Technical Bravo 1.6 16V CF3 - too low idle rmp at ECU

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Technical Bravo 1.6 16V CF3 - too low idle rmp at ECU

czareklca

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Hello everyone, on start, i would like to sorry for my english :)

i've got problem with my Bravo 1.6 16V CF3 from 2001 year, mostly since i bought it two years ago. In this time, i've changed cambelt with all neccesery elements, then check is it correct twice, with original locks, spark plugs and ignition cables to NGK, Coil old was Champion, new is Valeo, camshaft sensor MM and many other parts, to fix problems with power or stable drive (car was jumping when accelerating). Injectors were at cleaning, all got 16 ohms at 20 degrees. I've got second ECU, because we though that it could be broken, like in stillo 1.6 and making some strange problems.

For now, i've got two problems, and no idea, where to look solution, because everything look good.

1. When it warm up to 80 degree of Celsius, idle rpm go down to 700, and are stable. In FES expected idle speed is 700, so it isn't problem with idle speed actuator. I clean whole throttle body but it doesnt get any efect.

2. After replace camshaft sensor i reset autoadaptation and phonic wheel adaptation, all as it is described in FES. But, Bravo with broken camshaft sensor was starting like this:
type in YT "Bravo 1.6 16V długie odpalanie " (i cant add URL cuz dont have 5 posts :( )

and now, after replace is like this:
type in YT "Bravo 1.6 16v CF3 - problem z odpalaniem po wymianie CPW"

I replace sensor, because it had short circuit and gave +1.89 on body of ECU after ignition, and engine didnt start. When ECU was isolated from earth in car, engine work normal.

Today i made compression test, this is result:
type in YT: "Bravo 1.6 16v CF3 - test kompresji"

I can do static or dynamic test, if you tell me, what need to be logged.

I will be grateful for any advices
 
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2 days ago, i've unscrew camshaft position sensor and change its angle. Now there is no more missfire on start, it just need more time to catch. After start, work normal on idle rmp. Problem is only after few hours stand. If i stop him just after first start, and try to run again, it will start in second.

Now it start like this:
[ame]https://youtu.be/FYTz3IEpYpM[/ame]

It's better but still it take to long :(

Any idea, what could be wrong?
 
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Perhaps worth replacing Crankshaft sensor
If not expensive as you have already changed cam sensor.
 
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My mistake with translate :/

Of course i didn't touch camshaft sensor. In whole story, everywhere "camshaft" should be "crankshaft" (i can't edit anymore).

For sure that i dont use wrong name again, here is photo:
 
yes that is crank shaft sensor.
I don't know how close it should be to the phonic wheel but you could find out and check
 
It should be between 0.5 and 1.5 mm. For now i'v got 0.55mm, before angle change was 0.95mm
 
I just finish checking my intake for any vaccum leak and didnt find anything.

When i test my vaccum on running engine i notice, that it is a little bit to low. Tester show reason of it, as "too late timing".

Anyone knows is it possible to correct timing, or it is full electronic controled, and reason of problem is physical damage of something?

This is how it looks on vaccum tester:
[ame]https://youtu.be/dtb3AujojrM[/ame]
 
I still dont get what is the problem.

The engine is taking too long to start?

Only the second engine didn't have cam sensor so it fires blind every revolution (might take almost one crank rotation before firing injectors and coils) until it starts.
The first gen and the CF3 have crank sensor so the ECU waits for signal (might take almost two crank rotations) so it knows if it is on compression or exhaust stroke (or if the cam sensor is broken)
 
My major problem, is long first start. It is important, that only first start after few hours not using, taking so long. If i start it, after few secs turn off and start again, it will fire up, without even half crank rotation.

The other thing is, that it has a two weeks, when everytime, fire up like this:
[ame]https://youtu.be/TRCPmt4hqXc[/ame]
It happen, after disassembly coil, and assembly it after heat up (dont ask why i did it :) )

In my opinion, it is the only normal way, to fire up engine. I'm not sure, that ECU need to find "zero" position on crankshaft, to syncho coils and injections. Most engine's have crank sensor (even my old polo 1.0 from 1995 year) and all starts normal.

Second problem, is idle rpm, which is at 700 rpm. Some time ago, i have found topic:
https://www.fiatforum.com/fiat-boo-archives/415928-low-idle-speed-1-6-marea.html

Same engine, and also 700 rpm, so maybe it is correct, that on work temp (up then 80 degree of Celcius), ECU is lowing idle speed to 700, but engine start shaking on this speed. RMP are stable, 698-703, but this shaking making me nervous.

As u have saw (or not) on my movie in my last post, i check vaccum on hot and it's to low. Normal vaccum is about 600 mbar, in my it is about 540 mbar. This same show MAP sensor ~400 mbar pressure in intake mainfold, as i have found, it should be ~320 mbar.

At all, Brafko is driving very good, accelerating (only sometimes a little jump when i press throtlle to strong). I feel, that it should have a little more power as for 103 KM and be more agressive when i accelerate on higher rpm (it looks like it have to think a sec before start speed up)
 
There is crank sensor, but the engine needs to find the gap in the sensorring on the cranksaft to determine the angle in relation to the piston movement.
The second engine injects fuel and sparks every rotation even if it is on exhaust stroke. Once a cylinder fires, the crank acceleration is used to determine which stroke the engine is on.
The first engine and third (CF3) use the camshaft sensor to determine the stroke and do not inject fuel on the exhaust stroke when starting up.

If haynes states that the idle should be 800 +- 30, that is wrong.
The CF3 is completely different engine: 1596cc (78,4mm stroke) where the old ones are 1581cc (67,4mm stroke) with just different electronics.

Even the fiat manual states the idle to be 700 +-50 rpm (ignition advance of 4 degrees).

The CF3 is not that great as making the stroke longer seems to have caused more load on the pistons and atleast in Stilo they start to consume oil as they get older.

As for the shaking, depends on how much. My 1.6 shakes a lot if under load and under 1500rpm, but that is normal. As for shake on idle, I can feel the car vibrate, but it has always done it (last 9 years) so I don't really care.
 
If the ECU is requesting an idle speed of 700 rpm then that's what fiat programmed the idle rpm to be.
No one knows how shaky your engine is at idle when at normal operation temperature.
Why not post a video? then you may get some helpful responses.
 
If the ECU is requesting an idle speed of 700 rpm then that's what fiat programmed the idle rpm to be..
The problem is that in all books i've found, for 1596 ccm bravo, idle speed was 800 +- 50 rpm. Now, Neverth wrote, that he saw one with 700 rpm idle speed for CF3.

No one knows how shaky your engine is at idle when at normal operation temperature.
Why not post a video? then you may get some helpful responses
i'm not sure, does phone would be able to record it, but i will try.
 
If ECU requests 700rpm that is what Fiat programmed engine speed to idle to be.
 
Neverth you're the man :) i double check "bravo/brava workshop manual" and im sure, that i saw 800+-50 for 1596 ccm. Maybe somewhen i look for it once more time :)

jackwhoo here You have:
[ame]https://youtu.be/yNo0oN6DXEk[/ame]

This is how it start on hot engine. The funny think is, that vibrations come with door closing. Look at airbag after close door (time: 2:08). Before i have close the door, i didnt feel any vibration on wheel
 
Sorry I can't see the vibration on video.
Perhaps a video of engine ?
 
jackwhoo i'm trying to find something to record it without any stabilization. Or it was bad idea, to glue phone to airbag :) i will try better next time.
 
Neverth i just remember, that in winter, when outside was -10 and lower, engine starts everytime like now on warmed up. There was no mather, does it stand 8 hours or 8 days, first start was like this:
[ame]https://youtu.be/TRCPmt4hqXc[/ame]

When temp out was going up, problem with long start back.

It suggest that there is a problem with colant temp sensor or intake temp sensor, but i've checked both few times. What do You think about it?
 
Vibration on steering wheel is normal, the engine mounts are over 15 years old so the rubber is not what it was when new.

As for coolant sensor, there should be two, one for the dash gauge and one for the ECU (not sure if on same housing, depends on the engine). To test if they cause the problem, just unplug them.
Same for intake air temperature.
 
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