'84 GL Wagon throttle delay (39K original miles)

[pacerfrog]

I just got at 1984 GL Wagon with 38K original miles. The car looks show room new, but because of the low use, some of the engine components are a bit gummed up. I had to replace the carb, which made the car run much better. However, I still had a throttle delay as I accelerate from a stop. I just replaced the distributor, which helped make this pur like a kitten, however, the delay is still there in the throttle. My mechanic cannot figure this out, and he has worked magic on many of my cars. Does anyone have some advice on what else this could be?

[DaveT]

Just a wild guess, is the accelerator pump working?  It's been a long time since I did anything with a carburetor car, but there isn't much else involved.

[naru]

Bad spark plugs or weak spark.

[Crazyeights]

Have you tried the fuel filter under the back of the car by the fuel pump?

[pacerfrog]

Guys, thanks for the posts. I do have new spark plugs in it, so I don't think that is it. I haven't looked at the rear fuel filter, but this shouldn't explain it as I can't imagine how that would create a lag from a stop. The carb is full of gas, so this shouldn't cause the issue. The comment on the accelerator pump could be the problem as you never know when you have a new carb; maybe it is not working right. I'll look into all these possibilities and get back. Thanks for the comments. If anyone has anything else to throw out there, please do. I want this baby running perfectly. I'll post some pictures of this 'barn find' sometime this week. 

[DaveT]

My experience with clogged fuel filters is that you loose full power at high demand long runs first.  Idle to open throttle, no effect, since the bowl can fill up during the idle time.

[pacerfrog]

I'm going to check that filter. Everything on this car seems to be original. Some of the stuff gummed up. That could be a nasty filter. Any chance the fuel pump could be the issue?

[wagons]

How long again did you drain the tank? If things are gummed up then get a good fuel cleaner that aids in softening up things and cleaning them. If the car has been sittih for months on end, then the gas can be bad and that can make it hesitate.I did the same thing on my Chevy, inspected tested and replace only to find the gas was old

[colemanapp]

we picked one up with 50000 miles, cleaned and rebuilt the carb but it clogged up again right away due to the build up in the gas tank. Had to pull and clean the gas tank as well as remove a metal mesh sock around pickup area of gas tank. Ran perfect after another cleaning of the carb and new filter.

[pacerfrog]

Two good ideas with the tanks. The car has not been sitting, I've been driving it around on short trips for the last several months to the store and such. However, I've heard the fuel tanks on these Subies do get nasty, especially the ones with low miles as water sits under the fuel and causes rust issues. I'll have to check this, but I don't think this is the issue. I had the same throttle delay on the original carb, as well as the new carb. The new distributor didn't change anything in this regard either. So, I can't tell if it is a fuel or spark problem that is causing the delay. I need to find a good 'vintage' car mechanic in San Diego where I live. 

[pacerfrog]

One more note: the throttle delay was present from the time I bought the car. The new carb did not fix that. The new distributor didn't either. What else could it be, the computer? Every now and then the 'ECS' light comes on (Engine Control System). I've only been driving the car around for a week with the new carb and distributor, so I haven't had a chance to take it to my mechanic for this. However, I believe I've maxed out his knowledge at this point. 

[GeneralDisorder]

Seriously - swap the carb to a Weber. The old Hitachi's can act like that and you can't tune them. The engine wants more fuel on tip-in and even rebuilt Hitachi carbs are prone to this bogging. It's a waste of time and effort. The car will be much more driveable with a Weber.

 

GD

[wagons]

I second the weber. In my high 5200 ft elevation I gained 4mpg and way more power to get through the mountains. If you do it right it is possible to keep all the emissions and pass, just make the original carb hat work with the weber. If its the carb, even rebuilt ones suck.

[pacerfrog]

Getting a new carb is not what I was hoping you guys would say. As I live in California, I decided to go with the rebuild Hitachi as the Webers supposedly are not smog legal here (just incase I need to sell the car in California). However, I have all my vehicles registered out of state, so I could do the Weber conversion if need be. This is good information on the Hitachis, thanks; I didn't know they were not generally considered as good carbs. I think I will have one more mechanic try to fix this issue, then possibly swap to a Weber if this doesn't work.  I'll keep you guys posted.

[DaveT]

If you do the swap, keep all the original stuff, and some good notes. Swap it back one for tests and or selling.

[GeneralDisorder]

You can modify the factory airbox to fit the Weber. Then just paint it black or something to hide it. As long as it's tuned properly and put together right they won't be able to tell.

 

GD

[turfman454]

HAd the same problem on my 84. The squirter that sprays into the bowl was clogged. It is so small an orifice that we actually had to use a wire from a wire brush to open it up and clean out the gunk. No wonder it can clog being so small. Old ethanol gas is what caused mine. We also redrilled the lever from the accelerator pump to the throttle linkage so it dumps i little more gas at first throttle. Im getting ready to actually rebuild the carb again by letting t soak all night in solvent and get a carb drill to open it up a little more. I have driven it a little over a 1000 miles since the rebuild and as long as  dont try to run it wide open it is just fine at highway speeds. Hopes this help

[pacerfrog]

Guys, several more great ideas. I've just been causually driving for the last several weeks to see if my problem clears up. No luck. However, I can now give a better description of what is going on. As I accelerate from a stop, the engine will sputter and sometimes die. I have to 'feather' the throttle to get it past this stage. Once I'm past, I'm fine. However, sometimes the engine dies, which is somewhat dangerous if I try to jump out into traffic. It seems as thought there is a gap between the 'idol jet' and the pick up of the 'throttle jet.' I'm guessing here. I don't know if this is a gas issue or an electrical issue. 

[DaveT]

Sounds like the accelerator pump isn't working correctly.

If it will accelerate very gradually, but wants to die if you step on it, that;s a sign of that.

[pacerfrog]

I just went to the 'Carburetor guy' in San Diego (actually "San Diego Carburetors"). His shop was pretty impressive with probably a thousand carbs hung all over the place. Appearantly he is the guy in San Diego. He said he would not even look at my carb when I told him in was a rebuilt version, as they supposedly are all remade with Chinese crap and almost impossible to dial in. And they don't last long. He told me to get an all original non-rebuilt version on eBay in any condition (all Japanese) and he would get it going again like new. He told me what to look for to ensure it was all original. I got one for $65 with shipping. I think I will try this route. I'll keep you guys posted. 

 

I'm doing this as I can't find anyone that will touch the thing I have on it.

[Gloyale]

 It seems as thought there is a gap between the 'idol jet' and the pick up of the 'throttle jet.' 

 

Exactly.  You probably got a clogged emulsion tube.  Primary main tube most likely.  Pulling too much fuel and no air to mix with it.

 

As soon as the secondary main circuit begins to open, you get the mixed gas you need.  But in the transition between you get too much gas, no atomization.

 

remove the top of the carb.  Unscrew the 4 emulsion tubes (2 of them are under caps.  Need a very skinny flathead screwdriver)  Clean them out with carb cleaner and/or compressed air.  

[GeneralDisorder]

It would be better all around to just disguise a Weber under the stock airbox. More power, easier to tune, etc. And heck - who doesn't delight in pulling one over on the emissions police.

 

GD

[Sapper 157]

; I didn't know they were not generally considered as good carbs.

I would more say that they are considered one of the worst carbs ever made. They are overly complicated, difficult/impossible to tune, and are plagued with vacuum leaks. I would not get a new one from eBay... I really doubt that the Japanese version is any better. I spent hundreds of dollars trying to get mine to work right, but was always unsuccessful. You will find many people here with the same story.

 

Get a Weber.

They are worth every penny, and you'll spend a lot less on a new Weber than you will trying to get that piece of junk working again.

Edited June 19, 2017 by Sapper 157

[naughtJrunk]

first of all, I agree with everyone who says to get a weber, I used to have a similar problem on an 86 hatch and I could not fix it until I swapped a weber and started playing with all the jets, and in the process removed most of the emissions systems. The hesitation made crossing a street from a stop sign into a pretty awkward and serious situation! Anyways, whether you get a weber or do not, the excessively complex routing of vacuum hoses to various devices could easily hide leaks somewhere, or worse yet, they could be operating the emissions devices correctly, which may be causing your problem.

 

Sorry if this is getting too wordy, but what I'm getting at is I think it could be either 1 duh vacuum leaks, 2 the egr valve "operating normally" or 3 a combination of special problems only for people who reside in california. But really, since the egr among other things are operated off of the ported vacuum aka the vacuum hose coming out of the carburetor, anything in that vacuum circuit can wreak havoc on your fuel mixture, but especially right when you apply throttle off of idle. (you likely already know this stuff since you've tinkered with the carb, but I'll continue anyways), the ported vac is basically a hole in the carb right next to the throttle plate at a specific height where it is above the throttle plate at idle, which exposes it to the atmospheric pressure inside the air filter, but as soon as you open the throttle plate a dash, the plate opens above the hole and you expose the port to the low pressure of the intake manifold. This sounds like the point where in your car, perhaps anything can happen? If the hesitation happens every single time, and seems to be super lean at low throttle even when you're not starting from a stop, I would suspect an air leak somwhere, possibly one of the hoses that go up into the air filter (I think some of those connections under the air filter are supposed to have orifices to restrict air flow, and others are possibly not? wouldn't want to mix those up, but what do I know, I don't even have the stock air filter anyways). If it only happens off of idle, and doesn't seem to lean otherwise, I would think that the higher vacuum generated at idle suddenly being exposed to your ported vacuum could be enough to open your egr valve all the way, initiating a stall until the vacuum drops enough for the valve to close up enough for a decent fuel mixture to reach the cylinders, and then the hesitation is over, and you wait until the next stop light to see if it'll happen again. Once your away from the stop, the egr primarily operates under high vacuum aka very light engine load, but right when you leave a stop, the egr gets confused by the anomalous high vacuum and HIGH load, and spoob hits the fan. One thing about this problem is that the egr won't run at all unless the underhood temperature is relatively high, as the heat opens a thermovacuum valve that exposes the egr to the ported vac. That means that when you first start the car, it won't happen, but if you shut the car off for a while, the engine may cool down, but not cool down enough to close the thermovacuum valve, so when you leave the grocery store after a half hour of errands, the egr snaps open in your slightly cooled off engine, and you start running your starter motor to limp yourself out of a busy intersection.

 

Does that sound like it could be your problem!??!? I hope I'm right, because I would hate to have written such an intimidating and bloated paragraph just to be way off the mark, but I hope that gives some insight anyways. IF this sounds like your problem, I would recommend fitting a vacuum delay valve aka a spark delay valve into the vacuum hose going directly to the egr vavle. This type of valve lets air pass normally in one direction, and very very slowly in the other direction, like a one way orifice basically. If you face it the right way and allow air to travel very slowly from the egr to the carb, and normally from the carb to the egr, the egr will open very slowly, and close very quickly, it could take long enough to open to prevent any stumbling, but still open enough to kick in during long straight road cruising conditions. You can find some generic vacuum delay valves for other random vehicles, probably fords and whatever, who really cares. as an example, or just try this one, try a part number search on rockauto for part ec308.

 

If you're still not going to do the weber swap, you can maybe try a few of the mods people do when they swap for webers, like run your distributor advance diaphram directly to your intake manifold and not to your ported vac (known to reduce exhaust temperatures and make the engine run smoother and have better off idle response, but may create more NOx crap that the epa doesn't like, especially in california apparently).

 

Hope that helped....... if anyone read it, sorry again for the excessively long post
 

[pacerfrog]

All your great replies are starting to sway me to the Weber. If I go with the Weber, assume there is no way to connect the carb to the computer. I was told by my mechanic that this could cause me to not get very good milage. I was getting over 30 until recently, now I'm at 19 (don't know why). Also, would the Weber cause the 'ECS' (Engine Control System) light to stay on on the bash? I would assume the computer would trigger this off as well. My ECS comes on all the time anyways and when it does, I notice a corresponding drop in power.