Hello everybody (my first post),

I've recently bought Brava '97 automatic (with 71K kms) and found a strange problem which could not be detected before purchase, as it would only show up during cold start.

After the cold start in the morning the engine starts easily and runs smoothly, but pressing the accelerator pedal seems to choke it, and I have to let it run for some time before the engine will rev up.

The main concern, however, is that as soon I shift from P to R or from N to D, a kind of metal grinding (or rattling) erratic noise starts coming form the engine. After shifting back to P or to N the noise goes away. What I usually do then is drive slowly through the driveway (about 100 meters), basically without pressing the acc. pedal, after which the noise is practically gone. Once I noticed a flashing "gearbox failure" light which went away after restarting the engine.

Otherwise, when the engine is hot it runs perfectly and without any noise, and shifting to any gear is flawless. The gearbox and engine oil levels are normal, and both oils have been changed few weeks ago.

A guy who sold me the car told me that a "pump takes some time after cold start" before I should start driving, but I don't know which pump (oil?) he was referring to and if that was correct at all.

Any idea what's happening and if it looks like a serious problem? (My suspicion is that the gearbox somehow does not have sufficient oil right after the cold start, and that the noise comes from the rotating gearbox parts...)

My theory is you need a new gearbox, or a gearbox rebuild. But I hope I'm wrong for your wallets sake.

if you get a nasty noise when its put into drive it usually means the transmisison is on its way out, but the fact that yours is fine once warm suggests it isnt a problem you have to worry about in the near future. i would make sure you start your car and let it warm up for 5 minutes before driving on a cold morning, this is good for the engine and transmisison as cold fluids settle at the bottom and take some time to warm and circulate.
maybe the pump in the transmisison is having problems getting line pressure up to the operating level when the fluid is cold. thats not uncommon this time of year on autos, and although that shouldnt make any nasty noises, it is likely that changing into drive with little or no fluid on the main transmisison components could make it noisey until the fluid is sufficiently circulated.

jug said:

i would make sure you start your car and let it warm up for 5 minutes before driving on a cold morning, this is good for the engine and transmisison as cold fluids settle at the bottom and take some time to warm and circulate.

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Thanks for the advice, I'm going to do this next time for sure. In the meantime I checked the service manual and found that there is a gearbox solenoid required to provide an extra oil pressure when the transmission oil temperature is below 10 C. I'll check the resistance of the solenoid to see if it's correct, and also the oil temperature sensor. If either one of them is at fault I'll be happy to replace them.

did you also see the note in the service manual about putting the transmisison into N for at least a few seconds before engaging D. when N is selected the pump increases the line pressure if the temp is below 10 C. this can help a lot on a cold morning.

btomic said:

Hello everybody (my first post),


After the cold start in the morning the engine starts easily and runs smoothly, but pressing the accelerator pedal seems to choke it, and I have to let it run for some time before the engine will rev up.

Otherwise, when the engine is hot it runs perfectly and without any noise, and shifting to any gear is flawless. The gearbox and engine oil levels are normal, and both oils have been changed few weeks ago.

)

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Happened to me once & the problems were exactly the same as yours. So try to add another extra 1 litre auto fluid to the gearbox even though your gearbox fluid level is presently at normal level. As for my case problem solved!!

If problem still persist, you need to check gearbox temperature sensor & Pressure Control Selenoid.

good Luck

Hi,

Brava 1.6 Automatic owner here, sounds like your having the same problem as me. The metal grinding noise only occurs when you switch from D to N or P quickly, turn off the engine and turn it back on quicly, you should always wait 1-2 seconds between each gear change (from N to P to D to R etc etc). If the metal grinding noise happens on a first time start then i really dont know.

When you say it lets you drive but "chokes" it, does the red gearbox warning light come on? If so thats the same as mine, Mine lets you select Reverse though.

If your problems are the same as mine, then you can rule out do a complete new gearbox oil change as Jug has done this with my car already.

Does your engine seem chuggy in the morning, like it is stuttering LOL, if so, try the ISCV (?) clean with WD40/Petrol that Jug demonstrated in another topic. (It is called something along the lines Bravo starting problems)


What has been working for me is, put your car into N, start it, then put your foot on the brake pedal, press the gearbox button on the lever and quickly pull it down into Third (3) this will probably let you drive off, after about 5-10 mins of drivng, try putting it up into D

jug said:

did you also see the note in the service manual about putting the transmisison into N for at least a few seconds before engaging D. when N is selected the pump increases the line pressure if the temp is below 10 C. this can help a lot on a cold morning.

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Actually I didn't see this advice but it may be somewhere (I have Haynes manual and the one from babarmalic's homepage). I always wait several seconds between shiftings, but the noise is still there. I didn't have time to inspect those solenoids yet, hopefully tomorrow...

BTW is there a User's Guide in English anywhere, I only have the one in Italian...

subija said:

So try to add another extra 1 litre auto fluid to the gearbox even though your gearbox fluid level is presently at normal level. As for my case problem solved!!

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Good idea, I'll try that too, because the fluid level (measured when hot) was somewhere in the middle between the marks, not at the MAX.

if you overfill the box it will leak any extra oil through the breather, so you cant overfill it in the long run, but you can make a mess of your drive or garage.

there are english manuals on the babarmalik site. bottom of the page there are 4 pdf manuals to download, 2 for mk1 cars and 2 for mk2 cars

I've added more gearbox oil and guess what - it didn't change anything. On the other hand, idling for several minutes does help, and the noise is almost gone by that time. While waiting for those minutes, I've noticed that the noise (although much lesser) is present even in P and N, not just in R or D. As well, the idle speed would occasionally stabilise with noise disappearing, and then go erratic again with noise coming back.

This gave me a clue that the problem might have a different source altogether. I found that the noise is actually coming from the left hand side of the compartment, in the belts area, while the gearbox is located on the right (watching from the front). I spoke with a service guy who suggested tightenning the alternator belt, and I'll have to bring the car there next week (that's about the only decent Fiat service in Belgrade, so the appointments are scheduled two weeks in advance).

BTW, I found another interesting behaviour of my car. While driving from the cold start, the coolant temperature rises from COLD to the half way between COLD and MID markers. Then I hear the fan which keeps the temperature in that area for 5 to 10 minutes. However, the temperature then begins to rise, crosses the MID marker and reaches one third between the MID and HOT markers. Only then the fan turns on again, but from there it keeps the temperature constantly above the MID marker. What is the normal temperature I should observe at the instrument?

you said you have an erratic idle when the noise is there. its not uncommon to have noises during an erratic idle, but more importantly the idle should not be erratic at any time under any conditions unless something is wrong. have you cleaned the idle speed control valve and checked the air temp sensor next to it is working ok? your idle should be stable at any temperature, on a cold morning you should see at least 1200rpm (i get 1200-1400rpm depending on air temp) and it should be a constant stable rpm that slowly drops down to 850rpm over a few minutes until the engine is warmed up and ready for normal use. i never drive my car until the rpm settles at 850rpm.

your cooling system should maintain the temp at half way (mid) or just above it, even on a hot day in heavy traffic. the fan comes on at approximately the half way point. it sounds like your fan is coming on too early at first, and then coming on too late, i havent got a clue how that could happen, its a strange one

jug said:

have you cleaned the idle speed control valve and checked the air temp sensor next to it is working ok?

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No, I haven't yet. I thought that a sort of mechanical trouble was causing both the noise and unstable idling. Wouldn't the clogged idle speed control valve and/or faulty temp sensor cause idling problems at all times, not just when the engine is cold? I'll double check those things anyway.

jug said:

your cooling system should maintain the temp at half way (mid) or just above it, even on a hot day in heavy traffic. the fan comes on at approximately the half way point. it sounds like your fan is coming on too early at first, and then coming on too late, i havent got a clue how that could happen, its a strange one

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Yes, it's a strange thing but I'm absolutely sure the fan first turns on at half way to MID point, and then "sleeps" until it's third way from MID to HOT. I'll mention that to the mechanic as well.

btomic said:

Wouldn't the clogged idle speed control valve and/or faulty temp sensor cause idling problems at all times, not just when the engine is cold?

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no, when the engine is warm it does not need to use the temp sensor or iscv. you could disconnect both and the engine would idle ok when warm.
a good way to test them is to disconnect them one at a time, if dosconnecting one or both makes no difference to the idle when cold, it suggests there is a fault, because disconnecting either if they were working should cause the idle to get worse (lower rpm and more erratic). give it a quick go next time you do a cold start.

Just back from the service shop, with good and bad news. The noise is definitely coming from the alternator, which is the good news, but the bad news is of course - I'll have to remove the alternator and change the bearings.

The explanation is that the alternator rotor scratches the stator during cold start, and as the stator warms up and expands, the contact becomes smaller and eventually goes away. The guy told me that he listened with the stethoscope and is positive about his diagnosis.

The problem is that, according to the service manual it's unlikely I'll be able to remove the alternator myself, which means a visit to another service shop (which services alternators).

As for the weird radiator fan activity, I've found some explanation. Firstly, the fan does NOT actually turn on when gauge needle is half way to MID point. It is the radiator valve that opens up, allowing cold water from the radiator to start circulating around motor, which causes the temperature drop at that point. As well, since the amount of water increases, the temperature gradient decreases, and it takes some time before the fan really turns on. Sorry for the confusion I made with the wrong description of the problem.

try greasing the alternator bearing, you can do it yourself, its not difficult on the 1.6.

if the fan only turns on at a higher temp than it should, this suggests the coolant temp sensor may be faulty. if your car has A/C it could also mean the fan speed relay is faulty.

jug said:

try greasing the alternator bearing, you can do it yourself, its not difficult on the 1.6.

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You think it's possible to do it from the outside, without removing the alternator?

jug said:

if the fan only turns on at a higher temp than it should, this suggests the coolant temp sensor may be faulty. if your car has A/C it could also mean the fan speed relay is faulty.

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I'll see if I can double check the coolant temp sensor. I'm not quite following you on the other part, how is the A/C related to the possibly faulty fan speed relay and then to the late fan start?

btomic said:

You think it's possible to do it from the outside, without removing the alternator?

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do a quick check, spray some WD40 on the bearing, if it goes quiet it means that is definately the problem. if the noise comes back (because WD40 isnt usually a long term solution) you can try removing the auxilliary drive belt, and the alternator pulley, and then spray some grease into the bearing. you dont need to remove the alternator, although its not hard to remove if you did want to.

btomic said:

I'll see if I can double check the coolant temp sensor. I'm not quite following you on the other part, how is the A/C related to the possibly faulty fan speed relay and then to the late fan start?

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on models with an A/C there is a 2 speed fan relay. the second faster speed only comes on when the A/C is in use. I've seen faults in the past where the relay connections corrode and the relay shorts out, causing problems not too dissimilar to yours. it may be worth checking the relay even if you dont have A/C, its in front of the battery tray in the little plastic box. this is a good place to do signal tests with a multimeter. although in your case its far more likely to be a problem with the coolant temp sensor, or its wiring.

Jug, thanks a lot for your replies. You seem so knowledgeable, hopefully Fiat will offer you a high position in their headquarters soon...

In the meantime I checked the relays and found one with corroded contacts, sanded them and replaced the relay back. It's the one in the upper left corner but I'm not quite sure about its function, because there are 6 relays in the box, while the service manual depicts only 4.

I wanted to check the coolant temp sensor but the access to it seemed blocked by some hoses, and I wasn't sure if I should just remove the blue plastic cap to reach the contacts or unscrew the whole thing? There seems to be a sort of spring holding the cap in place, which is again hard to reach because of the hoses. As well, do you measure the resistance with cold or hot coolant or both, and how do you know when the reading is correct (you have to measure the coolant temperature by some other means)?

Another thing I wanted to do is to replace the air filter (which was pretty dirty and nobody-knows-when last replaced), but I had to wait till Monday (today) for shops to open.

Finally, I'm planning to bleed the cooling system today as well. I recalled that every time I start the engine, I hear the water circulating around for the first couple of seconds, especially when revving the engine. I located the bleed screw at the back of the engine (on the heater hose), but I'm not quite sure about the other one on the radiator (I have the A/C unit and the radiator does not have the cap - there is expansion chamber on the left side). Is that bleed screw actually a white knob on the right hand side of the radiator top?

Finally, after all the reading I've done the faulty coolant temp switch seems to be the only reasonable explanation of the "late" fan kick in (at two thirds between the mid and hot marks on the gauge). I'll be able to confirm that once I gain access to the sensor...

p.s. I don't know if I should've started a new thread because the topic has drifted away from the original "cold start noise" problem on Brava automatic... BTW, I'll spray some WD40 on the alternator bearing (which also seems quite hidden...) before I start the engine today and let yoo know the outcome...

when testing the temp sensor you can disconnect the wiring connector and use the contacts with a multimeter to read the resistance.

resistance will decrease as temperature increases. at 0 degreesC the resistance should be 10K ohms. at 20degreesC this should have dropped to 5k ohms, and by 60degreesC there should be almost no resistance at all.

measuring the temp of the coolant so you know what to expect is less easy (and so we avoid it), instead if you measure resistance on a cold morning you know the coolant will be approx 0degreesC (check weather forecast if you want an accurate 0 degrees morning). you could start with this point as a reference and then see how long it takes to reach the expected resistance at 60degreesC. if the resistance doesnt drop from 10k ohms to a very low amount (at least 1k) after 10-15 minutes of idle it means there is something wrong with the sensor.

it seems your sensor is not reaching a low enough resistance to activate the fan as soon as it should. measuring the resistance of the sensor at an accurate 60degreesC would be useful, but measuring the temp of the coolant will be tricky. this is why i often test the sensor using a cup of water and a thermometer. doing this will require the sensor to be reomved, causing a loss of coolant, so its a bit of an inconvenience, but a far more accurate method.

also check the reference voltage going to the sensor is 5Vdc. you can test this by measuring the voltage across the pins on the wiring connector. pin 1 on the connector (left hand side when spring clip is at top) should be used for the red terminal of the multimeter.

as far as bleeding is concerned, its safe to assume the rad will not need doing. you should try to bleed the highest bleed screw (on heater hose) with the engine running and up to temperature. be carful the fluid coming out will be hot!