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Discussion Starter · #1 ·
Hi guys

I'm driving a 156 SW 2.0 JTS '04. In the last month following happened three times, and always the same scenario :

- driving the car on motorway on 5th gear, around 100-110 km/h
- Cruise control ON
- suddenly : big power loss, car won't rev above 1500 rpm :wow:
- pull out, wait 1 min, restart and drive

This has never been predictable, and dunno if this has a matter, but Cruise was ON every time it happened. Between the last two failures, I drove around 1000 km without activating Cruise control. Then after holydays, I started using Cruise Control everyday on my way to the office (100 km/day) : it happened yesterday (after 700 km using Cruise control).

FIATEcuScan shows following errors :

- P1172/P1173/P1175 : I'm used to these, I'm going to change MAF (idle is rough, car is jerky but doesn't stall)

- P1337 (torque control - comparison) : this one only shows up when I get the "power loss while driving" problem

I've searched over the internet and hasn't really able to look for other similar problems on ALFA cars, mostly on Honda Civic (but don't know if codes are similar from one make to the other).

Any idea/hint/clue would be highly appreciated !

Cheers :thumbs:
 

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Discussion Starter · #2 ·
Could this be something related to the belt, timing, or any crankshaft related sensor ? Thanks !
 

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Discussion Starter · #5 ·
Ok... so found "P1336 Crank / Cam Sensor Range / Performance" in the list and then jumps to P1340 code. Then i would assume my P1337 (Torque Control - comparison) error code falls in the P1336 "family", right ?

That would point at something related to the Crank/cam sensor...

Questions :

- if Crank Sensor was failing, wouldn't that make the car completely cut out ? (which is not the case with mine, it's a clear complete loss of power, car won't rev above 1500 rpm).

- I guess that when it comes down to the Cam Sensor, only replaceable when doing the belt right ?

Still, it could be the sensor or related to, like the belt itself or its timing ?

Thanks for the link and for any other suggestion !
 

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The P1337 is probably there to protect your engine because of misfires (crank mismatch fluctuations) caused by bad fuel mixture. Change the MAF and see what happens. A bad fuel mixture can also destroy your lambdas (pre cats) driven long enough.
 

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The P1337 is probably there to protect your engine because of misfires (crank mismatch fluctuations) caused by bad fuel mixture. Change the MAF and see what happens. A bad fuel mixture can also destroy your lambdas (pre cats) driven long enough.
disconnect MAF first and drive to see but remember this is jts and could be running lean as in fueling problems ie injectors,poor connections relays ........... list can be endless
 

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disconnect MAF first and drive to see but remember this is jts and could be running lean as in fueling problems ie injectors,poor connections relays ........... list can be endless
true, but since the fault codes indicating outside spec for MAF and lambdas are already present, that would be a reasonable place to start looking. Problems at cruising speed is typical lambda issues.
 

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Discussion Starter · #9 ·
Got ya ! Thanks for the hints. I'm going to test drive her today w/o MAF and see what happens. I'll also try - as mentioned elsewhere - to disconnect the ECU connectors above the engine block and give them a good WD40 shower.

As you mention davalfa11, JTS seems to be an electrical nightmare, and after reading hundreds of threads, one might look around for solving a problem w/o actually really curing the core of the problem...

One last thing - that could be important to mention : the cat in my JTS is empty... While changing the front exhaust tube (the one with the flexible structure around) we've looked inside the cat, and have seen parts of the structure that had fallen. Cat was removed and emptied of all it's structure. Could this be related ? I would say that this is only going to affect post-lambdas, right ?
 

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Discussion Starter · #10 ·
Hi folks, here are some news :

- disconnected the ECU connectors above the engine and gave them a WD40 shower,
- same for the pre-cat lambda connectors,
- since I had disconnected the battery to do this, I've also done an ECU reset

Results : no good, car was still idling very rough (even more), and I even managed to get P1151 (Lambda2 signal upstream) and P1131 (Lambda1 signal upstream) error codes, which I never had btw... :thumbs: Is this due to the WD40 operation taking the connectors off and on again ?? :confused:

OK, then cleared the codes ==> after restarting the car idle was now super jerky, exhaust sounded just as if someone was getting drowned and trying to get his breath back...

This morning, tried to disconnect the MAF : I wasn't able to go beyond the 1st gear, the car would stall in a few seconds. I *think* that revving in 1st gear without MAF showed more power than with MAF, but I would not bet a lot there...

So... i'm kinda lost now... :confused:

I mean :

- 50% of the exhaust is new,
- cat is empty so nothing is in the way,
- coil packs and spark plugs are all new with the good reference (Bosch for coil packs and NGK platinum for plugs)

I've ordered a new MAF Bosch genuine : even if it is not that, it will probably be used sometime...

Lambdas ?? Using FiatEcuScan I'll try to log their output voltage and see how they behave.

Any new hints ?
 

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WD40 is actually not an optimal contact cleaner since it leaves behind an oil film to prevent rust, but if the connectors are corroded, it will probably help.

Have a thorough look for any cracks and air leaks around the inlet and exhaust manifold. Check the hoses for the crank case ventilation. If you don't change the oil regulary, the PCV valve could get stuck.

Measure the electrical resistance between the exhaust pipe (where the lambdas attach) and ground. Should be 0Ω
 

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Discussion Starter · #12 ·
Hi Astrix

ok, I'll remove connectors again and try to clean them with some proper contact cleaner, and will look at what you mention.

As for oil, it drinks around 0.7/0.8 liters/1000 km.

Thanks
 

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Discussion Starter · #14 ·
Trashbat : I thought the big brown connectors with purple were the ECU connectors... Are you talking about these ?

As for my JTS, it is 157.000 km. I would hate if this is an injectors problem... :mad: Can't really spend lotsa money at this time :(

Will receive new MAF on Friday, so I'll keep you posted....

Crap :rant:
 

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Yes - I thought that too, but I've got the old loom in my boot so I'm sure! I don't know exactly what the other one (black) next to it is, but the brown one goes to the coil packs and apparently is prone to failure.

I say it sounds like mine because I started off with hesitation and power loss, and then it developed into reporting random faults (lambdas, fuel flow, some others) and running like a tractor. It wouldn't idle properly, nearly stalled all the time, and once there was even no throttle response.

You could try injector cleaner, running on premium petrol (98RON) and driving for a while at high revs, but if that is the problem it might be too late.

Injectors don't seem to fare too well: mine is on 113kkm, and two were beyond repair.
 

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Discussion Starter · #16 ·
Astrix : dumb question when measuring the electrical resistance, where do you take the ground reference ?:eek:
 

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Discussion Starter · #17 ·
Cleared errors (misfire on Cyl 2 was registered) and used a cleaner for injectors.

Drove home (50km) : at low speed and up to 3rd gear car is lumpy/jerky. On 4th and 5th, went up to 130 km/h on highway and revved up to 5000 rpm on the 4th. Then back to cruising speeds (50-60 km/h) : engine light came.

At home : checked codes ==> misfire on cyl 3 now... Tested lambdas output using FiatECU : when up to 2000 rpm, post cat lambdas are stable altough going down gently (0.4V to 0.34V).

Pre cat Lambda 1 : remains at 1.494V and Pre-cat 2 goes up from 1.49 V to 3.4 V

Could this be related ? Bad connection on lambda connector or faulty lambda ??

When looking at the car, which one is #1 and #2 ?

Thanks
 

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Wiring loom photo attached. Moving misfires suggests injectors again I think, but you need a JTS expert which I'm not quite yet!
 

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Discussion Starter · #20 ·
Didn't had time yet to try other things as suggested. On my way to work this morning, car misfired dozen of times... Men, the 4 coil packs and 4 plugs are brand new from last month ! I would be really f$&#!d up if those misfires would ruin any of these !

Should get new MAF tomorrow. Hopefully it will get better. I can't believe things went even worse after me cleaning those connectors...:wow:
 
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