No idle. Some power issues. Help?
 

So I replaced my leading ignitor and that seems to have helped (i think?) but now the damn thing doesn't idle!

So, before the engine gets to operating temp (and the choke is stuck out at this point), I checked for vacuum leaks. I could find none.

When I jab the gas, it dies. If I slowly let into the throttle it will rev up. Above 3k or so there is little hesitation. Overall it seems like it doesn't rev as quickly.

Could it be as simple as my idle mixture being too rich and my idle being set too low? Does turning the idle speed screw clockwise raise my idle or lower it? (d'oh)b

Or could I just be missing the vac leak? I'm going to remove the rat's nest as soon as I get a blockoff plate.

Thanks, guys.
Vic

Check the exhaust pipe for how much pressure you have. If it feels like it's low, cats may be plugged. Warm up the engine and check timing. Vac leaks are best found at operating temp. Check the fuel filter. After you have done that, then play with the idle and air mix screws.

might it be the acelerator pump diaphragm perhaps?

Good call, forgot about that one, When they fail, they tend to leak externally too. Another possibility is the pump ball and weight are gummed up and sticking.

Well it was idling fine. I had messed with the idle mixture screw, and I messed with the idle speed screw but I'm not sure if the latter had any effect. Then I got a new air filter and popped off the air cleaner box a couple times and now it won't idle...so I thought it was a vac leak. But now I can't find anything. I wouldn't think that the accel pump would up and die. I tend to believe it's something I've done.

id say while your at it, rebuild the carb. most carb kits are only like 20-40 bucks and not too hard to do. if rebuilding the carb doesnt fix it go from there. wont be a waste anyway, good to keep the carb running 100%

well reason i said accel pump is i had the same trouble. it would idle rough but when i tapped the throttle it would bog and try to die, if i eased onto it it would slowely rev up to redline, but anytime i would get on the throttle hard it would bog and try to die

There is one hose that goes to the bottom of the air cleaner that affects idle. If the bottom of the filter assembly is off, this hose must be plugged, otherwise you have a large vacuum leak.

Bump, any other ideas before sunday, when I can work on it?

Turning the idle speed screw clockwise will raise the idle.

So you do have leading spark?

P.S. how's your sex life going? ;)

Heh.

It appears I have leading spark. The car runs and is driveable but it bogs bad, tries to die, and doesn't idle. But I can drive it around the block.
I didn't think it would run well enough with just the trailing plugs...At any rate, the ignitor issue was heat related. When the car got warmed up and when it was hot outside, the car would miss, couldn't accelerate. Turn the key off and then back on, problem solved, for a little bit.

Anyway. I am removing the rat's nest sunday, assuming my parts from Mazdatrix get here when they're supposed to. If it's not that I guess the carb has to come off. Maybe it got gummed up somehow.

Well, the car would run with only trailing ignition, but it would run like crapola, kinda like what you describe. So I would verify it. A timing light or other method to actually see if you have spark. If you're using a timing light and while you're at it, check timing. Retarded timing might also cause your symptoms. That is logical since only trailing ignition and no leading ignition is the equivalent of a very retarded ignition.

Of course there is always the possibility that there is a small vacuum leak somewhere. Eliminate that possibility before messing with idle speed or mixture, since you'll be wasting your time trying to set those while having a vacuum leak.

The plan is to raise the idle level (in case my silly self set the idle to like 400 rpm where the engine can't possibly run). Then I'll recheck the timing (but it was set not long ago and I'm pretty sure it's good). Then, rat's nest removal, which if performed correctly should eliminate any vacuum leaks I do have.

Then if it still does it I guess it's got to be the carb.

Raised idle screw, Idles at 1000ish without many issues. I do have leading spark (timing light approved). It's raining so I can't get rid of the rat's nest.

So if I was able to get it to idle by adjusting the idle, but it won't idle where it did before...I have a vacuum leak, is that correct?

It still bogs bad bad bad if I try to to give it any throttle. In fact, after I messed with the idle speed and mixture, now if I even pull the choke out at idle it dies.

Bah. I oughta just buy an F10 or a MegaSquirt and be done with it :P

I haven't examined the accelerator pump, but what am I looking for? A "steady stream of fuel into the primary venturies"? If I don't see that, can it be cleaned or must I rebuild the carb?

(As I side note, I spent thirty damn minutes trying to unlock my car after it started raining and I promptly locked myself out of my car (and my apartment!))

Oh, shit, I bet it's the accelerator pump. I messed with the nut a while back thinking it was something else.

Ok. Why don't you reset the mixture since you've been messing with it and by now I don't know where is it at - and you probably don't either. Engine off, screw it all the way in, CAREFUL at the end or you'll damage it and then will never stop having trouble; so screw it in gently until doesn't turn no more, and then screw it out 3 turns. Turn engine over, then gradually turn it in, until it tries to die, then half turn out. Then turn down the idle until it reaches about 800 rpm. If it didn't die, play with the mixture screw again. Screw it out a little bit, as long as it affects the idle speed. Repeat routine until smooth idling at 750-800 rpm. If it doesn't idle at that point, then yes you have a vacuum leak.

Yes, you're looking for steady stream into the primary venturies. If the pump diaphragm is old and brittle and the cause of the accel pump not working, you might see gas leaking out of the pump.

It happens. You wanna adjust the nut so that the SECOND the throtle starts to open, the accel pump starts to squirt. Otherwise you might get the bog when accelerating syndrome.