Kyle Lynch

I have a 12a 83 GSL that has sat for several years. It idles and revs fine in the driveway but when taken out on the street, the majority of the time it does not want to have acceleration. Even when floored the acceleration is slow at best. However, intermittently, it will decide to have power and if I accelerate fast and shift quickly I can make it through the first three gears with normal power and acceleration. I have begun to think it might be ignition related and am hoping someone might be able to chime in on this thought. Coils or distributor wires? I don't think its timing because it operates fine intermittently. Also i originally was thinking it was the secondaries not engaging but its happens at too low of rpm's/load. Any thoughts?

What I have done is as followed: I have drained the gas tank, replaced the fuel filter and pump. Rebuilt the carburetor and then took it out a second time and gave it another cleaning just in case i had clogged jets. Replaced spark plugs. New catalytic converter.

Zener_1

Leading igniter failing or bad connection to same perhaps?

Benjamin4456

Does the car 'miss' or stumble at all? A failing leading igniter would cause the car to run rough if it were not functioning properly - trailing would have no noticeable affect other than perhaps the tach depending on the year. Try swapping the igniters. They are little black units mounted either on the distributor (81-85) or on a metal box on the driver's side fenderwell (80). If that fixes it, you probably have a problematic igniter. On the 80 cars, the tach ran off the leading, and other years ran off the trailing. If your tack starts doing weird stuff after swapping them, that would also indicate one may have been the issue.

Other than that I'm not too sure. Maybe some weird smog stuff is confused, but I would doubt that. And it sounds like you've ruled out fuel delivery so, I'd say you're probably on the right track. The inconsistency is what's odd.

Kyle Lynch

The trailing ignitor may have been the culprit. I swapped them and i wouldn't say the issue has gone away 100% but is drastically improved. I can now make it through all gears and I am now starting to feel it run rough around 60 mph which makes sense given the fact the leading ignitor is now the bad one. I ordered two used ones off ebay so they should be here in a couple of days and I will update when I have them in.

Benjamin4456

That's odd. Rotary's will run just fine without trailing, but hardly run at all without leading. Some people remove trailing for simplicity, and the SA cars actually disabled the trailing above ~idle to keep the thermal reactor nice 'n toasty.

The only thing I can think of that would make sense with having a bad trailing, would be if it were somehow delaying the spark and causing it to fire too early or late causing really weird timing issues. Both leading's can fire at the same time no problem (that's how DLIDFIS works).

I would try swapping the 'good' ignitor back to leading, and disconnecting the trailing just as a test. You'll be able to do more experimenting when the new units arrive.

chuyler1

iTrader: (1)

What about issues with spark advance? If you still have the rats nest connected go through the emissions diagnostics to check and see that the vacuum advance solenoids are opening above 1,000 RPM and closing on deceleration. Is it possible for the centrifugal advance in the distributor to stick closed? That accounts for another 10 degrees of advance.

Kyle Lynch

Okay. So update. Ignitors arrived today. After putting them in the same problem persists. I decided to change the coils just in case they were the issue but no change was observed. In the mean time while I was waiting for the ignitors i dropped the gas tank and cleaned it along with the sending unit because its reading 1/4 tank when full. After checking the sending unit its operating fine and so my guess is its a grounding issue.

now back to the problem with the acceleration. I will try to be more specific with whats happening. before switching the ignitors the car would accelerate extremely slowly and only have normal power maybe 1 out of 5 shifts in lower gears and almost never have power in 4th and 5th gears. After switching the ignitors, I would say 3/5 shifts are good and if i shift fast i can make it up to 4th and 5th gears with good acceleration. however, if i let off the gas and shift while idling it will lose its power through the next gear. Also to note, when I get up around 60 mph whether its in 4th or 5th gear it starts running rough and stumbling but will still accelerate.

to answer chuyler1, i do still have the rats nest connected. ill have to read thought haynes to see what youre referring to. but as of right now im looking for any other possibilities it could be or what I could check.

chuyler1

iTrader: (1)

I would replace that fuel filter under the car one more time. I know you said you replaced it but I had the same symptom where I could floor it through two gears and then it would fall on its face once the carb bowls were depleted of fuel.

Kyle Lynch

I can give it a try since they are cheap. but since its intermittent (i can rev hard in 3rd or 4th gear without it ever letting up if i have power) rather than making it through two gears and then dying im thinking its something else. is it possibly the distributor cap/rotor going bad?

Benjamin4456

I think what chuyler1 was meaning was that if you shift quickly (like you said works), the bowls still have enough fuel in them to make power, before they 'empty' and you start lugging again. It may appear, and indeed be, intermittent as different load scenarios or whatever will affect the fuel consumption in seemingly random ways.

Essentially, it is very likely there is some sort of fuel restriction (most likely the filter as others have said) that is leading to the bowls not filling quick enough under acceleration. This causes your lack of fuel and voila, no power until the bowls are topped off again.

Edit: I suppose it would make sense in the above case that at some point the power would 'drop off'. Have you noticed this happening? Such as if you start out from idling for a little bit and then nail it, does it start powerful and then drop off after a while? Have you noticed if it happens more at low or high rpm?

Kyle Lynch

Ben, i have not noticed the power drop off only around 60-70 mph. Fingers crossed it Is just a fuel restriction and this will be the third fuel filter i put in however I had not cleaned my gas tank until now. Update in an hour.

Kyle Lynch

Update: I have replaced the fuel filter and the acceleration problem is still there but it no longer runs rough around 60 mph. it runs smooth all the way to 90 mph if i have good acceleration.

I have also replaced the distributor cap and rotor, spark plugs, and spark plug wire set today. I had thought i did the plugs in the past but I guess I just bought them and I found them on the passenger seat under the old trusty haynes manual.

So the reason I don't think its fuel related is because it will happen in 1st gear even when accelerating after sitting at idle speed. It is still intermittent and if I take it on the highway and get good power in 1st or 2nd gear I can accelerate through 5th up to 90 mph with no problem. however, once i am in 5th and i take my foot off the gas it will lose power and will begin to decelerate and at no point will I be able to regain power.

Benjamin4456

Well I deleted my message by accident, and the auto save doesn't work very well on mobile... Anyway, I think I can condense it better now that I know where I'm headed.


In the driveway, it is easy to rev all the way up on the primaries. However, under load, the secondaries sticking closed would be noticable.

I have two theories. You say that you lose power after letting off the gas. If this occurs after simply letting off the pedal (still in gear), I would say the secondaries are probably getting stuck. If it happens after you let off and allow the rpm's to drop, it might also be that the distributor mechanical advance is sticking. Either could explain an intermittent loss of power.

Those are my thoughts for now.

Kyle Lynch

Since the problem is happening in first and second gear at low speeds, i do not think its the secondaries sticking. at first I did but then i reassessed the problem and due to it happening in all gears and all speeds, especially ones that aren't under load i have all but eliminated that as a possibly

Benjamin4456

Out of pure curiosity, how do you experience a loss of power under no load?

Sticking secondaries easily ticks the boxes for all gears, and really all speeds too. What do you quantify as a low speed? Have you noticed if the issues coincides with any particular rpm? I would still say to check the secondaries. Until you know for a fact that they are operating all the time, you really can't rule them out. I don't know how many times I've moved on to more complex solutions only to come back and have the problem be something small I overlooked in the first place.

Here's a question. Have you ever been driving, trying to accelerate with no power, and then suddenly it kicks in? Perhaps not brick-wall suddenly, but has it ever kicked in a bit after you attempt to accelerate?

In my opinion there are a few possibilities: sticking secondaries, some remaining weird fuel delivery issue, and perhaps the ignition - plus a couple unlikely yet possible issues. Have you noticed any changes in accessory devices when you have no power? Perhaps dimmed headlights, interior, or dash lights? Does a lack of power follow a decent left or right turn, do bumps in the road proceed it? Does the car run rougher when you have no power? I think I asked this before, but is there any stuttering, bogging, or jumping that you notice? I feel like an ignition issue other than the advance systems would be easily noticeable as a misfire or some other irregularity.


This is what I would do for now. Either have someone press the throttle pedal for you, or use the dashpot arm (firewall side, and it's a sizable flat arm) on the carb to actuate the throttle. While holding the throttle open as far as you can, see how difficult it is to move the secondaries open (note they will not open all the way without the throttle being fully depressed). You can use the arm connected to the vacuum diaphragm (passenger side front) to actuate the secondaries. If you notice much resistance - there will be some due to the spring in the diaphragm - I would look into it further. Otherwise I would suggest you keep testing and note any connections between the loss of power and other conditions.

Kyle Lynch

Kyle Lynch

well i think ben is correct with the sticking secondaries. I took the car out today for a drive on the highway in order to pinpoint exactly what and when its happening.

so i have noticed that if I am WOT i can shift with power through all gears if I accelerate in each gear up to ~5k rpms. If i let off in any gear to about half throttle or less around 3500-4k rpms the power will be lost and can not be regained unless i put it into neutral and then rev the engine to ~4k rpms and then re-shift into the respective gear. Doing this revving and then shifting I can almost guarantee 100% that I will have power when I shift.

when I came home from my drive i then tested the secondaries and TBH i am not entirely sure how much resistance there should be but in my non expert opinion there is more resistance than should be. Also, when I took of the cover to the diaphragm, there was once again a combination of oil and gas inside. after reading up on it sterling once said

"I've encountered this a few times on older carbs. Never on a 83-85 carb.
At first I thought maybe the oil was put in by Hitachi to smooth out the vacuum opening, but of the few that I've found with oil, the amount is never consistant.
So after rethinking this puzzel, I came to the conclusion that the oil wouldn't really fioll the vacuum signal circuit to the primary bore, so then I thought about it being added with the idea of air volume displacement. (?) I dunno, but I can't figure ANY way that it got there by accident."

the diaphragm itself looked fine with no holes in it. so I am now at a loss but rethinking that it could be sticking secondaries. I did check for vacuum leaks yesterday with starting fluid but did not find any. Any thoughts of other tests or things i could try before just going to mechanical secondaries?

Benjamin4456

My theory on the oil in the diaphragm is that it's to prevent them from drying and cracking, but hey, it's just a theory.

I'm not sure how you tested the diaphragm for leaks with ether, unless, well no, I'm honestly not sure. The secondary diaphragm doesn't receive considerable vacuum until above 3500-4000 rpm's while under load. If you want to re-test it for leaks I suggest carefully removing it (as to not damage the gasket) and then depressing the linkage after which you cover the vacuum port. If it stays in place, or even moves very slowly you're fine (do note that the vacuum port has a pressed in sleeve with a slit in the side, so fully sealing it may be a little difficult by hand).

Honestly though I wouldn't bother testing it again, at least for now, as it sounds like it's in fine shape. I'd suggest you put a little WD on the secondary shaft and work it open and closed a bit. It might loosen up some junk that's gotten in there over the years that's causing them to stick.

And ironically, that bit where you shift to neutral and rev it does make some sense. Perhaps the sudden application of vacuum from free reving is enough to 'pop' the secondaries loose, while other times the gradual increase while accelerating isn't. Again, it's a theory, but I'd say a logical one at that.

Mechanical secondaries require more than just linkage work. I'm actually just about to start the conversion myself, but I would still suggest you try and get the vacuum ones working - if indeed that proves to be the problem.

Kyle Lynch

When i meant i checked for vacuum leaks it was throughout the engine bay not the diaphragm. I do have a question. When you press the lever for the secondary diaphragm, should it hit something and not be able to be fully depressed. because thats whats happening with mine. however, once i open up the primaries, thats when I am able to fully depress the lever of the secondary diaphragm. its quite possible that something is not installed correctly and thats whats causing it to not open around 3500 rpm but on WOT its able to open. however, that doesn't explain why when i have no acceleration power and then floor the gas pedal i still don't get the secondaries to open.

Could you clarify this up for me that the lever will hit something (maybe 1/4" movement) unless the primaries are opened up completely (get full movement of lever ~1")

Kyle Lynch

my other theory is the spring that came with the rebuild kit is a much bigger diameter wire and thus requires more vacuum force to depress. I tried cutting two loops off the spring but that didnt change anything. And of course I don't have the spring that i replaced. its long gone at this point.

Benjamin4456

There is a linkage that prevents the secondaries from opening until the primaries have been opened a certain amount. I don't believe the secondaries should be able to open at all (freely) until that occurs however, and you say that there is ~1/4 in of movement in them? That seems a bit off, although are they still under tension at that point - as in if you let go will they close themselves?

Some people do cut their diaphragm springs, although I haven't bothered to learn much about that so I can't provided much insight there.

Did you try the WD bit yet?

Kyle Lynch

yes. they are under tension. all i mean is if i force the lever to move it will go 1/4" and hit a linkage. however once the primaries open a certain amount the lever will move the full amount when pressed. as long as that sounds roughly correct i will go about trying to clean/lube the lever passage.

Benjamin4456

Yes, if my memory serves correct, that is right.

Kyle Lynch

Update: Good and still bad news. I sprayed some wd-40. took off the carb and made sure i had the linkages correct and washers all where they should be.

With a little more pinpointing and with my tweeting. I still will have slow acceleration. but once i hit 5k rpms in 1-3rd gears the secondaries will engage and power is restored. i can still have good power by revving and then shifting. I am also now noticing the same issue in the driveway just revving the engine. if i slowly rev rpms will increase slower than they should until 5k rpms then will finish with normal power. since the secondaries shouldn't be kicking in in the driveway what could be causing this issue?

Kyle Lynch

could this be the carb vent solenoid (just checked it and it is clicking)? and i also just read a thread with very similar problems and it turned out to be the apex seal springs... i just did a compression test and R1 had 50-60 psi and R2 had 60-70 psi with a constant compression for all apex seals for both rotor