Air Fuel Ratio

[80Merccapri]

I am going to check the pressure tomorrow to see if it drops off in 4 th gear. Ran out of time today and wanted to get the power valve question out there incase it took some time to hear back. Routing the gauge to where I can see it first thing in the morning. At 10 psi the chart I have says it will put out 72 gph so about 270 lph at that rate. So my pump should support that much boost but it goes lean very slow, at 1lb it goes to 12 af to 2 lbs jumping to 14 af thsn 3 lbs 16 af to 4 lbs taking it to 19 af. I'll know a lot more after getting the gauge visible while driving, but I have Friday off so I wanna get info incase the gauge doesn't move I have options and can get as much done with my time off. At this point if the gauge moves it would be easier because a new pump would solve this but I'm pretty sure it's not going to move.

[xctasy]

I'm a little busy now, but you


1. automativcally need need to get a new needle and seat,

2. a nitrophyl solid float, and

3. an earlier 3.6 power valve. Your is 8.5. And that's too high.


4. You need to do a gallons per minute check of your fuel deliver pump. I dislike electric pumps that don't folow Fords LO/HI system. Our 450 hp 63 Ford 250 Falcon Does 10's on Ford Six Performance used a stock EFI Ford fuel pump in his turbos, but he had a full return line system.


I have set views about never restricting flow to the engine, only pressure, and I believe, based on the evidence, that hot fuel handling issues and fuel pressurisation needs to be eliminated. There are some safety aspects to consider. But its all pretty easy to re gig your current system for a even 350 hp with that funny little carb. But its got some major restrictions, and Holley Webers are very restricted with respect to fuel control and flow.


See http://fordsix.com//viewtopic.php?f=1&t=74460

......As 64Ranchero200 noted, an electric pump is an option verses the mechanical fuel pump issues.

As for my 1981 Mustang 3.3 and 1984 Facon 4.1, yeah, the Carter fuel pump diaphram failed, and let fuel right into the sump. Its got some issues for sure when that happens. If using an electric pump, you then have to look at some really good Ford safety provisions so you don't pump raw gas into the engine bay in an accident. There is an inertial cutout used on the CFI and EFI Fords, a great idea for any electric pump Ford. You can bypass it manually.

https://www.youtube.com/watch?v=FhP9vZJSqsA

this is the fuel pump inertia switch.



these could be in MANY places depending on the year and exact model.. in the trunk on the left or right hinge brace.. in the trunk down in the wheel well.. usually with a hole in the plastic panel to push the button through...

could be in the left kick panel in the drivers foot well... look for a hole where the parking brake release is.. or the hood release.. in the panel to the left of your left leg when sitting in the driver seat.. and the hole is usually flat.. like one in a pool table..

Read more: http://forums.mustangandfords.com/50...#ixzz41MWjLzRu

The second major is. Any time an electric fuel pump is used, you have to decide how your going to do it CORRECTLY to eliminate emergency and 1/4 empty tank issues. You have to ask yourself, Do I fell lucky, Punk?.

It its a Hi Pressure EFI tank swap, its easy. Run a Mallory Hi Pressure Return Line Fuel Pressure Regulator like #29388, and wind the line pressure at the carb down to 3.5 psi tops, and have a return line fitted.


You must address some engineering issues the same way Ford did in the USA in 1980, and Ford Australia in 1982.

If the in tank pump outputs in the Lo 6-8 PSI range and yhen feeds the frame mounted pump, which is the hi pressure pump (approx 40 PSI), then you can just remove the Hi pressure pump, and use the in tank pump, running it to a pressure regulator to get it down to the 3-5 PSI needed for a carb. Job done. Sometimes, a return line is a good idea if hot fuel handling is an issue.


In Australia, Ford used the same fuel tank in station wagons and utlity pickups from 1966 to 1997. So they retrofitted the same US CFi special LO/HI system, same as the Fox and Panther CFI V6's and V8'S. The reason for the Lo pressure pump is that Ford knew it would need a Stillage/Surge Pot for an in steel tank Hi pressure pump.

A High pressure pump cannot self-prime (cannot generate net postitive suction head).

The Lo pressure Lift pump to Hi pressure external pump makes sure there is a constant flow of fuel to the high pressure pump on stock steel tanks, no re-engineering required.

Ford refused to re-engineer any passenger car tank untill they could make EFI manadatory. The CFI 5.0 1980-1985 Panther/ CFI 5.0 1981-1984.5 Fox/ EFI4.1 and CFI 3.2/3.9 1982-1991 Aussie Falcon steel tank system is the least you sould ever use when an electric pump is fitted.

Are you going to use the stock pickup in the tank? If YES, you have to cover off the net postitive suction head issues.

If the tank is NOT to be opened up and have a stillage/swril pot fitted, then you HAVE to copy the CFI 1980-1984 Fox/Panther LO/Hi Ford unit, and have an outside Hi pressure with an intank tank staging pump.

Or you will risk the four bad works of non EFI gasoline tanks below


Ford Australia did this for all station wagons with the metal tank from 1983 to 1991.


Normally, Ford use a swirl pot or stillage pot. No exceptions. The reason for this is that


1. at 1/4 of a tank and below, there is a severe risk of dangerous fuel starvation in gradient or moderatly mobile situations.
2. On my Exlplorer, a situation like that could cause being stranded on my steep driveway, or
3. on an offroad trail.
4. In hard cornering or emergency situations, same issue.

When, for instance, the sensortrac four wheel drive kicks in, its the same deal, possibility dangerous a momentary starvation.

The glib response from all other EFI and electric fuel pump appliers is the same, to "just don't let the tank get below 1/4 fill",

That is not an answer.

The reason people generally give that answer is they don't want to be the one dropping or swapping a fuel tank and applying a LO/HI system or well designed HI pressure stillage/swirl pot, and then potentially welding it up again.

http://www.xfalcon.com/forums/index....oject-into-xe/
http://vb.foureyedpride.com/showthre...-a-carb-set-up
http://vb.foureyedpride.com/showthre...stang%29/page2
http://forums.justcommodores.com.au/...side-tank.html

On page 167 on in David Vizards book on SOHC Ford engines, he showed use how to make a dry sump standpipe fuel deliver system with no float. Its a way to control the fuel level perfectly for your planned hp levels.


Somewhere tthere is a VW post on how to boost reference a 5200 Holley Weber. ou need to restrict pressure without restricting flow. The Holley Weber is the worst carb ever for float level hurting richness or leaness, all due to the needle and seat being totally overworked.


EC is on to it. Its the float bowl level dropping way down when you make it work..its dropping because the fuel flow isn't being controlled right, probably not fuel pump inadequacy. But an good mechanic checks that first.


The well tubes (emulsions tubes) are 97x something, designed for an 88 hp 2.3. They will lean out for a start. They are so sensitive to changes in the dynamic stage of gasoline in the float bowl.


PVCR's can be opened out, but its just a patch job for the real issue...float level, needle and seat, a lack of boost referenceing and emulsion tubes way too lean. The need soldering up with less holes.



You've done fine so far. I tried to find the boost referencing schmatic from the Volkswagen or Corvair Turbo forum...this carb is used on these engines, and those guys have it juicing there flat air cooled Dak Daks and Chebbies with particular finese.

[xctasy]

http://www.opelgt.com/forums/afterma...dfv-clone.html


Post 7 with respect to bigger needle and seat.

The operation of the parts, see http://forums.ihpartsamerica.com/showthread.php?t=3153


Boost referencing is really easy...drill a hole, isert a tube, cap another. I had a picture on the net, cant find it. Dang...

[Ethyl Cat]

Good call on the needle and seat size possibly being a restriction, X.

[80Merccapri]

Man idk where you find all this info but thank you, so you suggest trying a bigger needle and seat like the 250 mentioned? My float is already plastic so that would not be a problem. My power valve that i posted a picture of above has a 3 on the side of it also, unless the stamping is on the air horn part of the power valve. My car had a manual fuel pump which was removed and blocked off because it could not support my nitrous system last year, so the only pump I have is the electric frame mounted pump. I also had to enlarge the pickup and the return lines in the tank to support the new pump, because the return line was way to small and would not let the pressure escape back into he tank fast enough, however the feed line from the tank is the same diameter as stock so I was considering switching to bigger lines possibly. With a return style system I would still need a swirl pot, even if the problem is happening when my tank is 3/4 full? I have f5 emulsion tubes in it i believe and i can only go up to a f6 or f66, if you can find a picture on boost referencing that would be great, or possibly explain how one would do it on this carb. Thanks for the help

[80Merccapri]

So i routed the fuel pressure gauge where i could see it and here is what i found, fuel pressure is sent on 13 lbs, car pulls fine 1st thru 3rd still, car starts to pull fine in 4th than slowly goes lean than if i stay in it it richens back up to around 13 air fuel and pulls hard again. So confused the only changes made were i added 2 pounds of fuel pressure and swapped the secondary air bleed from 160 to a 150 other that i used 5/16 fuel line from the regulator to the fuel filter on the carb. My guess would be the air bleed did it or the 2 more pounds of fuel pressure, so i am going to back down the pressure to 11 and see if it reverses the progress I have made. Not sure why it starts out with a good air fuel in 4th gear than goes lean than if I get out of it a little than go to WOT again it pulls fine, it will also pull through 4th gear completely with the pedal 95 percent of the way to the floor even up hill with good air fuel?

[80Merccapri]

I should also add fuel pressure doesn't drop at WOT it drops slightly in 3rd gear but stays the same air fuel ratio than when it goes lean in 4th gear it's right around 13 psi still. Doesn't drop more than a pound ever even when making a 1st thru 4th gear pull

[80Merccapri]

I made some runs and got some good info now, the car is back to how it was 3/8 fuel lines dropped fuel pressure back to 11 psi am seeing 7 psi of boost now the only change I have made is the air jet in the secondary was switched to a 150 from a 160 now idk if that helped or not, but the air fuel at idle is 14.5-15.2 but every now and again it jumps to very lean? So now ive done some decent testing on the car, up hill car wont pull in 4th gear unless i am under 95 percent throttle. On a flat surface the car goes lean at WOT unless you are over 4000 rpm than it pulls to 7 psi like it should and air fuel is 11.8 to 12.2 to redline, anything under 4000 rpm it goes lean and wont run, down hill it will pull at any rpm to redline in 4th gear. So I am certain its not a fuel problem now because the fuel psi stays up and does not drop regardless a new fuel pump is on its way. So with the info I have gathered hopefully you can guide me in pin pointing the problem, I still believe switching to a 250 needle and seat will help and drilling out the power valve will help. But do you think going to a 140 air jet will help at all? The only other testing I can think of is to switch back to the 160 air jet and see if the problem gets worse? Thanks again everyone this has been a headache but I feel like now we are getting somewhere.

[80Merccapri]

no change when switching to the 160 air jet just cleared up the idle issues that I didnt correct with the 150 jet yet.

[Ethyl Cat]

What hole is the accelerator pump lever in?

Also is this an original fox body carb? From what I have read the fox cars have the smallest version of the 5200 and every other car had one that flowed 35 cfm more.

[Ethyl Cat]

Reads like you have a secondary metering circuit issue. Hard to get enough fuel.

My swag is try plugging the secondary air bleed and jet up the secondaries and see how it runs.

[80Merccapri]

Middle hole in the accelerator pump and yeah it's a rebuilt one from rock auto I had from my n/a motor for a 80s fox body. I have a 190 secondary jet in to there now had a 250 in it the other day ran really rich down low still went lean up top if that helps you any. Wouldn't plugging the air bleed make it run real rich obviously I would have to jet it down some.

[Ethyl Cat]

Rich down low part throttle or down low WOT?

Put the lever in the bottom hole on the accelerator pump.

[80Merccapri]

It was rich at idle and rich at a cruise and part throttle with the 250 jet. Car likes the 190 better all around, I will move it to the lower hole morrow. U think I can still benefit from a 250 needle and seat?

[Ethyl Cat]

I doubt it could hurt.

Idle and low speed rich is from the primary side adjustments.

Cruise could be an issue with the secondary if you are reaching 45% throttle opening or more.

It does have a secondary idle jet. I am wondering if it needs to be replaced with a secondary main fuel jet to keep the emulsification correct. Otherwise when you jet up the fuel the carb is still mixing the same small amount of air to it causing it to go real rich.

Also that carb has what they call a power enrichment circuit. It looks like the air bleed is under the lid of the carb.

I am wondering if when you build boost that if the air bleed is not also pressurize that the power enrichment circuit is being shut off. Please look at your carb and let me know.

Attachment 97275

[xctasy]

What hole is the accelerator pump lever in?

Also is this an original fox body carb? From what I have read the fox cars have the smallest version of the 5200 and every other car had one that flowed 35 cfm more.

Thats right. See http://www.mazdatrucking.com/B2200/5200.html

The HW 5200 and 6500 were downgraded in non turbo instillations with a smaller main venturi (from 1980 by my source, and only the non turbo) untill the late year, 1982. Ford did this to really significantly improve emissions and economy. For 1980, the 2.3 5 speed Capri with 3.08 axle tripped 38 pre revision mpg on the 55 mph highway cycle.

On the accelerator pump placement, you'll need the full stroke of the accelerator pump. On the squirter jets, you need the right primary only squirter, ( the 5200 secondary squirter is not drilled through).


The stock standadrd carb was an 88 hp benifit match. The Turbo had the earlier primary venturi size, plus well tube (emulsion tube) upgrades. Its the aftermarket parts industry which creates the problem. Even bore you talk about what needle and seat you using, you often start out with this.

From #104 [azzurro's 1969 FIAT 125: post #104] azzurro post http://oldschool.co.nz/2011/forum/in...iat-125/page-6



Once you've fixed that, you'll then find some other replacement parts spec issues....

Plenty of engine builders, having already upgraded the fuel suplly side by better fuel pump(s) or electric supply have found that replacment parts, such as the needle and seat, will top out even a little Kent 1600 OHV or the Pinto 1.6 liter or General Motors 1600 cc engine with mild cam, port work and headers. The combination on those and other engines of similar ilk is that


1. the float bowl empties by 4000 to 5000rpm in third gear from a standing start with the common aftermarket fuel inlet seat.

2. The orginal 2 mm Weber DGAV seat is also cross drilled, and eliminates the problem. The next step up is the 38DGAS/38DGES/38DGMS 250 micron 2.5 mm Needle and seat valve. The issue is that you can't be sure what needle and seat your getting unless you measure it.


Its a little like tunning a whole engine...just to find the valve spings are weak....


On the fuel tank, your your own boss. I'm a hardliner on gas tank systems...the stock Fox systems were great, safe and smart. I'd say that the fuel pump may be your other problem, not for any reaso except that electrics pumps are there own can or worms. They screw you over just becasue. 1980 Foxes and my early 81 had the smaller gas tank, and you can't swap in a CFI LO/HI system.


My personal recomendation is your best off with a cheap Carter or Facet low presure pickup electric pump on your existing fuel outlet (so you eliminate the need for a swirl pot; from my experience, the stock fuel out let is placed so you can get right down to the last few ounces of gas) .The Lo pressure pump can be turned off by oil pressure like the stock GM Chevy Luv process.They use the fuel pump oil pressure as a ground source to keep the engine running even if the relay is tripped.


Then your stock Hi pressure will do it all, but thats two pumps.

Then any kind of seperate bleed back to the tank if you can. The Does10's process was to have a line back to under the gas filler cap. If they aren't over worked, the right Mr Gasket, Holley or Carter regulator will do a good job returing fuel. It shouldn't pressurise if you are able to use your stock carbon reservior. Everyone strips them out, though. I would use it.

That's a lot of extra stuff, but it works and keeps the stock hydrocarbons emissions sealed to the air.


And I'd use the inertia switch for the High pressure pump.

https://www.youtube.com/watch?v=7JXbglWWOS8

I'd bet you'll probably regularly set that off when you get it all dialed in.

[80Merccapri]

So basically move to the bottom hole on my accelerator pump. Check my needle and seat for blockage and a carb builder told me he can get me the 250 needle and seat which I'll have him order me on Monday. Both my squirrels are drilled on my carb for some reason but I will double check that for sure. How can I check the power enrichment system. Would pics help you better? The float bowls empty at 4K in 3rd gear? I run my car pretty hard sometimes to 6k plus made a couple passed at the track on nitrous up to 6500 last year so I would assume they were pretty dangerously low while making a full pass with that needle and seat installed?

[80Merccapri]

Never mind the nozzle just has 2 legs, thanks again got some things to try and will get pics incase you need them.

[Ethyl Cat]

A pic always helps
Did you see my attachment for the power enrichment circuit?

[80Merccapri]

Yes but I'm not really sure what I am looking for to be honest. I'll get pics as soon as I can though.

[xctasy]

Yes but I'm not really sure what I am looking for to be honest. I'll get pics as soon as I can though.

Go over the Mazda truck 5200 video. Its pretty basic.

https://www.youtube.com/watch?v=j4qflAXIsZE



Ha ha. Found the power valve picture. There is another on how to boost reference somehwere, but here is how to measure it on your 5200. 01-31-2012 Its 38 DGAS, but the same as the 5200.



http://www.opelgt.com/forums/afterma...er-tuning.html

RallyBob:

Simple way to establish your power valve tuning. Get the engine running as well as possible, then measure the vacuum at idle. This means that your ignition timing and idle speed need to be correct for your specific combination.

Now, the stock power valves on a 32/36DG-series or 38 DG-series carb opens at about 14" of vacuum. If your engine idles at 15"-16" of vacuum or higher...leave the power valve alone!

If your engine idles at or below 14", you will need to modify the power valve. Cut ONLY enough coils so that the power valve opens 2" below your existing idle vacuum level. Example: Your big-cammed Opel idles at 9" of vacuum. Your power valve should open at 7" of vacuum. Using a vacuum gauge to test, cut the coils in small increments until that value is reached.

That's it.

This is the vacuum port to test the power valve 'cracking' point.

On the Weber version of your 5200, its in handed or reverse form.


Its Number 7 at the top of the spring end, but triggers "tipping point" supply pressure to the drilled passage above the spring. When the pressure drops out, the fuel pops out.





In context of the other parts, the power valve itself is item 4



Your carb is in reverse order to these pictures...its a mirrored carb, has its primary, secondary, and choke control in the opposite positions.

That oughta get you started.



The picture I am still looking for is the base of the carb, with the bottom of the throttle body drilled to boost reference it with presure from the fuel pump or turbo boost pressure...still looking for that one.

[xctasy]

Still looking for that photo of the exact drilling point to boost reference the power at the base of the thrttle body.

I know where it is on my 32/36, but not your 5200.

Getting closer.



Your D9xx series 5200 carb base.

Its got a 2.5 power valve on this one, but yours is stamped 3.5 instead.

Well tubes/Emulsion tubes...
The 1973 carb ran 15/16.
1978 F5/F4
In 79 carb id were
D9ZE-ND tag.. 259cc/min primary/283cc/min secondary, main jets (a/c car)
D9ZE-MD tag.. 263cc/min/275cc/min (non-a/c).
both have 14R974 main well tubes,
E0ZE-AAA are the same
The 1981 non turbo carb ran 994, 993.
AMC's with the Audi 2 liter ran 974's


Turbo 2.3's and other non tubros ran other kinds.

[xctasy]

This is still not THE photo, but it is almost there.

See http://forums.ihpartsamerica.com/showthread.php?t=3153







It shows the full routing of the power valve, except its supply to the emulsion circuits. The black line on the photos shows the upper path in more detail.


One particlar type of Holley 5200 has a different drilling arangement due to the idel circuit changes, but I don't think its your Holley.


The boost referencing detail shows where to drill. Conventionally, on other Holley 2300's and 41xx's its easy to drill a throttle shaft boost reference into the carb spacer, and then drill upwards.

In you case, it's better to tap into the base, and put in a brass line. I'll check on mine, and get back to you.

[80Merccapri]

Thanks for the info buddy, been real busy with work not leaving me with much time for the car. I did get some pics of the carb when I had it apart that I will upload when I get a chance. I hope you find that pic though. The only other thing is my car only makes 7 vacuum at idle, cam is pretty aggressive so maybe that's why.my other thought is the power valve is always staying open causing a rich idle. If I can get it to close than I could jet up the carb larger than use the power valve up top when needed. Have to test that but unsure how I would test the opening point of the power valve. Have a boost gauge on the car that shows vaccun also. Just an idea let me know if you think it's worth testing?

[80Merccapri]

Here's the update, I drilled the power valve larger 1/16 to be exact and swapped from a 160 main jet to a 140 in the primary side and boom issue fixed air fuel stays right at 11.4-12.6 at wide open throttle. Now I'm having problems with my catch can filling up again, I know the piston rings are right this time though, side clearance was .002-.003 piston to wall was .030-.032 and end gap was .018. So I pulled the head to check the rings again and I can see all the top compression rings if I look very closely and there all in one piece. So now I'm thinking valve seals or something else. If it's not one thing it's the other, thankfully the carb issue is fixed but now this. I can't get a break here valve seals were just replaced last year to by a local machine shop. Any ideas on this one.