Possible ECU failure of 216 SOHC?

[coralpolyp]

Hello

I have just joined this site. I have a flame red 95 SOHC manual car, which I've owned about 6 years now. It's been very reliable until recently.It now has 137k.

The engine check light has been coming on after about 5 to 10 mins of driving. I checked the ECU code and it suggested the oxygen sensor was bad. I replaced it with a high quality new item, but it didn't resolve the problem, even if I disconnected the battery to reset the ECU. The car ran fine however, but still logs the same fault.

Now I have a bigger problem. The light still comes on after the same time, but the car is starting to misbehave. The idle speed is too high and fluctuates, mostly around 1100RPM. It falls and then returns to that speed.

The MOT man says the emissions are up and down, like the car is running right, then it's not, then it is again.

In addition the rev counter is going haywire every so often, but it's very intermittent, and this is accompanied by hesitancy and sudden power failures which are very short. I can sometimes see the rev counter blip erratically when I press the throttle. Sometimes it drops to zero even though the engine is running, other times it flicks up almost off the scale. I've noticed if I stab the throttle, the worse it reacts - gradual throttle pressure is usually fine.

The car is well cared for and serviced. As a result of these issues and the logging of the fault on the ECU I am thinking the ECU is probably failing. I recently fitted a new ignition coil in the distributor, and replaced the throttle body with a secondhand item in case it was those items. It made no difference.

Can anyone shed any light on this?

Finally, if I am to replace the ECU, will any 1600 SOHC unit fit, or are the ECU's specific - to manual/auto, a/c / no a/c? I have a part number of 37820-PP4E01 on mine, and it's a manual car without a/c. Anyone out there have the correct Rover part number? I think it is probably MEQ101190.

A lot of questions!

Thanks for reading this.

Matt

[RIFF-RAFF]

Hate to say it mate but it does sound like the ecu.

Is that the honda or rover engine in it?

I hope its the rover as honda can be hard to get.

[SilverFox]

sohc i would say its a honda engine
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oldish git in young boys car but loving it

[RIFF-RAFF]

So would i but its best to check.

[coralpolyp]

Hi again

Yes, it's a Honda unit.

[RIFF-RAFF]

http://cgi.ebay.co.uk/ROVER-200-400-ECU-1600CC-...sh=item19b9969f29

Ok then it gets fun im afraid.

The ecu has to look like this any from the manual rover 200 and 400 will fit, but you have to make sure you get the immobilser box and keyfobs for the ecu unit as well.

I found mine on ebay but it took 14months to find what i was looking for. Also try scrap yards and beakers.

[RIFF-RAFF]

you could look inot the honda crx and concerto as well but i would have thaught the immobilser part will be diffrent someone else on here may be able to help with that side though

[RIFF-RAFF]

Obviously make sure its a 1600 engine.

[RIFF-RAFF]

http://cgi.ebay.co.uk/rover-coupe-216-back-brea...sh=item3a572de871

http://cgi.ebay.co.uk/BREAKING-FOR-SPARES-ROVER...sh=item3a56d04d3d f this is manual it will have what you need.

http://cgi.ebay.co.uk/ROVER-COUPE-BREAKING-O-S-...sh=item4394f08139 can ask if this is the same.


Just make sure the immobilser and keyfobs work ok before buying if not youll have to get everything reprogrammed.

[coralpolyp]

Hmm

I've been informed by several people that the Honda ECU can be replaced without the immobiliser and fobs. Just swap out the unit. Are you certain I need the other parts? Did you try without them? If this is the case, how useful is it if I buy a brand new ECU? Seems pointless.

I had seen the ECU on eBay you've pointed out, but I am not sure if an auto part will work on a manual car - if anyone is able to confirm categorically that would help a lot.

Thanks for your replies so far.

Matt

[RIFF-RAFF]

I didnt buy just the ecu after talking to these http://www.remotekey.co.uk/cars/rover/rover-200/faq.asp guys as i only needed keyfobs. Replaceing everything was the cheapest way of doing this.

If i tried to just change the immobilser side of it i would have had to have it all programmed. Sense would have told me that the same goes for just the ecu.

[coralpolyp]

OK - so it's your theory but it may not be the case.

I'll be a guinea pig on this and try to change just the ECU. I'll report back afterwards.

Still, can anyone tell me the Rover part number and whether an auto unit will work on a manual car?

[RIFF-RAFF]

Good luck mate, be interesting to see what will really happen and if that works it means the rover immobilsers are just as easy as the rest of them to get round.

[sasman si]

All else fails give tune my car in nottingham a call. They can provide a remapped ecu that basically fools the system into thinking it ahs received a signal from the immboliser. It does mean that you will not have an imobilser anymore- but your light will stil flash on the dash when you lock the car. I paid £120 for mine and worth every penny in my mind!
Si

[ericbell]

Before you go and spend masses of cash,have you checcked the main earth straps?You would be amazed at the faults they can throw up. The one that was giving me alsorts of problems is UNDER the battery tray and attached to the body/chassis by a 10mm bolt . I found that the wire was badly corroded and just about hanging together by a few stands .Changed this and the earth between engine and the slam panel( this 1 looked a bit brittle ) and have never had any prob since . Try the obviuos and cheapest option 1st and THEN go from there. Insurance companies are not the most understanding when it comes to the removal of immobolisers . Just try asking them ! ! !
Ment to say mine is a 216 sohc as well .( Batterys on drivers side )
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111,111,111. x 111,111,111. = 12,345,678,987,654,321.

[IrishRover]

I would agree to check the earths.

What ECU code was indicated?

Your symptoms sound like a faulty idle air control valve - error code 14 on the ECU - "IAC/ISCV Valve (Idle Air Control/Idle Speed Control Valve) defective circuit or unplugged / defective sensor"
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[coralpolyp]

I will check the earths now it has been suggested.

The error code I had was single flashes suggesting the oxygen sensor was at fault - as I mentioned at the start of the thread I replaced this part and tried to reset the ECU, but it still logs that same fault. This is one of the reasons why I am beginning to think it's the ECU that's the source of the problem.

I will check the ECU again and see if there is a secondary indication.

Probably, this will turn into more than one problem the further I investigate it.

[IrishRover]

There is an earth wire below the distributor which can be difficult to see. Inspect and clean this. If this wasn't making proper contact it could likely lead to ignition problems.

I take your point about the error code and ECU. It's worth being absolutely sure you aren't misinterpreting the flashes or not seeing the full sequence.
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[coralpolyp]

Thanks - if the weather isn't too Siberian I'll try and check the earth straps and the ECU fault code tomorrow.

[coralpolyp]

Hi all

I checked the car yesterday. I found 2 earth straps - which are fine. The main one connecting the battery to the gearbox, and the top one joining the slam panel to the valve cover. I resistance checked them and they are OK and making good contact.

I checked the ECU and it was showing single flashes only - so still the oxygen sensor fault. I reset the ECU and the fault light did stop. I opened the ECU and there is no obvious sign of damage or shorting out. I checked the connecting plugs and harness and it looks fine.

I have to drive it again today but I can guarantee after about 5 miles the engine light will come back on - same O2 sensor fault, and associated bad engine behaviour.

I wonder if the wiring from the sensor to the ECU is shorting out on some other wiring somewhere. This might explain the same fault being logged even with a new sensor and the worsening symptoms. I'll try some continuity checks on that next. Anyone know how to check if an O2 sensor is working properly?

Any other ideas - or are we back to a new ECU?

[IrishRover]

It is possible, at least in theory, to test lambda sensors:
http://rover800.gaima.co.uk/Rover800/www.pallan...r/tech/lambda.htm

You didn't mention that you checked the earth plug below the distributor.
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[coralpolyp]

Thanks - I couldn't find it. I thought you were referring to the main earth wire since that connects to the gearbox directly below the distributor. When you say earth PLUG, what do you mean exactly? Does it not appear like a normal earth wire connecting directly to a ground?

[sasman si]

[IrishRover]

[coralpolyp]

OK. Thanks for the reply. I'll have another look for it and check it's continuity.