85 Cabriolet Stuttering Problems

kamzcab86 · Post by **kamzcab86** » Fri Jun 22, 2007 11:35 pm

85Cabriolet wrote:When I turn on the power to the car on there is no sound coming from the rear of the car indicating no pumps running, however when I bridged the fuel pump relay it did start to buzz and stopped when I removed the wires,

That indicates a failing/failed fuel pump relay. I'd suggest replacing the relay as well as testing the fuel system to make sure the pumps and/or distributor are indeed getting fuel (and in adequate quantity) to the injectors. You might also pull out the in-tank (transfer) fuel pump (under the rear seat) to see what its screen looks like (as well as the gas tank).

85Cabriolet · Post by **85Cabriolet** » Sat Jun 23, 2007 9:35 pm

Replaced the transfer pump, and relay still nothing so now its down to the fuel pump, I went under there and went through hell and got a face full of gas and its still not out, I just quit after nearly throwing up. So if that doesn't solve it, i'll smash that engine

gull · Post by **gull** » Sat Jun 23, 2007 9:38 pm

Have you hooked a CIS fuel pressure gauge set up to it yet and determined the system pressure is low? If not, you're wasting money replacing the fuel pumps. You can get the gauge at J.C. Whitney for less than $100.

85Cabriolet · Post by **85Cabriolet** » Sat Jun 23, 2007 10:40 pm

It's more of a cost issue, I got a fuel pump from the scrappers for $20 in good shape, so it's either that or buying a gauge. I guess if it still runs like crap i'll move onto the fuel distributor. After being under the car it doesn't look like the fuel pump was ever touched in many, many years so I would have to assume the fuel pump is messed up.

gull · Post by **gull** » Sun Jun 24, 2007 2:15 am

Yeah, I guess if you have used parts on hand that changes the equation a little.

Have you checked the fuel filter, yet?

Also, make sure you didn't knock any vacuum hoses loose. If you knock a big one off, like the brake booster hose, the thing will fire but won't stay lit except at full throttle.

The same will happen if you don't have power to the Lambda system or the frequency valve is disconnected, so if your car has CIS/Lambda you might want to check that. You should be able to hear a buzzing noise coming from the fuel distributor area when the engine is started and for a few seconds after it stops. I've run into that one before. I'm not sure if yours has that system, though; my car us a U.S.-spec '89. If you don't have an oxygen sensor then you don't have CIS/Lambda.

85Cabriolet · Post by **85Cabriolet** » Sun Jun 24, 2007 7:20 pm

I'll definately check that out, but after I installed the "new" fuel pump it still didn't work. It performed exactly the same after I removed the fuel pump relay, so I have to assume that I got an even WORSE fuel pump than before, one that doesn't even work, so I might as well buy a new one

Damn car!!!

gull · Post by **gull** » Sun Jun 24, 2007 7:29 pm

Have you checked that there's power to the fuel pump? You don't necessarily need a multimeter; a test light will do, or even a brake light bulb and some clip leads.

85Cabriolet · Post by **85Cabriolet** » Sun Jun 24, 2007 7:50 pm

That's a good idea, does the car just have to be switched on or actually started?

gull · Post by **gull** » Sun Jun 24, 2007 8:29 pm

You should see power when the starter is operated, and for a second or two after the engine stops running (or the starter is disengaged, if the engine doesn't run at all.) Alternatively, you should see power when you bypass the fuel pump relay.

kamzcab86 · Post by **kamzcab86** » Sun Jun 24, 2007 9:57 pm

gull wrote:You should be able to hear a buzzing noise coming from the fuel distributor area when the engine is started and for a few seconds after it stops. I've run into that one before. I'm not sure if yours has that system, though; my car us a U.S.-spec '89. If you don't have an oxygen sensor then you don't have CIS/Lambda.

A little FYI: The frequency valve should buzz while the engine runs. Also, ALL 1980-1989 North American Cabriolets are CIS K-Jetronic (Lambda).

85Cabriolet · Post by **85Cabriolet** » Sun Jun 24, 2007 10:02 pm

I sure do have an O2 sensor, I already checked that and it works, I still blame the fuel pump. Fuel filter was changed, and also tried a new relay hoping that I wouldn't have to buy a pump but it looks like i'll have to

85Cabriolet · Post by **85Cabriolet** » Sun Jul 08, 2007 8:17 pm

Well after more work on the cabby I'm pretty sure the fuel pump works, and there is fuel that is pressurized all the way up to the fuel filter and the hose that connects the fuel filter to the fuel distributor. BUT all the lines from the distributor going to the injectors and all the accessories, when cracked open there is no squirt of fuel indicating no pressurized fuel, it sort of slowly oozes out. So since there's no pressure in the lines the injectors don't open. What's up with that, I don't have to get a new fuel distributor do I?

The throttle plate thing on the air housing was lifted while I was cranking the engine and all the injectors are out of the car. Maybe it has something to do with the system pressure regulator screw thingy?

kamzcab86 · Post by **kamzcab86** » Mon Jul 09, 2007 7:45 pm

If fuel is reaching the distributor but not the injectors, the fuel distributor is most likely the issue. Rather than replacing it, try cleaning it up first:

WackyWabbitRacer (CIS expert on VWvortex): "As ABA Scirocco said, do not attempt to disassemble the fuel distributor as it has many springs and rubber washers inside of it. Plus I understand that the VW factory uses a special wax to seal the top and bottom sections of the unit.

Most likely the Control Plunger is stuck if you are not getting any fuel at the injectors. This condition happens when the fuel distributor is not used for a very long time, such as a year or longer. The residual in gas will cause the Control Plunger to stick in its bore.

The Control Plunger is machined exactly to its bore, and Control Plungers can not be interchanged with different fuel distributors.

Remove all injector lines and fuel hoses from the fuel distributor. Make a diagram of all connections if you have not previously performed this removal. Next remove the three screws that hold the fuel distributor to the top section of the air flow plastic housing. Carefully lift the fuel distributor and place your hand under it in the event the Control Plunger moves freely. However most likely, it is stuck in in its bore.

I have had success with soaking the entire fuel distributor in solvent (ie lacquer thinner, etc) for several days. Prior to soaking, I spray WD-40 in all of the ports. After soaking, I use compressed air to remove the Control Plunger. Place a rag under the bottom of the fuel distributor and blow air into the top center port (control pressure connection), hopefully causing the Control Plunger to move downward from its bore. Do not use pliers in an attempt to pull the Control Plunger out as pliers can cause marks on the plunger and damage it.

You may have to repeat the soaking process several times, depending on the amount of gas residual in the fuel distributor.

Some of the fuel distributors have four (4) metric allen caps next to each of the injector line ports. If you remove the caps, you will find small filters under the caps. These filters can be cleaned and re-installed. Beneath the filters are metric allen screws that are "factory-adjusted" for the amount of fuel flow from each injector port. Do not attempt to turn these metric allen screws as you will change the amount of fuel flow. I know this from prior experience!!

Once the Control Plunger is removed, clean it with spray carb cleaner, and spray carb cleaner into all of the ports. Then use compressed air to blow the entire unit dry. The Bentley says to put a light coat of fresh gas on the Control Plunger and reassemble the unit. Good luck, WWR."

85Cabriolet · Post by **85Cabriolet** » Mon Jul 09, 2007 8:07 pm

Nice! I'll give it a shot and let you guys know in a few days! Thanks for the help I really appreciate it!

85Cabriolet · Post by **85Cabriolet** » Thu Jul 12, 2007 11:44 pm

Well tried cleaning it still nothing, although there is some hissing when I crack open the fuel injector lines though but still no gas, I'm just going to replace all the lines and distributor with the junkyard variety. Screw it, time to overhaul the whole fuel system, maybe I should do carbs...