# Ford street ka O2 failure **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [October 12, 2024, 10:06pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592 "2024-10-12T22:06:32Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:06pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/1 "2024-10-12T22:06:32Z")
Hi all again. Got a ford street ka that’s really annoying me. Had it for a long time now and a underlying issue is starting to terrorise me, the cars been with me for ages as it was my first car and I’ve kept it ever since as something to remember but it’s always had O2 issues that I couldn’t fix so I ignored them. Code p0131 O2 sensor bank 1 sensor 1 voltage low and “system running lean” warning as well. It’s had its O2 sensor changed and that didn’t work, many things have been done including, Injectors changed, MAP sensor checked, manifold cleaned, exhaust and intake leaks checked, PCV checked and valve changed, and more that I’ve probably forgotten. I’ve seen this code so many times yet I’ve never been this confused by it, even the ford dealership said they don’t know the cause which makes me feel uncomfortable. Any ideas? ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:07pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/2 "2024-10-12T22:07:31Z")
Also I forgot to mention the reason why I’m addressing them now, car recently started drinking fuel like crazy and spultters when it’s revved ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [October 12, 2024, 10:15pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/3 "2024-10-12T22:15:44Z")
> [@Pug1](#): > > system running lean” warning > [@Pug1](#): > > drinking fuel like crazy I can see why you’re purplexed … lol … Suggest to tell us more about your car’s configuration. no. of cylinders/banks? OBD II? Uses MAP but no MAF? issues with evap system, purge or vent valves? What about the exhaust system? Any leaks? With this sort of problem I’d probably monitor the output of the pre-cat O2 sensor at idle. After warm up it should go up and down in voltage , 5 -15 second intervals, usually in the 0 to 1 volt range. That would verify it is in closed-loop operation. The only other thing I can think of, Fords tend to have complicated to diagnose EGR systems. This seems to be more a problem in the mid-90’s to early 2000’s models. ---
**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\ **Post date:** [October 12, 2024, 10:29pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/4 "2024-10-12T22:29:20Z")
I don’t know what a “street ka” is. Do you have a scantool? Even the cheapest ones (that will, e.g., read generic OBDII codes like the P0131) usually give live data. See if you can graph out your short term and long term fuel trims, along with the upstream O2 sensor readings. No OBD codes can tell you that there’s a problem with a part (like an O2 sensor). In between the PCM/ECU and the O2 sensor are wires. That’s the link between the part and computer. So let’s say that the upstream O2 sensor plug has some corrosion on it (even a little bit). They only put out between bout .1 and .9V. It doesn’t take much for small wiring issues to create enough voltage drop to cause havoc. ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:30pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/5 "2024-10-12T22:30:47Z")
4 cylinders naturally aspirated petrol, only 1 bank. It’s a 1.6 liter. O2 sensor bounces between 0.4 and 0.7 volts in the idle (which seems fine to me) I hear no noises of an exhaust leak or Infake leak ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:32pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/6 "2024-10-12T22:32:09Z")
Checked all cables and connections, no rust or damage so ruled that one out. If really is a confusing issue lol ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [October 12, 2024, 10:33pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/7 "2024-10-12T22:33:26Z")
What about the intake air boot? Is it is good condition, no splits or other air leaks? Have you removed it for a bench inspection under good lighting? Are the exhaust manifold fasters that hold it to the head loose at all? They can come loose over time b/c of thermal expansion/contraction. ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:35pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/8 "2024-10-12T22:35:47Z")
Yup, intakes all happy and the boots got no tears in it ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:36pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/9 "2024-10-12T22:36:28Z")
I myself am starting to wonder if it’s a computer issue ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:37pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/10 "2024-10-12T22:37:14Z")
I will try tightening the exhaust actually, that’s a fair point but I couldn’t find any leaks. Still worth a try ---
**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\ **Post date:** [October 12, 2024, 10:39pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/11 "2024-10-12T22:39:08Z")
It should be bouncing .1 to .9v. What creates a .4-.7 I couldn’t say. When the O2 sensor was replaced was it generic or OEM? ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [October 12, 2024, 10:39pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/12 "2024-10-12T22:39:34Z")
You haven’t yet addressed the MAF or no-MAF question. ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:41pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/13 "2024-10-12T22:41:32Z")
Ah, now you mention it I think it was a generic. The denso one is £60 so possibly that may be why it’s only bouncing 0.4 to 0.7 ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:41pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/14 "2024-10-12T22:41:48Z")
Apologies forgot about that. It runs a MAP sensor with no MAF ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [October 12, 2024, 10:46pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/15 "2024-10-12T22:46:44Z")
> [@Pug1](#): > > Apologies forgot about that. It runs a MAP sensor with no MAF That’s the same configuration as my Corolla. Called a “speed density” mixture system I think. It is harder w/that system for the computer to adjust the mixture w/real time changes in engine power. So it is more important that there are no untoward paths for fuel or air to get into the engine. Be suspicious of the evap purge valve pathway. ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:50pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/16 "2024-10-12T22:50:38Z")
I just looked at the price of the EVAP valve, 160, or 20 for a generic but I feel uncomfortable using a generic one. I will definitely take a look at that, but all this is confusing me because surely ford would’ve checked all of these systems, they had the car for 2 days ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [October 12, 2024, 10:51pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/17 "2024-10-12T22:51:45Z")
I’m able to temporarily block the purge valve pathway on my Corolla, for testing purposes. I wouldn’t replace it unless you know for sure it is faulty, just introduces more variables. CR’s suggestion above for a fuel time test makes a lot of sense. Are you equipped for that? ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:54pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/18 "2024-10-12T22:54:09Z")
Yup, I’m definitely going to be running tests on that tomorrow. I’m desperate for a fix because the car means so much to me even tho it’s a scrappy cheap thing ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:55pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/19 "2024-10-12T22:55:07Z")
Fuel time test is something I haven’t heard of before, let me check because I don’t quite know if we call it something different here ---
**Author:** ![Pug1](https://avatars.discourse-cdn.com/v4/letter/p/ecd19e/32.png) [@Pug1](https://community.cartalk.com/u/Pug1)\ **Post date:** [October 12, 2024, 10:58pm UTC](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592/20 "2024-10-12T22:58:11Z")
Ohhh, you mean the long term and short term fuel trims. Sorry if I’m being a bit stupid lol I’m not usually this bad at mechanical things [Next page](https://community.cartalk.com/t/ford-street-ka-o2-failure/197592.md?page=2)