General Stilo 1.6 Misfire and other anomalies?????

[Depressed]

Hello - I'm a relative newbie. Have corresponed with some regular messagers regarding my Stilo 1.6 (under the "Map Sensor for fiat stilo" thread). I thought I'd solved my problem, but it has reoccured and I'm wondering whether you can provide any further suggestions.

Here we go:
Car had been playing up and running rough and finally conked out. Engine Failure message. Map sensor fault diagnosed (code P0105). Took car for service.
Map Sensor arm, wiring and plug all found OK.
Drove car home - still felt rough, but better than before.
Next day - engine fault light comes on again. Diagnosis: Misfire no 2 detected. Checked coils and plugs, no faults found. Reassembed. Misfire no longer there. Suspect injector faul, refer to main dealer.
Took car to Main Dealer. Carried out diagnostics. changed spark plugs. cleaned throttle body.
Drove car home - 2 miles - all fine.
Next day drove 2 miles and Engine Fault light came on; misfire.
Took car back to main dealer. Fault codes P0300, etc. for Random cylinder failure and ignition coil failure on 1, 3 & 4. Dealer suggests changing coil packs and replacing all 4 injector rails.
We couldn't afford for the Dealer to do the coil packs so brought the car home and bought our own coils (from shop4parts) and have changed all 4 coils.
We still have the engine fault light.
(We also added grease lightening to our fuel and we've had a new exhaust fitted.)

We have not replaced the injector rails yet as the price quoted by the Main Dealer is out of this world (i.e. they charge 105quid per hour for labour!!!!)

My questions are:

Will replacing the injector rails solve our problems (has anyone found this to be the solution)?

I am getting some contact cleaner; which plugs/pins should I be cleaning?

Is there anything else at all I've missed?

If I buy a fault code reader (as suggested by Steely) should I be purchasing a OBDII?

Help.......!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
(p.s thanks previously to Argonought, T14086 & Steely - any more ideas!?)

 

[Steely]

the engine fault light ( the amber one in the rev counter) has to be reset by a fault code reader, even if the part has been replaced,

depending on what the problem was:

it will either :

clear after 3 sucessful faultless starts,
clear if its just an advisory fault,
or flash if its a serious fault,

if you dont mind me asking? how much has it cost you in diagnostics up to now??

 

[Deckchair5]

Hard to diagnose from a distance but from what you say here and more so in your previous post in the other thread then i'd be suspecting your throttle body connections/ TPS feedback

Things to bear in mind is that P0105 isn't saying your MAP sensor is faulty, it's saying MAP sensor CIRCUIT giving unexpected feedback results. Subtle but important difference. The MAP sensor feedback should correlate to the throttle position, if it doesn't then BING warning! After that it will ignore the MAP sensor and guess what to do, mind you it's pretty good at that

Your previous problems (best to keep all related posts together)
b. a diesel - type chugging when in neutral waiting at traffic lights
c. stalling at round-a-bouts, and lights (no comments about my driving please)
d. lack of power accelerating, but surging when changed into third gear upwards
e. 1st gear feeling like it's going to stall (and then somtimes stalling)
f. 2nd gear running way/pulling forward

All this culminated in my car cutting out twice when driving off from parked (I only got 50 yards down the road) - this was during the last week of June 2008 - and the orange engine light came on, display flashed "engine failure" message, and a very scary ping, ping, ping.
All of that is throttle body related
Then
Anyhow, they carried out diagnostics, changed the spark plugs and cleaned the throttle body. I collected the car and drove home (only 2 miles this time) and all seemed well.
Big clue!

So, I'd disconnect and get a little contact cleaner in both sides of the throttle body connector, leave to dry and reconnect. I'd reset the MAP fault code as that will also reset the ecu in the process as it'll never run with good mpg with that there

Misfires? Well it WILL misfire if the throttle is messing about and with a mismatch in data from the MAP sensor the ecu won't have a clue what to do with fuel.

A flagged Multiple Misfire warning P0300 isnt really anything directly to do with a fault in the ignition or fuel. It's detected by a waver in the smooth engine rpm from the rpm sensor. So a multiple misfire is just that- engine isn't firing/ running smoothly

 

[Depressed]

if you dont mind me asking? how much has it cost you in diagnostics up to now??

Please, do I have to answer that question..... It makes me cry each time I think about it.

Lets say circa 500 for parts (ha! we all know who much spark plugs cost) and labour between 2 garages (Fiat Main Dealer and National Autocentres).
That's why we're trying the DIY route now. This is the newest car I have ever owned (trust me I've owned some fart boxes in my time) and it's the most expensive.

I feel like the biggest Muppet going right now.

 

[Depressed]

Steely and Decks, this is really helpful.

Will I find diagrams of the trottle body on the forum? What am i looking for and is it easy to get to? I'm a total novice, which is probably obvious... so all help is appreciated.

 

[Deckchair5]

You won't have to look far on a 1.6 it's right on top. Have a look in the Stilo Guides for "cleaning your throttle valve" (thought you'd already been there and done that. Ha!)

Just disconnect the electrical connector and use some contact cleaner sparingly. Let it dry and reconnect


Now if you really want to get into it deeper here's some useful info

throttle body connector pinout


the thing is only £400 to buy if you get it wrong so - no pressure

 

[Depressed]

Ok.....

The connectors on either side of the throttle body have been 'cleaned' with electrical contact cleaner (from Maplins); I unplugged them and sprayed both parts and allowed them to dry, gave them a light puff and reconnected.
And.... the throttle body was taken out to check that the garage had cleaned it as they had said, and indeed it was as clean as a whistle.

It's still running ruffffff.

Will resetting codes stop this happening. How do I reset the code, because the engine failiure message, organge light and ping, ping, ping is still happening and it's still running like a fart box. I tried turning the key (not engine) on for 10 seconds, then off, then on, then off - about 5 times in all and then restarted the engine and .... chugg, chugg, chugg - ping ping ping.

helllllp!!!!!!!!!!!!!!!!!!!!!

 

[Deckchair5]

Explain "running rough" more fully. Is it missing on one or more cylinders, does it start properly, can it hold a tickover or do you have to keep some gas on?

A fault code won't make the engine run rough, it'll point you to a suspect area for investigation though

I'd invest in a cheap fault code reader as you can then see what's suspect and reset fault codes too, I have a feeling you're going to make good use of it

In the meantime look for anything that might cause a vacuum leak at the inlet manifold on any of the vacuum lines

 

[Depressed]

Hi & thanks for reply.

Diagnostics (at the garage) showed misfire on Cylinder 2. We replaced the coil pack and it ran Ok for 150 miles, then it went rough again. Cylinder 3 was deemed to be new. So, we changed the other two (1 and 4) coil packs and still no change in running.

By 'rough' I mean when I turn the engine on it doesn't 'tick' or 'purr', it chugs more like a deisle and when driving it has little acceleration and it's like you can hear/feel the cylinders going 1,2,3,4, 1,2,3,4 but it's just not quite getting there. (Does this make any sense at all?) When it's idle, its almost a 'tink, tink' tink' like when your exhaust is about to go (and we've had a new exhaust fitted so it's not that).

The car does start OK. And it does hold a tick-over, but it's touch n go whether it's gonna conk out. So, you put some gas on and it sounds 'rough' - as above.

Would you enlighten me (I am a novice after all) on 'inlet manifold' and 'vacuum lines' - has this been discussed before on the forum? I can have a look at those pages.

What about the Fault Code reader? Is this the OBD2 I've read about? And if I get one (though not sure where from), where do I stick it (in a manner of speaking).

Finally, do you have any thoughts on the Dealerships conlusion that we should replace the injector rails???

Thanks again, You're the beezkneez.

What

 

[Deckchair5]

Well, information is everything so for an OBD2 fault code reader then look here
and contact these guys
www.talktomycar.co.uk
A simple fault code reader is all you really require but you can go more extravagant if you wish and obtain on the fly diagnostics of a running engine

The 1.6 connects real easy with no issues and your OBD2 socket is here on top of the the body computer front face

A P0105 technically is this
P0105 (1-T) MAP Sensor Circuit Fault Code Conditions: No PCM codes set, ECT over 158dF, throttle closed, engine speed under 1000 rpm, then test started and PCM detected a MAP signal of over 3.3v, or with engine speed under 2500 rpm and Throttle Angle over 1.0v, a MAP signal less than 1.0v.


What it's saying is "For that amount of throttle the pressure in the manifold isn't reading right". So you have to find out which of those two isn't putting out the correct voltage or whether those voltages are actually getting to the ecu


So for your P0105 fault there's a lot of possibilities
Have a look here
http://www.aa1car.com/trouble-codes/page3.htm

Checking for vacuum leaks, inspect the plastic pipes going to the manifold area, check the MAP sensor is sealed properly to the manifold. Checking suspect areas by squirting a small amount of water on it (not electrics obviously) whilst the engine is running willl often show up manifild leaks

With more comprehensive diagnostics then you can check the MAP output with engine running but you can check the voltage coming out of the MAP sensor directly with a simple multimeter and by back probing the connector (See Stilo guides- checking electrical circuits) . The voltage should be steady with steady rpm and move as you increase/decrease revs