Went round to the supermarket yesterday afternoon to pick up my wife in our 1990 214. Although the engine wasn’t cold, it seemed to behave a bit strange, with the idle revs a good bit higher than usual. I turned a corner to go up a slight hill, and there was no power. I put it into first and it really struggled to get up even with the accelerator well down. Thought it was going to stall. If it was a carburettor car, my first though would be blocked jets. It felt like fuel starvation. Then suddenly as I got to the top of the gradient it burst into life, as if somebody had flicked a switch, and behaved normally after that. It was fine going home.

The day before I’d been on a 50 mile round trip on motorways and was thinking how well it was going, plenty of power and speed. I took it out for some runs round local streets this morning including hills. It started and ran completely normally. It’s all a bit disconcerting, as I worry it might do that again far from home. What’s going on?

I wonder if anyone else has experienced this.

Our car is a very early SPi model and has a few unusual features including a potentiometer for the throttle position sensor (later cars used a Hall-effect device, I think).

My first thought was that the potentiometer was a bit intermittent and didn’t send the right throttle reading to the ECU so it didn’t inject sufficient petrol, but then suddenly reconnected and it burst into life. I believe these early sensors can be a bit unreliable, and the one on our car is nearly 35 years old. The part is MMJ10003, but it’s no longer available, as are all the other main parts on this early SPi system. Problem.

It could be that fuel pressure wasn’t correct but the symptoms seemed to change too quickly for that. It could be that the injector wasn’t working properly but seems unlikely.

The ignition is mostly less than two years old apart from the coil which is original.

I don’t think a fault in the MAP sensor would cause such an extreme problem.

I would be very grateful for any opinions about this and what tests you would recommend. Intermittent faults are a pain as there’s not much to go on.

Does anyone have any salvaged parts from these early SPi systems? I do have a spare ECU, but haven’t tested it.

Thanks for any help,

Hugh

Bad fuel?

I mainly run my Ronda on Esso E5 I know that my 89 216GSi started running poorly due to a combination of short journeys to work & supermarket fuel.


There was a early 214 GSi for sale down in Portsmouth back in the summer but they wanted big bucks for it.

It’s a lot of years since I had my SPi but I do remember having a similar problem with regards intermittent rough running. The car would run fine, then lose power, then pick up again. After a lot of head scratching and swapping out of parts I eventually solved it by replacing the rotor arm. Even if it’s only a couple of years old it might be worth swapping it, although this probably wouldn’t account for high idle revs on a warm engine. That might suggest a coolant sensor fault.

If you’ve got an Android phone it’s well worth downloading the Rovermems app. You’ll need a special cable (around £30) to connect to the diagnostic socket but it’ll let you read fault codes on the ecu and check various sensors. For example, as you open the throttle you should be able to check for a smooth output from the potentiometer.

Incidentally, I don’t know how many miles you’ve done but mine reached 209,000 on the original TPS (before the car was written off), so they seem to last pretty well.

And you’re right – intermittent faults are a real pain! I’ve also found that whenever the car feels like it’s running very nicely it’s usually a bad omen – something’s about to go wrong!!

Could you repeat the journey to see if the fault reoccurs, then it wouldn't be intermittent, you'd know more about the circumstances.

Could any foreign object have got into a fuel line, restricting flow?

Thanks for all the helpful suggestions. I run the car on E5 petrol, usually Tesco Momentum. The car's done about 113k miles. I hadn't thought about dirt in the fuel. The fuel pump has quite a large filter at the base in the fuel tank and there's the in-line fuel filter just before the injection head. I did replace the fuel filter about three months and 1000 miles ago. It's possible I disturbed some deposits in the fuel pipe. After 35 years there could easily be a build-up. John suggested repeating the route, presumably that if sediment is moving around it might cause the problem again. As part of my test run yesterday morning, I did the exact same route and without any problems.

Steve suggested I should look at the rotor arm. I've certainly had plenty of problems with those over the years on the Rover, and particularly the Rootes cars. A new rotor arm is no guarantee as modern replacements are sometimes poorly made. I've been on some wild goose chases with that one. I've usually found that if the rotor arm is breaking down it leads to poor performance, misfiring or difficult hot-starting. In this case it was virtually no performance and then back to normal operation.

I think the next move is to get the diagnostic tool Steve suggested, presumably this one https://rovermems.com/ and this cable https://shop.jmpe.co.uk/products/rover- ... -connector. I can see the test connector going to the MEMS. Does anyone know why it loops round and back to the MEMS? Maybe just to provide both sexes of connector for the diagnostics? This should give me quite a lot of information, and could be very helpful if the problem occurs again. Think the unit on my car is MEMS 1.2.

A final thought. I should check all the connectors and cables going to the injection head are good. Also the multi-way connector going to the MEMS. Everything is old, so there might be a potential bad connection somewhere. I did take off the injection head about three years ago to do the thermostat and since then the head gasket has been done which also disturbed the injector wiring. The fault did seem like an electrical one, as the performance switched from hardly working at all back to normal almost instantaneously.

Yes, that's the app I was referring to https://rovermems.com/. I notice on their front page they refer to MEMS 1.3,1.6 and 1.9, then mention 1.2 in the drop down list below.

Before you commit to anything it might be worth dropping James an email to check how much functionality it has with that earlier ecu. There's a contact link at the bottom of their home page. You'll probably also need the adaptor they mention to connect the USB to your phone.

The chap who recently acquired J990TMO, which has had a few mentions on here over the years,
has been having very similar frustrating problems. Unfortunately he's over on FB, so good luck
tracking down the posts, it's like a haystack over there.

I contacted James and Rovermems, and he confirmed the App should work fine with the MEMS 1.2. I also downloaded the App onto my Android phone and it looks like it works, though currently it shows disconnected. Need to wait for the cables to come. This is the diagnostic connector on my car. Looks like the three diagnostic wires loop round through a back-to-back connector so by unplugging it you can get either a male or female connector for the diagnostics. Is that what other R8 owners have? James said he hadn't seen it before, but he works on Minis.



Also found some useful information in the Electrical Circuits Manual AKM 7215 ENG Section 13, which shows the connections to the MEMS. It's available as a download on the Club website.



It was very cold this morning, well below zero. I tried starting the car and it started immediately and ran very smoothly up to temperature. I then took it for a run and everything was fine. The cold start does seem to indicate all the sensors are working, and also the stepper motor.

Will report back when I've done more tests.

Here’s an update. The 214 has been performing faultlessly since the strange event a couple of weeks ago, even with the low temperatures up here in Scotland. Maybe the suggestion that it was a bit of random debris blocking the fuel system is a possibility. My wife suggested that as I’m old I could have had my foot on the brake and the accelerator. I don’t really buy that, as I recall pressing the accelerator down without a great deal of resistance and nothing much happened until it suddenly burst into life.

I’ve now got the Rovermems App and the special connecting cables. Specifically this one for the early SPi MEMS https://shop.jmpe.co.uk/products/rover ... connector which James Portman sells through his on-line shop. I also needed an OTG cable to go from the Type-A USB to micro-USB on my Android phone.

I had a bit of difficulty pulling apart the diagnostic plug on the car – it probably hasn’t been used for 20+ years. There’s a rubber O-ring seal, so I put on a bit of silicone grease to make it easier to connect. The male diagnostic plug goes into the test cable.

The Rovermems App is pretty easy to use. Just select the type of MEMS, in my case the early SPi type 1.2. Connect it up to the diagnostic connector and turn on the ignition. The App will sense the ECU is live and start downloading data.

The App gives the option of graphical results.



This is the display as the engine warms up. The change in the MAP (Manifold Air pressure) sensor goes from about 100 kPa (atmospheric pressure) to around 35 kPa (partial vacuum) as the engine starts.

You can also view a much larger range of numerical data such as engine speed, throttle and stepping motor position, ignition advance, battery voltage etc. Some parameters aren’t operational on my car as it doesn’t have a catalyst.





At idle, I could switch on headlamps and see the idle control (stepping motor) increase to compensate. With the engine off and ignition on I could view the full range of the throttle potentiometer. The App polls the ECU every five seconds and reads the data, you can see the App going from connect to disconnect and then displaying the latest data. The App also allows you to export a .csv file of the accumulated data. I was able to email this to my computer and then open it in a spreadsheet, showing all the monitored parameters every 5 seconds.

James Portman has done a great job creating the App and making it freely available and also selling the special diagnostic cables. It gives a very useful window into what the engine is doing. If the car plays up again, I’ll have tools to do a more thorough analysis. I used the App to clear the fault history in the ECU, so I’ll be able to see anything new.

Nice work Hugh. I’m sorry you haven’t found the cause of the original problem but, as you say, at least you’ve now got a tool that could help diagnose any future electronic issues (and interesting that it shows a previous coolant sensor fault).

Incidentally, I can’t remember how the diagnostic plug was set up on the SPI but that does look a bit strange. For reference, this is how it looks on my ‘95 214 SEi – the cream coloured connector is for the engine management and the green one is for the 5AS alarm system (not covered by the Rovermems app).


I’ve found the app works just as you’ve described on my car, although I haven’t been able to download the CSV file – presumably because I haven’t been logged in to Google at the time.