Noisy injectors (UPDATE with video)

[felicia16v]

temp sender ?? maybe overfuelling by reading low.. i recon its the same as my missus car which i am convinced the cam timing is out on..

sold it now tho so dont care lol..

honestly i have worked on these cars from new and not been more stumped than i am with hers, and i have driven a few that have been a bot lumpy so maybe skoda had some bad cams/cranks to go with the dodgy sprockets that were kicking around..

i am convinced that the cam was a tooth retarded on the missus car but i found her a cheap felly diesel before i got around to trying anything

[myjalopy]

Yes I read about the dodgy cam thing, but the car pulls much better once it's warmed up. It's just that first few miles, but as I say it's a straight drive to work each day so most noticable when reversing off my drive first thing in the morning or reversing out of my parking space at work in the evening. I mention reversing as that seems to make it more noticable. Imagine having a 1.0litre 8v engine in a Bentley and that's what it feels like, really weak and stodgy.

Regarding temp sender reading low. Tthe car has been driven, for some time I suspect, with a duff thermostat. I changed that recently and disconnected the battery in an attempt to reset the ecu. The temp reads fine now and warms up within a couple of miles. The fuel consumption has not improved however.

If the gauge is reading fine, does the engine get the same information or is that from another semsor?

[djaychela]

The gauge and the ECU use two thermistors which are contained in the same physical sensor, so it's possible for the gauge to work and give you the right reading while the ECU is getting the wrong one....

[myjalopy]

The gauge and the ECU use two thermistors which are contained in the same physical sensor, so it's possible for the gauge to work and give you the right reading while the ECU is getting the wrong one....

So replacing the coolant sensor block, by the stat housing, would solve it as it would replace both sensors?

[djaychela]

Well, it would ensure that isn't the problem - whether it is is a different matter. Have you got a multimeter?

[myjalopy]

Well, it would ensure that isn't the problem - whether it is is a different matter. Have you got a multimeter?

Hmm, well I did but one of the wires snapped. I could get hold of one if you tell me what to do with it. No funny suggestions please!

[djaychela]

Well, you need to measure the resistance, preferably when it's hot and when it's cold, of both sensors. Not sure of the pinout, and CBA to go out to the garage, may do tomorrow when I get in from work!

[KaiserPingo]

A well known source of noise in a Felicia is the fuelpump.

It generates an annoying ticking (ratling?) noise.

[djaychela]

Er... you sure you're not talking about a Fav? (Unless it's a carbed Felicia, which this one isn't). The Fel fuel pump is under the car (in the tank), and just makes a quiet whizzing sound, unless it's knackered.

[myjalopy]

A well known source of noise in a Felicia is the fuelpump.

It generates an annoying ticking (ratling?) noise.

I can hear the fuel pump only before you start the car, when it primes. Not after that though. Anyhow, this noise is a constant clattering, seems worse when cold.

Tonight , I noticed the car was driving very lumpy too. Not misfiring, but just not smooth. Pulling up at a junction and then pulling away was a slightly unsure adventure. There is a also a noticeable muffled clunk or jolt in the drivechain when you pull away or change gear which is accentuated by this engine problem. When cruising along, if you can do that in a Felicia, it seemed to be slightly but regularly hiccuping too. In fact when I went to move off the drive this morning I stalled it fives times ! I had to rev it more than I should to stop this happening. Not the best thing to do at 5am !

I will check the plugs again tomorrow or anything else that I can think of on my day off.

[myjalopy]

Well, you need to measure the resistance, preferably when it's hot and when it's cold, of both sensors. Not sure of the pinout, and CBA to go out to the garage, may do tomorrow when I get in from work!

Cheers. I will see if that information is in Haynes as long as you tell what to do with any findings.

[djaychela]

OK, here goes... The temp sender, you know where that is, in the thermostat housing. It has four pins, and I've taken a pic to avoid any ambiguity.

note the double keying at the top for orientation (the two lugs that stick out, next to each other)

With my multimeter at room temp on this sender, I get 3k Ω between A and B, and 1.5kΩ between C and D. There is no connection between any other pins.

However, I don't know 100% that this temperature sender is OK (I have others, they're in the shed where the car parts are kept, and my bike is in the way, etc., blah blah blah moan moan moan), so I can't get to the others now to do a nice graph or something.

And I don't have my other Fel here at the mo, and the rally car is under cover, so I can't see which sender is for the gauge and which is for the ECU. The diagram in the book has pin numbers, IIRC, but there are no numbers on the sender.

[myjalopy]

That's fantastic Darren, thanks. I will check this out tomorrow.

[Neilos888]

have you tried listening to the engine with a stethoscope (piece of timber)?

get a length of timber 2x2 or something hold the one end with a cupped hand and place to ear and place other end on each cylinder/injector and listen to see if each is running ok, if the injector is 'knocking' you should be able to tell which.

[myjalopy]

have you tried listening to the engine with a stethoscope (piece of timber)?

get a length of timber 2x2 or something hold the one end with a cupped hand and place to ear and place other end on each cylinder/injector and listen to see if each is running ok, if the injector is 'knocking' you should be able to tell which.

Yep, I tried listening with a long screwdriver to various parts of the engine. The rocker cover is fairly quiet, but as it is isolated from the main engine by a rubber gasket I suppose it would be. The injector bar sounds like a mass of tiny pixies tapping away with tiny hammers!

I put it on the timing cover, I presume, but cannot hear any untoward noises. The clattering/tapping seems to be coming from the backside of the engine.

All in all fairly poor performance for such low mileage and regular servicing. :(

[myjalopy]

OK, here goes... The temp sender, you know where that is, in the thermostat housing. It has four pins, and I've taken a pic to avoid any ambiguity.

note the double keying at the top for orientation (the two lugs that stick out, next to each other)

With my multimeter at room temp on this sender, I get 3k Ω between A and B, and 1.5kΩ between C and D. There is no connection between any other pins.

However, I don't know 100% that this temperature sender is OK (I have others, they're in the shed where the car parts are kept, and my bike is in the way, etc., blah blah blah moan moan moan), so I can't get to the others now to do a nice graph or something.

And I don't have my other Fel here at the mo, and the rally car is under cover, so I can't see which sender is for the gauge and which is for the ECU. The diagram in the book has pin numbers, IIRC, but there are no numbers on the sender.

Ok, late reply but I have this:

Cold engine A and B=4.5kΩ B and D=2.38kΩ

Hot engine A and B= 0.26Ω B and D=0.13kΩ

Black wire goes to the temp guage according to Haynes. That is from pin D.

I have no idea what this means, do you?

[myjalopy]

Ok, I read up on it. The temp sensor is a thermistor and the higher the temp, the lower the resistance. Therefore, as mine shows a lower resistance when the engine is hot, it must be working?

Darren, my resistance values are different to the ones you posted, but you measured at room temperature so that may explain it.

Right, so I will be again looking at the sparks and air filter tomorrow and will post pix of the sparks so you can see if they look right to you.

[djaychela]

I think the one I had is probably not the right one for the car, but the ranges you have certainly look ball-park right, and as you say, they're going in the right direction, so that should be OK. If you have VAG-COM then you can read the temperature the ECU thinks it's seeing from it as well, I believe, so you can double-check, but I think that looks OK.

I've got my "recce" Felicia back, so I'll measure the values I get from that cold and hot when I get a chance, maybe tomorrow evening.

Yup, spark plug pics next...

Edited 10 March, 2010 by djaychela

[myjalopy]

Here you go:

http://pbckt.com/sm.XNF

Pix taken after a reasonably short drive, but the engine got up to temp.

Edited 11 March, 2010 by myjalopy

[djaychela]

Ok, late reply but I have this:

Cold engine A and B=4.5kΩ B and D=2.38kΩ

Hot engine A and B= 0.26Ω B and D=0.13kΩ

Black wire goes to the temp guage according to Haynes. That is from pin D.

I have no idea what this means, do you?

Sounds about right. Just been out in my recce car:

Cold engine A to B=6.09kΩ C and D=3.11kΩ

Hot engine A and B=0.30kΩ C and D=0.15kΩ

As you'd expect, really. My engine was stone cold, and the warm readings look similar enough to make no difference.

[myjalopy]

Sounds about right. Just been out in my recce car:

Cold engine A to B=6.09kΩ C and D=3.11kΩ

Hot engine A and B=0.30kΩ C and D=0.15kΩ

As you'd expect, really. My engine was stone cold, and the warm readings look similar enough to make no difference.

Sensor seems OK then.

What do you reckon about my spark plug pix?

Edited 11 March, 2010 by myjalopy

[djaychela]

How long have those plugs been in the engine?

[myjalopy]

No idea, they were in there when I bought it a few weeks back. Why?

[djaychela]

Well, generally you can't tell much from a plug chop if they've been in a while, 'cos then it's an average of what it's done over the course of the time. They don't look super-rich though. Or oily, thankfully. But you can't really tell that much if they're not of a known age. Nothing there to get too worried about, I'd think. I've seen 'em black from too much fuel on an over-rich mixture (awaits keyboard warriors saying this isn't possible!). But there has to be a reason why your car is giving such crappy gas mileage.

[GentleGiant]

I assume you have checked the obvious, like binding brakes? especially the handbrake.

But it keeps coming back to the temp gauge, if the ECU thinks the engine is cold, it is going to use more fuel.