Technical Stilo 1.9 jtd 8 valve 2004 plate

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Technical Stilo 1.9 jtd 8 valve 2004 plate

croy

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Hello
I am looking for Technical advice if anyone has gone through what I am about to tell you :- History
I bought the car brand new and sold it after 3yrs to a friend of the family, 7yrs down the line I have bought the car back for scrap value due to the water pump failing and snapping the cam belt and the intercooler hose had split and rubbed through on the inner wing. I am a mechanic by trade but have never rebuilt this engine before, so I removed the head and stripped and assessed the damage X2 exhaust valves bent, had head skimmed, rebuilt head with X2 new valves new valve stem seals and fitted X6 cam followers and new tappet Shims to get 0.30-0.40mm valve clearance.
Replaced Hose on intercooler pipe, fitted new water pump and timing belt and timed it up using crank locking tool on oil pump bolt. The engine runs fine
The problem now is I am getting P0235 fault code which is over boost, I am going through it at the weekend but just wanted to know has anybody had any similar problems the engine has only done 59000 miles ?
 
You may just have a faulty MAP sensor ..could be worth having a look at the sensor and giving a clean out and see if error clears..located back of engine block and just left of EGR valve when looking from front of car, only held in with single allen type bolt , I used a good squirt of brake carb cleaner when I gave mine a clean last as they do become gunked up after a while..some info in link below

https://www.fiatforum.com/stilo/254612-p0235-supercharger-error-code.html
 
P0235 error at 3000rpm

Hello
I am new to the site I have a 1.9 8 valve JTD Stilo but looking to sort a error code P0235 which is a boost fault and happens at 3000rpm seen lots of other people with this fault have any of you solved the problem ?
The History of the car I use to own it 7yrs ago and sold to a friend, but the car was very poorly intercooler hose split on inner wing water pump seized and cam belt failed. I have had the head skimmed and replaced X2 exhaust valves, valve stem seals and fitted new head gasket, new bucket and shims for the valves and set the gaps to 0.35mm inlet exhaust, new water pump and cam belt kit.
Engine run fine but lacked power ? so I stripped the EGR and it was stuck due to carbon build up, cleaned and refitted, still lacking power disconnected MAF sensor, went like stick, fitted new MAF sensor, goes like a dream but when I hit 3000rpm under load ENGINE FAILURE comes up fault code P0235 comes up, I suspect overboost valve or MAP boost sensor on the inlet manifold, there is no boost pressure leaks. Has anyone else had this problem and what was the cause and did you fix it ?
 
Thanks for that, you don't think the over boost valve could be the problem ?
 
Re: P0235 error at 3000rpm

P0235 Turbocharger Boost Sensor A Circuit Malfunction

sounds like your suspicions are right bud, check your boost sensor. i dont know if disconnecting would revert back to a 'basic map' and possibly bring some performance back or if it would just act the same... either way it could possibly confirm/deny sensor integrity
 
Re: P0235 error at 3000rpm

Thanks for that but when engine fault comes on dash and the light come's on, it does not seem to affect performance, when I rev the engine hard I can not see the waste gate move hence I suspect over boost solenoid ? if you disconnect the MAF sensor warning light does not come on, because I suspect it has no way of see air flow in to what's happening with the boost ? so do you think teaching the throttle and map could work ? How does the over boost solenoid work ? my theory is the Map sensor must send the pressure readings to the engine ecu and the engine ecu must signal the over boost solenoid to open causing the waste gate to work and relieve the boost pressure so not to cause damage to the system ie intercooler and pipes ? does it give it a 12 volt feed or a earth feed as I am thinking of checking it out ? and I have heard that you can also bypass it to check the waste gate ? but I was thinking of unplugging it and put a earth and 12volt feed to see if the waste gate moves ?
 
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Re: P0235 error at 3000rpm

Please don't post multiple threads about the same problem. I've now merged them into this thread.

As already mentioned, P0235 = "Turbocharger Boost Sensor A Circuit Malfunction". The boost sensor is the MAP sensor, and the fault code indicates a circuit problem. Check the connector, wiring and continuity between the sensor and the ECU. It would also be a good idea to clean the sensor as suggested last week in post 2 above.

If the problem was with the boost valve, the fault code would be P0045, 46, 47 or 48.

As you have an intercooler, you probably have a 115bhp JTD engine. The 115bhp engine does not have a wastegate, it has a variable geometry turbo, controlled by the boost valve.
.
 
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Re: P0235 error at 3000rpm

Thanks davren sorry for the multi links new to the site not sure how it all works yet, does anybody have a wiring diagram ? I will check continuity
Cheers Croy
 
Re: P0235 error at 3000rpm

Copies of the complete Engine Management wiring diagram are below, however for the task in hand, you should only need page 3.

M10 = Engine Management ECU
K82 = Boost Sensor (MAP)

Wiring colours on the diagram are shown in Italian. BC = White/orange. BR = White/red. BN = White/black. However, wiring colours on eLEARN wiring diagrams are often wrong, in which case, you would have to use the pin numbers of the components. (1 2 3 on the sensor. 93 95 94 on the ECU). A pinout diagram of the ECU is below.

While you have access to the sensor, it would be prudent to remove and clean it with carburretor cleaner or similar.
 

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Hello
I have invested in the diagnostic leads and downloaded the free multiecuscan software and have this afternoon managed to connect to my fiat stilo 1.9 jtd 8valve with the p0235 fault code, I road tested in graph mode with air temp and boost pressure and desired boost and noticed when the fault came up I was at 3200rpm in 4th and I noticed the air temp on the boost dropped to the bottom of the graph whilst the boost was at the top. Davren said check the wiring which he sent me the diagrams thanks davren again, and I am doing that tomorrow, but I think it all points to the boost sensor ? i can get a motor factor sensor £40 or genuine £70 if i end up changing the sensor what do you think is best and have any of you fitted motor factor boost sensor if so was they genuine Bosh ? and have you had any bother ?
 
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