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Hello Murran, how are you today  Look, I knew it was missing, that's why I was having a look. I've been doing this 20 years now, and I'm telling you that the scope makes it quicker to track down the fault. Although I can tell it's lost a pot while cranking (who d'ya think said "oi, autofive, this has lost a pot!") I can't synchronise my ears and eyes to the point where I can know for certain that no3 is the problem, and thereby only remove one plug. You don't get diagnostics help on a mk3 granada. And yea, the scope would tell me if an inlet valve was burnt out, by EXACTLY the method demonstrated above. I accept that it wouldn't differentiate between that and any other form of mechanical failure leading to compression loss but there isn't a diagnostic tool on the planet that could *except maybe you. |
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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
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I'm fine thanks. ready for bed tho at this time of night. got a 1900 transporter td to build up tomorrow. crank pulleys fallen off, center bolt had snapped. stripped it all down monday morning. new head coming from tps in the morning. as its snapped the cam and mullered everything. front pulley sat on the undertray was the giveaway in dianosing the fault. didnt need one of these...... en.wikipedia.org/wiki/Tricorderyour favorite tool by the sounds of it?? :lol: |
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I'd go to bed then. I'd say even an AA roadside patrol could have sussed that the transporter you mention had lunched itself, so it's hardly a fair example but let's just agree to differ, eh? I like my scope, you seem to like volkswagens. Live long and prosper!
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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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apparently recovery turned it over on the starter and said the cambelt had snapped, don't think they even opened the bonnet.
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Dec 22, 2011 14:55:09 GMT
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I've noticed something else about this.. hindsight is a wonderful thing   The peak for no2 cylinder is higher than the rest - this should have told me something about what was happening inside. You see, because of the displaced pushrod (which could equally have been a snapped rocker, or a collapsed tappet) the inlet valve on no3 was not opening. This means that on the inlet stroke the starter had to work harder as it was creating a vacuum in the cylinder, and the compression stroke was "helped" by the same thing. Had it been a burnt or damaged valve, the peaks would all have been equal except the missing one. I drew a quick diagram to make it clearer..  You can see from this that no3 induction stroke corresponds directly with no2 compression. I rest my case m'lud ;D |
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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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Dec 23, 2011 20:50:46 GMT
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just to answer a question; i pulled the plugs and no3 and no.6 were both wet, but as this engine had not been run for 11 years it made sense to change a few leads, fresh plugs and dizzy cap.
THEN it was noticed that it still ran on five, and as scary was virtually walking past the car with the laptop in his hand, why not hook it up rather than walk 20 feet to get the compression tester?
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Someone just shot the elephant in the room. |
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Hey murran, I've decided i want you to come and work for me. I'll give you a large bag of nuts a day and all the bananas you can eat. What do you say?
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R.S. Autotech. Servicing/Repairs/Diagnostics.
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froggy
Posted a lot
Posts: 1,099
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Dec 24, 2011 17:41:46 GMT
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being of a certain vintage i had several years of pre efi experience so still have the routine of mechanical checks before looking at the electronic side ,all the younger lads that have worked for me tend to jump towards the electronic side too quickly the most common one is condemning a maf with low voltage/input before exploring the reasons that cause it .
it is nice when you spend ages tracking something down then another car comes in with the same issue .
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bortaf
Posted a lot
Posts: 4,549
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Dec 24, 2011 17:44:25 GMT
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I had a sun diagnostic machine with a scope and many, many leads but never used it, if i had seen this thread i may have kept it and used it but at the time it was way too complicated for me, Mr Scarey makes the translation nice and simple even for twerps like me  Get into the details and it's a great tool, shame it was a generation too early for me to grasp fully till it was too late, mind you i sold it for good money so i hope the new owner gets to use it to it's full potential |
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R.I.P photobucket
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Dec 24, 2011 18:29:53 GMT
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Froggy - I know what you mean! I looked at an astra recently that was running badly/using lots of fuel - it had already had a MAF and a temp sensor, and plugs/leads and they wanted me to scope it to rule out the catylist (!?!). It was a blocked air filter Bortaf - I'm glad you are enjoying it. My dad always said I should go into teaching. For a scope to mess on with, I recommend searcing ebay/freecycle for stuff like this because they go for pennies.  |
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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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bortaf
Posted a lot
Posts: 4,549
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Dec 24, 2011 20:29:21 GMT
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Froggy - I know what you mean! I looked at an astra recently that was running badly/using lots of fuel - it had already had a MAF and a temp sensor, and plugs/leads and they wanted me to scope it to rule out the catylist (!?!). It was a blocked air filter Bortaf - I'm glad you are enjoying it. My dad always said I should go into teaching. For a scope to mess on with, I recommend searcing ebay/freecycle for stuff like this because they go for pennies. He was right mate you have an easy manner and a real good way of putting stuff accross All those knobs, must... twiddle.... them...................... lots ;D useually followed by a loud bang and smoke  |
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R.I.P photobucket
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murran
Part of things
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Hey murran, I've decided I want you to come and work for me. I'll give you a large bag of nuts a day and all the bananas you can eat. What do you say? don't think that beats 22k my current wage....... I'm pretty old school for my age. rarely does it let me down tho. I reached for a scope on a 2006 audi a3 3.2 last thursday. esp/abs and strangly the hdrc light (when the lights are on) after 10/15 mins of driving. fault codes said the n/s/r abs sensor was faulty, despite gilders already fitted a new one about a week before. scoped both rear sensors with the car ticking over in first. showed up fook all. no decernable difference between the two signals. as these newer type sensors just don't go wrong ever..... vag seem to think its a good idea to have the magnetic ring sat in the wheel bearing which goes wrong even more than the old style sensors did/do. knew it was the bearing but I did continuity checks on the wiring which were fine. I replaced the wheel bearing as it was what I thought. we got a phone call from the guy saying thankyou for fixing what he had been to gilders 3 times to be sorted out. he has booked in for a full service and his rear flange oil seal leak in the new year. got a £400 cash christmas bonus coming on wednesday. despite my lack of use of a scope, I do ok. |
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Last Edit: Dec 26, 2011 12:55:13 GMT by murran
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Here we go again.... I fitted an engine to a Punto last week, owner purchaced it on ebay, it was delivered and I fitted it. Started quickly and easily, but only on two pots - 3 and 4 were both obviously not firing just from checking exhaust manifold temperature. So where to start looking? Obviously not going to be a coil pack (3 and 4 don't share a coil) but they do share an injector driver. I don't know how many cylinders the original engine ran on either, because half of it was in the boot when the car arrived on a recovery. Seeing as there could be an eBay dispute about this engine I haven't dismantled or changed anything (I haven't even removed the sparkplugs yet), other than a fresh oil filter it is completely as delivered, right down to the yellow paint and luggage tag applied by the scrapyard. I was expecting to have to run traces on injectors and plugs, but did a relative compression reading first (pulled the fuel pump relay)  Oh, no need to go any further with this one then! No compression on 3 and 4. I'm waiting for the ebay seller to reply before going any further with this (I did check that all the plugs are firing and the injectors do pulse) Interesting thing is that you can't really hear that it is down while cranking, it doesn't sound lopsided like a 4 cyl motor with one pot off - it does buzz over rather fast, but with nothing to compare to I would have been hard pressed to say what was up just by listening to it. This makes it 100% obvious straight away. Oh yeah, and I ran the codes on it too - MIL off, one stored code P0300 - random misfire detected. No use at all, and probably wasn't even stored by this engine.... |
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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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stealthstylz
Club Retro Rides Member
Posts: 14,840
Club RR Member Number: 174
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Diagnostics - a real examplestealthstylz
@stealthstylz
Club Retro Rides Member 174
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Would the management still store fault codes even if the MIL isn't lit? Our lasses Kia Rio has suddenly started using a curse word load of fuel and intermittently hesitates at low throttle/low gear acceleration. No MIL light, was just gonna give it a service and hope for the best.
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^ yes, you can get stored codes without the MIL being on all the time - sometimes you get the light flashing but going back out. In your case though, I would start with a service too.
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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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yer kia rio will have simple engine management, it might not even have logged any problems and that after you've paid kia 80 odd quid for the privilage of putting it on their machine! I myself use a divding rod put it over the engine and it tells me whats wrong, only thing is it doesn't give me a print out  |
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Feb 19, 2012 10:47:08 GMT
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The only problem with faults that don't put the light up is they are not EOBD faults. Therefore they cant always be read with a basic EOBD reader. You'll need something model specific or manufactures diagnostics to read it.
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R.S. Autotech. Servicing/Repairs/Diagnostics.
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Feb 20, 2012 19:13:34 GMT
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Coo, that's complicated, them newer cars' management systems. I'll stick with cable-op emergency brakes thanks! Before I got the GTA I knew very little about the operation of fuel injection and engine management. I'm still learning, it's been a steep curve. I have however learned something today reading this (Thanks SOC!) that puts my oscilloscope to new use. I didn't realise the oxygen sensor wafted about like that between exhaust pulses. I thought its reaction was much slower than that. My ECU gives a much slower picture of what's going on mostly due to the nature of the serial connection but I'm going to have to have a poke about with the scope and see what I can liberate from this new oxygen sensor. The old one was shot- the heater had burned. That much I could determine without resorting to a computer Still working on the hard to start (Fuel delivery methinks) and strange idle issue (EGR methinks) but I've another avenue to explore now! --Phil |
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Feb 20, 2012 19:30:32 GMT
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Serial data will refresh once every second if your lucky, and even then your probably seeing events that happened a second ago. To actually see whats happening inside your engine down to a microseconds accuracy the only way is with a good quality scope. Ever wanted to know the exact point that a spark traveled from a rotor arm to a dizzy cap? Nor have i really, but I could show you if you wanted |
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R.S. Autotech. Servicing/Repairs/Diagnostics.
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