Popping/backfiring/shifting issue

[Whisler]

Tail shaft has to come off, the governor is bolted to a counterweight on the output shaft. The valve itself has a specific weight, but the initial pressure is from a heavier weight with a spring. You might try a small washer inside the valve where the spring goes to add some weight. If this brings your WOT shift points down where you want them, then you can tweak the part throttle with the modulator.

Here are a couple of pictures for you:

When I installed my Eddy carb. I put in a pressure regulator at the same time. With a standard mechanical pump, I was near 7 PSI until adjusted. That pump may be putting out more PSI than you think. Regulator is a good idea.

[Angelo Voltura]

3k is where the MSD goes from multiple sparks to a single one, right?

Not the vacuum advance, a bolt in the works to lock it tight.

The truck should be bouncing off the limiter when you let off the line lock and launch.

No line lock on the truck yet. Just foot braking off the converter for the time being. Eventually I would like to have a trans brake put in but this is someday down the road. I beleive the multiple spark discharge is all the time. I could be wrong.

As far as the modulator goes I adjustd its few times and that got normal driving shifting correct. Never seemed to effect wide open.

I will be putting a regulator on that stock pump as soon as the engine get put back together. I have it in my cart ready to go.

Thank you for the diagrams on the governeror I'll be checking into that...sorry for the short reply guys I'll give more details shortly!

[ArdWrknTrk]

No line lock on the truck yet. Just foot braking off the converter for the time being. Eventually I would like to have a trans brake put in but this is someday down the road. I beleive the multiple spark discharge is all the time. I could be wrong.

As far as the modulator goes I adjustd its few times and that got normal driving shifting correct. Never seemed to effect wide open.

I will be putting a regulator on that stock pump as soon as the engine get put back together. I have it in my cart ready to go.

Thank you for the diagrams on the governeror I'll be checking into that...sorry for the short reply guys I'll give more details shortly!

Page 1 of the instructions states "above 3,000 rpm there is simply not enough "time" to fire the spark plug more than once"

To me, popping and backfire mean spark scatter.

And if it's not the 6AL, then it's probably the dizzy.

But that's just my experience.

You could be seeing something I never have.

[Frank Wyatt]

Page 1 of the instructions states "above 3,000 rpm there is simply not enough "time" to fire the spark plug more than once"

To me, popping and backfire mean spark scatter.

And if it's not the 6AL, then it's probably the dizzy.

But that's just my experience.

You could be seeing something I never have.

On the popping/backfire issue, I've experienced that on 2150 carbs before. In my case, it was always the same problem, a bad accelerator pump, an easy fix. I'm not saying the accelerator pump is bad, but perhaps it doesn't have enough pump volume when the pedal is lifted to let it shift. Then when the pedal is matted again, the engine is needing more pump volume at that engine speed than the accelerator pump is providing. However, once the shifting problem is resolved, that should not be a problem needing resolved as lifting the pedal to get it to shift won't be necessary. On the larger carb idea, I would use a CFM calculator and put in your RPM and go by that on your carb size. They are accurate. A matched combination will provide the best performance whether racing or just driving to get groceries.

[85lebaront2]

No line lock on the truck yet. Just foot braking off the converter for the time being. Eventually I would like to have a trans brake put in but this is someday down the road. I beleive the multiple spark discharge is all the time. I could be wrong.

As far as the modulator goes I adjustd its few times and that got normal driving shifting correct. Never seemed to effect wide open.

I will be putting a regulator on that stock pump as soon as the engine get put back together. I have it in my cart ready to go.

Thank you for the diagrams on the governeror I'll be checking into that...sorry for the short reply guys I'll give more details shortly!

Angelo, modulator settings do not effect WOT shifts, they are controlled by the governor pushing against line pressure on a different land on the 2-3 shift valve, 1-2 is still being controlled by the throttle boost valve according to the diagram. Basically, the valve body is a hydraulic computer, weighing engine load (modulator and throttle boost pressure) against road speed (governor pressure) to determine when to shift, the downshift valve applies line pressure to a different part of the shift valve train to either force a downshift or hold a gear longer.

[FuzzFace2]

On the popping/backfire issue, I've experienced that on 2150 carbs before. In my case, it was always the same problem, a bad accelerator pump, an easy fix. I'm not saying the accelerator pump is bad, but perhaps it doesn't have enough pump volume when the pedal is lifted to let it shift. Then when the pedal is matted again, the engine is needing more pump volume at that engine speed than the accelerator pump is providing. However, once the shifting problem is resolved, that should not be a problem needing resolved as lifting the pedal to get it to shift won't be necessary. On the larger carb idea, I would use a CFM calculator and put in your RPM and go by that on your carb size. They are accurate. A matched combination will provide the best performance whether racing or just driving to get groceries.

Thing is he is above the accel pump travel at the RPM he is running when this happens, foot to floor and only backs off a little to get it to shift into high.

If racing go for a Holley carb and shelf that Eldy. I believe that is the only good place for a Eldy carb and even more so when racing because of the fuel PSI issues.

I run Holley's on my cars I have dragged raced, 2300 v2 on a stock AMC 304 and v4's from HPDP 650 to 750's on a built AMC 360. I also run a full MSD set up on the 360 as it is my drag only car.

I think the governor is what the issue could be.

I run a full manual reverse shift pattern TH400 on the drag car after burning up a new trany with just 2 1/4 mile runs. Not enough vacuum from motor (big cam) to shift.

It also has a custom 3000 stall converter now.

Now the 304 car is a street car, TF999 (HD TF904 but less than a TF727), and I would also have to back off the throttle to get it to shift into high but with the rear gear the car had the times or speed did not change thru the lights in 2nd or 3rd gear at just under 90 MPH, 2.89 rear gear.

Car did have a shift kit and would shift normal til you got on the gas and would chirp the tires going into 2nd gear. This car only used a down shift rod no vacuum so I adjusted it to be the best it could be both on the street and at the track. I was building the track car and did not want to start making a lot of changes.

I would find a transmission shop that does race tranys and run it by them on the shifting to see what they have to say.

I am sure once the shifting is tanking care of the miss / back fire will not happen.

If it does then fix that issue.

As they say "Only fix 1 issue at a time" because if you try fixing all at the same time and now you have other issues what did you "fix" before that caused this new issue?

Good luck and keep us posted on the fixes.

Dave ----

[Angelo Voltura]

On the popping/backfire issue, I've experienced that on 2150 carbs before. In my case, it was always the same problem, a bad accelerator pump, an easy fix. I'm not saying the accelerator pump is bad, but perhaps it doesn't have enough pump volume when the pedal is lifted to let it shift. Then when the pedal is matted again, the engine is needing more pump volume at that engine speed than the accelerator pump is providing. However, once the shifting problem is resolved, that should not be a problem needing resolved as lifting the pedal to get it to shift won't be necessary. On the larger carb idea, I would use a CFM calculator and put in your RPM and go by that on your carb size. They are accurate. A matched combination will provide the best performance whether racing or just driving to get groceries.

Thing is he is above the accel pump travel at the RPM he is running when this happens, foot to floor and only backs off a little to get it to shift into high.

If racing go for a Holley carb and shelf that Eldy. I believe that is the only good place for a Eldy carb and even more so when racing because of the fuel PSI issues.

I run Holley's on my cars I have dragged raced, 2300 v2 on a stock AMC 304 and v4's from HPDP 650 to 750's on a built AMC 360. I also run a full MSD set up on the 360 as it is my drag only car.

I think the governor is what the issue could be.

I run a full manual reverse shift pattern TH400 on the drag car after burning up a new trany with just 2 1/4 mile runs. Not enough vacuum from motor (big cam) to shift.

It also has a custom 3000 stall converter now.

Now the 304 car is a street car, TF999 (HD TF904 but less than a TF727), and I would also have to back off the throttle to get it to shift into high but with the rear gear the car had the times or speed did not change thru the lights in 2nd or 3rd gear at just under 90 MPH, 2.89 rear gear.

Car did have a shift kit and would shift normal til you got on the gas and would chirp the tires going into 2nd gear. This car only used a down shift rod no vacuum so I adjusted it to be the best it could be both on the street and at the track. I was building the track car and did not want to start making a lot of changes.

I would find a transmission shop that does race tranys and run it by them on the shifting to see what they have to say.

I am sure once the shifting is tanking care of the miss / back fire will not happen.

If it does then fix that issue.

As they say "Only fix 1 issue at a time" because if you try fixing all at the same time and now you have other issues what did you "fix" before that caused this new issue?

Good luck and keep us posted on the fixes.

Dave ----

Dont worry the Eddy is going to get shelved for a 670 Street Avenger I beleive. I have always been a Holley guy, the Eddy is just what came on it. I do run this thing mostly on the street and it has good manners, but I'm building it for "stop light" races for lack of a better term. I run 1/8th mile often. The goal with this truck is to be able to scare myself so that I don't drive like an idiot but also have fun with.

Yes I am far above accelerator pump travel when this happens, I'm all in it and then as mentioned back out just enough to get a shift into 3rd and then I'm back in it all the way.

I'm starting to agree that the governor is the culprit here. I'm also agreeing in that I think the backfiring issue is also due to it...remember it does not always happen, just more frequently than not. Like I said it has good street manners shifting otherwise. I'm just worried about vacuum loss at wide open, I have never put a gauge on it to see what it pulls but I'm willing to bet it's probably around 12-14 psi at idle which is just enough for the brakes and trans.

As I mentioned I do beleive this thing needs around a 2500 stall converter. Whatever is in it (I'm assuming whatever a stock car stall speed is) is just not cutting it for what I do with it.

I guess I'm going to have to dig into my transmission a little bit or stop down and talk to my buddy who worked at one of the local trans shops and see what he has to say. He told me putting a converter in it would probably help but who knows.

 

[Angelo Voltura]

Dont worry the Eddy is going to get shelved for a 670 Street Avenger I beleive. I have always been a Holley guy, the Eddy is just what came on it. I do run this thing mostly on the street and it has good manners, but I'm building it for "stop light" races for lack of a better term. I run 1/8th mile often. The goal with this truck is to be able to scare myself so that I don't drive like an idiot but also have fun with.

Yes I am far above accelerator pump travel when this happens, I'm all in it and then as mentioned back out just enough to get a shift into 3rd and then I'm back in it all the way.

I'm starting to agree that the governor is the culprit here. I'm also agreeing in that I think the backfiring issue is also due to it...remember it does not always happen, just more frequently than not. Like I said it has good street manners shifting otherwise. I'm just worried about vacuum loss at wide open, I have never put a gauge on it to see what it pulls but I'm willing to bet it's probably around 12-14 psi at idle which is just enough for the brakes and trans.

As I mentioned I do beleive this thing needs around a 2500 stall converter. Whatever is in it (I'm assuming whatever a stock car stall speed is) is just not cutting it for what I do with it.

I guess I'm going to have to dig into my transmission a little bit or stop down and talk to my buddy who worked at one of the local trans shops and see what he has to say. He told me putting a converter in it would probably help but who knows.

If it helps, here's a quick pull of it NOT doing it because of shifting manually 2-3 with the ratchet shifter instead of being in drive.

At the top of the run I'm touching 5,000rpm. I would say at the shift it was about 3500. The mid range is super strong in this truck.

I'm not sure how to embed videos.

[FuzzFace2]

If it helps, here's a quick pull of it NOT doing it because of shifting manually 2-3 with the ratchet shifter instead of being in drive.

At the top of the run I'm touching 5,000rpm. I would say at the shift it was about 3500. The mid range is super strong in this truck.

I'm not sure how to embed videos.

Are you flashing the converter?

By that I meant foot on brake but motor at idle till the green (or 2nd to last yellow for my street car) comes on and floor it. This will "flash" the converter over stock stall a little.

Because of the high gear in my street car, being a auto and had a Lock Right locker with street tires I would run a little higher tire PSI to get a little tire spin and flash the converter to help get the RPM's up and out of the hole. The car also had leaf springs and the front of the spring pack was clamped to act like MOPAR SS springs used in the late 60's. Again did not want to do a lot as I was building a drag only car but had to control wheel hop.

Street car on trailer in drive after a race yep 15.70 in the 1/4 mile

Drag only car 13.xx in the 1/4 but runs the numbers all day long with low .00x RT numbers

As for hurting your self driving crazy I would get that way with a road race car I built. I would park it for a few weeks then pull it out for a week till to crazy and park it again! I was not racing it enough.

When drag racing I never had that issue, guess I got it all out on the track as I was going just about every weekend?

Dave ----

[Angelo Voltura]

Are you flashing the converter?

By that I meant foot on brake but motor at idle till the green (or 2nd to last yellow for my street car) comes on and floor it. This will "flash" the converter over stock stall a little.

Because of the high gear in my street car, being a auto and had a Lock Right locker with street tires I would run a little higher tire PSI to get a little tire spin and flash the converter to help get the RPM's up and out of the hole. The car also had leaf springs and the front of the spring pack was clamped to act like MOPAR SS springs used in the late 60's. Again did not want to do a lot as I was building a drag only car but had to control wheel hop.

Street car on trailer in drive after a race yep 15.70 in the 1/4 mile

Drag only car 13.xx in the 1/4 but runs the numbers all day long with low .00x RT numbers

As for hurting your self driving crazy I would get that way with a road race car I built. I would park it for a few weeks then pull it out for a week till to crazy and park it again! I was not racing it enough.

When drag racing I never had that issue, guess I got it all out on the track as I was going just about every weekend?

Dave ----

I'm foot braking holding the RPMs up against the converter then all in once the tree goes green.

I have been running 235/75 bald Firestone all seasons with about 30-35lbs in them and I was getting massive wheel spin and 0 traction...I still managed to pull a 9.6/89+ mph in an 1/8th mile with a second gear start and a MASSIVE bog off the line. I have finally put spring clamps on it but I will be putting traction bars on it this year due to some wheel hop issues I was having. I have yet to air down on the drag radials I am putting on and have not tried with the clamps yet to see what it will do. I am confident with the engine running better, a 1st gear launch and good traction I will be deep into the 8s, enough the track wants a driveshaft loop and a helmet.

I would run the ratchet shifter all the time to stay in the power band but due to I beleive a stretched cable I cannot get the trans to manually shift into first...so all my launches have been in 2nd unless I start in drive. That is how I figured out that I need to pedal it...