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Tue May 06, 2003 9:26 am

Hello.I'm having some problems with this vehicle.
If the fuel pump is disconnected(and hooked up to a 12v motorcycle battery)the car start.Doesn't idle very well-but starts.

When the fuel pump is connected to the harness the car will not start-starves for gas...Any thoughts ?

Tue May 06, 2003 9:55 am

Check the connections on the car battery. If the connections are not tight, the battery will not deliver enough voltage to power both the fuel pump and the starter. This would explain why the car starts without the load from the fuel pump. If the connections are tight and clean, the battery may need charging. Below a certain charge level it won't be able to power both things. Had I known this little quirk of fuel injected beetles I could have avoided an $80 tow charge when all I needed to do was tighten the battery connection.

Tue May 06, 2003 10:37 am

79Super gives good advice. Also check out this page http://www.conservatory.com/vw/manuals_nyx/L-Jetronic.html

It's an L-jetronic manual scanned to the internet. Start on page 5.

Good Luck

Tue May 06, 2003 10:42 am

Thanks, aircooled. BTW, Muir's book says that the type 1 fuel injection is not L-Jetronic, but rather AFC or Air Flow Control. Less parts, easier to work on. Varies only the amount of air entering the engine, keeps the fuel intake constant. L-Jetronic is supposedly the type found on Type 4's, varies both fuel and air, has lots more sensors and electronic parts. Can't remember what it said about type 2's and 3's.

Tue May 06, 2003 1:16 pm

You could convert it to a carb set up. Just a thought to get you back on the road sooner! Good luck

Tue May 06, 2003 1:24 pm

Hello- and thank you very much-I will consider all feedback...Keep the thoughts coming ...

Wed May 07, 2003 6:45 am

There is a small ground wire on the negitive battery cable if that is bad you could be loosing ground, if it breaks the pump will not work at all.
Also after the engine starts the fuel pump circuit runs through the air flow meter you may be having a problem there.

Wed May 07, 2003 9:24 am

Actually we are both right 79vert. AFC and L-jetronic are the same thing. Check out this website http://www.type2.com/library/fuel/vfityp.htm

Scroll down to L-jetronic. When ordering parts or troubleshooting it is important that you use "Bosch L-jetronic". As Bosch made many fuel-injection systems. All being made up of different parts and sensors.

Again, yes it is AFC fuel-injection, but the technical name is in fact L-jetronic. Side note, Don't believe everything in the Muir Book! Lol. I made that mistake with my first bug. He has good info, but he seems to have an aversion to the later model Bugs, and as such alot of the information is incomplete, missing, or wrong that he gives regarding the mid to late 1970's models.

Wed May 07, 2003 10:12 am

Well, if Bentley says it, I believe it! But is it still true that the type 4's use a different type of FI with many more parts and sensors than type 1's? Did that have another name? And what about type 2's and 3's? If I ever wanted to consider a late model other than type 1 and it had the more complicated FI I would pass it up.

Wed May 07, 2003 11:23 am

The FI used on type 4's was different than that used on Buses and Bugs. It was much more complicated and horribly unreliable. I believe it was some form of D-Jetronic, which used manifold pressure to determine how much air the engine was using. Then Bosch came out with the L-Jetronic, which was much more reliable, and less complicated. I'm pretty sure that type 2's and 3's use some form of the L-jetronic system.

Wed May 07, 2003 11:57 am

Regi, you may have a faulty fuel pump or Double Relay. I assume you have checked the fuel pump pressure? If not you should do so. Clamp, and disconnect the hose that goes to the cold start valve. It is located between the alternator and the top of the intake manifold. Connect a fuel pressure gauge to the hose you took off of the cold start valve. Have an assistant operate the starter while you watch the gauge. Pressure should be between 33 to 37 psi. If there is no reading, then it is possible that the pump is faulty, or that you have a bad double relay. Use a test light at the fuel pump to see if it is getting any juice. If it isn't, then you probably have a bad Double Relay...

Wed May 07, 2003 4:02 pm

The pump-pushes well.(i have not mettered it, nor know how)However -along the lines of the ground wire (Ref:bettleman)-There was an issue with that paticular wire-I believe i've corrected it-As ref: to 79superVert-your right I need to tighten the terminal bolts on the battery-I've just snugged them on-Any one have a complete Scematic ? Fuse Box overview ??? Thanks again ...

Wed May 07, 2003 4:06 pm

Hey aircool-yeah.I've purchased a relay-just haven't tried it out yet-part of my problem-I didn't want to cross/short out a $100.00 part...My car is a week-end project-I can't wait to get it going...Thank you all again !!!