TheSamba.com :: View topic - Anybody got starting problems with 1600 Fuel injected?

Tue Jun 22, 2004 9:13 am

1978 FI 1600, catalytic converter - Sounds like bonanza so far, but won't start anymore. Any idea where to look? Ran a couple procedures, everything seems fine, can't locate some of the parts mentionned in manuals. Anybody know where voltage regulator supposed to be?

could it be that leaking oil cooler thing?\

Tue Jun 22, 2004 10:27 am

The number one issue with FI is usually vacuum leaks. Check an make sure all the hoses are attached and not dried out or cracked. Also check out the big rubber intake boot on top. Look closely at the sides and make sure it’s not cracked either. A little to much air will prevent the motor from starting. There's another large hose that plugs into the back of the boot. Make sure that is good too.

-jeffrey

Wed Jun 23, 2004 9:15 am

Thanks for the tip. Hoses do look all right. Boot seems fairly new actually. Had a friend help with checks yesterday and found out the fuel pump won't pump gas into the system. That could be why starting was always kind of a two step process, with multiple pushes on gas pedal beeing required every morning.

That pump just went out one morning i guess.

Thu Jun 24, 2004 9:29 pm

My fuel pump quit working one afternoon, after much checking of everything it was determined that the wire lead came loose. I sure was happy when it turned out to be an easy fix.

Fri Jun 25, 2004 3:14 pm

Never had an easy fix myself. Except at that time when the battery was emptied overnight for no apparent reason and the windshield wipers had not switched off all the way. It never rains anyway.

Hey what about washer fluid, do you have the whole connection to the spare tire for it to work thing?

Sat Jun 26, 2004 5:48 pm

Ok, got a replacement fuel pump, used. Still did not start, let me check a couple things:

1 - The lead wire connects to the plus side of the pump, and that wire is the red one. The connector on the pump is the largest one of the the two.
Am I right?

2 - If I disconnect the fuel hose coming out of the fuel pump, and have a friend start the car, and no fuel comes out, then something between the gas tank and the fuel pump is broken, right?

3 - What's that black plastic box between the tank and the pump. Fuel hoses go through it and it's maybe one inch apart from the pump? Tried to open it or something but nothing will move.

4 - Finally, some of the gas pouring straight from the gas tank was put in a glass jar, and it looks like there are tiny little rust bits, any clue if that could be the problem?

Any advice is appreciated.

Tue Jun 29, 2004 9:53 am

Reply to

#1 Not sure. You should have voltage at these wires when cranking. It not the issue could be the double relay next to the FI brain behind the back seat. One of these relays supplies the fuel pump voltage.

#2 If you disconnect the line after the fuel pump and someone try to start it, gas should shoot everywhere. Good pump.

#3 The black plastic box sounds like the filter, mines white. There is a short connection rubber line between the filter and the pump. Sounds like it hasn’t been changed for a while if it would come loose easily. The hoses should slip off each end. Get a new filter ASAP

#4 Rust in the gas tank causes big problems for fuel injection. I had rust in gas tank and it kept plugging up filters. Made my car run poorly, starved for gas.

So if your pump is running, perhaps the filter is so plugged it doesn’t let gas through.

Tue Jun 29, 2004 10:18 am

If you remove your fuel pump and no fuel pours out you have something wrong. Whether it be a clogged filter or clogged hoses. I had to replace all of the hoses from my gas tank to the pump because of the same problem. No fuel flow there is a block in the lines somewhere. Take out the tank it's very easy. Theres probably rust in the bottom of the tank blocking the gas feed.

Tue Jun 29, 2004 6:22 pm

I had a '79 Super Conv myself -- and also had problems with it starting easily. Unfortunately, for me, it took replacing every fuel injected component to remedy the situation.

But I think I know what might be causing your problem with the fuel pump.

The electric fuel pump on fuel injected beetles should begin "humming" (pumping fuel) as soon as you turn the key - even if you don't start the engine. If it's not, check the "Double Relay" -- the small black box attached to the Electronic Control Unit (ECU) which is a larger silver box located just behind the back seat. If this is not hooked up properly OR just simply no longer working as it should -- it will not "tell" the fuel pump to start pumping fuel. The "Double Relay" as its commonly called will cost about $70 - $80. See if that fixes your problem.

ALSO -- VERY IMPORTANT!!!! Never jump start OR charge the battery of a fuel injected Beetle with it still connected to the car. This will short out sensitive parts of the fuel injection system -- specifically the DOUBLE RELAY. You mentioned you had a dead battery once -- did you jump start/charge the battery with it still hooked up to the car?

Hang in there! You'll get it going!

Wed Jun 30, 2004 9:43 am

Thanks all.

For a start, I will change fuel filter and tank to filter rubber hose. In the process i'll check for rust in the gas again. Don't know if the fuel pump was humming, i think it was, could be clogged too or something.

thinking also of air pressure cleaning fuel hoses and putting some of those fuel system cleaners in, that's after the car gets to start again.

The relay behind back seat, I will have to look again, i think it might be the one behind the seat on the left opposite the battery. Better check the connections on that thing too i bet.

And yes, it got jump started once, before i found out it was a big no no.

Hopefully it will drive for the fourth of july parade.

Wed Jun 30, 2004 12:28 pm

I went out of my mind trying to get mine to start. Here's the thread. Maybe something there will ring a bell.

http://www.thesamba.com/vw/forum/viewtopic.php?t=73074&postdays=0&postorder=asc&start=0

Good luck.

Tue Jul 06, 2004 8:30 am

79SuperVert, did you end up keeping the car?

You know, there is crap in the gas that comes out of the tank. Maybe I ought to shake that beetle up and down a little.

Replaced the fuel pump and fuel filter yesterday but still won't start. I am curious to find out if you changed your gas tank and cleaned your fuel line and engine one way or another...

Tue Jul 06, 2004 9:28 am

No, I didn't. I think if I was going to keep the car I would do that next, even though the tank looks new. It looks like I'll be selling the car by this next weekend, however, and I've already told the prospective new buyer about this situation.

Tue Jul 06, 2004 11:22 am

but it runs?

Tue Jul 06, 2004 2:48 pm

Oh, yeah, it's running really fine. In fact the prospective buyer took it for a test drive yesterday, and a couple of days before that I drove it around for a couple of hours, and it's running better than ever. You'd think if it was residue in the tank, by now (a month after it came back from the mechanic) the gunk would have settled back down to the bottom of the tank and plugged the line up, since I only drive the car once every week or two. But no sign of that.

Mon Jul 12, 2004 9:08 am

Ok, this week end I found out there was no juice going to the fuel pump connectors. After running tests as per the great bentley manual, turns out terminal 86c on the relay is where the problem is. The manual says it is not getting juice from the battery. So I guess from here it's all about figuring out how that wire comes from the battery to behind the back seat...

Tue Jul 20, 2004 10:33 am

Still not starting. No juice going to the fuel pump. 86c terminal on relay not testing ok, same for 88d going to fuel pump. Could it be the relay?

Tue Jul 20, 2004 1:52 pm

vwplanet wrote:

The electric fuel pump on fuel injected beetles should begin "humming" (pumping fuel) as soon as you turn the key - even if you don't start the engine. If it's not, check the "Double Relay" -- the small black box attached to the Electronic Control Unit (ECU) which is a larger silver box located just behind the back seat. If this is not hooked up properly OR just simply no longer working as it should -- it will not "tell" the fuel pump to start pumping fuel. The "Double Relay" as its commonly called will cost about $70 - $80. See if that fixes your problem.
The pump will not operate if you simply turn the key on. For safety reasons, VW didn't do this. Think about a crash where a fuel line is broken, fuel would pump all over the place.
There are two sources of voltage for the pump.
The first is from the crank position of the ignition switch. If you disconnect the small wire at the starter you can hold the key in the crank position and listen for the pump. If your car starts then stalls 2-3 sec later, and you can repeat this forever, your pump is getting voltage from the crank position of the ignition switch.
The second source for voltage to the pump is a signal from the air flow meter. There's a set of contacts in it that close as soon as the flapper moves off its stop. Like when the engine starts to run. If the switch inside the AFM isn't working, or the wires going to it are broken, it will never run. On my car when I had this problem it turned out to be the cable passing over the fan shroud to the AFM. The cable was rubbing on the shroud and wore right through the wires for the pump signal.

vwplanet wrote: ALSO -- VERY IMPORTANT!!!! Never jump start OR charge the battery of a fuel injected Beetle with it still connected to the car. This will short out sensitive parts of the fuel injection system -- specifically the DOUBLE RELAY. You mentioned you had a dead battery once -- did you jump start/charge the battery with it still hooked up to the car?

This is a myth. It is perfectly safe to jump start any VW. When VW designed the EFI they installed the double relay that completely isolates the EFI when the key is off. Thus there is no possibility of any voltage spikes getting to any EFI component.
This myth originates from GM. They didn't do an isolation relay like VW and they are notorious for blowing up EFI components when jump starting.

Tue Jul 20, 2004 10:03 pm

Yea, I've jumped my car several times with no ill effects. I've even on occasion used a Battery Tender charger to bring a winter weary battery back to life.

-jeffrey

Wed Jul 21, 2004 10:49 am

Thanks guys.

Bruce, that cable going to the AFM on mine sure is in bad shape going over the shroud area.

did you replace or overhaul it? did you find a replacement easily?