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Nov 15, 2011 12:36:39 GMT
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I'd tend to agree with you there. If you give it a vacuum leak both sensors should swing to lean. If your post cat stays rich then its definatly shot. Tried that this morning - I pulled the vac pipe off the fuel pressure regulator and the pre cat lambda went lean, the post cat didn't change. Golf has now gone home with the customer, and I'm happy because I was able to say "this was wrong" rather than "I changed this bit, it might have worked". |
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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murran
Part of things
Posts: 610
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Nov 16, 2011 19:13:59 GMT
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had some time on the a8 today.
I'm lost with this bloody thing.
the switch ive got 10 wires to the switch. one is the live it should be, one is earth, one is the p sign immumination. the other 7 are between the switch and the pbc ecu. they all seem to do different things signals are different on each wire but not CAN. they all seem to make sence tho if you know what i mean. fitted a new switch but no different.
can lines have continuity to the can hub on the o/s of the dash.
every thing i check is ok!
its getting built up and sent to the dealer tomorrow. id love to know whats wrong with it!
i hate all these ecu can contolled modern wibblepoo cars. ecus littered all round the car just waiting to go wrong and cost you a fortune. hardly built to last electornically are they?
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Nov 16, 2011 19:38:18 GMT
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What are the fault codes?
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R.S. Autotech. Servicing/Repairs/Diagnostics.
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murran
Part of things
Posts: 610
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Nov 16, 2011 23:23:36 GMT
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i will write them down for you tomorrow.
ive had enough of it.
one from today.......
had an 07 audi a6 2.7 tdi in today. fault code in the engine ecu for the variable manifold on bank two (n/s bank) and the no.4 glow plug is open circuit....... the manifold flap motor isnt working as you can see it and the rod to the manifold flap you can move the rod with your finger with the engine running, whereas the o/s motor you cant, the motor resists you pushing the rod with your finger...... run thru the actuator test on the vas5052 with just the ignition on..... the ecu is telling the motor to move, and the motor moves between the range of movement, but the position sensor isnt mirroring the specified value.
i ran thru the basic setting and it started working. cleared the fault code. all good!
5 mins into a test drive engine man. light is back on. same fault code for manifold flap. got the wiring diagram up, pulled up the ecu, did continuity checks on the position sensor wires which seemed fine.
new manifold flap motor is coming tomorrow. hope it fixes it!
glow plug no.4 light hasnt come back, but ive told my boss it was there!
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Is no.4 glowplug on the nearside bank? Might be worth checking the loom and multiplugs cos sometimes random unrelated codes in the same physical area of the engine are down to a bad connection...
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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rtlkyuubi
Posted a lot
Low and Slow
Posts: 2,922
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Murran its a shame I didnt know you was looking for a better paid jobs. Just had 2 chimps set on at our place (fixing trucks  ) which are probably on about £10-£15 p.h easy work too lol. As for scope tools, will they tell you if an injector is faulty? Weve got a scope tool at work but never use it. To diagnose injectors, we have to perform a DLS test which ups the fuel rail pressure to about 1500bar-ish and it measures the resistance over the injector to see if any fuel is leaking back. 6 ohms or higher = broken injector. I hate all these ecu can contolled modern wibblepoo cars. ecus littered all round the car just waiting to go wrong and cost you a fortune. hardly built to last electornically are they? On MAN trucks, the drivers and passenger window switches are their own ecu's that control the windows and electric mirrors. If you change one, youve got to reprogram them LOL |
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Last Edit: Nov 17, 2011 0:35:00 GMT by rtlkyuubi
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you can find leaky/sticky injectors with a scope, yes. Or at least narrow the search down so you don't have to do specialized testing on all of them to find the dud....
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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Ok, here's another example of how a scope can save you time - 2.9v6 granada today, running rough. Owner has just fitted new plugs, leads etc but no different. I ran a quick scope of relative compression against no1 HT (for reference) and got this back  Seeing as the firing order is 1,4,2,5,3,6 it's pretty obvious that no3 is very low. One plug out and a compression test later proves that no3 is actually on zero, and the most likely cause is a burnt or sticking valve. |
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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yes, what jolly fun it was to find out the head has got to come off and i wont be MOTing it on saturday  |
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Someone just shot the elephant in the room. |
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Dec 21, 2011 23:57:40 GMT
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Fixed this today - Luckily it turned out to be a displaced pushrod on no3 inlet and not a damaged valve so it was running on six within half an hour rather than all day stripping and rebuilding the top end. MoT on the cards before christmas.
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Ok, here's another example of how a scope can save you time - 2.9v6 granada today, running rough. Owner has just fitted new plugs, leads etc but no different. I ran a quick scope of relative compression against no1 HT (for reference) and got this back..... Out of interest how did you get the reading of relative compression? |
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Out of interest how did you get the reading of relative compression? I think it's a case of measuring the starter's current draw while turning the engine over. Certainly the Y axis is in Amps, and has big numbers. |
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It is starter current, yes. There is a 600A current clamp around the starter main cable while cranking. It's a surprisingly simple, yet useful test.
You do need to prevent the engine from starting though - I couldn't disconnect the coil because I needed no1 HT for reference so I activated the inertia switch to cut the fuel pump instead.
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Ah cool, yeah, that makes a lot of sense, cheers. I did spot it was measured in amps, and in rather large numbers, but didn't even begin to think of that. Interesting stuff.
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murran
Part of things
Posts: 610
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hang on why the scope? once youve figured out the misfire isnt spark related..... the first thing you do is get the comp tester out!!
had a 2008 saab 93 estate 4x4 thing in about 3 weeks ago. woman has always come to us since the car was new. misfire very obvious!
diagnosis said no.2.
plug obviously different colour to the others. unplugging the coil to that cylinder made very little difference to idle. swapped coils round fault stayed with that cylinder.
next was a comp test...... said no.2 had 70 psi all the others 200psi or just over.
got the endoscope out for a look down the plug holes...... you could see the inlet valve on no.2 was a white powder colour to the other cylinders just being brown.
reason for the colour difference is the fact the "shut time" of the valves is the main way they get rid of their heat (conduct) to head, thru the valve seat. if the valve seat gets scruffy/carbonised the valve cant do this and so over heats and burns out..
at this point we rang gordon lambs to enquire about goodwill warrenty on the owners behalf...... to which they collected it and repaired it at a fraction of the cost at which we would have charged her.
diagnostics side of this took no more than 30 mins and at no point did i get the scope out!
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hang on why the scope? once youve figured out the misfire isnt spark related..... the first thing you do is get the comp tester out!! But if the 'scope is available, it's a 2-minute job to put the high current clamp on, connect the other channel to No.1 plug lead and spin the engine over. Saves a lot of mucking about taking plugs out. |
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murran
Part of things
Posts: 610
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but the scope meerly says "yeah, you have a misfire on the cylinder you already know you have a misfire on the minute you unpluged the coil or pulled the plug lead off".
totally pointless.
taking the plug out and looking at it tells you much more than a scope.
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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but the scope meerly says "yeah, you have a misfire on the cylinder you already know you have a misfire on the minute you unpluged the coil or pulled the plug lead off". totally pointless. taking the plug out and looking at it tells you much more than a scope. But it told him that the compression was low too, which narrowed things down quite a lot. |
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but the scope meerly says "yeah, you have a misfire on the cylinder you already know you have a misfire on the minute you unpluged the coil or pulled the plug lead off". totally pointless. taking the plug out and looking at it tells you much more than a scope. No, the scope didn't tell SOC anything about a misfire. It told him that cylinder 3 was down on compression, without so much as pulling each plug lead off in turn. |
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murran
Part of things
Posts: 610
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a clamp around the starter cable attached to the scope to measure the amps drawn from the starter as it cranks over the compressions??
use your ears, feel it cranking over, you can instantly tell if its down on comp as it turns over on the starter.
are you guys from mars?
that saab I knew it was down on one cylinder the minute I started it outside before I even drove it in the garage.
....... d, d ,d, bur, d,d,d bur fires up misfiring. its not rocket science.
dianosics said cyl 2.
does the scope tell you the inlet valves burnt out?
jrevillug if its down on compression it will be misfiring, thats the point. thats why you check compression first and formost before anything else pretty much.
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Last Edit: Dec 22, 2011 1:12:34 GMT by murran
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) which are probably on about £10-£15 p.h
