78 Super Beetle Fuel Injection problem. HELP!

[rubrbulits]

I'm selling for a friend and agreed to look it over b4 the sale. Car would sit most of the time but he never had any issues for years. I drove it home and noticed it lacked power. BTW I'm familiar with carbed air cooled VW's, but not FI. When I got it to my garage I found a plug wire disconnected from a spark plug. Easy fix, ran perfect now! Took it for a test drive and the front right tire blows out. Put spare on and drove home. Got home and while parking it in the garage it started running rough and finally stalled. Fuel gauge said 1/3 full, but was really empty. Also found out the gas tank is full of rust and since I emptied it all the crud plugged the fuel filter. Pulled the tank and cleaned it as best as I could. Put a new filter on and it fired up and ran perfect, for about 5 minutes. Tried to drive it around the block and it would barely idle then stall. Neighbors helped push it home. Pulled the tank, cleaned it more, sealed it with a tank liner, let it dry for two days, reinstall the tank, fresh non-ethanol gas put in, turn the key, still barely starts and dies. Fuel pressure at fuel pump is 35 psi. Fuel pressure at fuel rail is 32 psi, and drops to 0 psi shortly after fuel pump is turned off. Fuel pump is running when its supposed to, have already rigged the double relay to confirm it is running. It runs when I open the flapper. I can hear fuel circulating back into the tank when I have ignition on and open the flapper as well. All vacuum lines, hoses, intake boot look good. Basically whatever went wrong happened in an instant. The car ran fine up until I ran it out of fuel and from that point on it's a mystery. Any ideas would be great.

[VW_Jimbo]

Is the fuel filter in the correct direction?

[rubrbulits]

It has to be. Its the correct square one with different sized inlet and outlet.

[busdaddy]

Where are you measuring fuel pressure?
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[sawed off]

Did it backfire even just once? fuel injected bugs very susceptible to hoses blowing off and or damage to air flow meter with just one single backfire.

[rubrbulits]

Measured fuel pressure directly after fuel pump, 35psi. Then measured at the cold start valve, 32psi. I dont remember hearing any backfire, I have checked all hoses and connections many times so far.

[rubrbulits]

Also, I have tried to manually open flapper on the air intake while it tries to idle with no noticeable change.

[rubrbulits]

One more thing, It seems if it was getting fuel but weak ignition you would smell gas, but instead it seems to be a lack of fuel because I get no sign of an overly rich fuel smell. My guess at this point is that fuel isn't getting to the cylinders.

[Randy in Maine]

Fellow Hawkeye here!

Either the fuel pressure regulator is not working due to dead fuel in there, or you have a leaking fuel hose. That is why the fuel pressure is dropping when off.

Been here? http://www.itinerant-air-cooled.com/viewtopic.php?f=50&t=213

It would be good if you could get the injectors cleaned and calibrated for about $100 from www.cruzinperformance.com (send them the cold start valve also). It will come back with new injector seals (big and little) as well as new fuel hoses.

Also make sure the battery and starter connections are 100% as that is what powers up everything. Do the chassis ground strap at the same time. Costs nothing and rules out electrical connections.

Make sure the Temp Sensor II is firmly attached to the head and is making a good electrical connection to the engine wiring harness. Do not reef on the TSII as the thread pitch is pretty fine at 10mmx 1.0mm.

[VW_Jimbo]

You have fuel pressure within specs. Now you need to perform a volumn test. Preferably at the engine compartment. It has been awhile since I performed this task. The jist of it is this; DISABLE the ignition coil and anything else that can create an open arch. Disconnect the fuel return line at the cold start valve. Find a way to get a graded container to catch the fuel when you turn the fuel pump on. Need it to measure over a quart. I like the white Valvoline oil containers. They have a clear strip in them to see fluid. I have cleaned one out and then labeled, with a black sharpie, on the exterior of the container, graduated marks for every 1/4 cup of fluid.

Set up a direct batterey source to the fuel pump. I use a remote starter button, so that I can be near the fuel catcher during the test.

When you are all setup. Press the button for 30 seconds, and then measure the amount of fuel collected. You should have between 3/4 of a quart up to a full quart in that time frame.

Let me know what you get.

FYI, decent article here on basic fuel injected testing.
http://www.aa1car.com/library/2003/us60324.htm

[rubrbulits]

Thanks for the replies! Here's more info on this car. It has 37,000 original miles. It's always been garaged and never driven here in the midwest winter time. The battery is brand new and fully charged. I have checked all connections at the battery for corrosion and its still like new under the back seat. The ECU and double relay are clean with no sign of any corrosion or moisture. I'm sure that most of the parts on the engine are original from 1978. The problem is that it ran fine up until I ran the gas tank dry not knowing the fuel gauge was inaccurate, then, realized the tank was full of rust. Then I cleaned the tank,"didnt seal it", replaced the fuel filter, re-installed the tank, it ran good for 5 mins then this problem started. I pulled the tank again, cleaned it out thoroughly sealed it with red-kote, re-install the tank, another new filter, fresh gas, and still wont run.

Is it normal to hear fuel circulating back to the gas tank with fuel pump running. This is when I turn the key on and open the flapper activating the fuel pump but not running the engine? I'm beginning to suspect the fuel pressure regulator.

[rubrbulits]

Thanks Jimbo, I will do this test this afternoon and let you know the results.

[Randy in Maine]

[rubrbulits]

Yesterday I disconnected the fuel rail from the right side of engine and placed a cup under the fuel line and ran the fuel pump manually. There was a clean strong stream of fuel. However I didn't do a volume test, which I will do this afternoon and report the results. But I do know that fuel is getting to the injectors.

[Randy in Maine]

When you re-do the fuel pressure test, be sure to note the change in pressure when the vacuum line is removed from the FPR.

[rubrbulits]

Jimbo, I just did the fuel pump volume test. I pulled the fuel line at the cold start valve and at 30 seconds i get just shy of 1 quart.

[VW_Jimbo]

That sounds on the fair side. Typically a L-Jetronic fuel system will fill a gallon jug in about 2 minutes, so if you have a quart in 30 seconds you would be right on track!

Maybe blocked injectors, if it is indeed a fuel issue. But first lets check spark. Pull a plug wire off of one of the plugs. Take a known good extra spark plug off of the shelf and stab it into the end of the plug wire. Take the spark plug and ground it on the engine, I typically ground the spark plug body with a large alligator clip around the steel nut portion of the plug, then attach the other side to an engine stud. Put the car in neutral (tires blocked), turn the key to the ignition on position. Then, while starring at the spark plug, crank the engine over with the starter button. You should see a bluish-white spark fly across the electrode tips of the spark plug. If you have spark, the engine probably started and scared you! Put it all back together as the fault has left. Check all of the ground wires. Take them off, clean them down to bare metal, squeeze some dielectric grease on all surfaces then reattach. If the car did not run while testing, then do this.

Reattach the plug wire and then remove the air boot from the air meter. Spray a shoot of carburetor cleaner into the air boot heading towards the throttle body. Go inside the car and try to start. It should run on the carb cleaner. If the car runs, the injectors are not firing or are plugged. If the car did not run, we need to check valves cold and go through a compression check. You also need to check the point gap, the ends of all of the plug wires (pull them out of the coil and cap one at a time and check for corrosion).

Let me know what you find.

Let me know what you get.

[rubrbulits]

Thanks Jimbo. After i did the fuel volume test I removed the two injectors on the passenger side to inspect them. I hooked them up to a 9 volt battery and attached a 35 psi line from my compressor and shot carb cleaner through them 5 or 6 times. They were a little dirty but not clogged. Put them back on and tried to start it. I also checked the harnesses that attach to the injectors. They are showing 11-12 volts ignition on. ABSOLUTELY no difference. Even though I didnt do anything with the other two injectors I figured there should be an improvement. Before any of this started and it was running perfect I had checked the spark plugs because it seemed like it was lacking power. Thats when I discovered #3 plug wire wasnt connected to the plug. At that time the plugs were very clean, looked like new. When I checked them today they are now black and the spark is bluish and seems a little weak. Not so weak that it wouldnt start though. Could it be that simple, if so, how could they all foul out almost immediately? The dist cap is like new, the rotor is clean, points are clean and gap is correct. I'm sure the valves are fine. This car was just running perfect two days ago. I also checked the double relay with ignition on and the two terminals that need to be hot are good. I am going to post some pics for visual reference and try to post a video of me trying to start it.

[rubrbulits]

[rubrbulits]

Here's a youtube video of me trying to start it. https://www.youtube.com/watch?v=_UYocFm2-uM