Hello...
I read the other post in this forum about open loop mode- but it didn't really give me much information.
I think I have a pretty good idea of whats going on w/ my car- but other opinions are always nice.. I mean, I'm smart, but I'm not THAT smart.
Anyway. 97 2.4 Cav- currently running a stock tune minus a few things (not fuel related), stock injectors, stock fuel pressure etc..
The car is turbo- but the engine was just rebuilt so I need to put some miles on it before I boost it- the wastegate is propped open & the turbo just vents off.. Its N/A.
I have a heated primary o2 sensor, i think casper makes it? Its a 4 wire sensor...
I also have an o2 simulator for the missing sensor in the non existant cat.
When I first start the car in the morning to warm it up- the wideband shows 14's but slowly creeps the AF in the low 10's & It will stay that way until I actually drive it for a few mins- then the car idles around 14.7.
It only dumps fuel when the car is first started & when it warms up. While driving/cruising- it stays in the 14's.
Im assuming this means the car is going into open loop mode- completely ignoring the A/F & dumping fuel.
I also think it's because of the o2 simulator OR the heated 02 sensor, but I'm leaning more towards the simulator...
Has anyone ever ran into a problem like this & have any ideas?
I think I might have to go back to the secondary o2 & just use that simulator trick w/ the extended bung. Or, if theres a setting or something in HPTuners I could adjust to eliminate this..
Thanks for any info.
-=Marc
I am pretty sure this is exactly what my car is doing. I am not running a o2 simulator though but it only seems to smoke on start up. I am also running no cat as well. For tunning I have the reflash and 2 bar installed with the 310cc injectors.
~Boost. Its what's for dinner!~
Whar are you using for a secondary o2 sensor?
The car will run in open loop, and thus rich until it reaches operating temp. This is normal. Once it reaches operating temp, it goes into closed loop, and maintains an idle AFR of 14.7, which is what you're used to seeing.
15.3 @ 89.97mph, 14's on the way?
damn I need to get wide band lol. I am still running the secondary o2.
~Boost. Its what's for dinner!~
this is not caused by your secondary o2 (or in this cause simulator) at all. the 2nd 02 does nothign for A/F ratios..just tells the ECM that the cat. is operational.
the car has a warm up enrichment, which is probably what your seeing, as the car warms up it requires less fuel thus the reason why you have so much fuel during startup and before it warms up
It's not supposed to run that rich during warmup... I can smell the car when I step outside... You can hear the car stumbling a little bit.
The fuel system is stock.
It doesn't need that much gas during warmup- I gotta find a way to fix it.
Even my car runs pig rich on startup guys. I'm talking 9:1-10:1 on a cold morning where it's dipped below freezing. This is normal. It helps warm the car up. As soon as your O2 sensor hits temp, about a minute or so TOPS, it'll come down the your idle speed and 14.7:1 switching idle AFR. If you have a cat it has to be warmed up to 600F before it will start working properly. Adding raw fuel into the cat heats it up quite quickly. Hence the UBER rich conditions.
I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26
Quote:
Adding raw fuel into the cat heats it up quite quickly.
Actually, no. Adding raw fuel
and excess air can heat it up quickly. Look at the older engines which used an AIR pump. Often the AIR was diverted to the converter during initial warmup conditions. The excess fuel from startup enrichment combined with the air from the AIR system worked together. Adding fuel alone will shut a cat down which is why you can get AFR readings at the tailpipe on a dyno. If the cat was working you'd see super lean mixtures all the time.
RedDevil, you didn't give the temperature that you're having a problem at. Like Hypsy said, below freezing temps result in very rich operation. But if you're talking temps between 60 degrees F and fully warmed up, then you've got something to look at. Even OBDI engines generally are at 12:1 to 13:1 in that temp range. If the head is ported, or if you have a non stock cam grind, or both, then you've altered the VE and it makes sense that the fuel delivery isn't exactly right. If the engine is stock in terms of cam and head then I'd suspect that adding the turbo changed the VE slightly at idle so fuel delivery is a little more than it needs to be.
-->Slow
Yeah- I live in PA- so it's not freezing temperatures just yet...
Maybe 50-60 degrees...
Its definately runs rich longer than a minute. It would probably idle rich like that all day if I let it.
I let the car warm up to full operating temp before I drive it & until I actually get it down the street, hit a few stop signs- it will run in the 9's/ low 10's.
The head has been ported a little bit, but Im still using the stock cams.
It doesnt bother me that much- but If I can help it- I'd like to fix it.
I bought the heated o2 sensor to try & avoid problems like this- get the sensor up to temp quickly. Ive just heard so many different things about the simulators- I thought that might have been causing my issue.
The car is an automatic-- Putting it in any other gear other than PARK will change the A/F slightly, but then it would creep slowly down back into the 10's..
Its wierd.
RedDevil do you have some white smoke sometimes as well I have noticed it ocassionaly with mine but I think it was mainly from excessive turbo oil which i fixed.
~Boost. Its what's for dinner!~
Sounds like it's so rich the AFR never crosses stoich. The pcm usually needs to see the sensor get active, signal bouncing between low and high, before it enters closed loop. But it's possible that the system is going into closed loop and getting a faulty signal from a poisoned O2. You might try disconnecting the O2 and see if it runs better (you'll get a CEL). If you have a scantool or datalogging you can look at the fuel trims to see if the ecm is adding fuel or removing it. Positive trims mean it's being added. If you're in closed loop and the ecm is adding fuel when you know it's too rich, it's probably the O2 sensor signal.
Also might look for fuel leaks into the engine. Leaking injectors? Sticking EGR can also cause low speed rich operation.
gl
-->Slow
I have a MAC Determinator I could use. Do you guys think if I installed a cat. it would help. Because I only started noticing it when I removed the stock exhaust.
~Boost. Its what's for dinner!~
Quote:
It only dumps fuel when the car is first started & when it warms up.
I may be mistaken here, but i'm probably not. The car will run in open loop when it's first started, until certain conditions are met. (Like coolant temp and such). I believe there's also what is called 'warm-up enrichment' which could explain why it runs rich when it's cold.
The car runs in open loop when started until it has run long enough to be certain the O2 is warm enough to read.
It also runs richer (cold start enrichment) depending on temperature when its 1st started.
It bases all this on the VE table. If your injector constant and VEtable are correct, it will run exactly at the commanded A/F ratio. Typically on our Js, the commanded A/F is 13:1 when started at 70°F.
Also, if its that rich when started, then fuel trims should be huge when it does go into closed loop.
sig not found
My car does the same EXACT thing. My wideband says 10.0 when I start it up. Doesn't matter if its 20 degress or 80 degrees outside. If I let it run for a minute, and then rev it up a few times, let it idle, then the A/F goes to 14.7. If I don't rev it up at all, it just sits at 10.0 My primary O2 sensor is stock, non heated. I can't figure it out either...
2010 Subaru Impreza WRX Limited
1999 Cavalier Z24 Supercharged
1999 Grand AM SE (Beater Car)
1997 GMC Sierra
2007 Honda CBR 600RR
2005 Honda TRX450R
Yep..
I've played with it a little bit- but not much...
If the primary 02 sensor is unplugged- it runs really rich. Low 9's & pretty much stays there...
Ive also noticed that if the car is all warmed up and running like it should- If I shut the car off for a few minutes, it will run rich all over again until I actually get moving.
Like Luke said above, it helps to blip the throttle a few times- but it only takes a minute to start running normal-- Cold or warm... Doesnt seem to take as long when it's warm though.
Im thinking it might be the secondary 02 sensor... I might try that o2 bung trick or maybe just throw a cat in there for the street.
I made a small section of exhaust I can remove & replace if I want, set up an extra pipe w/ a cat... Hrmmm.
^^Yup, mine does the same thing. I can get it running right, turn it off, restart it, and it does it all over again. The secondary O2 sensor has nothing to do with it. I have the O2 bung trick on my car. It keeps away the CEL, that's all it really does. The only thing the secondary O2 sensor does is tell the computer if the cat is functioning correctly. My car ran fine almost 3 months even after I had the cat taken out, so I know that's not the problem.
2010 Subaru Impreza WRX Limited
1999 Cavalier Z24 Supercharged
1999 Grand AM SE (Beater Car)
1997 GMC Sierra
2007 Honda CBR 600RR
2005 Honda TRX450R
Luke Heier wrote:^^Yup, mine does the same thing. I can get it running right, turn it off, restart it, and it does it all over again. The secondary O2 sensor has nothing to do with it. I have the O2 bung trick on my car. It keeps away the CEL, that's all it really does. The only thing the secondary O2 sensor does is tell the computer if the cat is functioning correctly. My car ran fine almost 3 months even after I had the cat taken out, so I know that's not the problem.
he's right. the downstream 02 sensor has nothing to do with it. and it wouldn't make sense for your car to run rich if the downstream is a problem anyway. even if cars were set up to actually use the downstream 02 for anything other than monitoring the cat. if it saw a problem with the cat the last thing you'd want it to do is run rich. unburned fuel from misfires that can be caused by rich (or lean) conditions will break down your cat and give you an even bigger problem.
:Bump:
Was there any solution for this, my car is doing the exact same thing?!
No solution because this is how it is programed to run from the factory.
FU Tuning
There has to be a solution, my car ran fine for multiple flashes, then with the recent flash, this happened.
Bobby Higgins wrote:There has to be a solution, my car ran fine for multiple flashes, then with the recent flash, this happened.
See now your talking a different story. You posted in a thread about a car with a stock factory tuned ecu. Yours has been flashed.
So since your profile is not filled out what all is done to your car?
Still not likely alot can be done because some hidden files we do not have access to.
FU Tuning
Did the OP find a solution?
Vacuum leak, Bad O2 sensor?
Anything???
