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long term @ -20 short -50 at idle. both o2 sensors full rich. pulled vacuum hose from booster no change. unplugged o2 sensors has 450 mv bias. replaced o2 sensors. still rich. checked converter for clog. checked evap purge for leaking. checked map voltage. ect reads 175 at idle. tried driving it jerks. might try unplugging the egr just to rule out a sticking egr. need some help on this one. its older but its licking my butt!
seems better after the o2 sensors. it was actually running -11 long and 13 for short at idle for 10 minutes then went back to the same thing. maybe its a programming in saturns pcm to cut fuel with extended idling?? it runs smooth when its idling even with the numbers that negative. maybe theres a saturn expert on here.. thanks in advance
After replacing the 02's did the FT's improve with higher engine rpm? Before they crapped out again?
You said both O2's were rich, which would make me suspect a high fuel pressure issue, and a very leaky injector. If its a fuel issue, with those neg FT's you should be smelling unburnt fuel at the tailpipe. The Fuel regulator is the fuel filter for this vehicle, FP spec is 40-55 PSI.
A very dirty or poorly performing MAF will cause this as well. What were the g/s at idle?
Because both sensors were rich, I'm leaning toward a fuel issue.
This doesn't sound like a fuel trim relearn. But you could disconnect the bat cable and cross them to drain the ft memory.
plugs are new. owner changed them. i had a few egr codes in it. trim numbers dont really improve at higher rpms. fuel pressure holds doent bleed off. im kinda starting to lean toward a pcm. ive always had a rough idle with sticking egr valves. i dont see any black smoke or really smell any unburnt fuel.
Thats interesting, now I think you need to verify if B1S1 is lying or telling the truth. That's Fuel Control. There has to be a reaction to Major VAC leak or the introduction of propane fuel
The vehicle is in closed loop I take it? How does it sound on cold startup...smooth or sluggish? I concur about the egr valves. Starting to wonder if you're dealing with a false rich condition.
May I ask if you have any evidence to support a pcm?
Does this have a vacuum controlled fuel pressure regulator that could be leaking?
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the original o2's didnt repond by pulling the vacuum line off the brake booster. i unplugged them check for the bias at the connector with a multimeter. it was there. put 2 new o2s in and now the front fluctuates. BUT why is it so rich..... ill check the egr for sticking. when i drive it it has like a trailer hitching like the egr valve is sticking open. on the scanner i see a pid called egr error im assuming it should be 0. but its been awhile since ive looked at that. it goes to 15%
I don't suppose anyone replaced the injectors? :silly: Just thinking about the last extreme rich condition I saw. Was the tip of the O2 you replaced sooty black, or normal-ish?
I know u said u checked the purge solenoid, but give it another check, pinch off the manifold vacuum to it and watch the trims. Fixed a hyundai yesterday morning with these symptoms, and a stuck open purge
If the EGR checks out ok, what about looking for leaky exhaust valves?
Kinda like how Hondas do, where the exhaust valve lash tightens up so bad they will run rich?
You could do a cylinder leak down test and wrap a rubber glove around the tailpipe to help identify a small leak.
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