Running rich, poor mpg, fuel pressure regulator

[PineClone]

A list of questions from a gear head wannabe. I have a recently purchased '78 b210, weber carb added by previous owner. 

 

- Car was running very rich, with black stuff spewing from muffler. Plugs were black. I tuned the carb and made a lot of progress. Seems to be running VERY smooth. Plugs look good, and greatly reduced black coming from muffler. Still smells a little gassy. MPG still bad.

 

- There is a pressure regulator (the crude looking style with the dial, currently set at the "3" setting). Would fiddling with the settings on this make a difference?

 

I think the previous owner was knowledgeable enough to install the new carb correctly. I'm not sure where to go next here to increase my mpg. My last tank got me 16mpg. But if its dumping that much gas, wouldn't it be spewing smoke?

 

On a potentially related note.....In general, the car runs great. Having never owned a B210 in the past, i'm not sure of expectations with regard to power. My observation is that the car lacks pep at low RPMs, but is fine once you get going. Certainly not going to beat anyone off the line at a stoplight. It this normal??

 

Thanks!

 

 

[Dguy210]

A list of questions from a gear head wannabe. I have a recently purchased '78 b210, weber carb added by previous owner. 

 

- Car was running very rich, with black stuff spewing from muffler. Plugs were black. I tuned the carb and made a lot of progress. Seems to be running VERY smooth. Plugs look good, and greatly reduced black coming from muffler. Still smells a little gassy. MPG still bad.

 

- There is a pressure regulator (the crude looking style with the dial, currently set at the "3" setting). Would fiddling with the settings on this make a difference?

 

I think the previous owner was knowledgeable enough to install the new carb correctly. I'm not sure where to go next here to increase my mpg. My last tank got me 16mpg. But if its dumping that much gas, wouldn't it be spewing smoke?

 

On a potentially related note.....In general, the car runs great. Having never owned a B210 in the past, i'm not sure of expectations with regard to power. My observation is that the car lacks pep at low RPMs, but is fine once you get going. Certainly not going to beat anyone off the line at a stoplight. It this normal??

 

Thanks!

 

The pressure regulator is not needed but is nice.  The best way to up your mpg would be to put the original Hitachi back on.  16mpg is still very low. 1. You need to independently verify the speedometer/odometer is working correctly before taking mpg calcs anyways. 2. The best the Webber will get you fully tuned up is around ~29mpg combined.  With a 5 speed I rarely get over 35 and that is with almost all freeway driving and being very fuel conscious. If I put my foot into it I get around ~24.  Total average is around 27 taking everything into consideration (with pretty tall tires though). This is about the same mileage as the Hitachi with a 4 speed though (I found my log book of +2 years of mpg calcs, 27-31 is the normal range).  With a Hitachi and a 5 speed I almost never got below 30 and freeway mpg was usually in the low 40's.

 

Low RPM should still be ok from the line, but they do like to rev. Are you seeing hesitation when you hit the gas pedal?

[PineClone]

 Are you seeing hesitation when you hit the gas pedal?

 

I am not noticing hesitation. Just takes some pedal to get the RPMs up.

[Dguy210]

I am not noticing hesitation. Just takes some pedal to get the RPMs up.

I just checked your previous posts, you've got an auto right, with a bit of an issue anyways? Gas mileage is pretty miserable on those compared to a stick, and even running perfectly they rob a lot of power from the little A series. Also they are relatively particular on their fluid levels too.  So...Ehh, sounds reasonably normal than.  I would also check for fuel leaks on the rubber lines while your at it, especially back near the tank, where the tank connects to the hard lines.

[PineClone]

I just checked your previous posts, you've got an auto right, with a bit of an issue anyways? Gas mileage is pretty miserable on those compared to a stick, and even running perfectly they rob a lot of power from the little A series. Also they are relatively particular on their fluid levels too.  So...Ehh, sounds reasonably normal than.  I would also check for fuel leaks on the rubber lines while your at it, especially back near the tank, where the tank connects to the hard lines.

Yes, its an auto which was low on fluid. Works fine now. 

 

Will check the lines. Thanks for the tips!

[Slinky Dogg]

Sounds exactly like mine, just took my hitachi carb for a rebuild, I'll let you know how it's going afterwards, mine is 74 auto, black stuff squirting outta the muffler and bad mpg. Takes a while to get up to speed also.

[datsunaholic]

16MPG is horrid.  I get better than that with a 4X4 620.  I got better than that on a '78 B210 that ran on 3 cylinders and used about a quart of oil per gallon of fuel (the engine was toast, but still starts).

 

The fuel pressure regulator was put in to solve a problem likely created by the prior owner trying to "clean up" the engine bay.  Your '78 B210 should have, or at least mine has, a fuel return line that goes back to the tank.  Without that line, the fuel pump tends to overpressure the Weber's float valve, causing excess fuel to dump at higher RPMs and no load.  That's what the regulator was put in to solve, although simply hooking up the return line (and making sure it's not plugged) would have the same effect.

 

However, a Weber is really too much carb for an A14.  It CAN be jetted to work, and I've seen them work fine, but the normal factory weber jet sizes simply aren't right for an engine that small.  The oversize carb is why you have such poor low-end power.

[datzenmike]

Post some pictures of the motor.

 

Does it have an electric choke?

 

Get the stock carb. You should be able to get better than double that mileage.

[Dguy210]

16MPG is horrid.  I get better than that with a 4X4 620.  I got better than that on a '78 B210 that ran on 3 cylinders and used about a quart of oil per gallon of fuel (the engine was toast, but still starts).

 

The fuel pressure regulator was put in to solve a problem likely created by the prior owner trying to "clean up" the engine bay.  Your '78 B210 should have, or at least mine has, a fuel return line that goes back to the tank.  Without that line, the fuel pump tends to overpressure the Weber's float valve, causing excess fuel to dump at higher RPMs and no load.  That's what the regulator was put in to solve, although simply hooking up the return line (and making sure it's not plugged) would have the same effect.

 

However, a Weber is really too much carb for an A14.  It CAN be jetted to work, and I've seen them work fine, but the normal factory weber jet sizes simply aren't right for an engine that small.  The oversize carb is why you have such poor low-end power.

 

'75 and later B210 have the fuel return line. However, while it is a good thing, and he probably has it hooked up, a fuel return line it is NOT required for correct operation of the Weber on an A series. The auto's really have very bad mileage though. New they claimed around 26/34 city vs 29/41 for the 4spd. The auto plus Weber is why he has bad mileage.  The auto is why he has poor low-end power. My car came as an auto when I first got it, and I remember how miserable the acceleration off the line was, and the cut to the mpg was much more than the stated 10% since you basically had to keep your foot into it.

[datzenmike]

While auto get slightly worse mileage it's impossible that this and the weber is the cause of 16 MPG. I had a B-210 and yes it was a 4 speed and you had to literately drive the absolute piss out of it for 250 miles to get it into the 20s.

 

Either the choke is stuck, the carb is flooding, the timing is retarded or a combo of these things.

[Dguy210]

While auto get slightly worse mileage it's impossible that this and the weber is the cause of 16 MPG. I had a B-210 and yes it was a 4 speed and you had to literately drive the absolute piss out of it for 250 miles to get it into the 20s.

 

Either the choke is stuck, the carb is flooding, the timing is retarded or a combo of these things.

You're right, 16mpg is very hard (short of hill climbing) to get if everything is working correctly even with an auto and a weber. The auto on the B210 avg'd about 24mpg real world as I remember with a hitachi, but was seriously gutless.

 

Stuck choke is a good first place to look, very easy to check and they can shift around a bit. If I remember that drops about 5mpg right off the top too.  I'm not so sure I trust the way the 16mpg was measured though, he may be getting a bit better than he thinks on the mpg.

 

We definitely need some pics by now also.

[PineClone]

Thanks all for the help. Will get pics soon.

[PineClone]

  I'm not so sure I trust the way the 16mpg was measured though, he may be getting a bit better than he thinks on the mpg.

Checked the odometer last night on my drive home. Seems to be right on the money with the mile markers along the highway. 

 

My supercharged frontier gets about the same mileage...in other words, CRAP. Something is definitely not right...and i'm not saying it couldn't be my math. 

[datsunfreak]

FWIW, my stock auto '75 B210 could never manage more than 18-19mpg no matter what I tried. Exact same car instantly got to 24-25mpg with a 5spd swap. 

 

Also, if you want to swap to a "better" carb for MPG reasons, I would suggest getting a stock 1200 Hitachi carb, not a B210 carb. Same bore size (but slightly smaller jets), but no emissions crap or wiring associated with it.  :thumbup:

 

Best case, find a stock B210 carb to get the jets out of, put those jets in the 1200 carb, go on down the road.  B)

[datzenmike]

FWIW, my stock auto '75 B210 could never manage more than 18-19mpg no matter what I tried. Exact same car instantly got to 24-25mpg with a 5spd swap. 

 

I got thinking about my previous post. That would have been 33 MPG using Imperial gallons. X 0.354 = 11.682 kilometers per liter X 2.352 = 27.47 MPG US gal. This was a '76 2 door A14 4 speed. I think twice I was able to drive it into the 20s.

[PineClone]

PICS!

 

Also including my newly refurbished 280Z 6 spokes and new Barum Bravuris 2 tires

 

Start here and flip through pics.

 

Thanks.

[datsunfreak]

Looking good.  B)

 

[Dguy210]

Very nice and straight, and if that is an uncracked dash I am totally jelly.

 

I would check that the choke is operating correctly first. That wire looks a little dodgy. You've also got the Ford starter solenoid bypass done for the starter, so the electrical/ignition is automatically somewhat questionable.

 

You need two key things for proper operation. 1. Power to the choke when the key is on and 2. the choke is adjusted correctly.  Check power to the wire first since that is easiest. You can check the choke is adjusted by pulling the clips on the air cleaner and watching it open with the key in and power on but with the engine off.

 

A full rundown on checking the choke is available multiple places, so I'm not going to repost all the details.

[datzenmike]

The power to the choke is only on when the motor is running. They all have a choke relay that requires alternator output to be on. It's a small thing but here's why...

 

 

You go out to your car on a cold morning set the choke and start it. It's running on fast idle and you go back inside to finish your coffee and let it warm up. Unknown to you it stalls. Now if the choke heater were on the choke would continue to warm up and turn the choke off while the motor remains below freezing. You go out and try to start the car again but without the choke this is almost impossible, if you do get it running the motor is dead cold still and hard to drive.

[PineClone]

Very nice and straight, and if that is an uncracked dash I am totally jelly.

 

I would check that the choke is operating correctly first. That wire looks a little dodgy. You've also got the Ford starter solenoid bypass done for the starter, so the electrical/ignition is automatically somewhat questionable.

 

You need two key things for proper operation. 1. Power to the choke when the key is on and 2. the choke is adjusted correctly.  Check power to the wire first since that is easiest. You can check the choke is adjusted by pulling the clips on the air cleaner and watching it open with the key in and power on but with the engine off.

 

A full rundown on checking the choke is available multiple places, so I'm not going to repost all the details.

 

Thanks, and i'm sure the dash is cracked, as this is a dash cap. I didn't realize it until after i had bought the car. Was sitting in the garage the day i brought it home, flipping through the old paperwork.  Found the receipt for the dash cap and said, "Well $hit!" Oh well, still looks good.

[PineClone]

By the way, note the plug to the right of the fuel line. Is this correct?

 

Plug

 

I have noted that when the engine is cold the choke is mostly closed. When warm (at idle) the choke is wide open. I'm sure there is more to it.

[Dguy210]

The power to the choke is only on when the motor is running. They all have a choke relay that requires alternator output to be on. It's a small thing but here's why...

 

 

You go out to your car on a cold morning set the choke and start it. It's running on fast idle and you go back inside to finish your coffee and let it warm up. Unknown to you it stalls. Now if the choke heater were on the choke would continue to warm up and turn the choke off while the motor remains below freezing. You go out and try to start the car again but without the choke this is almost impossible, if you do get it running the motor is dead cold still and hard to drive.

Hmmm, I believe mine may be wired wrong as it comes on with the key. Does the anti-dieseling solenoid get constant power with the key? I wonder if it is cross-wired. I had forgotten about the relay being used. Thanks, Mike I need to check this when I get home.

 

Edit: Yep, weird, mine gets power when the key is in but the motor off, hasn't caused problems in the 14 years I've had the car so I'm not messing with it.

Edited March 14, 2013 by Dguy210

[Slinky Dogg]

Dude I just got my carb pro rebuilt and I'm still gas guzzling ??? Wtf

[PineClone]

Dude I just got my carb pro rebuilt and I'm still gas guzzling ??? Wtf

Frustrating. You're sure about your odometer readings? If so, what next?

[datzenmike]

Dude I just got my carb pro rebuilt and I'm still gas guzzling ??? Wtf

 

Float set wrong... maybe too high and fuel bowl overflowing. Look at the sight glass on the front. Where is the fuel level when running?

 

Choke heater not connected. Usually a blue wire on the harness. Or not set correctly. When warmed up is the choke plate completely open???