Which sensor?

[Simpler=Better]

My 1994 5SFE recently started going into a 'limp mode'
History:
Car would die if given more than 1/8th pedal. Felt like an extremely learn(fuel starved) condition so I changed:

Fuel filter, fuel screen, plugs, valve cover seal, plug tube seals, air filter, oil flush, oil changed to Mobil 1 synthetic
Cleaned and tested the EGR, cleaned the TB out. Seafoamed the vacuum lines.

Now2,000 miles later)

If I give it more than 1/8 pedal, the car stutters and dies, as if is experiencing an extremely lean condition.


Should I throw money at a new MAF, IAC, or what?

Does anyone know how I can test different sensors?

These modern computer controlled cars are making me like my 300D more each day....The only electronics are the alternator and starter

[ASG14]

Cel?

[hill8570]

http://www.camrystuff.com/manuals/Gen3/eg1.pdf starting at page 145 has a good bit of detail on testing the various sensors.

Like ASG14 asked -- is there a check engine light? If so, have you checked the code?

How's idle operation? Rough? Much higher or lower than 750rpm?

Does it matter whether or not the car is warmed up?

Have you checked the air intake hose for cracks? How about the vacuum lines? No cracks or hissing noises when the car is running?

Once you're up to speed, how's the throttle response? Still doggy, or does she do OK once you're >2000rpm or so?

[Venom_5]

a car will often do this if you run intake cleaner through a vac line ... basically its flooding it, and misfires until it dies

since youre not running a cleaner, i wonder if the rest of it is still the same ... would point towards an injector issue or possibly a spark issue if for some reason the distributor can no longer keep up, idk - just speculation

[Simpler=Better]

Thanks for the link!

There is no CEL. All the bulbs in the dash were replaced when I had the cover off for a stereo install.

All fluids are where they should be.

The idle is normal in the 750-850ish range. When idling in gear the idle occasionally stutters and shakes, as if it wants to die. Shifting into neutral or park and the idle smooths out again.

Engine temperature doesn't affect anything, all hoses under the hood are in good shape or have been replaced recently.

Here's the catch: It can't get up to speed. My max speed is~35ish, because if I give it more throttle than 1/8th it immediately begins to die. The exception to this is when in neutral/park I can get it to rev into the 3k range, but more than 1/8th throttle and it dies.



And now for the ultimate weirdness: After sitting in the parking lot at work all night, I tried it out this morning. A quick spin around the parking lot and it behaved almost normally, with a couple stutters every few seconds. I only had 5 minutes, so the cold engine may be helping?

[hill8570]

Originally Posted by Simpler=Better

Thanks for the link!

There is no CEL. All the bulbs in the dash were replaced when I had the cover off for a stereo install.

All fluids are where they should be.

The idle is normal in the 750-850ish range. When idling in gear the idle occasionally stutters and shakes, as if it wants to die. Shifting into neutral or park and the idle smooths out again.

Engine temperature doesn't affect anything, all hoses under the hood are in good shape or have been replaced recently.

Here's the catch: It can't get up to speed. My max speed is~35ish, because if I give it more throttle than 1/8th it immediately begins to die. The exception to this is when in neutral/park I can get it to rev into the 3k range, but more than 1/8th throttle and it dies.

And now for the ultimate weirdness: After sitting in the parking lot at work all night, I tried it out this morning. A quick spin around the parking lot and it behaved almost normally, with a couple stutters every few seconds. I only had 5 minutes, so the cold engine may be helping?

Hmmm. It'd be nice to know if this happened only with a warmed-up engine or not -- troubleshooting closed-loop-only problems is a different kettle of fish that always-happen or open-loop-only.

Assuming for a second that it happens all the time -- did you check the fuel system pressure after you replaced the fuel filter? Not much can happen if the juice can't get to the injectors fast enough.

If it happens warm-only, I'd check the output of the upstream oxygen sensor (check voltage between connectors OX1 and E1 of Data Link Connector (DLC) #1 -- this connector is in the engine bay, passenger side, near the firewall, and all of the connections are clearly labelled on the underside of the connector cover when you flip it open). If OX1 is constantly reading high (like 1V all the time), then you might be looking at engine being starved due to the O2 sensor constantly indicating a "rich" condition. I'd also check the output of the input air temperature sensor, the MAP sensor, and the Throttle Position Sensor.

[Simpler=Better]

Thanks for the advice, I'll check those tonight/tomorrow.