Hi,

first of all, I'm new on this forum, so don't blame me too much

I have a problem with my 1997 1.6 Felicia. When you drive, sometimes it just powers off when you push the cloutch and no one knows what's wrong with it. Some said it's the air intake thing, some it's crankshaft sensor. The problem is that most of the times it power's off you can power it back if you release the cloutch pedal, but if you're in the middle of some jam and it powers off, you are f*****d sometimes. Because it's possible that it won't power up immediately. There were times that I tried 3 times to power it back on and it didn't. Than I waited for 20seconds in the middle of the road, than it powered up. One time happened that it died in my street, and I parked it at my neighbours, because it won't power up for 2mins

Did anyone ever had a similar problem ?

Later today I will get a vag-com 409.1 and try to recalibrate or change the air intake throttle body, but I don't know how it's done. I have never done it, neither have I ever connected it to this computer.

Thanks in advance for all the answers:)

Edited 15 February, 201313 yr by Skynetz

Ok, let's see if I've got it right.

You say that the engine stalls (dies) randomly, and when that happens it is ALWAYS after you press the clutch pedal.

In other words, engine stalling is always clutch related.

If that's the case, it's not such a big mystery. Your clutch mechanism is almost dead (most probably the pressure plate), the clutch disk is slipping, gets hot, begins to stick and finally binds to flywheel. You then have to wait to cool off, contract and unbind.

Bottom line, change pressure plate, clutch disk and thrust bearing. Look for scratch marks on the flywheel too.

Ok, let's see if I've got it right.

You say that the engine stalls (dies) randomly, and when that happens it is ALWAYS after you press the clutch pedal.

In other words, engine stalling is always clutch related.

If that's the case, it's not such a big mystery. Your clutch mechanism is almost dead (most probably the pressure plate), the clutch disk is slipping, gets hot, begins to stick and finally binds to flywheel. You then have to wait to cool off, contract and unbind.

Bottom line, change pressure plate, clutch disk and thrust bearing. Look for scratch marks on the flywheel too.

No, it doesn't happen always when I press the clutch, but most usually (90%). And it's not happening every day. Sometimes you can drive normaly for a week, or a month too or it can stall 4 times in a day. It depends.

And I think it must die because of rpm is too low. I see the tachometer usually behaves in a strange way. When you press the clutch pedal, the rpm don't go slowly down in same steps, but go too much down (like 500-600 rpm) and than back on to 750 cca. Because of this it sometimes stalls, sometimes not.

Sounds like the throttle body is playing up.

Good idea to check for fault codes first though.

A tb reset with a full vagcom may be necessary, although disconnecting the battery overnight and then reconnecting followed by turning on ignition without touching accelerator for 2mins may do it.

Contact points inside the throttle body activate the tickover circuit.These are accessible inside the black cover and may be dirty. Clean the throttle flap and venturi first.

Other suspects are temp sensor,ecu and a poor connection with the multi plug on the inlet mani that links manifold pressure /temp to the ecu.

Yes been through a few steps getting a good stable tickover on the fun lately

Sounds like the throttle body is playing up.

Good idea to check for fault codes first though.

A tb reset with a full vagcom may be necessary, although disconnecting the battery overnight and then reconnecting followed by turning on ignition without touching accelerator for 2mins may do it.

Contact points inside the throttle body activate the tickover circuit.These are accessible inside the black cover and may be dirty. Clean the throttle flap and venturi first.

Other suspects are temp sensor,ecu and a poor connection with the multi plug on the inlet mani that links manifold pressure /temp to the ecu.

Yes been through a few steps getting a good stable tickover on the fun lately

2 weeks ago I checked with the original vagcom, from the porche dealer and there weren't any fault codes for throttle body, only for crankshaft sensor, but I think that error must be because someone disconnected the sensor to try something. Because later we changed the rotor with the sensor and we did a fast check with the rpm falling in idle and I thought that's not the problem.

The throttle body was cleaned like a year ago and is really clean, but I didn't check in that black cover. Temp sensor was changed a year or so ago too and the thermostat too, because they weren't working.

Right hello, I'm here

firstly your car does not have a crankshaft sensor, it has a hall effect switch mounted in the distributor, I don't think it's a problem with the clutch either.

In my opinion your problems are ignition/electrical related, first thing i would check is the ignition timing at the distributor, you need a 5mm Allen key to slack the bolts, then you can turn the distributor, I would put it in the centre of it's travel as a starting point, to set the ignition timing properly you need a timing light and you need to do a diagnostics function using vagcom.... Secondly i would check the ignition coil and leads ( especially the one from the coil to the cap).... Thirdly I would check the electrical earth connections at the battery/body/engine.

Right hello, I'm here

firstly your car does not have a crankshaft sensor, it has a hall effect switch mounted in the distributor, I don't think it's a problem with the clutch either.

In my opinion your problems are ignition/electrical related, first thing i would check is the ignition timing at the distributor, you need a 5mm Allen key to slack the bolts, then you can turn the distributor, I would put it in the centre of it's travel as a starting point, to set the ignition timing properly you need a timing light and you need to do a diagnostics function using vagcom.... Secondly i would check the ignition coil and leads ( especially the one from the coil to the cap).... Thirdly I would check the electrical earth connections at the battery/body/engine.

Yeah I know it's not crankshaft or camshaft, but something in the middle, ie hall effect switch, but didn't remember how it's called

You mean to check the timing belt position if it's right ? I did this before, and it's set right and I checked the earth connection in the trunk and abraded it too, it didn't help.

No, it doesn't happen always when I press the clutch, but most usually (90%). And it's not happening every day.

That's why I used the word randomly in my answer.

I don't think it's a problem with the clutch either.

So how do you explain the relation clutch depressed -> engine stalls?

Everybody seem to overlook the clutch part as it was never mentioned, although it's this thing that baffled local mechanics.

So how do you explain the relation clutch depressed -> engine stalls?

Not depressed, but pressed, that's a big difference, the relation is, that when you press the clutch pedal the computer must adjust the body throttle and other electronics, obviously it doesn't do this well.

Depress means to push down on or to apply pressure to.

Are you suddenly both an English language critic and a brilliant mechanic, mr. cloutch?

Oh sorry

The clutch basket and the push bearing was changed too a year or two ago.

Edited 15 February, 201313 yr by Skynetz

One hour ago I connected the vag com to it and tried first the channel 098 in basic settings, nothing happened, than I tried with 001 (but I have merelli comm) and I heard some sounds for some seconds, so that was calibrating ?

Nothing changed on the screen though.

I didn't change the throttle body, only recalibrated this one. If nothing will change, I will replace it with another one I have and recalibrate again.

, the relation is, that when you press the clutch pedal the computer must adjust the body throttle and other electronics, obviously it doesn't do this well.

no I was not talking about the belt, i was talking about the poisition of the distributor in relation to the engine.

the marelli ecu has no electrical sensors relating to the clutch pedal, I think the root of this is that the engine is being driven by the momentum of the car, as soon as the clutch is pressed it stalls, this can only be caused by a limited number of things, I know that you say you have checked it but would hazard a guess that the ignition timing at the distributor is too far retarded.

the only other thing I can think of which would cause these symptoms is the idle switch (internal part of the throttle body) is stuck in the closed position, this is not all that common but I have seen it happen.

Here is a diagram of how the throttle body is wired up, there is an electric stepper motor which controls the idle speed, a switch which closes when the throttle is fully closed, and 2 sensors which feed the ecu with data relating to how far open the throttle is and it uses this to work out how much load the engine is under and a few other minor functions... Dint think your problems are throttle body related in this instance.

sorry this is the best picture I can find that shows the distributor, it is held on by 2 5mm hexagon shaped Allen key bolts, if you see there is a huge range of adjustment available, you can slacken these bolts off 1 turn, then the whole body of the distributor can be turned in relation to the engine, I would guess that your one is turned too far anti clockwise, only make small changes movements at a time.

what this is doing is changing the position of the magnetic sensor in relation to the trigger wheel, the ecu uses this to know the rotating speed of the engine, and as a reference point to tdc.

Yeah, but as I know if I rotate it clockwise rpm are going down, anticlockwise, rpm up ?

And yes, we moved it for one small move anticlockwise, to have some more rpm, but apparently that neither helped.

I think the root of this is that the engine is being driven by the momentum of the car, as soon as the clutch is pressed it stalls, this can only be caused by a limited number of things.

Good point. I went for the mechanical cause (random extra load from a defective clutch, acting as a 'brake'). You went for the sudden engine power loss. But bad ignition timing doesn't explain the randomness of the issue. Car goes well many times with that 'bad' timing, unless the distributor is very loose. Or let's say ignition timing is so messed up that sits at the threshold of stalling and any minor event kills the engine. But that would render in a low power condition most of the time, no matter how clever 'ECU' is. God, I hate computers on cars... They become a problem in themselves.

So that leaves us with a random no fuel or too much air condition. And that points to idle circuit. Dirt, vacuum leak, corroded contacts. It's a bitch to diagnose a random problem, you have to be very lucky to capture it with VAG-COM hooked (remember there are no error codes stored). So, Skynetz, if you are 100% sure you have a good clutch mechanism, I recommend clean whatever you can throttle body related, blow whatever orifice air related, check for vacuum leaks, and clean all socket contacts ECU related. Be methodical.

Maybe I will clean the throttle body in that black part too and check if there is any grease or just clan the other throttle body I have and replace it. Than we will see. The clutch must be good, because if it would really overheat and bind to flywheel, than when I would try to power it up again when it stalled the car should move ? Or not ?

I cleaned the other throttle body I had with carb cleaner and replaced it. For now it's all working great, no simptoms of rpm going too low when clutch is pressed or stalling for now. I will report back in a week or two, when I will had some more km done.

The throttle body didn't resolve the problem, the car stalled 2 times today when I was going to ski. Maybe a problem with gas intake ?

Is it possible that the problem is with the ignition coil ?

I still think it's ignition timing related, can't help much more than that.

But why would the car stall only sometimes than is it's timing related ? I think it may be a problem witth the ignition coil, maybe it overheats if driving for some time and than you have to wait sometimes for it to cool down, because else it won't do a spark, makes sense ?

I told you it's a b*tch to diagnose random malfunctions. They are the Nemesis of any mechanic because it's almost impossible to replicate them and gather data. In those cases you need to go back to basics: what an engine needs to start? It needs 6 things

1. fuel
   
2. air
   
3. spark
   
4. timing
   
5. compression
   
6. unrestricted intake and exhaust
   

In your case we can safely rule out cause # 5 and 6. Then we have to take into account WHEN the issue occurs and the environment. You say it happens only when the engine is warm and you take it out of gear to stop. So we have heat and engine going back to idle. In terms of environment, you didn't mention if moisture might be a factor too (raining, snowing, condensation, driving over puddles, etc.)

All other 4 causes might be a factor in itself or in combination. Here is what I recommend. Triple check all contacts and wiring looms, especially from ECU to engine and sensors. I usually spray WD40 in every socket; that kills rust and keeps moisture out. Clean the inside of spark wire rubber 'sock' with a proper solvent (the part that goes over spark plugs). Next you have to be prepared to do 2 basic things if engine stalls on the road (yeah, it sucks): 1) clean the inside of distributor cap, and 2) crank the engine and check for spark by pulling out a spark plug wire.

If after all these recommendations you still have the same problem and you ruled out any random engine sensor issue, I think you have an ECU with an attitude when hot.

At what intervals do you have to change the fuel filter ?