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Error Code Car runs with jerky acceleration


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1994lhs
User

Dec 26, 2011, 3:41 PM

Post #1 of 21 (3271 views)
Error Code Car runs with jerky acceleration Sign In

1994 Chrysler LHS 3.5L engine

Car wouldnt start during wet day. Did a tune of up plugs, wires, air filter. Car started right up, Now it accelerates with a jerky feeling like misfires. And its consuming A LOT of Fuel now.

Ran the error codes and got 12 51 55. Which 12 and 55 are not the problem but 51 is O2 sensor running lean.

Well i call around and No one knows WTH their talkign about. I need to replace Both 02 sensors coming off the manifold on each side. And i tell them its the upstream square connector. But they dont know what im talking about or they dont have it in stock.


What are them sensors called exactly that come right off te manifold just before the flange where the exhaust pipes bolt to

Picture below is the right side just under the Trans Dipstick.



The left sides the same just before the flange on. Any help so i know exactly what i need to order.


Hammer Time
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Dec 26, 2011, 4:05 PM

Post #2 of 21 (3258 views)
Re: Error Code Car runs with jerky acceleration Sign In

If they don't know what an upstream 0/2 sensor is, then you probably need to hit a different parts store. There is nothing wrong with your description. Just leave out the part about the connector.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



1994lhs
User

Dec 26, 2011, 4:09 PM

Post #3 of 21 (3254 views)
Re: Error Code Car runs with jerky acceleration Sign In

Thing is, they sell a round and a square connector. The ones i need are square, as the 2 upstreams in picture are the same. One store asked if their square or round. I said square and its 44$ each so I ordered 2 to replace both of them.


If i replace these, and car is still doing this what else would cause the car to run so rich and jerky acceleration


Discretesignals
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Dec 26, 2011, 4:10 PM

Post #4 of 21 (3249 views)
Re: Error Code Car runs with jerky acceleration Sign In

They can both go by several names:

1.Bank 1 and Bank 2 upstream O2 sensors
2.Bank 1 sensor 1 O2 and Bank 2 sensor 1 O2 sensor
3. Left and Right pre catalyst O2 sensors

I am really surprised they don't understand what your talking about.

The OEM part number is 5233088

Denso is a popular brand which is number 2344004 which has the square connector and a harness length of 11.81.








Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


Hammer Time
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Dec 26, 2011, 4:10 PM

Post #5 of 21 (3246 views)
Re: Error Code Car runs with jerky acceleration Sign In

The round ones are the downstream.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Dec 26, 2011, 4:12 PM

Post #6 of 21 (3241 views)
Re: Error Code Car runs with jerky acceleration Sign In

I don't think this one has downstream sensors because it was before OB2 (I am not being a smarty pants).

If you believe the O2 sensors are the cause of your jerkiness, unplug them and see if your symptoms go away.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 26, 2011, 4:15 PM)


1994lhs
User

Dec 26, 2011, 4:17 PM

Post #7 of 21 (3233 views)
Re: Error Code Car runs with jerky acceleration Sign In

Im not sure what else would cause this as car idles fine and drives fine when its cold. Once it warms up it begins to get jerky and eating up gas.

this is the one i ordered from this part store locally.

link deleted....not allowed


(This post was edited by Hammer Time on Dec 26, 2011, 4:20 PM)


nickwarner
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Dec 26, 2011, 4:19 PM

Post #8 of 21 (3225 views)
Re: Error Code Car runs with jerky acceleration Sign In

If you do unplug them and run the engine, remember that you will create codes because of this. The ECM will know the circuits are open. By all means give it a try, but don't get nervous that it will have more codes after doing so. You will know that you have created them and not a different issue coming to light.


Discretesignals
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Dec 26, 2011, 4:23 PM

Post #9 of 21 (3218 views)
Re: Error Code Car runs with jerky acceleration Sign In

That looks like a good number.

Unplugging the O2 sensors forces the computer to go into open loop operation. That means it doesn't trim the fuel. If a sensor is stuck lean and causing the engine to run rich on one bank and unplugging it makes your problems go away, then the sticking O2 is the problem.

If it doesn't go away after you unplug them, you have something else going on.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


1994lhs
User

Dec 26, 2011, 4:27 PM

Post #10 of 21 (3207 views)
Re: Error Code Car runs with jerky acceleration Sign In

Thanks for the replies, Ill have my dad do this as i dropped the car off at his hosue as mine dont have any tools.


Hopefully he can reach and find the plugs to unplug them. Does it matter if its unpluged when engine is cold, then let it warm up and drive.

I alreayd paid the 95$ for the 2 new O2 sensors. So ill have them incase they are bad.


Hammer Time
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Dec 26, 2011, 4:29 PM

Post #11 of 21 (3202 views)
Re: Error Code Car runs with jerky acceleration Sign In

Even if they aren't the source of your problem, it would be a good idea to change them. They do deteriorate.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



1994lhs
User

Dec 26, 2011, 4:32 PM

Post #12 of 21 (3198 views)
Re: Error Code Car runs with jerky acceleration Sign In

Figured, as i bought this car back in 2005 with 65k miles on it. Its now at 120k miles, and everything i have been replacing on it has been OEM. My guess is the o2 sensors are oem as well.

Just by the descriptions i read abotu faulty o2 sensors it has me thinking for sure its that. When your hear car it smells very strong/rich.


1994lhs
User

Dec 26, 2011, 4:34 PM

Post #13 of 21 (3192 views)
Re: Error Code Car runs with jerky acceleration Sign In

A buddy of mine said to also check the Cold start temp sensor thats located right by the Thermsotat Housing. Said that could be causing this as well, but error code i got didnt indicate that was problem. Find out tomorrow once I unplug the o2 sensors and drive around.


Hammer Time
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Dec 26, 2011, 4:39 PM

Post #14 of 21 (3184 views)
Re: Error Code Car runs with jerky acceleration Sign In

That temp sensor is a full time sensor, not just cold start and a problem with it won't necessarily set a code.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Dec 26, 2011, 4:41 PM

Post #15 of 21 (3181 views)
Re: Error Code Car runs with jerky acceleration Sign In

Doesn't matter when you unplug them. When the engine is first started the O2 sensors aren't active until the get heated up. Once they start sending off their voltages is when the computer goes into closed loop and trims the fuel injector pulse width.

Like Nick typed they'll set codes when they are unplugged, but you already know that.

Another thing that you could check, if unplugging the O2 sensors doesn't cause your symptoms to go away, is the engine coolant temperature sensor (ECT). If the sensor's reading is saying the coolant temperature is cold when actually the coolant is at operating temperature, the ECU will cause a rich fuel mixture and retard ignition timing.

Also inspect the MAP sensor vacuum hose and make sure that there is manifold vacuum to the MAP sensor (18-22 in/hg at idle). A MAP sensor that is telling the computer the manifold vacuum is low all the time will cause the computer to richen the fuel mixture because the computer thinks the engine is under load or your flooring it.

You have to be careful too because a rich running engine can foul out your O2 sensors. You can't clean them either.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 26, 2011, 4:42 PM)


1994lhs
User

Dec 26, 2011, 4:49 PM

Post #16 of 21 (3175 views)
Re: Error Code Car runs with jerky acceleration Sign In

I did notice the car does heat up like normal and temp sometimes drops lower than normal temps. When engine is fully warm, i turn it off and start it up again its reading 50% cooler, then heats back up.

When im driving it harder as in 3k rpms or higher the car wont have the jerky acceleration. Only at the crusing speeds of 40-55mph


(This post was edited by 1994lhs on Dec 26, 2011, 4:53 PM)


Discretesignals
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Dec 26, 2011, 4:54 PM

Post #17 of 21 (3167 views)
Re: Error Code Car runs with jerky acceleration Sign In

The temperature gauge works off another sensor/sender. The computer reads the coolant temperature from it's own dedicated sensor.


Start by checking those things first and make sure they are within tolerance.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 26, 2011, 4:57 PM)


1994lhs
User

Dec 26, 2011, 4:56 PM

Post #18 of 21 (3163 views)
Re: Error Code Car runs with jerky acceleration Sign In

Thanks for all the help so far, Im off to clean the snake room and rodent barn. Need to get my mind off this till tomorrow when i unplug the plug to o2 sensors.


1994lhs
User

Dec 27, 2011, 4:55 PM

Post #19 of 21 (3130 views)
Re: Error Code Car runs with jerky acceleration Sign In

Just Updating the Thread as the car is fixed. Tested car with one O2 unplugged at a time. When passenger was unplugged, car had a strong fuel odor and egg smell.

Unplugged driver side and nothing happened with fuel mixture at all. So i replaced the driver side one and gas mileage is up now and car runs smoother.


Tom Greenleaf
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Dec 27, 2011, 7:14 PM

Post #20 of 21 (3120 views)
Re: Error Code Car runs with jerky acceleration Sign In

Good thread with good resultsSmile

1994lhs: If you did just the one consider doing the other as it will probably go and the over-fueling for any reason is tough on or kills cat/converters. Give it a good run while right to heat them up and clear out,

T



1994lhs
User

Dec 27, 2011, 8:20 PM

Post #21 of 21 (3108 views)
Re: Error Code Car runs with jerky acceleration Sign In

Once I noticed the Egg smell, I pulled over and pluged in the o2 asap to stop the rich smell.

If the other one does decide to go, I hope its in summer, as today was 25F and snowing and sucked changing that out today.

But all in all its fixed and car isnt wasting fuel anymore and MPG is now up to 24.9Smile


(This post was edited by 1994lhs on Dec 27, 2011, 8:22 PM)






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