Scoty

Pulling into my street last night and the car died
It will start, but the idle is bollox, loads of blue/black smoke coming from the exhaust.
Even when I rev it, it doesn't clear it.
Fan went straight on this morning and it wont go off, but the car has been sitting over night

Last thing that got done was the GEMS

RRH

check the hose from the intercoller is tight. My old RA used to pop the hose off every now and then, with exactly the same results.

simon

Gidney&Knowlesy

YHM

[Edited by XtremeScoobies - 1/10/2004 12:07:25 PM]

john banks

Don't know how GEMS controls it but if the fan is on immediately perhaps the coolant temperature sensor is giving a funny reading and it has gone into a default mode and overfuelling? Blue smoke may be something else though.

Are you able to plug a laptop into the GEMS unit to read sensors/fault codes?

Can you plug in an original ECU and see what that says if not?

Scoty

Thanks very much for the quick replies

Simon checked all the hoses there, everything is tight.

Checked the water and there isn't any oil contamination, fans are still coming on though and it's stone cold steve austin.
Would it be safe to sit with the car and feather the trottle to keep it running and try and get it up to running temp, to see if the top an bottom hoses get warm?

Scoty

John I'll give Steve a call and see what he say's about a default mode.

I've still to get the software for the GEMS so I cant do anything in that respect yet.
I still have the standard ECU, but no MAF
Could I try the standard ECU or would that also run crap without the MAF?

Scoty

Car wasn't overheating either.

Never had any bother with water temps or leaks, although the water in the expansion tank has dropped a bit, but could this be becuase it's just cold and will rise again when warm?
Did notice a lot of bubbles to start with but they have now cleared.

john banks

Speak to Steve first of all I would say. The car should start without a MAF but will report an error, but you could get it to flash out other codes.

My only fear is IF it is something internal (wondered about the blue smoke) and you keep starting it it will probably damage it more.

Also though the ECU "knows" something if the fan is on.

Scoty

John, Steve's exact words too mate, the coolant temp sensor has gone if the fans are on all the time.
Say's that will be sending different readings and could effect the fueling?


No smell of burning oil, definately no big white plumes of smoke coming from the exhaust, just looks like black carbon and some blue coloured stuff

Scoty

Just reading a few post about coolant temp sensors.
On the Rovers the ECU doesn't go into a cloosed loop fuel mod if the coolant temp sensor is knackerd.
Dont realy understand what that means, but if fueling and coolant temp sendors are being mentioned on the same thread??

john banks

If it goes open circuit the resistance will be very high. If the ECU then thinks the coolant temperature is very low it will overfuel.

If the ECU recognises an open circuit it may go into another default mode.

As it is is may be putting in the fuel for a -25 degree Celcius cold start for example.

I can't find anything more definitive than the above graph in the extracts I have from the 97/98 service book.

Bob Rawle

If the coolant temp sensor is playing up it should still be reasonable at starting/running if the engine was cold however it would depend on how it had failed, for example if it sudenly read low it should start and run when cold, if the fans running and the sensor is duff it must be informing the ecu that it is in the high 90's, that should not be a problem when hot, you have had both issues, you could have a grounding issue, the Gems grounds through the ecu case iirc, the fact that it starts the car is encouraging, there are also default values that Steve probably set into the ecu maps so try unplugging the coolant temp sensor, if it stops the fan then you know thats the problem, if not then its something else depending on the default values. If you have the software and cable its easy to check as you can get a direct readout. The coolant temp sensor should read between 3 and 4 k ohms at 20 deg C nd between 0.35 and 0.4k at 80 deg C so you could also use a DVM to check that.

cheers

bob

john banks

If you find a Link manual for MY98 it might have the usual coolant temperature sensor voltage range at idle I think and you could measure this at the ECU.

Just seen your post Bob, makes sense it is reading too hot if the fans are on.

[Edited by john banks - 1/10/2004 1:13:55 PM]

Scoty

Thanks for all the help so far it's much apprectiated

I disconnected the coolant temp sensor (brown plug under the alternator) and the fans are still on.
I dont have the GEMS software yet, would you's recommend I try the standard ECU and see what faults it shows, how do I tell what fualts the standard ECU is registering?

Scoty

Just changed the ECU over to the standard MY98 ECU and the car is running fine!!!
No smoke, idles OK considering no MAF or Lambda, and the fans are also not running now.

Would I be OK to get it up to running temp with the standard ECU?
Not planning on driving it though.

john banks

At least your engine is OK then. Speak again to Steve.

Scoty

Yeh thanks John, well relieved my engine's OK

Scoty

Bollox.

Got the car up to running temp's with the standard ECU, idle was great, reving very smoothly, water temp guage just reached half way, and it started to hunt again and cut out.
Started OK, no smoke at all from the exhaust, water in the header tank was a bit frothy but was getting better as the car got warmer.

I have a bad leak in the up-pipe which I'm waiting on gaskets, i'm guessing this could make the car cut out on idle sometimes, but with the check engine light on too it must be something else

john banks

Apart from you disconnected MAF sensor?

Scoty

John, no MAF at all, custom 76mm turbo intake, and no lambda sensor either, not needed with the GEMS.

Scoty

Fan was still off, looks as though it is working OK now

john banks

Yes but you mentioned a CEL, with original ECU in no MAF alone will give you a CEL.

Andy.F

Running again on GEMS or JECS ? Std JECS will not like having no MAF and 550 cc injectors !!

Andy

Scoty

Ahh right John understand.

So the CEL is probably nothing to worry about then, it's lit becuase the MAF is missing.

Any ideas why it would be cutting out?
If I sit the idle at a constant 2000rpm, sometimes the revs will just die,
I cant control it with the throttle when it does this, I just have to restart it.

Scoty

Andy, running JECS with no MAF, Lambda and 550's.

As soon as I changed to the JECS I noticed an imediate improvement.
No more smoke from exhaust, fans weren't on all the time and it would idle and rev like a standard car.

It's just when it heated up it cut out again(JECS), same as when it did last night with the GEMS
If I put the GEMS back in it wont idle at all, run very rough when reving it, and loads of smoke from the exhaust and will cut out as soon as I lift off the trottle.
With the JECS idle is fine, reving is fine, no smoke, no fans on all the time, but it cut's out when it's hot.

So it's possible 2 different situations?
Sometjhing needing done with the GEMS and the JECS wont like how the car is set up and is causing it to cut out sometimes?

tweenierob

Just a guess here

But could it be the ECU switching to Closed Loop on the lambda perhaps(std ecu)?? as it is not there it doesnt know what fuel to add?
Complete stab in the dark...

Rob

Scoty

Wah?

The JECS switching to closed loop on Lambda when its warm?

Pavlo

Jecs will switch to closed loop fairly quickly I think.

With 550s and JECs you should be very rich, but closed loop will pull it in quite close if working, so that means correct lambda response mainly.

Of course if you had the software for the GEMS you would be able to plug in and tell straight away if the temp sensor was reading properly.

You could also just unplug the temp sensor and put a resistor in it's place of around 535 ohms as that will be equivalent to 85ēC.

If this stabilises things then you know.

Paul

Scoty

Cheers Paul, been advised to send the ECU back!!
Advisable?

Pavlo

I think so.

can you check the resistance of the temp sensor?

It should be 5k ohms at 25ēC I think. if it's open circuit (resistance = infinity) , then it's dead.

I would check sensor anyway, but ECU appears suspect to me.

Paul