Nick E Posted September 9, 2022 Share Posted September 9, 2022 (edited) Three weeks ago, cylinder 6 blew a gasket and got oil in the spark plug well. Loss of power and misfire ensued. I had the rocker cover and spark plug gaskets all replaced. I'm still having misfiring problems on cylinder 3 and 6. I've always had issues with cylinder 3 since I bought it 2 years ago. compression is fine. My garage reckons worn piston rings as everything else is ok Today, I changed the plugs, and replaced the coilpack on cylinder 6. still misfiring on that cylinder though. I'm going to put a new coilpack on cylinder 3 tomorrow. I'll be cleaning the MAF tomorrow. what other things should oh look at? All other cylinders are fine, but I'm getting misfire on 3 and 6, crap power output and poor petrol consumption. I've been advised to pressure test the cylinders again. Anything else I should look out for? oh.. and what is the recommended plug gap size for NGK Platinum? I know they're pre gapped, but i want to rule that out too. Edited September 10, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
E39M5 Posted September 10, 2022 Share Posted September 10, 2022 I’d get it on a laptop (inpa and cables from Jimmy at cable shack) and check the specs of the o2 sensors that there pulsing correctly, it’s something that’s going to effect both banks of 3 as you have issues on both banks, cam sensors and crank sensors can go bad and not give a code all the time, again a bad maf can cause similar issues, it’s worth looking at the live data and working from there what’s going on. also Ccv and air leaks can cause many issues, without really seeing what the engine is doing on a screen the only other option is to keep throwing parts at it and hope for the best but that be quickly expensive! Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 10, 2022 Author Share Posted September 10, 2022 I've got an OBD Creator. I'll do a full live stream to see what's going on. If I post up here, would you be able to help me decipher the results? Cheers, Nick Quote Link to comment Share on other sites More sharing options...
Bigpow Posted September 10, 2022 Share Posted September 10, 2022 8 hours ago, Nick E said: Three weeks ago, cylinder 6 blew a gasket and got oil in the spark plug well. Loss of power and misfire ensued. I had the rocker cover and spark plug gaskets all replaced. I'm still having misfiring problems on cylinder 3 and 6. I've always had issues with cylinder 3 since I bought it 2 years ago. compression is fine. My garage reckons worn piston rings as everything else is ok Today, I changed the plugs, and replaced the coilpack on cylinder 6. still misfiring on that cylinder though. I'm going to put a new coilpack on cylinder 3 tomorrow. I'll be cleaning the MAF tomorrow. what other things should oh look at? All other cylinders are fine, but I'm getting misfire on 3 and 6, crap power output and poor petrol consumption. I've been advised to pressure test the cylinders again. Anything else I should look out for? oh.. and what is the recommended plug gap size for NGK Platinum? I know they're pre gapped, but i want to rule that out too. Get the codes read once you’ve done the obvious, are the leads to the coil pack in good condition ?. they are a good old engine so I’d be looking at electrics first Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 10, 2022 Author Share Posted September 10, 2022 I'll look at getting a compression test done. I'll check the leads too. It's come at a crap time. I really don't have the time to be arsing around with this at the moment but it needs doing. What's an average, healthy compression figure per cylinder I should be looking at on a 20 year old 525? 180 psi? And again, what's the best gap size for the NGK plugs? They went in out of the box. Quote Link to comment Share on other sites More sharing options...
Guest Posted September 10, 2022 Share Posted September 10, 2022 1 hour ago, Nick E said: I'll look at getting a compression test done. I'll check the leads too. It's come at a crap time. I really don't have the time to be arsing around with this at the moment but it needs doing. What's an average, healthy compression figure per cylinder I should be looking at on a 20 year old 525? 180 psi? And again, what's the best gap size for the NGK plugs? They went in out of the box. Plugs shouldn't need changing really; they're sized from factory All the data you need is here Nick: https://www.engine-specs.net/bmw/m54b25.html Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 10, 2022 Author Share Posted September 10, 2022 4 minutes ago, danb1979 said: Plugs shouldn't need changing really; they're sized from factory All the data you need is here Nick: https://www.engine-specs.net/bmw/m54b25.html cool one.. thanks Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 11, 2022 Author Share Posted September 11, 2022 (edited) Ok, here's some results to think about. Compression test Cylinder 3 is dead. Won't crank. Can't get any compression readings at all. The rest are alright. Some live data streams.. and after the test was completed.. So. One buggered cylinder, and a few other bits to sort out. Leakdown test next to find out what's happening with the cylinder and where it's leaking. Edited September 11, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
E39M5 Posted September 11, 2022 Share Posted September 11, 2022 Have you tried a squirt of oil in cyl 3 to see if the compression comes up? Not sure what would cause the lack of compression I’ve read some can be bore washed when started and turned off pretty much straight away something I experienced myself with an m62 a few years back Quote Link to comment Share on other sites More sharing options...
E39M5 Posted September 11, 2022 Share Posted September 11, 2022 Maybe The 3rd injector is leaky and causing bore wash in cylinder 3? It would be great if it’s not something deep in the engine that requires more work and could be resolved without taking the head off etc Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 11, 2022 Author Share Posted September 11, 2022 4 minutes ago, E39M5 said: Have you tried a squirt of oil in cyl 3 to see if the compression comes up? Not sure what would cause the lack of compression I’ve read some can be bore washed when started and turned off pretty much straight away something I experienced myself with an m62 a few years back Yeah. I put a little oil into each of the cylinders to do the wet test. No difference at all. Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 11, 2022 Author Share Posted September 11, 2022 (edited) 9 minutes ago, E39M5 said: Maybe The 3rd injector is leaky and causing bore wash in cylinder 3? It would be great if it’s not something deep in the engine that requires more work and could be resolved without taking the head off etc I'll take a look at it. I just changed the plugs. I don't seem to remember cylinder 3 spark smelling badly of fuel, and it definitely wasn't sooty I'm definitely going to get a leak down test done. That will be the only way to rule out head gasket, piston or valve. I'm hoping it's neither Does the E39 fuel injection system automatically shut down an injector to a misfiring cylinder, or am I going to be running rich here? I think that's the case. My fuel consumption has been shocking recently Edited September 11, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 11, 2022 Author Share Posted September 11, 2022 (edited) I've been busy on other things today, so am now trying to evaluate these figures.. Dry on all cylinders was around 120psi. Wet was 150 to 170 psi. Plus 30psi with the introduction of oil on each cylinder. That leads me to assume that all my piston rings are worn. True? Manufacturers PSI for the 525 should be 145psi per cylinder. The car is 20 years old, so that's a given they'd be a little worn out. However, we then have cylinder 3 not cranking at all. If I follow the assumption that all piston rings are worn, would this be much worse than others, or am I overthinking this? I may repeat the compression test on cylinder 3 tomorrow to see if I get anything out of it. As far as a leak down kit is concerned, has anyone done one before? I'm not taking it to a garage and will do it myself. What type of canister of compressed air would fit on one of those leak down kits you get off Amazon? Edited September 11, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
duncan-uk Posted September 12, 2022 Share Posted September 12, 2022 What do you mean by "not cranking"? The piston has to be going up and down but if no compression wet or dry i think i would be looking at a stuck valve or something - i don't believe HG failure would give 0 psi as youd have other issues. Can you get hold of a inspection scope and have a look in plug hole? Wickes sell a bosch one: https://www.wickes.co.uk/Bosch-Universal-Inspect-Colour-LCD-Screen-Inspection-Camera---2-3in/p/178293 cheaper on amazon Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 12, 2022 Author Share Posted September 12, 2022 (edited) 22 minutes ago, duncan-uk said: What do you mean by "not cranking"? The piston has to be going up and down but if no compression wet or dry i think i would be looking at a stuck valve or something - i don't believe HG failure would give 0 psi as youd have other issues. Can you get hold of a inspection scope and have a look in plug hole? Wickes sell a bosch one: https://www.wickes.co.uk/Bosch-Universal-Inspect-Colour-LCD-Screen-Inspection-Camera---2-3in/p/178293 cheaper on amazon When you do the compression test, normally the cylinder will make a noise like it's engaging/cranking.. an audible individual "movement" if you like. I did ten of these for each other cylinder. As far as cylinder 3 is concerned, floor the accelerator, as per the other cylinders, and turn the ignition, and it would not make the same noise. It wouldn't register any compression at all on the gauge. My layman's head is ruling out HG. The piston rings on all cylinders are shagged anyway. It's a 20 year old motor, so although they're ok, they're not minty fresh. Cylinder 3 valves maybe? That's still a cylinder head off job to fix it isn't it? What would I be looking for on an inspection of the cylinder? I'm going to do another test on that cylinder today to see if I get any different result. Edited September 12, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
duncan-uk Posted September 12, 2022 Share Posted September 12, 2022 Just to see if you can see anything. Whilst noise is different piston must still be pumping as they are all on the same crank. If that had broken somehow I suspect you’d have a hell of a racket! stuck valve maybe? Which is what you might see? yes rings won’t be fresh but 10% down is not a huge concern Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 12, 2022 Author Share Posted September 12, 2022 (edited) 2 hours ago, duncan-uk said: Just to see if you can see anything. Whilst noise is different piston must still be pumping as they are all on the same crank. If that had broken somehow I suspect you’d have a hell of a racket! stuck valve maybe? Which is what you might see? yes rings won’t be fresh but 10% down is not a huge concern Yeah. I'm not concerned with that level of wear. Normal for a car that age. As far as the other error codes that just threw up since the compression test, what do you think? 82 Signal, CAN ASC/DSC - that's ABS right? I've not got that signal on the dash 45 Activation, fuel pump relay - If the relay wasn't working, surely the car wouldn't start? I pulled both fuses for the fuel pump when I did the test. I'll clear both codes and see if they come back Edited September 12, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 13, 2022 Author Share Posted September 13, 2022 The saga continues.. Cleaned the MAF yesterday, cleared those codes and went for a drive. Misfire on 3 and 6 comes back up again. F**cking car. Unplugged the MAF and cleared the codes. Have taken it to another mechanic to get him to have a nose around with it. Don't have the time to be dicking around like this. Makes me wonder though. What is the actual compression on cylinder 3. Can't be completely dead can it? He'll do a test on it to see if he can get anything out. Quote Link to comment Share on other sites More sharing options...
norseman Posted September 13, 2022 Share Posted September 13, 2022 Never known a zero compression, unless it's so low as to be outside the range of your gauge. Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 13, 2022 Author Share Posted September 13, 2022 (edited) Re-tested the compression on 3, and it's 50psi. It was low last year when my regular garage tested it, but it wasn't that bad. I now have two choices. Scrap the car for very little money, or bite the bullet and get the head off it and get whatever the problem is fixed. I'm looking around 1, 500 minimum to get that done, provided nothing is wrong with the head. Compression on 2 and 4 are ok, so we're assuming HG is ok. No blue or white smoke from the tailpipe BUT oil consumption has always been fairly high, so I'm hoping it's not piston rings. Valves or valve seats? Maybe. So. Scrap for bugger all and buy a 2 grand car with who knows what faults, or spend 1, 500 and better the devil you know. I'm inclined to look at the latter, but with no money to spunk on it at the moment, I'm going to have to drive as is and cane through the fuel whilst I make my mind up. Edited September 13, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
Guest Posted September 13, 2022 Share Posted September 13, 2022 For me, chucking that kind of money into it would be hard to do; the 525i has never been that sought after and it may be worth selling it as is and putting that money towards another E39, 530i ideally... There's a 530i touring on eBay currently for late £3k's, could be worth looking into But could also be worth looking at a used but looked after replacement engine The M54s rarely have HGF; but I know they don't like to have the heads removed and issues can arise after stuff like that is done Worth considering Quote Link to comment Share on other sites More sharing options...
E39M5 Posted September 13, 2022 Share Posted September 13, 2022 I’d consider replacing the engine, m54b25 can be picked up fairly cheap Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 13, 2022 Author Share Posted September 13, 2022 (edited) Contemplating both. Difficult to know if you're getting a good engine at face value though, despite what a seller may say. I'd probably be looking at at least a grand for the engine, removal of the current and refitting a new one yes? I'm getting quotes for reconditioned engines at around £2k, but I think that's a little too much. What's a good guide range for a spares or repair 525i Touring? Still runs alright. Just that cylinder needs sorting. Aside from that, and the usual cosmetic surface rust on the rear arches and tailgate, and at 160k, it's not in bad nick Edited September 13, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
Guest Posted September 13, 2022 Share Posted September 13, 2022 7 minutes ago, Nick E said: Contemplating both. Difficult to know if you're getting a good engine at face value though, despite what a seller may say. I'd probably be looking at at least a grand for the engine, removal of the current and refitting a new one yes? I'm getting quotes for reconditioned engines at around £2k, but I think that's a little too much. What's a good guide range for a spares or repair 525i Touring? Still runs alright. Just that cylinder needs sorting. Aside from that, and the usual cosmetic surface rust on the rear arches and tailgate, and at 160k, it's not in bad nick Contact Nick or Simon Garland of Roptrip on Facebook Nick They're well known buyers/breakers of E39s; so they'll give you a genuine price figure etc Quote Link to comment Share on other sites More sharing options...
Nick E Posted September 13, 2022 Author Share Posted September 13, 2022 (edited) 13 minutes ago, danb1979 said: Contact Nick or Simon Garland of Roptrip on Facebook Nick They're well known buyers/breakers of E39s; so they'll give you a genuine price figure etc cheers mate. Rotrip! Edited September 13, 2022 by Nick E Quote Link to comment Share on other sites More sharing options...
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