krystar

so I installed a wideband o2 and just verified how pig rich I'm running. while cruising, it maintains a consistent 12.5 with the FQS at setting #3 for -6%.

what would be list of things to check? off the top of my head, O2 sensor, Engine Coolant Temp, fuel pressure?

list of stuff done: I replaced the fuel rail that cracked the new rail has a extra outlet and a port that's plugged. no sure for what.



I also gutted the vaccuum system of this car ALOT. there's just the FPR ones and big ones going back to the j-boot remaining.

V2Rocket

O2 sensor

choinga

the port is probably for a fuel pressure gauge. I'd guess O2 sensor as well...

DarylJ

I have to agree with the O2 sensor being a likely culprit. But I'd check the FPR first if you can get your hands on a gauge easily. DME temp sensor is typical also, as you mentioned.

As far as what order to do them in, it really depends on what you have laying around and what tools you have. Without a proper socket and torches, you might have a bitch of a time getting the O2 sensor out. DME temp sensor should be fairly easy, as should the FPR if you have a gauge.

As always with these cars, don't forget that you are likely looking at multiple failures, so fixing one will only make things a bit better.

krystar

ok so then question. I see there's actually part# for two engine temp sensors...both in the same area. how should each be tested?

DME temp sensor = coolant temp sensor?

#21 and #23?

V2Rocket

i believe that if the O2 sensor fails or gets disconnected somehow the DME switches to a richer fuel map, kind of a safety 'limp home' mode so that it doesnt damage the engine

Johnny Player Special

He said Limp.

krystar

at least noodle wasn't in the same sentence.

944Ross

My understanding is that #23 is the DME Coolant Sensor and #21 is the gauge sensor.

I'd vote for the FPR, high fuel pressure is a likely culprit at cruise speeds.

krystar

well replaced o2 sensor. no change.

just bought the #23 sensor. will put it in once the engine is cooled down tonite.

i guess FPR and FPD are next on the list if the sensor doesn't do it

krystar

so....with the FPR and FPD. if there isn't enough vacuum, would they run rich? or lean?

krystar

hmm...i have a feeling it ain't the temp sensor. i measured it at the sensor and at the dme plug. when i just turned off the engine, it was 300ohms. after about half hour of cooling down, it's now at 500ohms.

944Ross

It could be a leak in the vac lines to the FPR/FD, but from what Clark says etc, FPR's sometimes just lock in one position (hi pressure) which makes it rich at medium/high vacuum conditions, like idle and cruise. Would be close to right while accelerating. He notes it can make the fuel pump sound loud. I just went thru this this weekend, my FPR appeared to be sticky. I cleaned it out and it seems to run smoother at idle, but it's still smelling rich when cold and idling.

By the way, have fun getting the big nut off the back of the FPR! I ended up using needle-nose visegrips. No wrench on earth can get on it.

Check your DME temp sensor when stone cold, but those numbers sound about right for hot/warm.

knfeparty

I replaced FPR, Fuel Damper, fuel lines, vacuum lines, BOTH of those temp sensors, and the O2 sensor to pretty much no avail...I think the car is just doomed to spew black soot out the exhaust pipe.

944Ross

Why is the FQS at #3, are you using a chip?

Have you run a compression check?