Alfa Romeo Forum banner

1 - 20 of 100 Posts

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #1
Symptoms are a series of flat spots, most notably between 1500 rpm and 2100, also somewhere between 3-4000, little or no boost until 2100, horrific fuel consumption, drives better on part throttle than full on, suspicion is never giving full amount of horses at any stage.

codes read:
1555. Accelerator sensor.
0110. Air flow meter, air temp, signal.
0101. Air flow meter, signal.

Turbo hoses perfect, VNT rod moving, MAF, MAP and EGR cleaned. Runs worse with MAF disconnected, as if no boost anywhere in the rev range.

What you guys think, definitely MAF, or something else going on.

Thank you in advance.
 

·
Registered
Joined
·
401 Posts
Hello Hugh,

If I were you I'd change the MAF, clear the faults and do an ECU reset...will probably restore her to health... Only go for genuine Bosch, ( I'm sure you've heard that before) - there was a guy on eBay doing genuine ones for a reasonable price( reasonable= a lot less than alfa!!)

Hope that helps,

Cheerio
The Captain:thumbs:
 

·
Registered
Joined
·
231 Posts
Hello Hugh,

If I were you I'd change the MAF, clear the faults and do an ECU reset...will probably restore her to health... Only go for genuine Bosch, ( I'm sure you've heard that before) - there was a guy on eBay doing genuine ones for a reasonable price( reasonable= a lot less than alfa!!)

Hope that helps,

Cheerio
The Captain:thumbs:
Change the MAF as The Captain says. They should only cost around £70 for a Bosch.
 

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #4
Thanks guys, was just wondering if the accelerator sensor was something to worry about first, or is it related to the maf being duff. Has anyone got a link to where on ebay you'd get one for 70 quid ? And any ideas as to why mine runs much worse with the maf disconnected unlike everyone who has posted here saying they run better unplugged if the maf is gone ?
 

·
Registered
Joined
·
2,012 Posts
I know you've mentioned Turbo hoses being fine, but have you checked the small bore boost control hoses for splits? even a little crack or a few pinholes will give very similar symptoms to yours....

'tis odd that it doesn't improve with the MAF disconnected if it IS the MAF at fault - i left mine disconnected accidentally once and it wasn't too bad, even after the warning light came on :)
 

·
Registered
Joined
·
401 Posts
Hello Hugh,

As Photodave says, I would double check for splits in the hoses; btw there is a throttle sensor on eBay for £15;251310888168 should bring it up, but try an ECU reset first...

Hope that helps

Cheerio
The Captain:thumbs:
 

·
Registered
Joined
·
1,928 Posts
ok ecu reset will reset throttle if thats a problem

does the car dump smoke when power arrives? a clean egr is no good if the solenoid isnt working

and lastly you have a vacum pipe problem, look down rear of engine near battery see if small bore pipe it disconected.......did that to me on my 156 2.4 jtd.........it does not matter that the actuator is moving...u dont know if its far enough and when engine is at revs
id really check the vac hose from the turbo all along its lenght and at rear of engine
 

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #8
Thanks all for your help/advice. The small bore hoses are original, so probably due replacement at this stage, replaced the valve in 2008 as part of a bigger turbo problem, and the maf. I have no smoke, and an ecu reset has not really solved anything, other than my climate control seems to be behaving itself a bit better..... Will replace the hose then as a first measure, and take from there. HDSEVEN, you feel sure it is pointing in that direction ? I have checked the hose, and everything is in its proper position, and though it looks 10 years old there is no visible sign of wear/tear. but I will certainly replace, is it 3 or 4 mm diameter ?
 

·
Registered
Joined
·
1,928 Posts
all it takes is one split........i had a hose come loose and the car drove fine except it was gutless, but cannot figure out your horrific fuel consumption apart from a cold running engine........
was baffled so read my definition of fault codes
the 1555 could be cause of fuel as i did read a sticking brake switch could cause that and the theory is itll fuel harder when accelerator is pressed......id really give them a good look at as someone said it made the car run with flat spots
the 0101 could be caused by dirty throttle body and butterfly to bad wiring to the maf, but the throttle problem you have could cause that as well it seems, and make sure if you have had the wire unplugged it does not run near motors/relays/solenoids/ignition wires......as that could affect it

not sure it will be vac hoses now but no harm in looking...
 

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #11
Ok, vac hoses good, pulled them off, blew through them, no leaks, connected and felt vacuum through them, fitted new pipe, same amount of vacuum, same result. Just on the off chance, vac hose from manifold should go into top connector on the valve, yes ? Was just wondering if it was fitted wrong way around, valve is fitted with connectors closest to you when looking down at it.
Had a look at the brake and clutch switches on monday, both free moving and working correctly.
HD, is it possible that a wrong adjustment on the actuator rod could cause these symptoms ?
As for bad wiring going to the maf, that would not explain it running much worse with it disconnected.
How easy is it to take throttle body off and clean, any guide available, sick and tired of mechanics wreaking havoc all around them when doing the most basic of tasks...:mad:
 

·
Registered
Joined
·
1,928 Posts
Ok, vac hoses good, pulled them off, blew through them, no leaks, connected and felt vacuum through them, fitted new pipe, same amount of vacuum, same result. Just on the off chance, vac hose from manifold should go into top connector on the valve, yes ? Was just wondering if it was fitted wrong way around, valve is fitted with connectors closest to you when looking down at it.
Had a look at the brake and clutch switches on monday, both free moving and working correctly.
HD, is it possible that a wrong adjustment on the actuator rod could cause these symptoms ?
As for bad wiring going to the maf, that would not explain it running much worse with it disconnected.
How easy is it to take throttle body off and clean, any guide available, sick and tired of mechanics wreaking havoc all around them when doing the most basic of tasks...:mad:
actuator rod should not be played with....its set on a rig in the factory......the ones i build, not garret ones but far better and for trucks, cannot be messed with as they are set inside and no adjustment can be made to the actuator.....messing with them can lead to problems yes, have you messed with it as there is no mention of that
 

·
Registered
Joined
·
401 Posts
Hello Hugh,

Just thinking laterally; I know you said you had a positive vacum, but if the the vacum generator is failing then perhaps it won't provide the suction to move the actuator either smoothly or correctly, hence poor acceleration / flat spots? Just an idea/theory; what do you chaps think?

Cheerio
The Captain:thumbs:
 

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #14
No, haven't touched it, but it is a reconditioned one from Alfa, been in it since 2009, and to be honest, I don't recall it ever running right, but other issues have always distracted me from concentrating on it, so my thinking is, and as you have mentioned yourself, reconditioned turbos are only as good as the man doing the job, that it was not properly calibrated in the beginning. If so, is it possible that the vanes are opening in an incorrect, incomplete manner, this is where your experience is better than my ignorance. I have no idea as to whether the rod opens the vanes or closes them, whether there are 2 stages to the vanes or more. BTW, fuel consumption is down to 33, which is horrific, 45-49 has been the norm since it left the factory. The bottom turbo hose, which had a leak, was replaced last week with a samco, and fuel consumption which was poor, is much worse since. And if anything I am driving it easy, because it is so frustrating giving it a bit of welly. So question is, could the turbo rod calibration be responsible ?
 

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #15
Back on the case again. Have finally got a cable and it has agreed finally to talk to alfadiag, but alas, will have nothing to do with multiecu. Anyway, cleared faults, and they have stayed clear. But car runs no better, and consumption still lousy. Brief flick through the sensors shows fuel and turbo, required and actual, pressures to be fine, but, air flow is out, max required is 1200, actual max is 800. Any ideas ?
 

·
Vendor
Joined
·
45,299 Posts
Back on the case again. Have finally got a cable and it has agreed finally to talk to alfadiag, but alas, will have nothing to do with multiecu. Anyway, cleared faults, and they have stayed clear. But car runs no better, and consumption still lousy. Brief flick through the sensors shows fuel and turbo, required and actual, pressures to be fine, but, air flow is out, max required is 1200, actual max is 800. Any ideas ?
OK so its either not getting the air it needs (air filter or housing?) or it is getting the air but for some reason its not being reported correctly, possibly MAF meter or wiring/plug or possibly there is a leak. It could be possible your EGR solenoid is holding the clean valve open, flooding the engine with exhaust gas instead of boost leading to a lower than desired MAF value. You could also have a leak on either the hard plastic U-shaped pipe that comes out of the top of the airbox, or on the rubber pipe just below that which connects to the compressor housing inlet on the turbo, there is also a breather than connects here so also trace that back to the engine looking for leaks. This is a common one, as the rubber deteriorates.

Whats the reading for the air mass meter at idle?
 

·
Vendor
Joined
·
45,299 Posts
Possibly, I don't use Alfadiag anymore though. It usually gives a reading in kg/h for air mass or just the actual volts output of the sensor. You must have been looking at it when you saw this: "air flow is out, max required is 1200, actual max is 800."
 

·
Premium Member
Joined
·
1,624 Posts
Discussion Starter #19
No, was reading 'target air flow' and 'measured air flow'. Will see what ADC air mass throws up.
 

·
Vendor
Joined
·
45,299 Posts
There should be target air flow and measured air flow for when you're idling too, its a good test as it can be compared against readings from other 2.4s, for example some working normally, some working with EGR blanked etc. Mine reads higher than desired due to my EGR being blanked.
 
1 - 20 of 100 Posts
Top