Using one 02 sensor (feedback fault)

[xztraz]

First post here

Problem:

After revving a bit onto the highway the ignition just cut out and engine stalled.

Immobilizer led was off. took key out. locked the car (car-guard alarm). no imob led (should blink slow)

unlocked car again and tried to start. led still dead (no blinks or anything). engine turned over but no ignition.

disconnected the battery for 20 sec. reconnected

now the led started blinking slowly and engine fired up when starting.



one time before a similar thing happened but the ignition was only out for 10 sec then i could start the car.

I'm quite sure I've seen the imob led blink one time during normal driving. it shouldn't do that?

and also the engine stalled 0,5 sec on a bump on the highway yesterday


battery connections seemed to sit properly, was using the red key when driving.


start with checking oil level and power/ground to ecu?
any grounding points that i should check. where are they?


/Mike T - Sweden

 

[PumaNoob]

The PATS immobiliser is switched off after a few seconds of running, i think its about 5 seconds. You could run your car and then remove the transponder and it would still run until you turned the ignition off so it wont be that causing your car to cut out. If its happened when going over a bump then id check electrical connections

 

[xztraz]

That is good information!

Allright. checking cables and connections

 

[xztraz]

I've gone through a couple of earth points (stripped away paint, put new thorned spacers or what they are called.. and some electrical fat to stop future corrosion), changed the ground lead between engine and chassis and re-seated the battery clamps. I haven't had the problem for a couple of days now so hopefully it was just some bad connection somewhere there.

Thanks again for the info on the PATS. that would have been a lot more headache to solve.

 

[PumaNoob]

Good man, hopefully you've sorted it!

 

[xztraz]

Hi again. Well seem like i cheered a bit too early. :|

Today the car halted again. After 5 minutes it started juddering, lost power and stopped. on a straight low speed road just before a roundabout No bumps. Raining and cold outside.

Could kind of start the engine but no revs and struggling to keep idle.
Could at least with some effort get the car to a nearby parking.

Filled up some fuel (it was running low). Did not help.
Checked for engine fault codes via odb and tourque on my phone. nothing.

The engine could be started a couple of seconds and then started to judder as it wasn't getting enough fuel. and died after about 10-20 sec. Pushing the accelerator only made the engine halt. like to much or to little fuel. I didn't notice any unburnt petrol smell. alternator light flickering a bit when juddering but i think its just because the low revs.

disconnected the battery 20 sec. reconnected and now it ran just fine.
A faulty wire or clogged up fuel filter would not be reset by this?

battery cables and connections are in good condition and the battery terminals where set tightly. Haven't checked the alternator end of cables yet.

The previous owner have put in some light trim chip disabling the tourque limiter. Could it be that? it should be some sort of plug in thing. if i just could find it i could try to run without that for a while

Other common faults when the engine is misbehaving that gets reseted when disconnecting battery?

 

[xztraz]

I wounder if the obd-bluetooth reader works as it should with fault codes. i get some engine values like rev. any easy reachable sensor i could disconnect to get a guaranteed fault code so i can test the reader?

I read there is a killswitch for the fuel. where is that located in a left-hand driven puma? next to the odb plug? is that reset by disconnecting the battery?

 

[Sjoerd]

An example would be the MAF sensor. Right front under the bonnet.

Regarding the kill switch; with it activated your car would not run at all. It is located (on all older Fords I think) near your left foot, next to the OBD connector. Would not be my bet on this.

I would rather check the fuel pump and it's connections. Read our lambda values, it might try to overcompensate some effect when heating up the engine. Then check your MAF and TPS values. Worth a check in this might be your clutch sensor (under the pedal).

PS: these kind of torque limiter removal stuff is a waste of money. They make your driveshafts and gearbox wear a lot faster. Plus it can be achieved with one meter of wire and a few cablebinders. I even made a fancy switch built into the empty slots in my dashboard. 15 min job.

 

[xztraz]

I checked all connections i could reach in the engine bay. I think it might have been that darn battery connector again. A relay clicked when i pushed it around. Cleaned and re-seated again. Have to change thoose to better ones.. Checked clutch switch that was in place.

Ah maf for faultcodes. Good have to see if the odb thingie works as it should.

Ah yeah the tourque unlimiter. I think he said it also remaped some stuff but i have no idea. It should be connected somewhere on the ecu i guess.
I try to not floor ot on first an second. But nice to be able to

Thanks for the info on killswitch. I thougt i might have hit it with my foot or something

Well hopefully this is solved now.

 

[Sjoerd]

I checked all connections i could reach in the engine bay. I think it might have been that darn battery connector again. A relay clicked when i pushed it around. Cleaned and re-seated again. Have to change thoose to better ones.. Checked clutch switch that was in place.

Ah tps for faultcodes. Good have to see if the odb thingie works as it should.

Otherwise just get a ELM327 cable from eBay. Works brilliant for me.

Ah yeah the tourque unlimiter. I think he said it also remaped some stuff but i have no idea. It should be connected somewhere on the ecu i guess.
I try to not floor ot on first an second. But nice to be able to

Don't forget it functions in second too normally. What's your max.rpm? Usually a quick way to see if it's chipped or not.

Thanks for the info on killswitch. I thougt i might have hit it with my foot or something

Well hopefully this is solved now.

To knock the kill switch over really only happens in an accident. On some cars it can be a bitch to reset it. I remember some old Volvo banger which we trashed where it was located between the rear seat and the fuel tank (under the steel protection!). Took us 3 hours to cut it with only some scissors at hand haha. The good old days. :roll:

 

[xztraz]

Well something is still wrong with the grumpy puma..
Today when trying to start it it ran for 3 sec then died. ran for 3 sec died and so on. had to disconnect battery to get it running. and it was still a bit hesitant then. it was a cold morning -2 degree c

Later i checked with obd again with another app. obd doctor or something and it says:

Mil off.
Closed loop o2 regulation active but there is a fault in the system (or something similar).

sounds like the lambda? I think i only have one. Going to check if i get pulses from it with a scope in the weekend.
Also changing fuel filter and taking a look at the connections to the pump

 

[Sjoerd]

Definately seems to be the Lambda sensor. Disconnect the plug and see if it runs. If yes, it's the lambda. If you have the same problems you have to dig deeper. Did you check the idle control valve allready?

 

[xztraz]

In the evening the car ran quite ok. might be low on power. hard to say. when i was checking for codes i tried disconnecting the lambda with the engine idling and the engine still ran without it and couldn't notice any difference in the idle. I didn't check for errors when I did that thou.. should i try driving it around wit the lambda disconnected? or just check if have the same fault on the obd with the lambda disconnected

Idle control valve nope haven't checked that *add to list* where is it by the way?

It's a bit tricky to find the fault when it's not easy to reproduce..

 

[xztraz]

Checked lambda with another older cable connected hardware based obd reader. it was fluctuating around 0,1-0,5v seem ok. if i disconnected lambda it i got open loop instead.

i get around 40 degrees inlet temp. is that normal? its maybe 5 degrees outside. when car cold the reading seemed more like outside temp.

disconnected tps and readings in obd (on the phone got to 0) and engine ran funny when throtteling. seem ok.
disconnected maf. engine ran like shit. seem ok.

fuel filter change and electrical lookup left to do.

 

[xztraz]

idle control should not stall the engine completely if faulty right? a little gas should be able to compensate for that?.

the latest problem i had where the engine running for 2-3 sec then died. extra gas did not help. should not be affected by lambda or idle control valve?

when i was out today trying to reproduce the fault (driving around with a heavy foot) i got mil off, spark ignition. sounds like the 02 regulation totaly shut of then?

rpm limiter is around 6500. probably just a tourqe unlimiter then.

 

[Sjoerd]

Hmm when you get such a high inlet temperature I think you might have your first real clue there. Should be much lower depending on the engine temp. For example a screenshot of my car's data logging. The outside temperature was +/- 25 degree and the engine was nice and warm. With car standing still (as in the screenshot) the value can be up to 10 degree higher. When driving I saw it drop to +/- 28 degree.

If it was up to me I'd try and clean the MAF first. No effect? Replace it. If you need one I have a used one I can send you cheaply.

 

[xztraz]

todays fixing

* Fuel filter changed. Old one quite dirty.
* MAF cleaned. (before clean ~2,6 g/s idle, after ~2,8 g/s idle) seem to work.
* Air filter box leaking (broken threads), fixed.
* Removed the trim-chip (Evolution Chips) it was plugged in the top of the ecu.

The temp on the inlet is a bit high (outside + 10-15 degrees) so have to change that sensor.
And i haven't checked the connections to the fuel pump.

I still have the feedback fault. but the car runs smoother now.

previous stuff fixed

*Ground cable engine-chassis changed and connection points cleaned
*Battery connectors. cleaned and tightened

Where is the fuel pump grounded?

 

[xztraz]

just read that the MAF value should be around the same as the displacement of the engine.. so it should be around 1,7g/s at idle. mine is wayy to high then. and i also have short term fuel trim up to 30%. It's pointing towards a fault maf.

I've ordered a new inlet temperature sensor.
varied between 30 to 15 degrees on the highway. maybe 5 degrees outside

does anybody have standard values for all sensors at idle and some other rpms?

 

[xztraz]

car doesn't seem to hickup on bumps anymore atleast but im stil wondering about the closed loop fault. anyone else using tourque? just to verify that it isn't the obd program that is making something up.

 

[Sjoerd]

Did you fit a new MAF sensor? Are you still receiving the closed loop fault after driving for a bit? Myself I use ScanmasterELM, works pretty well.