HALF of my engine running like crapola HELP! :)

[Daddy Long Stroke]

I have a weird one.

My car has been acting up the last few times I have been out in it. It feels like it's "missing" or "loading up" while driving. If I give it, say. 3/4 throttle, the car will accelerate, then start "missing" again, then clear up,start missing, clear up, etc... Now this problem comes and goes, but lately I would say 70% of the time the miss is there. The missfiring can happen anywhere in the throttle range from idle to full throttle.

One evening I was out in it,it was missing at first, then the problem cleared up almost all night, and only returned after I went out on the highway and went through the gears. It pulled hard and everything felt fine until I let off the throttle and the problem returned.

Anyway, the last time I drove it, it was missing again, and I got on it, it cleared up momentarily, but as I looked in my rearview mirror, it looked like I had hit a newspaper that was on fire in the street. I was thinking "was that me??!!" so I immediately pulled over and inspected the car. No signs of anything wrong. I mainly suspected the cats, but the side sills were not that hot on either side. (*note, after I got home and the car sat for 1/2 hr., the passenger side sill was much hotter than the drivers).

I got home and let it idle in the garage. I have a laser temp gun, so I started checking each individual header tube-

Every header tube on the Drivers side of the car was 500 degrees, and the exhaust out of the drivers side back was LOTS of pressure, and the air was "warm".

Every header tube on the passenger side of the car was 200ish degress (much cooler), and the exhaust out the passenger side was only HALF as much pressure, and the air was VERY HOT.

-So, because this is an intermittant problem, I'm suspecting something electrical that controls the spark to the right side cylinder bank. All 5 cylinders are doing the same thing, which I suspect is a very weak spark. I'm thinking it's spark because I figure, weak spark, fuel injectors working normally, excess fuel getting out the exhaust and going into Cat, hence my fire show. I figure maybe a piece of the cat came out and hit the street causing the sparks.

The engine is not throwing a code.

I have tried another ECU, same problem.

This problem started after I had a dead battery from leaving an interior light on, but I have pulled the battery (MOPAR, less than 2 years old), had it checked for 40 minutes, and it appears ok. Car has NO trouble turning over and firing, even after sitting for a weak since re-charging it.

Any advise would be appeciated I suspect something electrical that controls spark to the 5 passenger cylingders, but who knows.

I do have an extended warranty, but I would like to have an idea what Im dealing with in case its something simple I can check out for myself. Yes, I'm one of those guys that likes to know whats going on!

 

[Joseph Dell]

1 - replace the battery
2 - replace plugs and wires. you are due anyway
3 - see #1 and #2.
4 - it _could_ be coil pack, but highly unlikely.

good luck!

JD

 

[Daddy Long Stroke]

Does a single coil pack fire all of the cylinders on the passenger side, and a different one for the drivers side cyliders?

I thought of that JD, only thing is, car only has 8000 miles on it, battery was replaced right before I bought it, and if plugs were bad, would it be an intermittant problem?

Ever since battery was recharged, it has been super strong (like it was before). I guess I'm just suspecting something different due to the right side cylinder bank all having the same issue, like something that controls those cylinders.- but I guess anything voltage related is possible!

I just didn't want to spend $300 on new wires, plugs and a battery and then have the same issue! I'M SAVING FOR A LITTLE SOMETHING!

 

[Joseph Dell]

If the battery is older than 18 months, replace it. otherwise, just replace the plugs + wires.

I have sympathy for a viper owner... can't afford the maintenance but can afford the car?

it's an 01... it should be on its 3rd or 4th battery by now!

JD

 

[hemibeep]

I beieve the coils are split. 4 on one, then 6 on the other. You can check the plugs on the back of the coils.
BUT,
I agree with J.D. Battery.
If battery doesn't correct it, return the battery.

A battery may test well, but when running with a 100amp alternator, strange things can happen.

 

[grcforce327]

Does a single coil pack fire all of the cylinders on the passenger side, and a different one for the drivers side cyliders?

NO! What do the plugs look like on the right bank while running bad?

 

[Daddy Long Stroke]

Lol... Now $300 on "Maintenance", and $300 on "Troubleshooting" are two different things JD!

DAMMIT! I guess just not what I was hoping to hear...but if thats what you suspect, I'll get on it!

 

[Joseph Dell]

6 and 4, actually... not 5 and 5.

 

[Daddy Long Stroke]

Ok, was out playing in the garage, and hooked up an OBD II. CAME BACK WITH TWO CODES:

P0175 : 2/1 fuel system rich

P0153 Pd : 2/1 02 Sensor slow response

Pd means "pending", but I'm not relly sure what that means.

I reset the codes and tried to duplicate them, but my Harbour Freight Tools OBD Scanner is not co-operating anymore. $25 I'll try again later. Not sure what the "2/1" is.

Could a faulty 02 Sensor cause the problems I described?

Should I swap it out myself, or does warranty cover this?

(But I guess it May be time to order them 02 sims and get rid of the Cats anyway.....)

 

[grcforce327]

Could a faulty 02 Sensor cause the problems I described?

YES!I think it's a good idea to invest in a scanner with real time data.It takes out alot of the guesswork, and aids in problem solving!Check all the plugs on the right bank and tell us what they look like!

 

[Tom F&L GoR]

I believe "2/1" means Bank 2, Sensor 1. That would make it the passenger side, upstream O2 sensor. If it comes back, a replacement is easy. However, you might want to rent or buy the special socket - it looks like a deep socket, but has a cutout to allow for the wires.

 

[grcforce327]

I think if an injector is dumping alot of gas,you may get the same codes!

 

[hemibeep]

I don't think a bad O2 is your problem. Usually it will throw "check engine" if the motor goes into "limp" mode.

If you have warranty, take the car in and let the dealer scan the codes.
O2's are not bad to change, but I still really suspect the battery.

Vipers are the most sensitive cars that I have seen in relation to battery condition.

 

[Jack B]

Daddy:

a couple of insights, I had a similar problem and it came back to a slow O2. I have an onboard wideband and you could see the a/f rise. My headers also run about 500 degrees.

The second item, if an injector is stuck or leaking you will actually read leaner because the O2 was not consumed.

 

[grcforce327]

They were leaking past the injectors on mine and the O2 sensor couldn't keep up because it was running and showing TOO RICH!

 

[Daddy Long Stroke]

Jack- Did replacing the 02 sensor fix the problem? was it a upstream front or downstream rear sensor?

Tom- According to my manual, it says the 2/1 is the rear downstream sensor. I only state that because I'm not sure if the rear sensor plays as big of a role in A/F correction as the upstream one. If that is my problem, obviously it does!

I will try a battery this weekend.

I thought about swapping the 02 sensors on the left and right side of the car to see if the problem switches sides.

One more thing, it seems that in "Open Loop" mode, or while the car is just running in my garage, I have no problems, and also the car runs fine for the first 5-10 minutes I'm out driving it. I'm guessing that once it warms up and goes into closed loop operation, the problem starts.

Does anyone know if 02 simulators keep the car in closed loop or open loop at all times?

If there was a way I could keep the car in open loop (warming up mode), I suspect it would run fine and I would have my answer. I wonder if disconnecting all the 02 sensors would keep the car in open loop?

-And once again, I will try a new battery this weekend!

 

[grcforce327]

Closed loop should occur within 1-3 minutes.It doesn't take that long for the O2's to kick in!

 

[Jack B]

Jack- Did replacing the 02 sensor fix the problem? was it a upstream front or downstream rear sensor?

Tom- According to my manual, it says the 2/1 is the rear downstream sensor. I only state that because I'm not sure if the rear sensor plays as big of a role in A/F correction as the upstream one. If that is my problem, obviously it does!

I will try a battery this weekend.

I thought about swapping the 02 sensors on the left and right side of the car to see if the problem switches sides.

One more thing, it seems that in "Open Loop" mode, or while the car is just running in my garage, I have no problems, and also the car runs fine for the first 5-10 minutes I'm out driving it. I'm guessing that once it warms up and goes into closed loop operation, the problem starts.

Does anyone know if 02 simulators keep the car in closed loop or open loop at all times?

If there was a way I could keep the car in open loop (warming up mode), I suspect it would run fine and I would have my answer. I wonder if disconnecting all the 02 sensors would keep the car in open loop?

-And once again, I will try a new battery this weekend!

Daddy:
2/1 is the passengers side front. The rear O2 doesn't do anything but provide a check on the cat. All you have to do is see if the O2 voltage stays around .5 volts (actually .45 volts equals 14.7), if it strays too much the sensor is bad. I replaced mine and the problem seemed to go away. You can also watch the voltage when you de-accelerate and it show show 0.0. As I said before, the other culprit could be the IAC or stepper. If you use a scan tool and log the IAC and the O2 voltages you will find the problem - more than likely.

I will try this again, the O2 sensors don't care about the fuel in the exhaust, that will not make it show rich. It is strictly showing O2 content, as an example a miss that shuts down the spark and dumps unburned fuel into the exhaust, that will show lean because the O2 was not utilized. you could dump a gallon of fuel into the exhaust and it would not show rich. You also have to remember, the oem narrowband really doesn't tell you a lot about rich and lean, it is only a switch that actuates off/on and it is only a guess where the actual a/f is - it is only accurate at 14.7. Gauges that utilize the oem narrow band input are a joke.

If the pcm sees the O2s are inoperative during closed loop at a low rpm/load, the pcm will set a code and the car will enter a safe mode that makes the car super rich. The sims just create a fixed voltage less then .5 volts.

 

[Oldwilsonian]

I'd agree with Tom, 2/1 indicates Bank 2, Sensor 1 (2/2 would indicate Bank 2, Sensor 2). In this case Passenger side, upstream sensor (before the cat.).

Don't confuse the purpose of these O2 sensors though. The upstream sensor (before the cat.). measures Air/Fuel and via the signal the PCM receives from the sensor the computer will then adjust fuel injector pulse accordingly, either making it run leaner or richer.

Now the downstream sensor (after the cat.). reports to the PCM on the efficiency of the cat. in relation to your exhaust gas. If you remove your cats. all the O2 sim. will do is basically send a correct reading to the PCM that is within the parameters of a correctly functioning Cat. Basically simulating the reading, and telling the PCM everything is normal.
From the symptoms you have described installing O2 sims. will have no effect on your problem. I would definately start with replacing the Upstream O2 sensors - if you can get access to a more comprehensive diagnostic scanner you will be able to view senor 2/1 in real time and see if it is functioning correctly and eliminate some of the guess work. Hopefully this is the problem.

Good Luck.

OW.

 

[grcforce327]

I will try this again!Stick some injectors that flow 50 at 43psi on your stock viper,fire it up and watch the scanner.O2's with show and stay rich and will eventually throw a code,unless for some unknown reason Gen II's are different from Gen I's!I have injectors that flow 30 at 43psi(ford redtops)and this was my experience before trimming them with the Vec3!I bet yours does the same thing!!!

 

[Daddy Long Stroke]

Thanks guys. looks like this real-time scanner is an invaluble tool. I will have to invest in one. My harbour freight scanner wont cut it I guess! Any recommendations on a good real time scanner?

I will be trying a few things this weekend and let you guys know.

 

[grcforce327]

You could probably find a good used one on ebay.I got mine for a multitude of vehicles!

You must be registered for see images

 

[Jack B]

I will try this again!Stick some injectors that flow 50 at 43psi on your stock viper,fire it up and watch the scanner.O2's with show and stay rich and will eventually throw a code,unless for some unknown reason Gen II's are different from Gen I's!I have injectors that flow 30 at 43psi(ford redtops)and this was my experience before trimming them with the Vec3!I bet yours does the same thing!!!

That is entirely different, in your example the combination of air and gas are igniting, the result shows rich because the ratio of the gas (bigger injector and not offset)in the consumed mixture was greater.

When you dump raw fuel into the system it doesn't change the a/f ratio, other then the air (O2) doesn't get totally consumed (more O2 present), therefore, it shows lean when you have a misfire and raw gas flow into the exhaust. In other words if the injectors were doing their job and the engine wasn't firing, the outside air would flow thru the exhaust and you would read 20.9, even though you had gobs of raw gas flowing into the exhaust.

That is just the way the O2 sensor works, it is counter intuitive.

 

[grcforce327]

When you have a misfire,the gas isn't totally consumed either,as in the problem I had early last year when the powdercoater media blasted my injector bores causing gas the seep past the o-ring and causing misfire and also showing rich on the scanner.Another rich sign on the scanner is watching the computer constantly trying to take away fuel to set the adaptives.
Maybe we are talking about totally different things,then again,maybe we can just agree to disagree!

 

[Daddy Long Stroke]

GRC, that is a hell of a scanner you got there. I DO believe it is about $2500 out of my price range though.....

 

[grcforce327]

GRC, that is a hell of a scanner you got there. I DO believe it is about $2500 out of my price range though.....

You can pick up an MT2500 on ebay for $300 to $500 depending on condition and adapters!