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Ford Ka - System too rich - jerky

5K views 14 replies 2 participants last post by  Philip Coetzee 
#1 ·
Dear Forum Readers,
I trust this message finds you well.

I have an issue with my 2007 Ford Ka 1.3 Rocam engine :crying::crying::crying::crying:. The symptoms I'll describe comes and goes i.e. is very intermittent , but comes more than it goes.

Symtoms are the card will idle smooth at first start, but then start to idle in a very jerky fashion. When I drive there is no power, even at full throtle. But sometimes it's like I push a magic "turbo boost" button and the car all of a sudden as all the power back.

It's really frustrating. Technically, what I have done is the following steps:
1) Did a OBDII diagnostic scan with my scanner tool, found that the O2/ sensor was faulty. So I replaced it, and then cleared the faultlog...Then the car seemed fine for about a week. Then the symptoms slowly started to return and get worse or rather get more regular.

2)Removed and cleaned both the MAF sensor and idling control valve (on couple of occasions), upon restart, car seems ok, but then symptons just return intermittently again.

3) I have checked all the vacuum hoses, found some tiny areas where I thought it could leak, fixed that. No difference

4) I have checked the Smart Charging harness for wear and also cleaned all the wiring plugs with contact cleaner, removed and cleaned and retighten battery terminals. No difference.I have a ELM 327 scanner and using Torque Pro.

I did a re scann this morning on the OBD and I have attached re full report below this message.
Can someone please give me some advice to check again?



Fault log report generated by Torque for Android
=================================================

Vehicle VIN:
Vehicle Manufacturer:
Vehicle Calibration ID:

Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
P0172: System too Rich (Bank 1)

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
P0137: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
P1000: [Ford] OBD-II Monitor Testing Incomplete
[Mazda] OBD II Monitor Testing Not Completed

P1632: [BMW] Throttle Valve Adaptation; Adaptation Condition Not Met
[Chrysler] Theft Deterrent Fuel Disable Signal Received
[Ford] Theft Deterrent - Fuel Disabled
[Hyundai] Traction Control System Malfunction
[Kia] Battery Voltage Detection Circuit for Alternator Regulator (1.8L).
[Mazda] Battery Voltage Monitor Circuit
[Dodge] Theft Deterrent Fuel Disable Signal Received
[Jeep] Theft Deterrent Fuel Disable Signal Received
[Seat/Audi/Volkswagen] Accelera.Pedal Pos.Sensor 1 Power Supply Malfunction
[Triumph] Fall detection sensor circuit high Voltage
[Volvo] Real time clock (RTC).


End of report.
:crying::crying::crying:
 
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#2 ·
Checked the basics like plugs and air filter ? Was the o2 sensor a genuine Ford one or a cheap import ? If cheap import , replace , usually crap .Possibly a plug lead breaking down intermittently under load ? May be time for replacing . Dont know if they fitted a fuel filter in cars for your country or if it only has the one in fuel tank sending unit .If got an inline filter , worth changing .You don't say what mileage ?
 
#3 ·
Hi R.S,

Thanks for your reply, what I forgot to add, is , i have serviced the car which included new plugs and new air, oil filter fuel filter (underneath he tank) + new oil, which did not help.
Yeah, the O2 sensor is not a genuine one (aftermarket), i'll do some voltage measurement this afternoon to see if it's a "dud"..

Have spark plug leads look of, but they will get replace next too..
The milage is now about 70K miles on the ODO.

I'll also check the fuel pressure regulator on the fuel rail to make sure it's not leaking..

Thanks for your advice mate
Really appreciate it.
 
#8 ·
Hi There R.S. Logan,

I did a couple of more tests on the O2 sensor to see it operation.
One thing I am not 100% clear about, does the O2 sensor voltage fluctuate up and down when the RPM is at a constant speed?

I've attached some graphs I took with scanner. I also measured with a digital voltage meter (DVM) directly on the plug of the O2 as the engine was idling. I did rev the engine in one of the graphs you'll see it)
The DVM also indicated the voltage fluctuating between 0.9 and 0.1 (ish)

Not Sure if they are correct or not.
Is this operation correct at idling?
or should the 02 volt reading only change when the throttle os opened up for more fuel>
What do you think?
 

Attachments

#11 ·
Hi There R.S. Logan,

i looked at that article you sent, it does help a bit. Somehow I'm still not sure where the problem lies. Perhaps' I'm just over complicating the issue.

So I took the time over the weekend and removed / stripped the intake manifold, throttle body and all vacuum pipes, cleaned them thoroughly, applied a tiny bead of silicon around all gaskets and pip ends and added some cable ties over the vacuum pipes. I let the car sit until this morning because I did not need it until today to get to work.
I also put back the old O2 sensor (Bank1 Sens 1 on Manifold) ,

On the way to work no system rich complaint from the ECU, but initially it complained about the same O2 sens circuit malfunction which was the reason I replaced it in the first place. This error though is not constant and went way as the engine heated up.

However the car was still slugish and at randome intervals had big power surges and on the freeway there interesting measurements I saw for the fuel trim. It was not fluctuating at all, neither was the O2 sensors (both) voltage readings as attached picture. Only time they briefly fluctuated was during those random power surges.

To me, based on the Torque pro screen shot (I attached), if I understand the readings correctly, the car's STFT running rich all the time, meaning the card thought the mixture measurements from O2 sensors was lean, and was trying to compensate.

Is my understanding correct?

Are we still looking at faulty O2 or possible blocked CAT?


:surprise::crying:
 

Attachments

#12 ·
Could be the sensor is intermittently switching between rich and lean , an injector over fuelling which would show on a leak off test , faulty engine coolant temp sensor intermittently sending wrong signal to ecu . timing chain worn / stretched throwing timing out , low cyl . compression .Hard to say for certain with this type of fault .
 
#13 ·
Hi There R.S. Logan
Finally got the measure of the issue.

As you suggested, I replaced the O2 sensor again.
I took a chance and purchased an original Ford one from a scrapyard , where the guy said I could bring it back if it does not help / work. So I had nothing to loose especially at around $23.

There was only one difference though, it was the connector. The O2 sensor 1 on Bank 1 (upstream) which is the faulty one, has a grey plug, and the downstream one has a purple one. They both have the same wire / pin locations, look the same from sensor perspective, but their connectors have different slots locations so you can not inter change them.

The one from the scrap yard had a purple plug. So I took a chance knowing I could exchange it after I Sorted our the plugs so it fits on the grey plug from the car harnes.

As it turns out. There was an immediate improvement on the graphs for both 02 sensor voltage readings, as well as the short term and long term fuel readings.

I've been driving with the car now for about 5 days now to work and back. In total about 550->600km with no issues.
the car's fuel economy has improved from what I can see quite significantly.

If I have to be paranoid & picky, the only difference I see, is at the top end of the rev's, she feels like she's loosing a tiny bit of steam. But I might also be dreaming because I purchased the car second hand and I might only have know the car with a sensor going bad. it's the best fuel consumption I have gotten from it.

Perhaps the Ford Mechanic was right, there might be a difference between the upstream and downstream sensors or as he called it (Oxygen sensor = Upstream) and (Lamda sensor = downstream).

Whatever.... I'm happy with the car as it is and the graphs remain good irrespective of the driving conditions.


Thanks for all your advice and help.

Kind regards,
philip

:hy::grin2::driver:
 
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