Hi everyone,
I am new here as I recently bought a 2005 MX5 icon (1.8 VVT) which I have a problem with.
The car is modified with an Eaton M45 supercharger and is running a ME221 ECU (Gen 1) that was mapped by Skuzzle about 12 months ago (prior to my ownership).
The car had been running fine for the 2 or 3 months since I bought it (slight oil leak aside) but a couple of weeks ago after driving for about 100 miles (with a 45 minute stop in between) the engine lost all power and stopped running. The AA couldn’t diagnose the problem and recovered the car back to where I live. Now the car cranks but wont start. I have done the following to figure out what the problem is:
1) I can hear the fuel pump priming (the AA man also checked with stethoscope and said it was running).
2) I pulled one of the spark plugs and tried starting with it resting against the cam cover but got no spark.
3) I have replaced the Cam Angle Sensor at the top of the engine.
4) I have replaced the Crank Position Sensor, measuring the gap using a credit card based on what I read online. I did notice that even with the bolt tightened as hard as I could, given it is quite old and rounded, it was still possible for me to move the sensor by hand (not easily but with a bit of force). I am trying to source a new bolt just in case this is an issue so any help with where to get one would be much appreciated.
5) I unplugged the ME221 and reconnected the stock ECU. When I tried cranking again, the car sputtered once (rich burning smell from the exhaust) but didn’t start. After that it behaved the same as with the ME221 and just cranks but doesn’t start. The fact that it seemed to spark once when I changed ECUs makes me think it might be sensor issue rather than failed coil packs??
6) I have checked all the fuses, disconnected the battery and reconnected it after pressing the brake for 30 seconds (just trying everything I read on forums…).
7) I haven’t yet checked all the wiring using a multi meter as I am pretty new to all this and am not sure I would know what to look for.
8) I checked the passenger footwell and there was no moisture or dampness area at all.
9) I tried cranking with the oil filler cap removed and can see the cams turning, so have ruled out a snapped belt.
10) I haven’t plugged the ME221 into a laptop as I wouldn’t really know what I am looking for. I have bought the FTDI cable and am happy to have a go if someone can guide me…
A few other notes:
1) I ran over a small (3-4 ft) branch just before the problem started, is there anything under the car that could have come loose and caused the issue?? I haven’t been able to get underneath and check for anything out of place.
2) The fan to be on constantly once I put the key on the on switch with the ME221 plugged in (not with the stock ECU)
3) The check engine light comes on and stays on when I put the key in the on position (previously it would flash on then switch off almost instantly)
The next step is to call an auto electrician but I would like to check if there is anything else i should be doing before I do. I live in SE London (Canada Water area) if anyone wants to pop round and have a look (bit of a long shot I know!). Can offer tea/biscuits/pickled onion monster munch or a bit of money for your time.
Thanks for reading!
Imran
Given you have an engine check light the next step would be to connect an OBD reader to see if any error codes are stored which may point to where the fault lies. You may gave already done this but I can’t see any reference to it in your post.
Hi,
Thanks for getting back to me. Unfortunately the OBDII reader won’t detect anything (due to the aftermarket ME221 ECU). I will try and connect to the ME221 using a laptop (once I figure out how to do this!) and let you know what it shows.
I’m having a guess at crank sensor/toothed pickup plate or possibly MAF(possibly removed anyway - not sure how this would work with stock ecu) but tis a stab in the dark without an OBDII error code check.
Have you tried checking the diagnostic with the original stock ecu connected? If there is an EML on, there will be an associated error code, MAF error for a start I guess.
Kind of surprised that the reader does not work with the ME221 ecu but don’t know enough about the interface with the car to comment. Perhaps the ME221 has its own diagnostic error code system?
Thanks. I don’t think the ME221 has OBDII compatibility as it has its own interface. Unfortunately it requires pulling the ECU out of its case and plugging it into a laptop via a serial cable (so a bit of a PITA).
Having spoken to a couple of people, once it is set up with a laptop it is quite useful at diagnosis as it will show the response from the CAS and CPS and whether they are syncing up properly. Will have a go at this after work this evening or later in the week and will report back with what it says.
So quick update on this. I managed to run the ME221 diagnostic tool. The tool showed the Crank position sensor is syncing up (giving good readings) when Cranking but the Cam angle sensor is not giving any output. I have tried replacing the CAS with a new sensor but this doesn’t seem to have fixed the problem. Any other reasons why the CAS is not giving readings?
I assumed the next step is to check for voltage to the sensor but I am not too sure where to start?! Is this something I could figure out myself with a multimeter and some guidance or do I need to admit defeat and call an auto electrician (hopefully the former!)?
So another update on this. Having checked the grounds/supply it appears the fault is either ECU, faulty new cam angle sensor(unlikely) or issue with the CAS trigger on the cam itself. I spoke to Skuzzle, who mentioned that the CAS trigger on the back of the cam on VVT engines often fails when hot oil gets underneath the ring and causes it to slip off the cam (not a servicable part!). I haven’t seen this discussed much on forums but will check if this is the case after I have tried a different CAS.
Any tips on replacing a cam would be very much appreciated!
Hi everyone, just to update you on where I have got to.
So after looking at every possible problem online, changing the crank and cam position sensor checking the cam shaft and wiring from all sensors, I went back and re-tried the stock ECU. To my surprise, after slight hesitation, the car fired up!
Obviously it ran terribly (v rich) and filled my garage with smoke as it is not tuned to deal with a supercharger but this has at least helped me diagnose the fault as being the ECU. I called up Motorsport Electronics who seemed surprised that a fault with the ECU would only result in the CAS pulse not being detected (as the crank and cam sensor feed into the same board) but I can’t see any other problems. So the ECU will be off to Motorsport Electronics for inspection this week.
Will keep people updated on what happens (mainly as I hate looking through problem threads where the owner doesn’t give the solution once the car has been fixed!).
Yes thanks for updating us on the saga.
You reckoned that the cam angle sensor was not giving an output but you would need an output from the cam angle sensor as that is what tells the ecu to open and close the injectors on a Mk2 with the standard ecu.
Let’s hope you get it sorted soon.
If you have some time, I suggest that you check the valve timing!!!
Latest update on this. Received the following response from Motorsport Electronics
“It was circuit mount components that have been damaged, it’s hard to identify the exact fault and pinpoint it down however voltage spikes are always likely to cause some damage well worth having a look at what your alternator is reading and of course checking over your wiring if you’ve adjusted anything.”
Slightly surprising as the ECU was only 18 months old. Anyway, new one on its way. Any checks I should do before installing it to make sure it won’t suffer the same fate?
Honestly I would just do as they suggest, as you say these things don’t normally fail but voltage spikes will cause rapid wear.
Great thread, let us know how you get on!
Hi all, quick update on this now that I have my car back (decided to get some rust and other work done whilst it was in the garage). The fault was with the ECU (most likely caused by a voltage spike) and as it was out of warranty ME would not replace the unit but gave me a discount on a new unit. This has been installed and the map copied across. Unfortunately, as the ME221 has been upgraded the map isn’t quite perfect, particularly when idling or coming to a stop so will have this fine tuned by Skuzzle in March.
To try and prevent this happening again, I had the alternator replaced with a MK1 1.8 alternator as this regulates the voltage (the MK2.5 alternator needs the ECU to regulate the voltage) as suggested by the guys at the MX5restorer. The only issue I have now is that my multimeter gives a reading of over 15 volts when the engine is on which seems a bit high to me. The car was fitted with a Dynamic Diamond 063 battery (I had never heard of the brand) by the previous owner and had just been fully charged using an external charger before I did the test.
Has anyone else encountered anything similar when running a MK1 alternator on and MK2? The battery did die within a week of me bringing the car back from the garage but I assumed this was due to a lack of use, am starting to think it might be an alternator/battery issue though.