Car running Rich all of a sudden
06-30-11, 06:30 PM
#1
Car running Rich all of a sudden
here's the setup:
Map Ecu 2
PTE 525cc injectors
fuel filter about 1 1/2 yrs. old
Walbro 255
IK27 spark plugs
spark plug wires, 4 runner cap, rotor all has about 5k miles.
remanufactured distributer about 1 1/2 yrs. old
TT hg
well it happened about a month ago. usually when i'm just driving normally around town or highway my wideband will show around the mid 14's. now it's like low 11's to even high 9's sometimes. car will sometime stall out at a red light and hard to start sometimes. and when i do get it to start there will be a lot of smoke coming out of the exhaust and a strong smell of fuel. just installed some new plugs on it but still the same thing. tried resetting the ecu and the map on my Map Ecu 2 but still running like crap. last time i checked the timing it was at 10* BTDC. i'm thinking it could be a stuck injector maybe? will a bad wideband o2 sensor cause this? what do you guys think?
Map Ecu 2
PTE 525cc injectors
fuel filter about 1 1/2 yrs. old
Walbro 255
IK27 spark plugs
spark plug wires, 4 runner cap, rotor all has about 5k miles.
remanufactured distributer about 1 1/2 yrs. old
TT hg
well it happened about a month ago. usually when i'm just driving normally around town or highway my wideband will show around the mid 14's. now it's like low 11's to even high 9's sometimes. car will sometime stall out at a red light and hard to start sometimes. and when i do get it to start there will be a lot of smoke coming out of the exhaust and a strong smell of fuel. just installed some new plugs on it but still the same thing. tried resetting the ecu and the map on my Map Ecu 2 but still running like crap. last time i checked the timing it was at 10* BTDC. i'm thinking it could be a stuck injector maybe? will a bad wideband o2 sensor cause this? what do you guys think?
Last edited by SC300_704; 06-30-11 at 06:52 PM.
07-01-11, 05:59 AM
#4
Driver School Candidate
If you suspect it is the O2 sensor, couldnt you just disconnect the sensor in which case the vehicle will be running open loop and the CEL will be on but at least so you can see if the condition is indeed being caused by the O2 sensor. As for the wideband being the cause of the problem, I would doubt that is possible. Your wideband is only monitoring the AFR' right? You're not using it to do the duty of the real O2 sensor? I can't see how that might be causing your problem
Last edited by rexst; 07-01-11 at 06:05 AM. Reason: added response
07-01-11, 06:49 AM
#6
Driver School Candidate
I didn't know that the MAP ECU2 was considered a full standalone. I always thought it was a piggyback system that still relied on the stock ECU for the other functions of the engine. I believe the AEM EMS is a full standalone system but that's not what he said he has on the vehicle. Nonetheless, you may have a point on it being a fuel mapping issue probably brought about by a change in ambient temp or even the climate.
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07-01-11, 02:30 PM
#9
Driver School Candidate
If you're not running the stock O2 then maybe your suspicion that you have a stuck injector is possible. I assume you have already checked to see if you might have a vacuum leak. As for the wideband, these do go bad over time but I don't know if they will be causing the problem because the MAP ECU2 isn't getting data from it that is used in calculating the programmed map. Is it possible that the Long Term Fuel Trim has changed over this period of time such that your ECU has learned certain parameters and is affecting the equation? Just throwing this out there. I could be completely wrong. It wouldn't hurt to reset your ecu though and clear everything. You may also want to check if there are other problems that have been logged in the ECU since I assume your CEL is either permanently on due to a disconnected O2 (or did you install an O2 simulator to fool the ECU?)I hope I'm making some sense.Good luck
07-01-11, 06:38 PM
#10
ok just installed a new universal o2 sensor and did the 12v mod, now it seems to drive a lot better when cruising at highway speed. wideband showing high 13's to mid 14's which is a lot better than high 10's and low 11's. but there's still one issue, most of the time when i exit off the interstate while still going about 40 mph or so and put it in neutral, it will show rich on th wideband then the engine will shut down unless i put it back into gear. anyone w/ any ideas what might be causing this?
07-01-11, 06:41 PM
#11
no, for some reason the cel never came on until my car started to run really rich. i forgot what was the code but i remember it had something to do w/ the engine running lean. i'm not sure why it would throw that code when it's running pig rich?
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07-02-11, 04:12 AM
#13
Driver School Candidate
Unless your tank is nearly empty, this should not be an issue. If you look inside your tank, you'll see that the filter on the fuel pump gets its fuel supply from an enclosed plastic tub/reservoir (if you can call it that). This ensures that the fuel in the tank will always accumulate in there first so that the fuel pump has a steady supply of gas unless you're running extremely low on gas. Have you checked to see if your air filter might be dirty or clogged making it difficult for the intake to suck in air especially when the engine has no load. Just a thought. It is also possible that you have a small vacuum leak that isn't too evident upon visual inspection. All these situations can exhibit the symptoms you are experiencing to some degree. If the filter is clean and you're positive there are no vacuum leaks, you may want to check the TPS and the IAT. If any of these 2 sensors are going bad, they can give those symptoms too. When you are coasting at 40 and you shift to neutral, I am assuming that your foot is off the gas so a bad IAT may be more likely. You didn't mention if your rpm is fluctuating but if it is, the TPS may be the more likely culprit between the 2. Good luck.
Last edited by rexst; 07-02-11 at 04:22 AM. Reason: added info
07-02-11, 09:58 AM
#14
Unless your tank is nearly empty, this should not be an issue. If you look inside your tank, you'll see that the filter on the fuel pump gets its fuel supply from an enclosed plastic tub/reservoir (if you can call it that). This ensures that the fuel in the tank will always accumulate in there first so that the fuel pump has a steady supply of gas unless you're running extremely low on gas. Have you checked to see if your air filter might be dirty or clogged making it difficult for the intake to suck in air especially when the engine has no load. Just a thought. It is also possible that you have a small vacuum leak that isn't too evident upon visual inspection. All these situations can exhibit the symptoms you are experiencing to some degree. If the filter is clean and you're positive there are no vacuum leaks, you may want to check the TPS and the IAT. If any of these 2 sensors are going bad, they can give those symptoms too. When you are coasting at 40 and you shift to neutral, I am assuming that your foot is off the gas so a bad IAT may be more likely. You didn't mention if your rpm is fluctuating but if it is, the TPS may be the more likely culprit between the 2. Good luck.