Idle Speed and Engine Performance

[ninjazombiemaster]

Heres a video of how its going. All these properties are much worse in the cold, which its getting lately....

http://www.youtube.com/watch?v=2sB0B11Rnm8

Sorry about the video, it looked fine before I uploaded it....but it gets the point across. I'll be heading to the shop in a bit to look at the battery, spark and possibily the Dizzy.

Hopefully this sheds some light on the problem.

[madkaw]

Okay, so you said you checked the carb tune and it was good-can you explain what or how you tuned or synched the carbs?It seems to me a carb tune issue. What experience do you have with SU's and what experience does the "shop "have? Did you check the synch at 3000 rpm?

[ninjazombiemaster]

No, just at idle. I got it to speed, and put propane in the air horn and monitored the raise in RPMs. They both seemed perfect. It's a little archaic, and I could be wrong. The "shop" belongs to my father, who has been doing this around 30 years. He's no carb master, but he knows his stuff. The spark plugs checked out good,I'm working on te timing now.

Edit: looked at the timing, it was basing at 22 and advancing over 40. I trimmed it back down to 10 and will keep my eye on it. The new fuel sending unit comes in a few days, so I'll have it on the lift next week, and will take a look at the fuel pump then. The Distributer looked fine to me, but if it persists I'll take it apart and see what's going on. I'll let you guys know how it runs.

Edited October 8, 2012 by ninjazombiemaster

[ninjazombiemaster]

Okay, we've still got trouble. With the timing back at 10, it now seems to have started backfiring (as in the pop is from the front, vs after-fire) and stalling. I'm guessing the PO advanced the timing in order to half-arse fix another issue. I'll definitely take a close look at the distributor. Any other suggestions or ideas?

Edited October 11, 2012 by ninjazombiemaster

[madkaw]

Better start from ground zero. Set the engine to TDC compression and remove dizzy and check alignment of shaft and alignment of rotor. You might be off a tooth and the way advanced timing was to make up from there. You never know what the PO has done with this car and don't take anything for granted.

[ninjazombiemaster]

Guess so. I'll get around to it as soon as I can. It's tough to find time when its your daily driver, haha. Thanks.

[Lazeum]

How do your spark plugs look like? you might want to check them and try new ones if you haven't done it in awhile.

If it was running fine before and not now anymore, start looking for little stuffs instead of big tune-up moves.

I'm the first to look for major issues but no later than Monday, I got stuck on the side of the road with the Z because plugs were bad (brought it to a shop who did a lot of cold starts to move the car around the parking lot). I put some new plugs, the power was back. it cost me 10-15$ to fix the issue.

Before changing the plugs, of course I've tried to set up advance since the car was backfiring & pop at 3k rpm :/

[ninjazombiemaster]

How do your spark plugs look like? you might want to check them and try new ones if you haven't done it in awhile.

If it was running fine before and not now anymore, start looking for little stuffs instead of big tune-up moves.

They looked fantastic, actually. I double checked the vacuum advance and insured it was indeed working. I think something is causing the timing to drop by a factor of 12 degrees sporadically, and since the timing is now set to 10 instead of 22, it drops down -2 causing a backfire. If thats the case, the PO must have advanced it so that the when that happens, it drops to a healthy 10, and doesn't backfire or stall. I'm pretty new to this so, I could be totally off. But I think I'll have to take apart the distributor and see if something is catching it.

[ninjazombiemaster]

Okay.. Well two nights ago she broke down. The rotor sliced the wires in the distributor and tore them from their sockets, so I couldn't solder it back together. Turns out it was equipped with a Pertronix Ignitor - Don't know how I missed that. Regardless, a $60 a tow and a few bucks in parts later shes running again. Ive got my Dwell at 40 and my timing at 12. That should be fine, right?

Anyway, its still backfiring and stalling and hard to start cold - Once its hot, the only problem is it loses tons of power at exactly 3000rpms. Anyone know the power curve on these cars? I thought it was more in the 4-5k range. Mine seems to haul arse in 1,000-2,500 and then just flop. I'll give the valves another look over, any other thoughts?