LR45

What is the final effect on the DEC if one were to disable the O2 sensor and the engine temp sensor. I am troubleshooting a pulsing accel. problem and don't have the money to shotgun parts to fix. Ant suggestion and or help!
Thanks,
Stumped

special tool

What kind of car do you have?

Danno

Check for vacuum leaks and loose hose-clamps. These are the primary culprits in causing acceleration stumbles. Might even be a good idea to disassemble the entire intake and check each and every part.

LR45

History: R&R all fuel injectors, idle control valve, all vacuum lines, plugs, cap, rotor, wires and engine temp sensor. have checked for vacuum leaks with a propane torch, no leaks noted and did not notice any rise in RPM. Had the the dealer do the belts.Still have a pulsing accel problem. That brings me to the O2 sensor. Any hints or tips, Iwould be grateful
Stumped
86 944 N/A

mmmbeer

If it happens during full throttle it is probably not the O2 sensor. It only adjust fuel ratio at part throttle. It could be a faulty fuel presure regulator. Try measuring the fuel pressure.

Eirik Kvello-Aune
<a href="http://www.diateam.no/porsche" target="_blank">www.diateam.no/porsche</a>

LR45

I have R&R both FPR and the pressure dampner. The pulsing only happens at part throttle. At full throttle up to red line the accel is good. That is why I am leaning towards the O2 sensor. I would like to disconnect it and take the "ol" girl for a short drive and see how she performs, but don't know what effect by disconnecting the O2 sensor will have on the engine computer.Any comments will help greatly
Stumped

Ski

It will just run in open loop,,

LR45

Well just got back from the test drive with O2 sensor disconncted, and she ran the best I have ever felt. Strong accel, no pulsing what so ever. I guess I know what my next purchase is going to be.
Thanks for the help

RJP 951

Bruce, I hope you've pinned down the problem, but I was chasing a similar issue until recently and after all was said and done it turned out to be vacuum leaks under the intake manifold. That was despite the fact that disconnecting the O2 sensor seemed to make a big improvement. I'm assuming that the computer was ordering up an extra rich fuel mixture as a safety measure (lacking O2 sensor input), and that somewhat compensated for the air leaks.

In your case it sounds like you've tested thoroughly for air leaks, but don't be surprised if a new O2 sensor doesn't fix the problem.

Good luck
Ron

LR45

I know everyone on this topic has leaned towards vacuum leaks, but if one uses a propane torch with a long hose attachment and probed all connections with the propane and did not notice and rise in RPM's wouldn't one assume that the O2 sensor is at fault, based on the test drive that had no pulsing in the part throttle phase of driving when the sensor is disconnected.
Thanks,
Any comments ar welcomed

RJP 951

Bruce, you didn't mention what mileage is on the car, but if it's north of 60-70K or so and has the original O2 sensor, it's not a bad thing to spend money on. If it doesn't fix the problem, you can chalk it up to preventive maintenance.

Ron

nine-44

AFM?

Danno

Hey there's an idea! I've heard of people opening up their AFM to find a worn-out trail where the sweeping arm rubs on the resistor traces. They bent the arm so that it rubs on an unworn section and that fixed it!

fusionsport

yep- that does work (bending the arm) and I have bent the arm to correct a CO reading as well. Just make sur ethat you reseal the unit well- as it wont like any water that might get into it- dont ask how I know

LR45

Well, just check out the O2 sensor with a volt meter, .835 to start and leaned to 750. Does any body know the the medium number I should see on the volt meter with the O2 sensor disconnected at idle and should it maitain this number all the time. I know the range is 200 thru 800. all so does any body know the resistance of the inlet air sensor on the airflow meter and what pins to read this from.
Thanks,
Stumped but still trying