Stupid_fast

Hey all, I'll try to include as much information here as I can remember and think of. I've had my car running for a few months, over that time vastly improved how it runs. Its a rebuilt L20b(hard break-in), weber 32/36 w/ L16 intake/ no smog, dual point dizzy modded to pertronix with ignitor coil no ballast, headers and full 2.5" exhaust(sounds mean... I doubt the muffler is doing much), NGK iridium IV plugs(replaced twice, these have about 200 miles on them) with bosche wires, pretty much every accessory is new ... everything has been bought and installed by me... I got the car with longblock motor, trans, and rolling shell. Has about 3k miles since I first started it. Comp was 170-170-175-175 last I checked. The PCV system is hooked up with the upper one filtered, the one out the block goes back into the intake manifold with a PCV valve. Dunno if that's useful. It runs strong, makes really nice torque even low rpm like 2000 up hills it does better than I expected (I live in oakland hills, some really steep stuff) and even runs pretty strong in the high end, pushes it along as fast as 100hp will go. I've run it the hard break in(theres an article online I followed.) Oil and K&N filter changes at 20 miles(30w), 150 miles(changed to 10w30), 1000 miles using valvoline VR-1 non-synthetic racing oil. I've changed the fuel filter about 200 miles ago, valve lash has been done about 5 times since it first ran, fixed some low voltage coil problems, fouled plugs, ect, tuned carb countless times.(to weber recommended lean best idle) I have checked over and over again for vacuum leaks, since it is so likely yet I have found nothing. Tried spraying carb cleaner around all the gaskets, no change in the idle. Now for my best description of the problems... The idle is rough, it will have troubles stalling around corners, ect if idle is much under 800rpm's, I've adjusted and readjusted the carburetor over and over again blasted it out with carb cleaner, adjusted the float, checked the ignition countless times and everything has made it a little better but never solved it. The idle is most smooth at 900-1000rpm, which would be OK but its not optimal I would rather have it running right. Something odd I noticed, if I unplug the idle cutoff solenoid(anti dieseling) nothing happens, I pulled off the jet and applied power watching it work. It definitely works but makes no change to idle? Going to replace it. Since I'm getting a new one anyway, if I remove the jet and cut the needle to bypass it would this be a good test if that is in fact the issue? When driving, if I get on the throttle hard sometimes it will cut out for half a second and then the power will come on, but half the time it will respond immediately. Sometimes it will do it when shifting, I have to be really gentle on the throttle to avoid it. when running, if I gradually increase throttle and into the 2nd progressive barrel it will run strong at WOT. If I get to WOT too fast, really onto the 2nd barrel it will bog a bit, that's normal of course just needs rejeted. I notice if idle I hold the throttle about 15-20% open, there is a spot where it runs really rough. This is probably related, seems to run pretty smooth through the rest of the throttle range. Responds well from idle to lots of throttle, revs right up. There is a lot of water coming out of the exhaust, I notice it while idling in my driveway tuning in... Its odorless and is not slimy like coolant, just condensation? I pulled the plugs and they are a nice tan, indicates the fuel ratio is running nicely? The motor is timed to 12btdc, valve lash is set I spend an hour on it getting the valves perfectly adjusted, again improved the problem but never made it go away. If I advance the timing to like 25btdc it will run a bit more smooth, but not much. Thanks for any advice or ideas. I've tried almost everything I can think of and have gathered from extensive online searching. Nothing has helped by much so far! I can get a video of it if it would be helpful. TL;DR, L20b, Y U NO SMOOTH?!?!!!1!!!!

Its been done on L6's. There was an LSx swap thread in the Z section, I'm pretty sure he pulled out an L28 with a 6-speed on it. GLWS. edit, nevermind i was wrong, it was a Z32 trans on a L28... http://community.ratsun.net/topic/27383-no-more-ls1-v8/

Stalling fixed! Bogging/hesitation is better but still there. Float adjusted a few times, its good right now could use some more adjustment. The spark plugs got carbon fouled due to the coil only getting 6.5v, fixed the wiring and now full 12v at coil. Replaced the plugs with new of the same NGK iridium IV's, decided to leave gap at stock (0.050) to see how the bigger coil handles it, runs nice and smooth 2,000-5k's(tach is not working so have not pushed it much). Idle is a little rough, maybe the gap is too big. Does not like to idle under 800rpm still, will idle really rough. Adjusted valves cold as accurately as possible (like 5 min per valve getting it just right) runs better now! Timing adjusted to 12* , I need to redo that since the plugs replaced. Thanks everyone for help...

Oh.. whoops.

I had a very similar problem which has been improved by finding a problem in the ignition coil power... was only getting 6.5v ... 8v running. Check the coil with a multimeter, see if its getting full 12v. Maybe someone suggested this already, but I just skimmed the thread... It was cause by some high gauge wire in the tachometer circuit. Try it, check over electrical. Never can be too sure with the wiring.

I get paid Friday, can't wait to try this.

Yeah it runs GOOD now, not perfect. Stall issue is still there but barely noticeable and rarely does it now, still boggs/hesitates also in certain situations if I come on the throttle suddenly, not bad. Definitely runs more smooth, sounds nicer, and more power now that there is full 12v going to the coil. I set timing to 12, runs good. Idle still a bit rough, 800rpm its smoother than it was before though. Improvement is always nice! I'll replace the plugs next time the car is cooled down and check valve lash again. Thanks for the help.

The blue air cond wire I'm using for the cig lighter/DC jack... I wired it up nice so I can run a power inverter through there if I wanted!! Yeah, the 3 pin connector next to the wiper motor will work fine for the idle cut/choke... seems OK with a test wire on there. I found the problem!! It was my error, I screwed in the idle cutoff too far... blocking idle flow. I loosened it a bit, and now the car runs great!! I broke the O-ring though... gonna get a new one at the store. Thanks for the help.

Yeah I disabled the choke relay, I'll take a look at the circuit again and find a good place to pull power from. Tach is inline with the black/white ... one side goes into tach, other side comes out and goes to coil +... I like tachometers, as I don't want to exceed redline as I'm eventually wanting to autocross it. Timing mixture is like 1-1/4 turns out, tuned and retuned, idle speed screw is barely touching also, in maybe 1/2 - 3/4 turn ... 800rpm I will check the idle cut again, make sure its nice and clean. Timing set to 12 deg is OK, but runs better at like 25 deg.. not much change on the stalling. There is only the stock 32/36 return spring, the only other ones are on the pedal itself, otherwise the throttle will never close fully... Throttle does not slap shut, the springs on the pedal apply very little pressure on the throttle, all my testing was done opening the throttle on the carb itself, not pushing the pedal down. Gonna get back out messing around with it... thanks.

Thanks.. I found it! There where two high gauge wires from the blk/wht after the fuse block going to the tach... I hooked up the blk/wht wire bypassing that and it now gets about 12v on its own, and about 11v on + side of coil with everything plugged in. Idle cut/choke take like 0.5v, pertronix takes a little also. There is a 3-pin connector next to the wiper motor one, has 11.4v on one of the pins when ign ON, can I tap off this to get power for the choke/idle cut without effecting anything else? Now how do I properly wire up the tach? it does have to be inline with the blk/wht? If so I'll get some new same-gauge wire and hook that up correctly. Now its running better, idle has smoothed out. Have not driven it yet, just ran it in my garage(with door open, exhaust facing out!!) I tuned the idle as best I could and its almost smooth at 800rpm(can go lower... but rough, spark plugs need replacement already, I have new ones to go in soon.). There is still a lingering problem, If I revv it, hold it at around 2,000 rpms then drop it suddenly, it will die. When I throttle hard say idle to 25% to 0% it will respond fine, revv right up drop back to idle. This is the same problem I had before, it seems worse after fixing the ignition and tuning the idle? I've been messing with the timing too, it likes around 25 deg to run the smoothest, stalling does not seem to be effected much anywhere from 10-25deg advance. Just spent like 20 minutes fittling with things while it was running to get it better but with no luck. Before fixing the ignition i had nearly gotten it do go away, tuning the float timing ... It rarely did it anymore, but now it seems to be as bad as it first was? Thanks.

Last night before I posted I removed all the wires to test them indavidually, the blk/wht was getting low voltage on its own. Yeah, no balast. blk/wht, blk/blu, and pertronix red are connected to coil +. I do have the choke and idle cut jumped off the coil also, I removed those and only saw a 0.5v increase in voltage. Didn't run any better with them removed. I'm pretty sure I found some shitty too high gauge wire in the ignition circuit(blk/wht wire next to fuse block is going in to the tach through some higher gauge wire???), I just printed out a nice wiring diagram and am gonna go check it out. I'm gonna go take a look at it in a minute, see what I can find. I'll post back with more info if I don't find the problem. Thanks!

Wow, good info. Thanks! I always was under the impression that drilled and slotted rotors gave better cooling... Looks like I'm getting slotted rotors for my brake upgrade.

Hello everyone, my L20b has been running okay for a while, tuning the carb has gotten rid of most of the issues. The car is a 72 510 wagon m/t harness, L20b is rebuild, new carb(32/36), new dizzy(napa reman), new cap/rotor/plugs/wires, fuel pump, fresh fuel filter(less than 100 miles) ect. Has about 3,000 miles on it since I got it running. Plugs have been replaced since then, and I've got a new set waiting to go in. I've got a 60 amper internally regulated alt, other than that most is stock. It still runs rough, but pretty strong and decent power through the midrange(3-4k's) seems to drop off after 5k's and not get much power... ? also got a carb pop/backfire at 6k...(un-burnt gas maybe??) I decided to check over the ignition system, and found the coil + is only getting about 8v with the key to ON, and 6.5v with the car running. Isnt it suppose to get 12v?? Its a pertronix ignitor, with pertronix flamethrower coil. Bosche plug wires, NGK iridium premium(if it matters...). I have noticed some weird wiring done by a P/O, and I have to dig in and search through it but I wanted to get some more ideas of what could cause this low voltage. Battery is getting 12.76v(off) and ~14.5v while running. Most of the other wiring is good, most things seem to be working fine. (fan, lights, radio, wipers, ect...) Thanks.

The Forza series are such amazing games, my favorite to tinker around with cars and generally a lot of fun. Unfortunately I have a logitech G25, which microsoft wont support. This game really should be on windows, but sadly it will never be.

Yup.. my 72 does not need to be smogged. Or inspected. Or anything, really. Just registered, they sent registration and its done. For any pre-73 in CA.

Yup, was nice to talk to and meet everyone! Hmm about backing in and taking one space, yes unless you've got a kenmeri.

^That was your skyline? Very nice to see people with such nice condition cars bring them out! No pictures... ?

Hmm always need more gauges... Price?

Meh double clutch only when you have to , my ZX trans grinds into 5th so I double clutch up! Also any lower gears downshifting I always double clutch down, 2nd will make some nice chatter/whinning if I don't double clutch down from 3rd, same with 1st. (if I need 1st ... slow speed ~10mph corner? faster pull-away) Same with even a great condition S2000 or 350z trans, blocks you from going into 1st if going over 15mph(input shaft turning too quick ... synchro acts as clutch), hard to get into while traveling ~10mph ... So if needed clutch in and give it some revvs, goes right in. Helps smoothness of driving and probably saves some wear. The reasoning for the lower gears is that I live in the hills, all the roads around here are steep. There are some really hard hills that I roll up instead of stopping on. Too hard to get going, or e-brake wont hold the car ! Sometimes 1st is required. Won't accelerate in 2nd at 10mph up some of these hills here. And lol @ the fast & furrius, almost blew those intake welds! I wonder if they are JB-welds? Nevermind JB-weld is too strong... JB quik?

There was a kenmeri.