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Discussion Starter · #1 ·
I replaced the O2 sensors with aftermarket parts from Rovers North . Also replaced the exhaust system with a stainless steel unit. Now the check engine light keeps coming on and I am getting about 8 mi/ g. What's wrong?:confused.
 

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Likely your fuel mileage has gone for a **** because your engine light is on. I would say dealing with the light on ( codes set) is where you need to start
 

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Discussion Starter · #3 ·
Thanks Redtruck 12 for the info. I reset the computer and found code fault P 1316( misfire excessive emissions fault) and it was misfiring. I installed new plugs about 500 miles ago ( 1 month ago), plug wires looked good although I bought new ones , not installed yet. Any other resin for the misfire?
 

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Bad wires look good and good wires look about the same.....have you noticed a misfire? Rough idle, shuddering or backfiring? Wires are no fun to change but likely needed. Take extra care to ensure the connections where they attach to the coil packs are really good. Clean and tight
 

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Always post the fault code numbers so we can better help you.
Make sure to use good 8 mm silicon wires. When you replaced your 02 sensors, did you order them by your vinn number, you may not have purchased the advance emission 02's and this can throw your mileage off.
What octane gas are you burning?
Get the fault code numbers.
 

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Discussion Starter · #6 ·
Thanks again Red Truck 12 for the advice. I changed the plug wires with the 8mm wires and it started hitting on all 8, such a relief. Mike I did use the 8MM wires as for the O2 sensors I did give the year and model to Rovers North when ordering the 4 O2 sensors. I will go back and check on the invoice for the part numbers. The codes I recovered from my OBD-2 was P1185 (Oxygen Sensor Heater Circuit Short Upstream) and P1316 (Misfire Excessive Emissions Fault)
I have been using non-premium fuel Since the Rover was new. Milage has always been around 15/16 mpg. Just recently it dropped to 8 mpg. I'm hoping that changing the O2 sensors, plugs wires and changed to premium fuel will bring me back to an acceptable mpg level. I am conceerned with that p1185 code. I will wait and see if it occurs again. I will post and update at the next fueling.
 

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Discussion Starter · #8 ·
Yes, I cleaned and applied the di-electric grease to the connectors. I am going to refill the tank today and check the MPG on this next tank. should know in the next two weeks if all of the changes have had an effect. Thanks for the advice.
 

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Discussion Starter · #9 ·
I also have increased my tire pressure from a under pressure of 28 psi to 40 psi. Its been four days and the code light has not come on, hopefully it means no faults. This next tank of gas should tell me if I've made a difference.
 

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It may show a difference, but if you want better mileage and more low end power go to at least a 91 octane, might also run a can of 44K thru the tank to get rid of some of your low octane carbon build up.
 

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Discussion Starter · #11 ·
I am on my 2nd tank of 91 octane fuel. So far I have traveled approx 100 miles on 1/4 tank, so the milage has improved. I ordered two cans of the 44 gas treatment and when it arrives will use according to instructions. My code indicator has not come back on so I'm hoping that the changes made have fixed the problem. All of the miles are slow and in town. This next weekend I will be traveling to San Francisco (about 80 mi. so we will see how fuel usage is at highway speeds.
 

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Discussion Starter · #12 ·
Refilled with petrol (high octane 91) for the 2nd time. only got 8.6 mpg after all of the changes.
1. Replaced plugs and wires (used special contact lube)
2. Reset computer warning light ( it has not come back on in 186 mi.)
3. All driving is in town so we are using 3rd range on the transmission.
4. Using slow starts from stop lights and drive very conservative.
5. Using only 91 octane fuel.
6. Have ordered 44k fuel additive ( have not used it yet, as it has not arrived)
What else can I do to increase the MPG? It use to get 14/16 MPG when new.
 

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Years ago I replaced the O2 sensors on the family Volvo only to fail Arcare (CEL came on the same day). It turned out that one of the O2 sensors was the wrong one even though the correct number was on the box. So, it might be wise to check the actual numbers on the O2 sensors.
Any shop that fixes emission systems should be able to diagnose the problem in 1/2 hour. One way to test is to squirt some propane into the intake and watch to see the analyser respond.
 

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Refilled with petrol (high octane 91) for the 2nd time. only got 8.6 mpg after all of the changes.
1. Replaced plugs and wires (used special contact lube)
2. Reset computer warning light ( it has not come back on in 186 mi.)
3. All driving is in town so we are using 3rd range on the transmission.
4. Using slow starts from stop lights and drive very conservative.
5. Using only 91 octane fuel.
6. Have ordered 44k fuel additive ( have not used it yet, as it has not arrived)
What else can I do to increase the MPG? It use to get 14/16 MPG when new.
I used to have seased calipers on all four corners 6mpg in winter and short runs
Check your calipers .
 
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