Auto trans upshift problem

[TimmyG]

1 hour ago, datzenmike said:

Driving along at speed, flooring it to down shift to second and letting it up shift to third uses a lot less gas than accelerating the car from a stop through first and almost all the way through second.  Accelerating from a stop, uses a lot of gas very quickly, and by the time it's gets to the top of second the carb begins to run dry and it stumbles and can't shift. The carb runs dry because the fuel filter is partly blocked with debris. In effect you are using gas faster than it can be sucked through the filter.

 

 

The bog when you floor it is common with the Weber. At about 1/2 throttle the secondary is forced to open even though the engine is not ready for it. Try 1/2 throttle and learning to step into it as it's needed. Some practice and you'll be able to feel when it's best to step down the rest of the way.

 

All of this makes perfect sense. Thanks for the explanation.

 

I'm gonna replace the gaskets at the adapter plate/carb/manifold since I know there's a leak. Maybe this will help eliminate the hiccups. Also getting a throttle return spring would help with moderation since currently my gas pedal is very soft. Haha...but let's be honest. I will just mash it harder once it has a return spring. 😏 Might switch to a Weber 38/38 like I had back in the day, or dual side drafts (which I have no experience with).

[TimmyG]

Well the trans upshift problem is back! It's largely related to the carburetor not handling the engine demands very well in those WOT, hard load circumstances I think.

 

Pulled off the carb to change the gaskets and found the adapter plate bolts VERY loose. Not tightened AT ALL. Changed the gaskets and tightened the adapter plate bolts. Used blue lock tight on everything. 

 

To my surprise, the truck now runs WORSE at WOT high rpms. It struggled worse at the top of 2nd gear regardless, even if you were already cruising vs drag race situation. Engine is stumbling all over the place until you let off at the top of 2nd, let off, then shifts into 3rd and continues to stumble now... it never stumbled after the 3rd shift before now. It even lost power completely with the revs falling once.

 

It still cuts out if you floor it anytime. It still cuts out if you roll into the gas too quickly. And it still bogs when the secondary opens if you manage to mash the throttle quickly and the engine doesnt cut out for once. 

 

I did have to open the idle mixture screw beyond what Weber says is OK to get it idling smooth. (32/36)

 

The plugs (or at least a couple of them) look grayish white. 

 

Why would it run WORSE after fixing this vacuum leak at the base of carb? Maybe the fuel pressure is too high? Webee says 3 psi max.

 

It also says something about float adjustments, but I have no idea on that subject.

 

The hot looking plugs are confusing. Yes they are NGK OEM. 

 

This problem seemed to go away after fixing the vacuum line routing, then came back. Seemed to go away after changing the fuel filter, then came back after fixing the carb base vacuum leak. 

 

Edited September 28, 2019 by TimmyG

[datzenmike]

I think you'll agree this isn't the automatic's fault, but something to do with the engine tune. Weber is very specific about how to adjust their carbs. 

 

Go down to trouble shooting. There is a section on things to check, that if not right, will make tuning your Weber pretty much a waste of time. Your engine needs to be running correctly first.

 

http://www.clutchkitcenter.com/media/images/weber/K610.pdf

 

 

 

[TimmyG]

Thanks! Way ahead of ya. Lol

 

 

Also, this fuel line doesnt look great.

 

[TimmyG]

@datzenmike Could these symptoms be from an exhaust leak at the collector? Because I have one. 

 

I doubt it, because I've gotten the symptoms to go away and run smoothly a few times randomly.

 

When it ran smoothly enough to shifted out 2nd to 3rd at high rpms it did backfire a couple of time on deceleration when I let off. 

 

 

 

 

[datzenmike]

On 9/15/2019 at 3:50 PM, TimmyG said:

 

 

Truck warmed up and in D. From a stop, floor it and hold WOT. The truck revs out and upshifts from 1 to 2 normally, but when it reaches the top of 2 it won't upshift into 3. If you continue to hold WOT, it stutters and struggles at what I assume is redline (no tach). As soon as you let off the gas at all, it upshifts into 3. You can then immediately return to WOT with no problems. 

 

This no upshift into 3 problem ONLY occurs in this specific situation: flooring it from a stop and holding WOT all the way to highway speed using gears 1, 2, 3 sequentially as if drag racing. 

 

 

 

 

 

 

Struggling at the top of 2nd is not right. Something is amiss with the fuel delivery. I don't think ignition as it doesn't do this in first at high revs only after a long hard full throttle pull. Carburetor sounds like it's running out of gas, maybe.

 

Can you check your weber float height? If set too low, the engine may be draining it faster than the pump can put it in.

 

Check all rubber fuel hoses for kinks that could slow the flow down.

 

You could remove the fuel line to the carb at the frame near the starter and direct into a suitable container. With the pump on, you should get 1.4 liters in one minute or less. That's 1.5 US quarts. 

[TimmyG]

6 minutes ago, datzenmike said:

 

 

Struggling at the top of 2nd is not right. Something is amiss with the fuel delivery. I don't think ignition as it doesn't do this in first at high revs only after a long hard full throttle pull. Carburetor sounds like it's running out of gas, maybe.

 

Can you check your weber float height? If set too low, the engine may be draining it faster than the pump can put it in.

 

Check all rubber fuel hoses for kinks that could slow the flow down.

 

You could remove the fuel line to the carb at the frame near the starter and direct into a suitable container. With the pump on, you should get 1.4 liters in one minute or less. That's 1.5 US quarts. 

 

The symptoms are not as severe today for some reason. I did notice before and haven't mentioned the fuel hose going to carb is a little flattened out... 

 

[TimmyG]

The float I'm not familiar with how to check... the Weber directions do say where to set the float height I'm assuming I have to remove the carb, and unbolt the bottom half (bowl) to check the float. I do not have a new gasket and don't know if it's necessary.

 

I have swapped out a carb for new Weber 38 on a previous 720, got her set, and that's about my extent of carburetor wrench time. 

[TimmyG]

Intake side plug (all pics same plug) 

 

 

 

 

 

Exhaust side plug (all pics same plug)

 

 

[TimmyG]

1 hour ago, TimmyG said:

 

 

Changed this hose out. Made no difference. Used a formed hose from the fuel line return on my parts truck. Fit pretty well considering it's not made to go here. It's not flattened out like the universal hose was. Still it made no difference. 

 

[datzenmike]

 

 

The plugs are all white from overheating from an over lean fuel mixture. Not enough gas. Primary jet too small. This is why you had it turned out past 2 turns.

[TimmyG]

Just confirmed float is set at 18 mm per Weber instructions. First time taking carb apart and no you don't have to remove the whole carb lol. Hey, I'm learning. 

[datzenmike]

I don't know much at all about the 32/36 but those plugs indicate a very lean fuel mixture. Lean will run poorly

[TimmyG]

Yeah the intake side plug for sure I could tell is lean/hot. The exhaust side plug looks lean to you, too? Should be darker brown maybe?

 

Anyways, I don't know squat about jets or where they are. Here is a pic of the only ones with markings on them. I think my terms are correct. On the 32/36 the primary is the only throttle plate that opens until you give her enough pedal then the secondary opens.

 

No idea what the correct jets are for this engine or what this carb came with. Could you explain jets in a general sense? How many and where they are. I have alot to learn about carbs. 

 

Edited September 28, 2019 by TimmyG

[datzenmike]

 

 

 

NOTE the primary side has smaller numbers than the larger secondary side.

 

Assuming this carburetor is for a Z22? look for any blockage or piece of dirt that will obstruct fuel flow.

 

[Charlie69]

Is this a used carb when you got it, or did it come on the truck?

 

 

You are indicating air correcting jets.

 

Look at the chart above for your Weber model and check all the corresponding parts to the baseline.  The baseline is what the Webers ship with.

 

Is this a real Weber carb?

[TimmyG]

Carb was on the truck when I purchased it earlier this month. Not sure how to tell if it's a "real Weber." It says made in Spain.

 

My baseline jetting matches the above Weber chart except for my secondary idle jet. Chart says 50 and my carb has a 55. I will post a pic of what I found in my carb after spending time learning about carbs today. Here is what I found in mine: 

 

 

You might notice it says DGAV, which is water choke...it has an electric choke on it now. Don't think that's of much concern here.

 

I also found this on the site... @ggzilla

[TimmyG]

The main difference I see with recommend setup is the secondary emulsion tube... f50 vs f6. This could be the issue as I think f50 has more air holes...let me look it up.

[TimmyG]

 

Not sure what difference this makes as I'm new to this. Mine is running the stock F50 on secondary and the recommended per post quoted is F6.

[Charlie69]

There is also 2 floats and 2 settings.  The older carbs have a brass float and newer carbs have a composit float. I do not remember ther settings of of the top of my head.

 

If you look at the chart above the DGAV and the DGEV both ship stock with the F50s, the DGV (manual choke) ships with the F6.  I run the DGEV with all the stock parts.  the Webers are sinsitive to altitude.

 

Call Pierce Manifolds and ask them what jetting they would suggest for your altitude.

 

[datzenmike]

If it's close to what is recommended for jetting look for blockage, something not letting the fuel through.

 

[TimmyG]

4 minutes ago, Charlie69 said:

There is also 2 floats and 2 settings.  The older carbs have a brass float and newer carbs have a composit float. I do not remember ther settings of of the top of my head.

 

If you look at the chart above the DGAV and the DGEV both ship stock with the F50s, the DGV (manual choke) ships with the F6.  I run the DGEV with all the stock parts.  the Webers are sinsitive to altitude.

 

Call Pierce Manifolds and ask them what jetting they would suggest for your altitude.

 

 

It has the composite/plastic float and my Weber instructions for DGEV says set to 18 mm. I did verify it was correctly set after watching a video on how to check it. According to all knowing Google, I am approximately 308 ft altitude in my area. 

 

I don't know where those recommendations came from I quoted. I will call Pierce. Thank you. 

 

I should rule out low fuel pressure I guess. I could use Mike's method of measuring how much pumps in 60 secs... or maybe buy a fuel gauge? Hard to read a gauge under the hood at 60 mph lol.

[TimmyG]

1 minute ago, datzenmike said:

If it's close to what is recommended for jetting look for blockage, something not letting the fuel through.

 

 

Haven't seen anything obviously blocked.... one thing I'm not sure how to check is the power valve. Still learning. 

[bottomwatcher]

Forget reading plugs when there are accurate wideband guages available to read. Also the chart is to keep you within a certain range. Just remember the bigger the air jet to fuel jet the leaner the mix and Visa versa. I used a Weber book I dont remember the author when tuning my 32/36 dgv when I had a z 24 and bought a set of jet drillbits.  Interesting process but to run right you will need some trial and error tuning.

[datzenmike]

5 hours ago, TimmyG said:

Intake side plug (all pics same plug) 

 

 

 

 

 

Exhaust side plug (all pics same plug)

 

 

 

To super accurately tune, a wide band is indispensable but you don't need a $200 gauge to see there's something not right here.