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Technical Idle speed - CLX inj.

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Technical Idle speed - CLX inj.

VmanC

VmanC

The Panda whisperer
Parked in the garage
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Well, I've been using my new toy today, just to make sure it's ok for my Daughter to use until I find her a cheep little Panda of her own. All is well, apart from the idle speed being too fast. Now my 750L has a screw on the engine, and if I turn it I can alter the idle speed until it's where I want it, nice and easy, just like a Panda should be. But when Fiat built my blue CLX they had started to get a bit above themselves and had fitted it with fuel injection! I can cope with the dipping rear view mirror and the clock, but fuel inj! it's just not right.

Anyway, the point is, I've had little experience of it and am looking to you all for any advice on what may be the problem and how I can fix it. I suspect the idle sensor but would be grateful for any other suggestions. :confused:
 
might sound easy but the injection engines have the auto chocke. is it keeping the revs up after warmed up?
might be wrong but I think the idle speed is controled by the ecu which take readings from sensors
 
Without a rev counter it is hard to tell what it's idling at. i think it should be about 850-900rpm. Like panda ki says though, there is an auto choke, that when starting from cold, which is a solenoid that opens the throttle slightly more and should return to its previous position after a few seconds. Next time your having a look(make sure car is cold), look at the throttle body without the airbox get someone else to turn the key to ignition, but not start and you'll see the throttle control bit move a few mm. then get them to start and it should return as said a few seconds after. if it doesn't then this could be your problem.

If it isn't then im stumped...
 
Ok, thanks. That gives me something to do tomorrow. The idle speed certainly doesn't slow after warm up, I would guess it stays at around 1500rpm regardless. (y)
 
Hi, I had a similar problem on the selecta I converted to a manual. There is a stepper motor on the throttle body that is controlled ny the ecu and decreases the idle. I bought one from ebay and problem fixed. It is a linear motor and subsequently seems to get a "flat spot", there should be a thread here somewhere, someone suggested trying to clean it but I bought a new one.

If you can not find the thread or the part in question, pm me.


Dennis
 
Thanks Dennis, this is the part I'm most suspecting, will give it a clean today and hope this does the trick, I hate spending money! If not I'll be in touch. (y)
 
Ok, I had the Idle stepper motor out earlier today, left it connected and switched on the ignition, and it moved ok. I tested it a few times to be sure but then the plunger sprung out of the motor body completely and landed on the floor. So, I pushed it back in a far as it would go and refitted it, the idle speed was now 3000rpm, not good.

My Panda Haynes manual doesn't cover the inj. system but I do have a Punto one that does, so, assuming they are basically the same system I followed the refitting instructions in the Punto manual, disconnected the battery for 20mins, reconnected the battery, then started the car. Apparently, the ECU will then set the idle automatically. Well it seemed to do the trick at first, but now my idle speed has gone back up to 1200 - 1500rpm so I am no further forward. :confused:
 
Hi Vman,
I had this problem on my CLX - changing the temperature sensor on the manifold may be worthwhile. Made a big difference to mine. If it's sending a cooler than normal signal the ECU tries to compensate. Sadly I didn't keep the resistance readings I took over the few weeks while trying to sort it... I did discover a big difference between the old one and the new one though.
The new sensor only cost me about a tenner - may be worth a try, as it cured mine st away!
cheers and good luck
lwm
 
I'm glad you've mentioned the temp sensor because I now remember it being quite thirsty on the trip home from where I bought it, as if it's running rich. If the sender is as cheap as you say I think I'll get one as a next step. Cheers. (y)
 
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VmanC said:
I'm glad you've mentioned the temp sensor because I now remember it being quite thirsty on the trip home from where I bought it, as if it's running rich. If the sender is as cheap as you say I think I'll bet one as a next step. Cheers. (y)
Click to expand...

Glad to hear your good news. (y)Good luck.
 
Temp sensor on the manifold? i presume you mean the one that looks like a temp sensor after the cat?

If so thats the lambda sensor, it reads the o2 levels and if it is higher/lower than it's parameters, the it tells the ECU to add more/less fuel through the injector. usually problems for them to over read over is that there is an airleak either in the inlet manifold gasket to head, or TB to inlet manifold or the cat is duff now. this will cause over fuelling and rich running.
 
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Sorry Craig - me not being specific - meant the temp sensor on the inlet manifold - a variable resistance tells the ECU the engine temperature (well the temp of the coolant) - if it reads the temperature lower than it actually is, the ECU adjusts the fuel mixture accordingly. When head gasket went on mine it obviously damaged it through overheating... a new one made a big difference to tickover and fuel consumption.
(a faulty thermostat would have a similar effect... and a good sensor would correctly read the lower temperature)
fortunately I haven't had any problems with the lambda sensor...
cheers
mick
 
I had similar problems on a 1994 Tipo 1.4ie - when it was partially warm it would hunt up and down on idle, especially after you restarted the engine after getting petrol or something like that. I swapped the temp sensor and all was well. Mind you I also changed the idle control unit as well at a different time.
 
I've turned my attention back to this old problem that has been with the CLX since I first bought it. Panda 1408's 'LOW MPG' thread has helped regenerate my interest as I feel we have a similar situation, in that we both have to choose to approach our problems in one of two ways...

1. Take it to a garage with the necessary equipment to do a diagnostic check on the engine management system.

2. Start replacing components until the problem is cured.

I would normally favour plan two as I don't like paying garages for thier overpriced services, dealerships anyway, but I remembered seeing a Fiat/ Alfa Romeo specialist in a nearby town a few years ago so thought I'd see if he was still there, and if so, how much he would charge to do a diagnostic check.
Well he was still there so I pulled in. I walked into the workshop, spotted a guy with his head under a bonnet, so went over and started to explain my problem. He had no idea what the problem could be as he was a customer :eek:. The right guy soon came out from the reception though and I explained again. Before I could say " how much do you charge to do a check" he had the engine started and his head under the bonnet. He checked a few things then got his apprentice to fetch the hand held tester. Then he went into the passenger footwell, connected the tester and ran a check!
" I haven't got any money with me! " I said, but there was no stopping him.

He concluded that there was nothing wrong with the engine management and that I should change the temp sensor and check the seating of the idle stepper motor, which pretty much confirms what's been said here so far anyway.

So I had been there about five minutes and he'd done everything I was going to enquire about. Plus he refused to charge me anything! This is definately a garage I will use again (y)

He also asked me if I wanted to buy a bonnet as he had a new Fiat one upstairs that he acquired along with some other old stock. Of course I said yes, so he will get some money from me after all. Anyone know what it's worth?
 
Fitted a new temp sensor today and hey presto! no more fast idle, and hopefully, better fuel consumption. To think I'd gone all that time for the sake of two minutes work and £10.66. I probably used an extra £10 of fuel just on the pre Christmas cruise :(.

So thanks for all the suggestions, especially those who suggested it might be this. If anyone else plans on changing this, a couple of things to note...
My supplier had two options in stock (intermotor range), the difference being on the opposite end to the blue connector. One has a flat end, the other is like mine, having a smaller spigot and chamfer. One connector was supposed to be blue, the other light blue, but I could barely see the difference in them so I wouldn't recommend this as a reliable way to identify them.



You simply unscrew the old one and screw in the new. Do it with a cold engine and you'll only lose about half a cup of coolant, if that, and make sure the sealing washer is fitted.

I'm quite surprised at how much difference this has made, the car now drives like a dream, which is not going to help me keep the miles down.
I'm off to pick up that bonnet now while the seats are still out of Charmania.
 
Hey guys...got a similar problem with Giuseppe (CLX). Since i bought him, if im sat in traffic or the temp gets to fan operation temp (About 90c), the engine starts to hunt slightly and run abit lumpy (jolts with acceleration), and then as time goes on it will idle from about 900-2000 rpm within a few seconds. Sometimes it will randomly rev to about 5000 rpm until i pull out the key, let it cool down and start the engine again. Its only done it when i ive been on longer journeys than usual. My distance to work is about 7 miles each way, so Giuseppe rarely gets that hot. Still its annoying though and i need to sort it. Any ideas anyone?:confused:
 
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