My first 412... Pulling out my hair!

Kombi · Post by **Kombi** » Mon Aug 09, 2004 10:36 am

I've been lurking and reading as much as possible in the last week or so but find I still need some help.
I just bought a '73 412,wagon, Automatic EA 1.7 with D-Jet, it looks good but am having some frustrating running problems. This is my first T4 engine and I don't yet have a 411/412 shop manual so I'm lost.
It starts fine and drives well for about a block, then it bogs down. When it bogs down the fuel guage goes nuts full to empty and bouncing all around. It then will sometimes stall out. But usually just looses power. If I wait I can sometimes get another block but usually I have to limp along 20-30mph. It does seem to be running rich.
What I've gone through so far.
Drained gas/put in new gas, flushed out the injectors.
Taped up the boot from the manifold to the air cleaner... reatached vaccum lines, and tightened/regrounded misc loose wires.
I've also replaced the condensor (Bosch 02054)and the points (Bosch 01011). And the injector points.
There are two things I can think may be affecting the driving but maybe someone more knowledgeable could help me out.
The fuel pump was replaced with a unit that does not have a return line.
It only has an inlet and outlet. It does work on turns on but...
Also I'm not so sure about the distributor, what should I have?
It has a vaccum advance/retard distributor (two vaccum lines) But I can't find a listing or replacement. The vaccum mechanism does not seem to be fully functional. I brought down a T3 FI distributor but it was somewhat different. ( I stoll the injector points from it though)
I found a bosch part # 07140 for vaccum advance, does anyone know if this is the whole distributor or just the vaccum? I really apreciate any help. I've relisted it for sale out of frustration and if I can't get it running I will have to sell it since the car was not driveable enough to bring home. I will return in a week or so with some more parts(if needed) and more knowledge in an effort to pick it up.
I have nearly a complete set of spare FI parts from a 73 fastback that was running that I will use if possible.
I'm at a loss and open to all Ideas. Thanks!

raygreenwood · Post by **raygreenwood** » Mon Aug 09, 2004 8:10 pm

The gauge is telling you something. Its not hooked to the engine or the duel system...but it IS hooked to the power supply. You have a loose ground or power supply wire. Look under the seat at the ground strap. Make sure the 3 center ground bundles right under the fuel distributor on the engine are tight and clean. Make sure none of the dash swicthes are loose. They can make contact with the metal undre the dash an short the power.

The advance unit you listed is for the advance can itself. The type 4 distributor is different than the the type 3. it can be used with modification..but chancesare there is nothing wrong with what you have.

Not having a return from the fuel pump means it may be an L jet pump. What month is your car? Is it L or D jet? If its L-jet...you cannot run with taped up manifold boot. It must be air tight. Also...if its L-jet...there will be no return line. But if you have distributor triggers...its D-jet.
The L-jet pump can run OK...as long as there is a return line from the regulator to the tank. These are great cars to have....much better than bugs or type 3's. Read up a little on the back posts of recently. Ray

Kombi · Post by **Kombi** » Mon Aug 09, 2004 10:14 pm

raygreenwood wrote: Not having a return from the fuel pump means it may be an L jet pump. What month is your car? Is it L or D jet?

Thought I put that in. It was made Jan 31 1973 Production code 05-4-3922 .. Should be D-jet right?

raygreenwood wrote: But if you have distributor triggers...its D-jet.
The L-jet pump can run OK...as long as there is a return line from the regulator to the tank.

The distributor did have triggers on the base. The previous owner had the pump changed.. It was a mess just hanging down the return line has a bolt in it. I'm certain it is the wrong pump.
I'll make a call and have the grounds rechecked and a return line run.
Maybe I can get it running properly before taking the 600km round trip this time

Thanks Ray!

Dave

raygreenwood · Post by **raygreenwood** » Mon Aug 09, 2004 11:31 pm

Wait...this is serious...and simple. Do not confuse the return line from theD-jet pump...with the absolute need for a return line to the fuel tank for the entire fuel system. Both the D and The L jet...use a return line from the fuel regulator. If not....it will flood in less than a minute...and you will be dang lucky not to blow a fuel line and light the car on fire. The supply line runs from the pump up the passenger side to the right hand injectors, to the cold start valve , to the left hand injectors, to the regulator, through the firewall...down the left of the car to the nipple on the fuel tank. You must hook that up. It will probably work right away after that. Ray

Kombi · Post by **Kombi** » Tue Aug 10, 2004 10:54 am

raygreenwood wrote: Do not confuse the return line from theD-jet pump...with the absolute need for a return line to the fuel tank for the entire fuel system...

The hose with the bolt is from the pumps return line.
But I do not recall there beeing a return line.
From what you described I think this system is hooked us backwards.

I thought the sending line was on the left. I'll recheck.

Do you know where the aux gas heater connects?
I've got one above the transmission. It was having a problem... pouring fuel out intake and exhaust.
I closed a line going to the fuel pump of the gas heater, but it fed from what I think you described as the return line. I may be mistaken, I should have taken pictures

. There was what looked to be a mini fuel filter that tied into the line before the Aux pump.
closing this line did not change the performance (ie still ran pourly) but did stop fuel from pouring on the floor.
ps I've bought a couple manuals from e-bay and maybe when they get here I'll have less questions
Cheers
Dave

caxambas · Post by **caxambas** » Tue Aug 10, 2004 11:30 am

I will trade you a D-jet pump for your L-jet pump if that is what you need.
Jos

Kombi · Post by **Kombi** » Tue Aug 10, 2004 12:54 pm

caxambas wrote:I will trade you a D-jet pump for your L-jet pump if that is what you need.
Jos

I'd be up for that maybe we can work something out.
But you should know It looks like a generic pump...
I'll get back to you if your still interested early September.
I'm leaving for a VW show in Vancouver thursday and will be back next wednesday. Then I have to get ready for our clubs end of summer show.
In 6 years I've only seen 1 411/412 at our show, so you can bet I'm going to get this 412 to our show one way or another.

caxambas · Post by **caxambas** » Tue Aug 10, 2004 2:05 pm

No Problem. I'll still be around in September.
I have probably 5 D-jet pumps and only 2 L-jet. I have a fuel injected beetle (L-jet) and a fastback (carbs)
Jos

raygreenwood · Post by **raygreenwood** » Tue Aug 10, 2004 2:47 pm

OK...STOOOOOP!!!!>>>>fast warning here. Stop what you are doing...and get a book....you will light yourself on fire. There should never be any fuel flowing from the heater unit....EVER. It is supposed to have a metering pump between the heater and the RETURN line of the fuel injection. (1) there is no fuel pressure on the return line (2) the metering pump "locks" fuel flow out until you turn it on.

The pressure line on the car IS the right hand side....ALWAYS. It goes into the engine compartment above the starter. It connects to #1,2 injectors, loops to the cold start valves....goes to #3,4 injectors...and ends at the fuel pressure regulator on the drivers side firewall. You also cannot run the fuel backwards...or the regulator will not work..and it will burn up the pump.guaranteed!...

Regardless of what pump type you have on there.....There are two nipples on the fuel tank. The one on the right...goes into the filter FIRST....then into an inline fuel accumulator (looks like a metal bisquit). The line comes from the pump...and does the route listed above.

Now...coming off the fuel regulato,r on the firewall. on the DRIVERS side....a line will go to the LEFT HAND tube in the tunnel. It comes out the front.....and hooks to the LEFT HAND nipple on the fuel tank. THAT MUST BE HOOKED UP>>>>OR THIS CAR WILL NEVER DRIVE......AND you will guarantee....light it on fire.

THIS WILL HAPPEN! No SH*T...you are lucky! Hook it up exactly as I have listed here! Make sure which end of the pump is inlet and outlet. Hook the wires up to positive and negative on the pump...they are specific...and marked.

By the way....The heater hooks to the RETURN LINE ONLY.....on the LEFT side....AFTER the fuel regulator......outside of the engine compartment. It should have a small beige plastic tank the size of your thumb that hooks in line. The small nipple runs to the pump for the heater....NOT directly to the HEATER. If you do not have the heater pump...you must plug the line off....or it will either leak fuel...or cause a LARGE ball of FIRE if you accidently turn on the heater. Ray

Kombi · Post by **Kombi** » Tue Aug 10, 2004 5:03 pm

raygreenwood wrote:The heater hooks to the RETURN LINE ONLY.....on the LEFT side....AFTER the fuel regulator......outside of the engine compartment. It should have a small beige plastic tank the size of your thumb that hooks in line. The small nipple runs to the pump for the heater....NOT directly to the HEATER. If you do not have the heater pump...

Ok the gas heater was connected in the right spot. It was not beige but a clear tank thumbsize (like a very fat peanut with 2 nipples)
Fuel no longer goes to the heater pump or heater.

you must plug the line off....or it will either leak fuel...or cause a LARGE ball of FIRE if you accidently turn on the heater. Ray

As a side note:
On my trip across the city (point of purchase to parents garage) it nearly did turn into a ball of fire. The heater switch was on and I was getting smoke from the heaters tail pipe. Once it was turned off it no longer smoked. But as I said above it began leaking... pouring gas from both ends. That problem is fixed. Now if I can only get it running right I can drive it home.

raygreenwood · Post by **raygreenwood** » Tue Aug 10, 2004 7:44 pm

Well...you discovered what the main problem is. It is physically impossible in this universe for gas to be flowing out of the heater........unless....the fuel pump is hooked to the wrong line. It i a simple matter of putting the fuel pump output line to the right hand fuel pipe. Make sure the fuel pressure regulator hooks to the left and pipe going forward to the front. Then make sure that pipe goes to the gas tank nipple. Ray

Kombi · Post by **Kombi** » Sun Aug 22, 2004 9:37 am

raygreenwood wrote:The gauge is telling you something...

Turns out the guage was loose it had only one of the two conectors. So the wild guage problem is fixed. I also checked the battery and engine (again) for loose grounds and all was secure.

I rechecked the fuel supply/return lines and all except the fuel pump return look correct. Tranny fluid levels are also correct. However the original problem still persists.

When at idle in the driveway it could run until I use up the fuel supply.
But if i attempt to go for a drive, the vehicle bogs down after about a block or so, or when under load.
I am not getting electrical failure but to me this indicates some sort of fuel supply problem. too much? too little? ('73 412 wagon D-jet)

Not sure if it's of help, but the 412 starts first turn when cold, drives well a block or so then bogs down. If I let it cool a bit, I can limp home around 30mph. If I turn off the car and try to restart it gives me some attitude and will not start for a while.

I now have two workshop manuals (Clymer and Haynes

) So at least I have something to reference.

The manuals indicate that this may be a faulty pressure switch. Is this the oil pressure switch from the tranny? Or do they mean the fuel pressure sensor? Am I on the right track?

I guess getting manuals opened even more questions.
The car is still 300 km (190 miles) from home so if I can go down with a better idea (understanding

) of what might be wrong I'd appreciate it.

Thanks

Dave

raygreenwood · Post by **raygreenwood** » Sun Aug 22, 2004 11:26 am

HAVE YOU FIXED THE RETURN LINE WITH THE BOLT IN IT????????

This MUST....repeat MUST be hooked up. If you have no return line...the fuel pressure will skyrocket instantly. It will run hideously rich....and youwill be lucky if you do not blow a line and light the car on fire. The pump is capable of about 80 psi. The engine only uses about 1/10 of the fuel sent to it. The rest MUST return to the tank. If not, the pressure skyrockets....the fuel mixture increases aout 600%...the pump begins to overheat. AND......the fuel pressure to the heater system increases about 1000%...no kidding? The heater system is a "0" pressure feed system. If you have pressure on that heater connection....every time the heater pump clicks...it gets roughly 70 times the fuel volume it needs every 33 revs of the heater fan motor. FIX THIS NOW!!!!!Ray

raygreenwood · Post by **raygreenwood** » Sun Aug 22, 2004 11:48 am

None of the 411's or 412's ever used a pressure switch. That is a part only found in early type 3 D-jet injection. There is no oil pressure switch per se on the tranny. The tranny had no connections to the fuel system whatsoever.

You have the Haynes manual? Green or blue cover? Either way...look in chapter 3...for the diagramatci layout f the fuel injection system. Its on page 58 in the green Haynes manual. See the top part of the picture where the fuel tank is illustrrated?....see that there are TWO connections?

Part #4...is the fuel pressure regulator....yes, the fuel line illustration between part # 4 (which is on the engine firewall) and the fuel tank is shortened for illustration purposes. Ignore the pump hook-ups as you have the wrong pump...but it will do.

YOU MUST HAVE BOTH CONNECTIONS ON THE GAS TANK ...PERIOD!!!!!!!

WARNING....YOU MUST HAVE A RETURN LINE....OR YOU WILL...100%...cause a FIRE

YOUR CAR WILL NEVER....repeat NEVER!!!! run properly until you fix the return line. DO IT NOW...DO IT NOW.....DO IT NOW.....DO IT NOW!!!!!!!

simply put a fuel line on the stub pipe where is comes out of the body. Hook it to the left hand spigot coming out of the bottom of the fuel tank. Since they plugged it off....go to the back left hand side of the car and ensure there is a fuel line coming from the fuel pressure regulator where it comes through the firwall of the engine....and goes to the left hand pipe near the center tunnel . Ray

Kombi · Post by **Kombi** » Sun Aug 22, 2004 3:04 pm

Maybe I'm a bit dense today, or I didn't express myself clearly.

I will tripple check the return line.

I have the greenish Haynes manual. Using page 58 as a reference and from memory the bolt is in the line that would have conected to the fuel pump.

The aux heater is also completely disconected (no fuel or power)

I got the pressure switch idea from the clymer manual
Volkswagen 411&412 sixth printing.
p 24 it sugests
5. Engine output low - Defective pressure switch or loose conection

then it shows a 'transmission oil pressure switch'
p89 item 4

this is later listed as part of the air injection
p102 ... the air injection valve is electronically operated during deceleration. An oil pressure switch located on the left side of the automatic transmission operates the valve.

I have not yet looked for the switch and would not be surprised if it was not there as past clymer manuals have not been 100%.

So with the assumption that all fuel lines are now correct and no leaks are present in the vaccum system, grounds have been cleaned and all conections checked... What should I be looking at to fix my 412?