Another misfire thread, competant wrenchers opinions needed
- O2 sensors changed and wires extended
- Kleeman tune uploaded to permanently turn of rear O2's for emmissions puroposes (passed emmissions finally)
I think maybe my plugs are bad, and pumped bad E85, so I change to a one step warmer plug per Bruce's recomendation, thanks brotha, and gap them to .032
I also had to wait a month for our local gas stations to get E85, so I drained out the old gas, and filled up with a new tank of the corn. These are the list of misfires:
Current Fault Log 07/01/12
------------------
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P0300: Random/Multiple Cylinder Misfire Detected
Pending Fault Log
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P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P0300: Random/Multiple Cylinder Misfire Detected
Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged
End of report.
Current Fault Log on 08/05/12
------------------
ECU reports no current faults
Pending Fault Log
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P0507: Idle Control System RPM Higher Than Expected
P0304: Cylinder 4 Misfire Detected
P0307: Cylinder 7 Misfire Detected
P0308: Cylinder 8 Misfire Detected
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged
End of report.
The car idle is non-existant, it hunts from 500rpms-2000rpms and is breaking up under any type of boost.
What do you guys think is going on, a leak test was done to see if there are any vacume leaks, it came back negative. Correct me if I am wrong, but a tune cannot all of a sudden get out of whack can it, nothing on my tune was changed from Timmayfest, yet all these problems have arised.
Any help is appreciated
Last edited by chawkins2001; Aug 8, 2012 at 03:13 PM.
Once I had changed my front O2 sensors all codes went away and the car has been running strong ever since.
Sounds like it is a bad O2 or wiring issue. Although if you disconnect the O2s the car should just run rich by default.
What AFR are you seeing at idle ?
What injectors are you using for e85 ?
Bosch offers three replacement O2 sensors for our cars. I wouldn't even consider other brands or off-brands for this part. The universal sensor is Bosch part number 15733, and can be used in the front or rear. They have a decent length of wire attached and can be customized to the fit you need. The key to using this universal sensor is to 100% be sure to use the connector block that is supplied with it to get a waterproof, with no possibility of cross-wired or shorted connections. Contrary to what some may tell you, soldering the O2 signal and ground wires is an invitation to issues down the road. The universal sensor kit can be bought for around $50 each.
If you want exact fit replacements that plug right into the factory engine harness, the go Bosch part number 16272 in the front or 16328 in the rear. Note, however, that if your rear sensors are extended, the 16328 sensor will still need the extension. I extended mine for my MBH header install with two universal kits (15733), using the supplied connector blocks, and they have been trouble free ever since.
If you're running on suspect O2 sensors, I'd start there, particularly if the rear ones were extended by a means other than using the Bosch connectors. Wouldn't hurt to install front replacements while you're at it too.
I am on 1000cc injectors for e85.
Last edited by chawkins2001; Aug 9, 2012 at 09:58 AM.
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When both of my front O2's went the car did not know how to fuel itself. It would idle rough and bounce around the wideband between 13-15 at idle. LTFT shot up to +15 to +21 on both banks and the car would buck and **** and moan under any kind of boost because it appeared to revert to an extremely rich map under throttle bouncing between low 9 to mid 10 AFR.
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It really sounds like it is your O2 sensors. Also I was not aware that Kleeman did e85 tunes and as you know the fuel needs are very different and they would need to scale the injectors properly (but I know you know that)....
Good luck man, hope you get it sorted.
Nothing worse than a fire breathing dragon with the hiccups
Just throwing this out there since you didn't mention about this in your post. Good luck!
Three variables changed, new gas, new sensor with extended wires and kleeman flash for readiness. After that , the drivability has declined badly.
Last edited by BBBSS; Aug 6, 2012 at 05:49 PM.

Aaron
Putting my car on the dyno would also spill the beans in my opinion.
Not sure in your case, but my friend's clk went through the same thing when he put in some bad gas at a station in a rural area off i95... Had so many misfire codes for all cylinders and felt like cutting out when past 4000rpms. Ended up draining his gas tank and putting a can of BG44K and running it for 20 min on highway with new gas and all codes disappeared.
Not sure in your case, but my friend's clk went through the same thing when he put in some bad gas at a station in a rural area off i95... Had so many misfire codes for all cylinders and felt like cutting out when past 4000rpms. Ended up draining his gas tank and putting a can of BG44K and running it for 20 min on highway with new gas and all codes disappeared.
I dont have cats Jake. I feel like throwing these keys away in the lake, and pushing the car off a damn cliff. I am just sick and tired of battling this car, it just never ends man.
but you said even on boost it went south and that is not running off the 02s at all and using your wot map in the tune so I hope its not coolant in the plugs.
and you probably tripple checked but maybe a plug wire got pluged into the wrong plug.I mean I dont know if it can be done but if you have aftermarket wires that are all the same length I can see it happening.
Fixed the wires and back in business.







