On my way to work Friday, my 87 4000Q died 2 blocks from home. I assumed it was out of gas although the gauge was not on empty so I pushed it to the side and took other car to work. After work, I brought a can of gas and put it in but it would not start. AAA brought it home. I checked the pump and it was running when I cranked it, spark was good and timing belt looked like it hasn't jumped. I loosened up the fitting next to the CIS and there was practically no fuel coming out, I cracked the line at the pump and there was tons of fuel. After a new fuel filter, I now get good fuel up to the CIS but it still won't start. I pulled the cold start injector an does has fuel and works during crank. None of the other injector lines on top of the CIS have fuel pressure. The regulator thing on the front of the CIS is getting juice and has pressure. So, what am I missing? Should the injectors have fuel pressure in the lines when I crank? I took off the fitting going in to the CIS and blew out the little filter, still nothing. I need suggestions, or a big hammer to beat this thing into a cube and have it hauled away!

especially since you made it two blocks.. seems like the fuel system was working before something else went bad. how is your spark? wires, cap, rotor all fresh? plugs could be dirty or need to be replaced perhaps.

and as for pressure in the injector lines, they have fuel in them but no pressure unless you are cranking, in which case only one should have pressure at a time... if you wanted you could take the injectors out with the lines still attached and place it in a bottle and crank the motor to see if the spray is okay.

good luck, let us know how things turn out

Plugs are clean and recent, cap and rotor clean. Spark appears strong. There is no fuel at the lines for the cylinder injectors when I crank engine but fuel and pressure at CIS input line and th ecold start injector. Is there some electronic control that may be shot and keeping the fuel from getting to the injectors? Oh yeah, if I take out a few plugs, pour in a little gas, replace the plugs and crank it, it will try to start for a second.

I usually work spark then fuel and assume nothing about the state of the "plugs and wires that are pretty new". Assuming you've tested all the plugs for spark (ie pull the wire, insert an old plug and hold the threads to ground then crank...) etc. to rule out the hall sensor, next is to work the fuel. Parts to check out are relay, pump, temp sensor, ground connections, differential pressure regulator, ISV and CSV and air plunger. First try jumpering the Pump Relay's two large spades (it should be in slot 10). when you turn on the key now you should hear the pump. Now crank. If it starts now try with the relay back in. Now check all fuses. Next thing is to check the temperature sensor on the bottom of the water flange below the 1-2 spark plugs. It should be 2.5K ohms or higher. Next is to look for obvious ground wire failures and air boot cracks etc. You may want to remove the boot to inspect and check the air plunger to see how its seated. If all this looks fine you either need a pressure tester or may want to check out the CPU connections for voltages and resistance. There's a whole list of values to measure from the CPU connector in the Bentley. Hopefully you will figure it out before you get this far.

First of all "1981audi4k4e" remember that the initials CIS stand for Constant Injection System. That means that all of the injectors spray all of the time. Only the amount that they spray varies and that is due to the lifting of the sensor plate.

So, here's what you know.
You know it was running fine and then shut down. You know that replacing the fuel filter has gotten fuel up to the fuel distributor and to the cold start injector.
You know you have good spark.

That leaves....no fuel getting to the injectors as you've mentioned. My guess is that some crap came through the system and lodged against the plunger in the fuel distributor jamming it in place.

Remove the big air boot on top of the sensor plate in the fuel distributor/air filter housing. Lift the sensor plate using a pair of pliers grabbing onto the center nut. It should swing freely, but you should also feel some slight resistance as it moves that plunger up.

Pull an injector, jump the fuel pump relay and then pull the sensor plate up and down. That injector should give a lovely cone shaped fog that rotates and it should "sing."

If it does, put her back together and she should now fire right up.

Let us know what happens.

with the CIS

Thanks guys, I will give that a try after work tonight.

If youpull an injector you willhve no vacum to lift the paddle for the CIS. when cranking youhve to manual lift the paddle to seeif ther is flow.

While checking the fuel flow be sure the paddle is moving freely.
Good luck