
Well, doobie-doobie-doo

[silver2.0]

My advice is to go buy a timing light. 2 things most commonly cause backfiring, accommpainied by loss of power: your timing is too far advanced- you proably wouldn't loss power but might have some pinging; or your jetting is too lean at some point in your carbs. Hope this helps. Hope your date is understanding!

Slightly off topic but your date comment reminded me of a date I had with a girl once. I had a datsun 240z with a 400ci small block chevy and a 5 speed when I was 17, and I took this girl out for the first time. We were coming home about 2 am, and the throttle linkage craped out on the freeway. Apparently, when I did my motor swap, I didn't have the linkage lined up just right, and my shaft broke by the heim joint. She was super cool about it, and gave me her leather shoe lace to tie the linkage back together! Sure as "snap" , it worked, and when I went to take off again, it wouldn't go. I had lowered it so far, that when I pulled over, it got hi centered where the pavement ended! Luckily I have cool friends, and I had a couple buddies drive out, and we lifted the ass end of the car back on the road. I had to be to work by 6 am, so I just drove her home, and drank beer with her until it was time to go to work again! Those were the days. Enjoy it scooter!