Rx7carl

Normally the secs wont open with the car sitting still, dont worry about that. I use vice grips to remove stubborn screws (believe me I get alot of em). Ditch the mech secs till you get the AP at least working if not modded per Sterlings instructions.

Kentetsu

Will do. If I can't repair the AP today, then I will remove the mech mod on it. Thanks!

Kentetsu

I worked the AP lever by hand again, and when I push it in nothing happens. But when I release it a drop a gas comes out of each of two spots in the primaries. Does this sound right?

I still have the carb rebuild kit, so I have the parts to swap it out. Not sure how complicated it will be though. If I don't have to detach the linkage then it shouldn't be too bad I guess.

Rx7carl

Nope, not right. Something in the circut is stuck or you have missing parts in there.

Kentetsu

Ok, rebuilding the AP will be next priority. I installed the exhaust last night, and I thought the interior of the exhaust manifold looked a little odd. I don't know if you can tell how the engine is running by looking at this (like you can with spark plugs) but I took a pic of it and will attempt to post it here (wish me luck).

Well, nothing is ever easy! I'll have to figure out how to resize the photos first. Anyway, it looks like a white powder is coating everything (a thin layer). Figure it means I'm running lean, but not sure.

So Rx7Carl; Do the AP and the secondaries feed from the same source? I mean, maybe they are both starving a bit, even though I do have a little flow. Maybe the secondaries are shooting enough to be visible, but not enough to give me the power I'm missing.

I'll try to have some other RX'ers drive it today at the Lansing meet and I'll post any thoughts they may have on it. Sure would be nice if it was something stupidly simple that could be fixed on the spot (I'm dreaming I know).

Thanks for the assistance (again).

'78 Savanna

iTrader: (1)

I've read this thread all the way through... seems like I have a lot of the same problems, but I think I differ from everyone else in the point that my engine doesn't have to be under load to bog.. after I start up the car, it sits and idles fine, but as soon as I blip the throttle at all, any sudden (small or big) throttle change, and it stalls or bogs real bad, then jumps up in RPMs . I can get the RPM's up with very gradual feed, but even at mid RPM's if I blip it, it bogs. So car I've replaced the following: Plugs, Wires, Cap, Rotor, Points, Coils, Fuel Filter, Air Filter.

'78 12A Stock

Thanks guys.

'78 Savanna

iTrader: (1)

It was running, then suddenly started running like it was only on 1 rotor. Now it won't even start... or if it does start, it sounds like it's only running off of one rotor, and then dies a second after. Now there's something definately wrong with the ignition, but what? Everything was just replaced. Trying to start it, it just cranks and cranks, with the occasional sputter.

Help, I can't see anything wrong.

'78 Savanna

'78 Savanna

iTrader: (1)

Fixed it..

Kentetsu

Well, what was it?!?

'78 Savanna

iTrader: (1)

Well when I pulled the intake housing off to check the spray of the fuel again.. I noticed something I didn't before, that when I pulled on the throttle cable and fuel came out the ports, it was also coming out of the top of that housing, where that brass screw is holding the piece where the fuel comes out of.. so I touched it with my finger and sure enough that whole thing was loose, and was dumping out way too much fuel and flooding the motor. So I tightened up that brass screw and viola, everthing runs bichin'! Drove it around for a half hour romping on it to get anything out of the engine etc from it's many years of sitting... now she's very happy, and so am I.

Good luck with your guys' cars

kettlman

iTrader: (2)

i just gotta say one thing. when your car is running, take the air cleaner off and watch the fuel in the secondaries.(assuming you have it mechanically). put the pedal to the floor and watch the fuel. does it go straight down, or does it seem like it's coming up, then down? thats what my wifes car is doing. only on the front rotor though. same symptoms as you are getting. i've spliced the cat thinking it was that at first. then i did the poor mans compression test. sounded good. but the poor mans way of checking the compression isn't the greatest. so i compared it to my cars poor mans compression test. i'm assuming the compression sucks in my wifes.my friend who is more into the engines heard it and said "it might be a good sounding steady compression, but the compressions not good". so i've got another engine and i will be putting it in this week or next. and i'll have the same every thing else. so i'll let you know if it runs on WOT. cause right now it really pisses me off. goes good until the secondaries kick in.then it has no more power. so just my 2 cents, check your compression.

redrx

iTrader: (1)

well I was having the same symptoms and it ended up being my spark plug. the tip wasnt fully connected

University_seven

uhhhh... the alt. (why not) (sorry if someone allready said that i'm just not reading all those threads

Kentetsu

Electrical system and ignition seem good. I found out this weekend that if I slowly depress the pedal, I can get good power all the way up to the redline in 1st/2nd. Doesn't work in 3rd on up though. Also, I can feel when the secondaries kick in while in 1st/2nd.

I put the new exhaust on Saturday and the butt dyno says HOLY ****!!!!! Barely even have to depress the gas pedal to cruise at 60! Thought I was just putting along around 40, but looked down and I was doing 70 already! What a difference. Hasn't fixed my issue though

I'll try to replace the AP tonight and see what that changes. Thanks for all of the thoughts guys.

One other thing I might try is putting the old (ngk) plugs back in for a bit. I replaced them after flooding, but could only get the Nippon/Denso version at the time. Might be worth a shot, since that's about the same time the issue started. I'll keep you "posted".

Rx7carl

The AP is fed from the rear bowl. Each bowl also feeds one primary and one sec. Its not like a Holley that has both pri in one bowl and both secs in teh other.

Kentetsu

Hmmm, good info Rx7carl. Any idea if I have to remove the linkage to the AP to replace the innards, or do I just remove the four screws and pull it out?

Kentetsu

Just to keep you all informed, RX7Doctor has suggested removal of the check and cut valve, and a verification of fuel pressure.......


I put in the RB exhaust, pulled the air pump and associated BS off, and feel a lot more available power. I say available because its there if I can find the right spot in the throttle (at least through 1st and 2nd). Man, I know its there but tapping into it is a real bitch!

I had wired up the secondaries, but I didn't disconnect the vacuum action when I did it (not sure if that would hurt it or not) and it felt more powerful all around. Rx7carl suggested that I undo that until I get the problem sorted out, so I did that this morning and can feel some loss in power, but I can still feel the secondaries kick in a little bit.

I need to install one more exhaust pipe to complete my exhaust, so I'll be using my buddie's lift again to do that. When we have it up there I'll see about taking the check/cut valve out of the loop. I think you might be on the right track with that though. Before I parked it in the fall, it would fall off when I redlined it up to third. I figured a new filter would fix that and I put one in this spring, but I've had this issue ever since.

Good power in 1st/2nd, but none in the higher gears. Yeah, it sounds like lack of fuel. However, If I floor it in 1st or 2nd, I get nothing. I don't get any real power until I back off on the pedal an inch or so, then she kicks in. I guess that goes for any gear now that I think about it. Full throttle = nothing. 3/4 throttle = decent power. Pulling my freaking hair out!

I'll check into getting a fuel pressure gauge if the removal of the check/cut valve makes no difference. And I will check compression again when I try putting the old spark plugs back in.

I'll do my best to keep you posted. Thanks again for your help!

Kentetsu

Here's a question for the experts.....

How can throttle cable adjustment affect performance, say if its adjusted too tight, but not tight enough to affect idle.

I was just remembering that a long time ago when I was trying to unflood it I checked to make sure the throttle cable wasn't causing the flooding. I found the cable to be very loose and tightened it up considerably. Some time later I got her running, but I've been having these power issues ever since. Can having your cable too tight mess things up?

I pulled off the vacuum secondary thing-a-majigger and wired up the secondaries. Seemed like she had more power again. Still though, if I floor it I loose all power. So then I started adding slack to the throttle cable and the more I added the closer I felt I was coming to fixing this problem (finally). However, by the time I got enough slack in the cable to allow me to floor it without loosing power, the secondaries were barely opening. So now I have to adjust that again, but it will have to wait until after work. Could I be on the right track?

Kentetsu

Oh yeah, I pulled the check and cut valve out of the system and just threw a fuel filter in to replace it. Didn't make any noticeable difference though. Thanks for the suggestion RX7Doctor. I'll try to get my hands on a fuel pressure gauge this weekend...

Kentetsu

Just to put an end to this in case anyone comes across it through searching......

The issue ended up being a partially clogged main jet. During a rebuild on the carb it was found that both main jets in the front bowl were partially clogged with sediment. Once this was cleaned out, she was restored to full power. YEEHAW!!!!!!