Hi, Ive been having this problem for a while on my 99 1.25 fiesta.
when the engine is cold, somtimes putting the clutch down will now make the revs die completly to 0 and the battery light etc will come on. Sometimes it will save itself from dying at around 400 revs but the battery light will still flicker when it goes that low.
Its only ever when the engine is completley cold and once warmed up its absolutley fine.
Any ideas
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Any ideas?
A friend of mine suggests it may have something to do with either the engine coolant temp sensor or the gearbox speed sensor?
Can anyone shed any light on this? Thanks
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Yes; coolant temp sensor or idle control valve sticking - a squirt of WD40 can sometimes help with that.
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does it sound like a symptom of a failing ect sensor then? I hav a spare icv so will try this too.
Its hard to expaing but its only if I pull away totally cold a press the clutch down quick at the end of the road to slow down, i.e if im slower down on the clutch it wont happen
What do you think?
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ISCVs are easy to change, so try that first.
When it starts cold; is the idle speed slightly faster than normal and steady?
Does the temp gauge work correctly?
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Hi, yes when starting cold its idling at about 1200 - 1300 steady then slowly getting down to around 1000 after a bit
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and yeah, the temp guage works fine
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In that case; try an ISCV first.
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Hello gain, well tried a different icv and still the same :(
Could you elaberate on the syptoms of a failing ect sensor?
Cheers
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Rathert han guessing have you tried any diagnostics? Do you know for certain the new ICV works? Could this be an issue with a sticking throttle position sensor? When my old Fiesta started doing this it turned out to be a wire going into the TPS which was damaged so I cut it away and bodged a new wire in place.
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Hi, thanks for your reply, now you have mentioned it something comes to mind. While I was trying to find the cause of my over revving iss, ford advised me about a new tps wiring loom that was available on a (technical service bulliton). I bought this along with a new tps from them. Now thinking about it, when I replaced the old tps loom, of the 3 wires, I cut one at a time and connected it to the new loom as directed to not get them mixed up, But when connecting the new connector to the new tps, it clipped on the other way round if you see what I mean but I hadn't thought anything of it untill now.
Could it possibly be that I now have the outside 2 wires of the 3 mixed up (5v and earth)
Would this cause the revs to act like I said in my first post?
Thanks in advance
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No I don't *think* it will matter. From an electronics point of view the GND and VDD (either ends) are connected via a fixed resistance, the slider (middle) wire moves up and down between giving 0-5v.
Over revving can be the ICV stuck open, could also be the TPS sensor I think...
Unless anybody wants to correct me?
James
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Hi, thanks for the reply, Its not over revving thats my problem its when starting from cold if I clutch down at a junction when the engines cold it will lose all revs and die. Once slightly warmer its fine???
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Any blue smoke at the exhaust?
James
Edited by Javalin on 03/12/2008 at 16:23
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Hi, no blue smoke at all.
Not sure exactly what oil is in it, its due its service in the next month or so though.
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Just a thought; what oil is in it?
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>>But when connecting the new connector to the new tps, it clipped on the other way round if you see what I mean but I hadn't thought anything of it untill now.
>>Unless anybody wants to correct me?
I don't know the wiring layout, but, you're right about the three wires being a (ballasted) supply, a ground and a signal wire. Getting the wiring order wrong though can give all sorts of trouble. For example, instead of gettong 0 to 5v as the throttle is opened, you could get 5 - 0, or, you could be near shorting the supply to ground at one extreme of throttle opening or the other. 5 minutes work to check with a multimeter.
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Hi everyone, this is my first post here and I've got a Fiesta 1.25 Zetec 1999 just like sladey and am having EXACTLY the same problem as described in the first post.
I've been hunting for a solution for months with no luck. So far I replaced the following:
- New IACV from Ford dealer which made NO difference
- New spark plugs
- Checked throttly body butterfly valve but looks clean (no visible carbon either side of the valve)
- New oil filter and oil (Castrol 5W30)
- Used STP Complete fuel cleaner which has helped hesitation in low gears
- Checked for vacuum leaks but doesn't seem to be any
I've been told it could be the TPS or its wiring but I don't really want to replace it and find it's not the problem. I hear they are expensive.
Is it possible to spray WD-40 into the wiring looms to clean the metal connectors, or will that do nothing?
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Ok I tried cleaning the connectors but still no luck.
Anybody else having the same problem?
Edited by JN on 07/12/2008 at 14:07
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Hi mate, could you describe your exact problem cheers
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Does it misbehave whilst driving? Mine (a 1.3 Endura) seems to struggle and then pickup whilst driving even without you moving the pedal. It cuts out when coasting to a stop occasionally - more when cold. Injectors? Sparks?
Interesting that JN has had some success with fuel cleaner though.
The fiesta mk4's also suffer from corrosion on the ECU terminals from passenger side water ingress though - i've not yet checked that.
J
Edited by Javalin on 08/12/2008 at 17:32
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Mine hasnt done it for ages, it seem like, if if press the brake before the clutch when stopping it will never happen, again thats only when cold.
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Hi there, well basically my car runs PERFECTLY when warm, but when really cold like sladey says if i put the cltuch down when im doing 2,000+ revs the rev meter fails to 'catch' the idle and drops below causing the battery light to flicker. I can prevent it by lifting the clutch up or not using the clutch until i slow down to almost a stop with the brake.
In the case of really cold weather, it just drops to zero flat and engine cuts out and i have to restart.
Oh and i too was surprised about the fuel cleaner working aswell. It's still in the tank (haven't had to fill up since), so i hope it doesn't go back to being hesitant.
I'm thinking one of the sensors must be gone but I don't want to waste more money on guessing. Diagnostics show nothing.
Somebody told me it could be sticky valves hence the reason for me using STP Complete Fuel Cleaner. However i think i should really be doing an engine flush on my next oil change. May change oil soon as it's been almost 8 months since i last did.
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mine turned out to be the O2 sensor. Dead easy to change - if a little costly at £65 ish.
Mine was fowled with oil from blowthru (?) - the breather was blocked and oil was going into cylinders and out of the exchaust, making it very rich and fouling the sensor at the same time.
When the breather was cleared the problem of blue smoke comming out the back - but the car would hiccup and struggle then run ok for a few minutes and repeat. When this happens and the engine was coasting down (i.e. fuel cut mode) - it would not recover and die.
Hope this helps. Might be worth popping the sensor out and looking at it - see if fouled etc.
James
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oh - and as its a heated sensor - it kicks in whilst the engine is still "cold" (ish)
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I remember I tried to remove the O2 sensor a while back, but I couldn't unscrew it.
£65 is a lot for a sensor especially if I'm not 100% sure it's the prob.
Did your fault of the O2 sensor show up during diagnostic or did you replace it yourself?
Thanks.
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changed it myself. No code or other diagnostic information was shown.
You'll probably need a long 22mm socket with the slit for the cable and I needed my 18" breaker bar (my favourite tool!) just to break the joint, after that its easy. They are commonly overtightened.
I guess its worth looking at the condition of the sensor.
If you have an o'scope you can check its signal output, and if you have a multimeter you can check the heater resistance & voltage supply. You'll need back connector probe'ing bits too.
James
Edited by Javalin on 18/12/2008 at 12:05
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Thanks for the info. I'll try and remove it and check the sensor soon. I suppose I expect it to be fairly black at the tip if it's ruined.
Funny thing is you say that the sensor sometimes kicks in when cold, which is the time I experience the dropping revs, however if the sensor is fully operating when engine is warmed up shouldn't I get further problems? Apparently when warm car runs fine.
Thanks.
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Yeah. Id expect the slots in the tip to be fouled really.
See - www.lambdapower.co.uk - for a good reference for the sensor.
Let us know how you get on....
James
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Thanks for the link. Will look into it this week and post updates.
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>>If you have an o'scope you can check its signal output,
A multimeter with a bargraph, or an analogue multimeter is perfectly adequate for seeing the lambda sensor sweep at slow, <2000 rpm, engine speeds - an oscilloscope is nice, but not strictly required.
As long as you see a healthy sweep which speeds up with engine speed, then you have done the most fundamental check of the lambda sensor that you can without gaining access to the live data from the ECU which would give you the status of the integrators, or, trim values.
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I had a look under the bonnet and unfortunately I can't get access to the sensor because of the manifold shroud (metal shield) thats in place. I tried to unscrew the shroud but couple of the bolts are rusted and won't budge.
One more thing, I enquired with the Ford dealers about how much the lambda sensor would cost, and they said its £144 inc. VAT!!!!!!!!!!!!!!!
Personally I think thats ridiculous!!!!!!
Anyone know where else I could get a hold of a new sensor?
Thanks.
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Motor factors - Approx £65 (for my 1.3 anyway).....
that link I posted also sells them.
James
Edited by Javalin on 22/12/2008 at 09:54
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Sorry for the long delay, been away for a while.
I just replaced the lambda sensor yesterday but it STILL happened!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I did disconnect the negative battery terminal for a couple of minutes after to reset the keep alive memory but still didn't solve the problem. The old sensor did seem quite fouled though.
Am I suppose to disconnect the battery for longer because I'm on the verge of giving up now. I'm all out of ideas.
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Im still having this issue, only when first setting off with a cold engine, once its warm it catches the idle fine when the clutch goes down. However even when cold, if i brake slightly then put the clutch down its fine?
Anyone know any more about this
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>>I just replaced the lambda sensor yesterday
What checks did you make to come to the conclusion that the lambda sensor was at fault? Or, did you just guess?
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I havnt changed this on mine, did it cure it for you?
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Just a guess. I've had diagnostics done but no codes ever showed up.
Now I'm leaning towards maybe a dodgey alternator but I want to be sure. Spent too much time a money on the problem so far!
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I've had diagnostics done but no codes ever showed up.
Fault codes are just one small aspect of diagnosis procedures. I think that reading the live data while the engine is misbehaving would be a better thing to do. You need to be sure that the ECU properly recognises that the car should be idling, and that it sends sensible signals to the idle speed control valve.
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