beyerdbx

87 audi 5000s automatic nf running rich. car starts fine warm or cold, idles great, its only when i put the car in gear and hit the gas, its very week boost and starts to sputter and buck Once i get passed 3000 rpms car runs great, i can actually punch the gas and generate good boost and speed. I have to ease into the gas pedal to get it going in low gear. I have had 18 wheelers start off the line faster. I put a new o2 sensor on and it got worse, and gas mileage was really low. Disconnected the wires and gas mileage got better running about 22 miles to the gallon. When Im on hill or slight incline, it stalls almost every time. I would just keep doing what im doing, except the other day i tried to cross some north bound traffic that was going about 45mph, car stalls when i hit the gas and leaves me in the middle of the road. Almost get jacked up by an Suv. Time to get some Help?? Iv'e seen some post about the fuel pressure regulator, altitude sensor, vaccum leaks, leaky injectors, Intake manifold is pretty rusty exhaust is old, but stainless steal still in pretty good shape. Im not sure where to look.anyone have this sort of problem.

treehunter

Start with the basic stuff like plugs/wires then keep going once you're sure it's not an ignition problem move on to the fuel system.

Fuel filter
Fuel pump relay
Replace or have the injectors tested and cleaned. Can almost guarantee they are not healthy.
Pressure Accumulator
Fuel pump

S4for73

have exactly the same problem, but worse. I belch out large amounts of black soot. My WUR is way out of adjustment (6.5lbs), when I get it fixed I'll maybe know something and report back. 89200TQ

boxerfan

eg: With the car running disconnect the plumbing off the back of the IM. As each hose comes off it will run worse and worse until you will need to rev the motor to keep it from stalling (like if you remove the oil cap).

Black-Wolf

to start off with a 87 automatic NF car dont have boost.. it isnt turbo charged. try putting an o2 sensor in it.

875kcstq

Coolant temperature sensor shorted will cause an over rich condition. Rusted ground connection for CIS module can cause erratic modulation. Basic actuator current should fluctuate @ 10ma at idle, oxisensor connected.

Ben's e//S2

Not sure how your car is set up, but I know this can be a cause of rich running on the 20v engines.

treehunter

Hold on, is this a turbo or not?

boxerfan

Yes, temp sensor failure leads the ECU to think the engine is cold and runs in open loop mode. Anything causing open loop mode means the ECU is not looking at the actual operating conditions of the car and is running using some default settings.

iirc, the NF has a flex hose that connects the igloo to the IM. A tear in that or the igloo will mean the air sensor plate isn't metering fuel correctly.

Ben's got a good suggestion. I don't know if the NFs had that FPR either.

Senna4Life

87 5KS Auto with 2.3 NF engine (non turbo)