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Mems3 diagnostic socket http://www.gtmdrivers.com/forum/mems3-diagnostic-socket-t4101.html |
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Author: | Jaykart1227 [ Wed Oct 10, 2018 9:36 pm ] |
Post subject: | Mems3 diagnostic socket |
Hi all, Does anyone know how the diagnostic socket for the mems3 / 5AS equipped engine is wired? Mine has a red power wire, pink wire to the ecu and that’s it. It did have purple, orange and red/green wires that went to the 5AS unit but I ditched these when I found the 5AS unit was faulty so I did away with it and fitted a different immobiliser. Does this socket need an earth? I’m hoping to plug in an OSB2 code reader to see if it will tell me why my engine is in safe mode and limited to 5500rpm? it’s idling at 1200rpm also so it’s something to do with the VVC mechanism. At present the code reader won’t fire up? |
Author: | Jaykart1227 [ Thu Oct 11, 2018 7:24 am ] |
Post subject: | Re: Mems3 diagnostic socket |
That’s brilliant, thank you. I obviously need to earth the socket. Hopefully it will work fine with just the power, earth and ECU feed. |
Author: | Matty H [ Thu Oct 11, 2018 12:32 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
I wired one in just the three wires live, earth and communication. |
Author: | sanzomat [ Thu Oct 11, 2018 7:17 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
I'll be having a diagnostic socket soon when I finally get around to installing the TF160 engine. I've kept the loom intact so hopefully all the right wires are there. If anyone has watched the latest episode of Project Binky they used a MG ZR loom for their mini conversion so it was interesting to see how they stripped back the loom - not looking forward to that job! Re the limp mode - have you had the VVC mechs off? if not its hard to see how the timing of them could have gone out. I'd have thought that if you'd changed the cambelt and got the timing out you'd know about that from things other than the limp mode! Have you checked the camshaft position sensor or its associated wiring? I believe it is that sensor that reports to the ECU if the VVC's are miss-timed and that is what sets it into limp mode. I guess there may be other parameters that could do it too though. |
Author: | catsam [ Thu Oct 11, 2018 8:14 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
I did see the project binky i did that when i changed my engine and I spent days looking at car plugs and socks and pages of wireing diagrams have you seen this https://youtu.be/UM_w9VWZxwM |
Author: | Jaykart1227 [ Thu Oct 11, 2018 9:30 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
sanzomat wrote: I'll be having a diagnostic socket soon when I finally get around to installing the TF160 engine. I've kept the loom intact so hopefully all the right wires are there. If anyone has watched the latest episode of Project Binky they used a MG ZR loom for their mini conversion so it was interesting to see how they stripped back the loom - not looking forward to that job! Re the limp mode - have you had the VVC mechs off? if not its hard to see how the timing of them could have gone out. I'd have thought that if you'd changed the cambelt and got the timing out you'd know about that from things other than the limp mode! Have you checked the camshaft position sensor or its associated wiring? I believe it is that sensor that reports to the ECU if the VVC's are miss-timed and that is what sets it into limp mode. I guess there may be other parameters that could do it too though. Hi Dave, I used an MGZR engine loom for mine and it wasn’t too bad at all, it was quite therapeutic stripping out all the unwanted wiring! I have a spreadsheet that will save you a load of time and anguish with it, let me know if you want a copy. Regarding the safe mode, there are a few possible causes: Electrical connections ( I’ve checked and it’s all wired correctly, have to check the voltage etc) Sticky VVC mechanism - it’s a brand new HDU so I hope it’s ok though it could be sticky. Problems with the VVC solonoids - I have to check the resistance on these Dodgy cam position sensor - possible, it makes no difference to the 5500rpm limited if I disconnect? Mid-timed VVC units - unlikely as the head was built by expert Roger Fabry (sabre) Fried ECU circuits - hope not as it’s a new remapped Z & F jobbie Possible ECU issue - I have deleted the 5AS and fitted a different immobiliser as it was faulty, could the ecu be looking for an 5AS to ‘learn’ and this is having an effect? I need to ask mark at Z & F I’m hoping to see if I have any fault codes before pulling the cam cover off and checking the HDU is working with some compressed air. |
Author: | sanzomat [ Fri Oct 12, 2018 2:02 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
Its a while since I stripped a head but if I recall correctly the VVC timing can be confirmed by looking down the holes in the casting (with only the cam cover off, ladder still on) - if the holes line up then your static timing is good. I found I could operate a good HCU with a foot pump. My HCU was failing to turn the VVC link shaft and I found the fault was some bent teeth on the shaft gear where it interacts with the rack on the HCU. Pretty sure I left a picture on here somewhere back in late 2015/early 2016. I bought a replacement HCU thinking that was the problem but eventually traced it to the link shaft. I did all this before putting the engine in the car so never experienced the limp mode. It went straight to 7200 when it went in the car! I think I've got a good cam position sensor in the shed if you want to try that to exclude it from the diagnosis. Yes to the spreadsheet please (although I've a vague recollection you may have already sent me it - I'll check!) What I'm not sure about is the difference between mems 2 and mems 3 where it joins the body loom. Also, the TF set up has two lambda but my current set up only has one. There is nowhere on my exhaust for the second one so hoping it won't get confused with the second connector open circuit (I guess worst case I could but a suitable resistor across the terminals that replicates a good setting) |
Author: | sidewinder [ Fri Oct 12, 2018 2:05 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
Have you got the VVC control plugs in the right sockets? Black plug sideways into the alloy Control Unit and brown plug down 'under' the cam cover vent hose. I doubt it's the 5AS (or lack thereof) is it just stops the engine altogether by killing the fuel pump. |
Author: | sidewinder [ Fri Oct 12, 2018 2:08 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
Sanz - MEMS3, a missing post cat lambda will bring up a dual fault of missing sensor and failed heater circuit & have the MIL come on. I don't have a cat so had a boss welded to the left side U bend to fit the 2nd Lambda and used a bypass module to give the ECU a signal that keeps it happy. |
Author: | Jaykart1227 [ Fri Oct 12, 2018 2:25 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
Hmm, I only have the one oxygen sensor in the manifold and just deleted the other.....I wonder if that would make a difference? The car was like that originally but the engine loom was an MGF item with the second sensor left unplugged? |
Author: | sidewinder [ Fri Oct 12, 2018 2:33 pm ] |
Post subject: | Re: Mems3 diagnostic socket |
The post cat sensor is only for the ECU to check the cat is working and maybe (I read somewhere I think) does very fine trim to the fuelling. I ran my car with only primary one for years (with MIL LED disconnected) and never noticed it being 'limited'. I only fitted 2nd sensor recently cos I wanted the MIL to function properly and be able to warn of problem rather than just being on all the time due to missing sensor. If you have a none standard ECU it prob has a function to not use the 2nd sensor anyway - ask the maker? |
Author: | Jaykart1227 [ Sun Oct 14, 2018 7:48 am ] |
Post subject: | Re: Mems3 diagnostic socket |
Thanks for the advice chaps. My ECU was mapped by Z & F and I told him that I only run one sensor so I'm presuming all is ok there. Looks like I need to wire an earth to pin 4 on the diagnostic plug so I'm going to do that first and see what it throws up. After that a treble check of the wiring (the plugs are definitely in the correct sequence), followed by checking the solenoid resistances and trying a second cam position sensor I have. If its still doing it I'll take the cam cover off and check if the HCU unit is working correctly and look at the timing - I'd be surprised if timing is the issue though as Roger Fabry built the head and timed it up. Its an brand new HCU but I suppose it could be sticking?? Failing that it must be ECU related?? |
Author: | sanzomat [ Sun Oct 14, 2018 10:12 am ] |
Post subject: | Re: Mems3 diagnostic socket |
Attachment: bent tooth on VVC shaft.jpg [ 184.96 KiB | Viewed 11400 times ] This is what was stopping my VVC's operating correctly - slightly mashed tooth on the gear that is operated by the HCU rack. No idea how it could have happened but I guess one of those things you find on a second hand engine. Even with it like this I could get the HCU to turn the shaft with lots of pressure on the piston applied physically, but compressed air (and therefore probably oil pressure) wouldn't overcome the resistance the misaligned teeth were putting up. I probably could have filed the teeth back to straight but I found a perfect replacement shaft on ebay for £10. With the replacement shaft in the HCU would turn the shaft (and in turn the VVC's) with a puff of air from a tyre pump. Another thing I read somewhere was that a bit too much sealant when re-assembling the cam ladder can ooze into the VVC shaft journals and make it bind. Not saying that is what you have but if you run out of ideas might be worth checking. |
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