electric fuel pump+carburettor issue

[emircea]

Hello,

I registered in OC Forums for some time, I already contacted in private Rally Bob for some advices (and I am very pleased of his answers), but this is my first post.

I have a 1977 Manta B, 1.9l engine which was on injection. The former owner, not being able to start it on injection one day and not being able to find someone skilled to help him here, in Romania (Europe), switched the injection to carburetor, keeping the electric fuel pump.

I own this Manta since january 1995. It was not in a very good state. I made some investments in bodywork, removing the rust and painting, rebuilding the engine. All this being finished 2 weeks ago (my finances weren't so great, so my progress was quite slow) I started to run the engine and enjoy it...

Well, there is something which ruins my good time. With the Solex 32/35 carburetor and electric pump, with an uncalibrated 'T' pipe for fuel, I experience too much fuel on idle and not enough on high torque. Please help me solve this, any advice is great.
I try to switch back on the injection system, but parts and skilled people are hard to find; since then, I wish to find a decent solution to run on carburettor.

Thank you in advance.

[opelnut10]

Originally Posted by emircea Hello, I registered in OC Forums for some time, I already contacted in private Rally Bob for some advices (and I am very pleased of his answers), but this is my first post. I have a 1977 Manta B, 1.9l engine which was on injection. The former owner, not being able to start it on injection one day and not being able to find someone skilled to help him here, in Romania (Europe), switched the injection on carburetor, keeping the electric fuel pump. I own this Manta since january 1995. It was not in a very good state. I made some investments in bodywork, removing the rust and painting, rebuilding the engine. All this being finished 2 weeks ago (my finances weren't so great, so my progress was quite slow) I started to run the engine and enjoy it... Well, there is something which ruins my good time. With the Solex 32/35 carburetor and electric pump, with an uncalibrated 'T' pipe for fuel, I experience too much fuel on idle and not enough on high torque. Please help me solve this, any advice is great. I try to switch back on the injection system, but parts and skilled people are hard to find; since then, I wish to find a decent solution to run on carburettor. Thank you in advance.

If the same electric pump is being used that was on the fuel injection system that is your problem. The Fuel Injection pump carries far more fuel pressure than the solex can handle. For the carburetor fuel system no more than 4 psi can be used, the fuel injection pump puts out a regulated 38-43 psi which is far too much.

[emircea]

Originally Posted by opelnut10 If the same electric pump is being used that was on the fuel injection system that is your problem. The Fuel Injection pump carries far more fuel pressure than the solex can handle. For the carburator fuel system no more than 4 psi can be used, the fuel injection pump puts out 30-35 psi which is far too much.

Right, the same fuel pump...
And my question is... is there any decent solution to make things work in this combination?

A mechanical fuel pump deliveres the same quantity of fuel multiplied with the engine rpm; is there any decent solution to make things behave the same with this electrical fuel pump? I still have the fuel pressure regulator from the injection system (driven by vacuum), but it is not an ajustable one, it's encapsulated.

Keep in mind that I can't install a mechanical fuel pump, there is no hole provided in the engine cap where it shall be mounted.

[Manta Rallier]

There are many low pressure electric fuel pumps available for 12 volt operation, at least here in the USA. These pumps produce pressures of about 5-6 psi, and have ample fuel flow volume for a stock 1.9L Opel engine. Some of the manufacturers here are Holley and Facet. I assume that you can get equivalent parts in Europe.

Also, you can buy an in-line low pressure regulator that allows you to adjust the pressure at the carburetor in the range of 2-5 psi.

We have run these types of fuel pumps on various race cars with carburetors from the stock 32 mm Solex to large 2 barrel 500 cfm Holley carbs to twin weber carbs, all with good results.

Regards,
Mark B.

[emircea]

Thank you.

Can you name such a pressure regulator or post a link with this?

I hope it-s achievable in a range of 20$...

[baz]

emircea ,any low pressure electric fuel pump from a car with a carb will work
i dont know what will be avalable in a junk yard near you but if it has a carb it will work
do you get many west european/japanese cars there from mid 80's on ? there might be something i could say to look at if i knew

[tekenaar]

Originally Posted by Manta Rallier There are many low pressure electric fuel pumps available for 12 volt operation, at least here in the USA. These pumps produce pressures of about 5-6 psi, and have ample fuel flow volume for a stock 1.9L Opel engine. Some of the manufacturers here are Holley and Facet. I assume that you can get equivalent parts in Europe. Also, you can buy an in-line low pressure regulator that allows you to adjust the pressure at the carburetor in the range of 2-5 psi. We have run these types of fuel pumps on various race cars with carburetors from the stock 32 mm Solex to large 2 barrel 500 cfm Holley carbs to twin weber carbs, all with good results. Regards, Mark B.

American carbs may be able to handle those pressures, but Solex, Weber or Dell'Orto carbs should be run with no more than 3.5 PSI!!! Here's my recommended carb EFP setup which requires no regulator from a much earlier post.

[Manta Rallier]

Originally Posted by tekenaar American carbs may be able to handle those pressures, but Solex, Weber or Dell'Orto carbs should be run with no more than 3.5 PSI!!! Here's my recommended carb EFP setup which requires no regulator from a much earlier post.

And it's a very good solution. But like most things, there are multiple ways to solve things, and it gives folks some alternatives depending on what parts they can get most easily or cheaply. Your solution is even better because it has the cut-off switch.

Regards,
Mark B.

[Manta Rallier]

Originally Posted by emircea Thank you. Can you name such a pressure regulator or post a link with this? I hope it-s achievable in a range of 20$...

These pressure regulators will only work with low pressure fuel pumps; they will not work with high pressure pumps made for fuel injection systems. So you need to put in a low pressure pump in any case.

Try this link:
http://www2.cip1.com/ProductDetails....e=ACC-C10-5622

You can see both pumps and regulators.

OTTO gives avery good solution; maybe he knows where to get this pump an at what price.
EDIT: Summit Racing for about $58.

Regards,
Mark B.

[RallyBob]

I have actually used the stock EFI pump on a carb'd engine. I just used a Mallory pressure regulator (return-style), and set the pressure at 5 psi for use with a Holley carb. It has worked fine for 4+ years so far. Of course, that particular regulator is $85, not $20.

Bob

[emircea]

Thank you, guys!

One more thing, please...

tekenaar posted a picture with an electric safety switch. How does this work? When there is no oil pressure, stops the pump or what?

Thank you once again. When it's ready, I'll let you know what solution I succeded to apply (depending on the parts available).

[SpringGT]

Originally Posted by emircea Thank you, guys! One more thing, please... tekenaar posted a picture with an electric safety switch. How does this work? When there is no oil pressure, stops the pump or what? Thank you once again. When it's ready, I'll let you know what solution I succeded to apply (depending on the parts available).

The electric pump power source is wired throught this oil pressure safety switch. If oil pressure is lost, then power to the pump is interrupted and fuel flow stops, thereby saving the engine.
The third terminal on the safety switch would normally be used for a low oil pressure warning light, but is probably not used in this application, since the Opel already has a warning light.

[emircea]

Thank you, SpringGT.

<<The third terminal on the safety switch would normally be used for a low oil pressure warning light, but is probably not used in this application, since the Opel already has a warning light.>> - a good idea, with a relay, when the low pressure warning light is on, the normally closed contact on the relay is disconnected and the pump is off. Such a relay costs 2$ in my city.

I still have to find an electric pump or a pressure regulator - I'll keep you guys in touch with the solution. Thank you all!

[tekenaar]

Originally Posted by emircea Thank you, guys! One more thing, please... tekenaar posted a picture with an electric safety switch. How does this work? When there is no oil pressure, stops the pump or what? Thank you once again. When it's ready, I'll let you know what solution I succeded to apply (depending on the parts available).

Exactly, and here's my post in the same thread for the EFP safety switch wiring . . . all three terminals of the safety switch are used, BTW!

[tekenaar]

Originally Posted by emircea Thank you, SpringGT. <<The third terminal on the safety switch would normally be used for a low oil pressure warning light, but is probably not used in this application, since the Opel already has a warning light.>> - a good idea, with a relay, when the low pressure warning light is on, the normally closed contact on the relay is disconnected and the pump is off. Such a relay costs 2$ in my city. I still have to find an electric pump or a pressure regulator - I'll keep you guys in touch with the solution. Thank you all!

As I said, all three terminals are used and here's actual safety switch terminal connections listed in later post (same thread) for clarification.

[roadings]

Originally Posted by SpringGT The electric pump power source is wired throught this oil pressure safety switch. If oil pressure is lost, then power to the pump is interrupted and fuel flow stops, thereby saving the engine. The third terminal on the safety switch would normally be used for a low oil pressure warning light, but is probably not used in this application, since the Opel already has a warning light.

it not only saves the engine, but it also saves your butt in case of an accident with a ruptured fuel line.

[Manta Rallier]

And speaking of safety when mounting fuel pumps, if you have a Manta A or Ascona A, I would be mounting an external electric pump either in the axle tunnel in front of the tank and on the driver's side (away from the exhaust). Or on the left (driver's side) subframe rail in the engine compartment, behind the suspension. This would be to keep it somewhat protected in a crash.

Make sure the rear axle or associated parts like the anti-sway bar or panhard rod cannot get close to the pump if in the rear. One possible issue with the front subframe rail location is getting a good prime to the pump with it being higher than the fuel tank AND after 10 feet of tubing. (As a point of reference, we have never had an electric pump priming problem with various pumps mounted above the tank in the trunk in rally cars. But I never put one in front so can't tell if this is an issue.)

Regards,
Mark B.

[emircea]

Hello,

I started searching the e-bay and I found the attached item. Can this be helpful? I think it's the pressure regulator for the injection fuel circuit...

Anyway, I keep searching...

[tekenaar]

Originally Posted by emircea Hello, I started searching the e-bay and I found the attached item. Can this be helpful? I think it's the pressure regulator for the injection fuel circuit... Anyway, I keep searching...

This is definitely an FI!!! regulator, which CANNOT be adjusted to regulate at a low enough pressure for a carb, ~3.5PSI max!

[emircea]

Ok, thanks for the tip!

[tekenaar]

Originally Posted by tekenaar This is definitely an FI!!! regulator, which CANNOT be adjusted to regulate at a low enough pressure for a carb, ~3.5PSI max!

Wanted to add, pic looks like one from a D-Jetronic FI (mostly early VWs), not an L- or LE-Jetronic like used on Opels.

[emircea]

Hello;

I finally ordered and received today the #4309 Mallory pressure regulator. I think I expected much more from Mallory about finishings, but I found some metallic debris in it which I cleaned...

What I'm interested in is how can I tune this regulator without a pressure gauge - is it possible?

Thank you in advance.

[emircea]

Last night (between 10 PM and 01 AM) I fitted the regulator, trying to make some tune-up to the engine.

I found a position on the regulator where clearly the carburetor is not flooded and the engine was constantly fed with fuel upon demands.

Unfortunately, the pressure regulator was sent without fittings and with the ones I found locally (4$ for the whole set) I had to use teflon tape for sealing. I will post some pictures later...

Is this teflon tape ok for use with gasoline or do you recommend a different product?

Thank you in advance.

[namba209]

Teflon tape will work just fine on your fuel fittings. I used it on the high pressure fuel fittings on Willit?'s SFI system and have no leaks at all. HTH.

[emircea]

Finally!

In the picture you can see it fitted. Teflon tape did the sealing.

Inside the .zip, you can see a little mouvie with my beauty running... Enjoy!

Too bad I can't share the little mouvies I've made...