33 replies to this topic

[icklemini]

but if your CTS has stored a fault in the ECU's memory, it will always think the engine is running at 60 degrees, which will result in a faulty mixture, and faulty CO

Interesting - where did you find this info?, Personally I have found that:
1) with regards to the CTS, if you unplug it, the live data and ecu default to 59 degs... A fault is logged....
2) plug it back in, the fault status changes to intermitant, live data reports correct temperature, car drives ok again...

Maybe its ECU part number specific?

[RaLF020]

In case anyone suffering similar problems is interested where this has got to, I thought I'd add an update...

Clutching at straws I checked & adjusted the valve clearances and took it back for a 3rd emissions test - No change - still fails.

I then found a local specialist; 'Downton Motor Engineering' Russell there is very helpful and really seems to know his stuff. He spent a good hour running diagnostic tests on my car and determined; cylinders 3 & 4 are down on compression, the engine is running hot and the elecy fan is not cutting in. Tests with a laser temp reader showed the radiator had 10 degrees C variances across it. (New Rad needed then and Elec fan needs looking at). This combined with the emissions results led him to question what condition the head is now in. Taking this into account after all the other work I have done the only way forward seems to be to get the head off. Worst case possibility; a valve seal may have become dislodged by the heat. Better case possibility; the valve seals have become coated due to over fuelling. This will need sand blasting off and the valves lapping in.

If anyone has experience of this I would love to hear about it.

I have replaced the radiator and all hoses myself but the I will leave the head to Russell at Downton.

Anyway the car is booked to have the head removed and reconditioned as required next week so we'll see what happens.

[aspicer0]

did you ever sort out your problems with the emisions for the MOT

[RaLF020]

For anyone reading this topic wondering how i ultimately fixed this issue, the short answer is, I never did!

 

The longer answer is that the head was reconnditioned but the emissions were still failing the MOT.  We ultimately took a different approach when we worked out that since my car is a Dec '92 registration the car & or engine would have likely been manufactured before the Sept 1992 change in emmision legislation meaning that the car can be mot'd against the old emissions spec. Of course I cant prove that because I dont have any paperwork from Rover that backs it up but the MOT was done this way and off I drove.

 

I ran the car using this way of obtaining an MOT for a couple of years before laying the car up in the garage, each year intending/hoping to find the time and money to get it back on the road and sorted once and for all.  This year, lock down was my oportunity to do just that and the troubles of 2012 are very much still present. 

 

 need to pray to the SPI gods once again so i will start another post to explain and ask for help with the current symptoms that include:

- Starts and idles from cold no problem at all

- warms up and settles to idle at around 800rpm

- when driving the power goes flat for periods around 2000 revs and then picks up

- After running for 20mins or so the revs will drop to almost zero before the ECU catches it and picks it up again before dropping agian.

- eventually the revs will die completely and the engine stalls, regardless of any throttle input

- after this the car will not restart, even after 1 or 2 hours it will not start

- leave the car over night and it starts first time and runs fine for 20 mins or so before the revs begin to 'hunt' again and the engine finally dies

 

but lets discuss that in another posting...

[Pops_Guild]

For anyone reading this topic wondering how i ultimately fixed this issue, the short answer is, I never did!
 
The longer answer is that the head was reconnditioned but the emissions were still failing the MOT.  We ultimately took a different approach when we worked out that since my car is a Dec '92 registration the car & or engine would have likely been manufactured before the Sept 1992 change in emmision legislation meaning that the car can be mot'd against the old emissions spec. Of course I cant prove that because I dont have any paperwork from Rover that backs it up but the MOT was done this way and off I drove.
 
I ran the car using this way of obtaining an MOT for a couple of years before laying the car up in the garage, each year intending/hoping to find the time and money to get it back on the road and sorted once and for all.  This year, lock down was my oportunity to do just that and the troubles of 2012 are very much still present. 
 
 need to pray to the SPI gods once again so i will start another post to explain and ask for help with the current symptoms that include:
- Starts and idles from cold no problem at all
- warms up and settles to idle at around 800rpm
- when driving the power goes flat for periods around 2000 revs and then picks up
- After running for 20mins or so the revs will drop to almost zero before the ECU catches it and picks it up again before dropping agian.
- eventually the revs will die completely and the engine stalls, regardless of any throttle input
- after this the car will not restart, even after 1 or 2 hours it will not start
- leave the car over night and it starts first time and runs fine for 20 mins or so before the revs begin to 'hunt' again and the engine finally dies
 
but lets discuss that in another posting...

>>>sorry you’re still having a mare! I would keep it all here in this post if I were you.

It sounds like a fuelling issue to me, possibly that the ECU isn’t getting the correct info from sensors etc. But erratic idling is often a vacuum leak, usually in one of the 4 thin vac pipes or connectors. Check them first. Then the rubber pipes that run off the breather rail. Then check for a leak in the inlet manifold gasket, if the head has been off it’s possible the inlet manifold isn’t seated correctly. I don’t think it will be that but these things can be accumulative.

When did you last change the fuel filter?

The curious thing is that you say Downton used diagnostic equipment and found nothing unusual?

[RaLF020]

So back in 2012 I replaced the thin Vac tubes to the fuel trap & MAP sensor + the red & yellow ones.  At that time the CTS and Lambda sensors were also replaced. The car has done less than 900 miles since then.  

 

I have now just had the injector housing, throttle body & inlet manifold off.  I replaced the CTS again (because it's cheap) and also flushed the coolant system and fitted a new (tested) thermostat while i was there.  I did find a split in the injector to thorttle body gasket so I replaced that (you can't buy these gaskets anymore so I had to make one from 1mm gasket paper).  I checked all the vac tubes and all look good.  The inlet manifold gasket was changed when the head was done in 2012 and was in good condition so I didn't replace it this time. 

 

The fuel filter was also changed back in 2012 and I changed it again just now. The one i took off looked fine.

 

The other interesting thing i found was the accelerator pedal switch (mine is an early SPI so has one) was not being activated when the pedal was at idle.  I modified the switch by adding a nail head to the pedal arm switch plate and tested the switch again with an ohm meter.  With this switch working the car is definately happier to idle at 800 rpm now than it ever was before but i guess this has nothing to do with the problems i'm getting once it's fully warmed up?

 

As stated above the car starts first time form cold and idles nicely.  When driven there is a noticable loss of power at mid-range revs and possibly mis-fires lightly.  Once fully warm the revs begin to hunt (drop rapidly and recover).  At idle the egine will eventually stall when the revs drop too low.  After that the engine will not restart - it does fire but quickly dies. The temperature guage reads on or very slightly below the mid/white line.  (I've not seen the elec fan cut in at all during the recent troubles but when I changed the rad a few years ago it was certainly working).  With the air filter removed you can see that the injector is not spraying fuel into the manifold - it's only dripping at best.  2 or 3 hours later the engine still refuses to run but after being left overnight it then starts and runs fine.

 

So it seems clear to me that the ECU is massively backing off the fuel for some reason when the engine is hot and my quest is to find out why... 

 

(I found a previous thread that talked about a lambda sensor relay fault that meant the sensor was not being heated. When the car was at idle the sensor cooled down and gave a steady rich reading. When driven at speed the heat in the exhaust brought the sensor to life and the ECU leaned off the mix - could this be my problem?)

 

I'm also wondering about the TPS and CPS as i've not done anyting to verify either of these but I feel i need a diagnostic reading at this stage before i go blindly changing out components.

 

Anyone in the Fleet/Farnborough area got a ACR they are willing to share - please let me know?

[MatthewsDad]

As you suggest I think the next step is to get some readings posted - with measured data I'm sure you'll move things forward. Just checking is the lost motion linkage correctly adjusted?

Edited by MatthewsDad, 27 July 2020 - 09:42 PM.

[Pops_Guild]

So back in 2012 I replaced the thin Vac tubes to the fuel trap & MAP sensor + the red & yellow ones.  At that time the CTS and Lambda sensors were also replaced. The car has done less than 900 miles since then.  
 
I have now just had the injector housing, throttle body & inlet manifold off.  I replaced the CTS again (because it's cheap) and also flushed the coolant system and fitted a new (tested) thermostat while i was there.  I did find a split in the injector to thorttle body gasket so I replaced that (you can't buy these gaskets anymore so I had to make one from 1mm gasket paper).  I checked all the vac tubes and all look good.  The inlet manifold gasket was changed when the head was done in 2012 and was in good condition so I didn't replace it this time. 
 
The fuel filter was also changed back in 2012 and I changed it again just now. The one i took off looked fine.
 
The other interesting thing i found was the accelerator pedal switch (mine is an early SPI so has one) was not being activated when the pedal was at idle.  I modified the switch by adding a nail head to the pedal arm switch plate and tested the switch again with an ohm meter.  With this switch working the car is definately happier to idle at 800 rpm now than it ever was before but i guess this has nothing to do with the problems i'm getting once it's fully warmed up?
 
As stated above the car starts first time form cold and idles nicely.  When driven there is a noticable loss of power at mid-range revs and possibly mis-fires lightly.  Once fully warm the revs begin to hunt (drop rapidly and recover).  At idle the egine will eventually stall when the revs drop too low.  After that the engine will not restart - it does fire but quickly dies. The temperature guage reads on or very slightly below the mid/white line.  (I've not seen the elec fan cut in at all during the recent troubles but when I changed the rad a few years ago it was certainly working).  With the air filter removed you can see that the injector is not spraying fuel into the manifold - it's only dripping at best.  2 or 3 hours later the engine still refuses to run but after being left overnight it then starts and runs fine.
 
So it seems clear to me that the ECU is massively backing off the fuel for some reason when the engine is hot and my quest is to find out why... 
 
(I found a previous thread that talked about a lambda sensor relay fault that meant the sensor was not being heated. When the car was at idle the sensor cooled down and gave a steady rich reading. When driven at speed the heat in the exhaust brought the sensor to life and the ECU leaned off the mix - could this be my problem?)
 
I'm also wondering about the TPS and CPS as i've not done anyting to verify either of these but I feel i need a diagnostic reading at this stage before i go blindly changing out components.
 
Anyone in the Fleet/Farnborough area got a ACR they are willing to share - please let me know?

So, under normal circumstances I would be easily able to help but it’s not so straightforward. I’m in Guildford so not a huge trek from you and I have an array of diagnostic equipment. One of the tricky things is that even with diagnostic kit it will take a while to solve and fix, that’s just experience talking. Let me think on it.

[FlyingScot]

Some simple things to check.

 

Is the lambda relay supplying voltage to the sensor ? ( you can measure at the plug)

 

Is the PTC getting a voltage?
 

Examine the condition of the crank sensor and connector - a poor signal from this maybe dropping the fuel pump relay.

 

Without access to fuel pressure gauges it will be difficult to check the performance of the in tank pump (and filter gauze).

 

As you correctly surmise the injector normally can be seen spraying fuel when you look down the SPi body (when she’s running).

 

More commonly what’s am finding now is deteriorated wiring and plugs and not necessarily the components themselves - mini wiring was always pretty poor but add on the years and the heat cycles and often it’s the cores themselves which are creating problems.

Its definitely worth spending a bit of time with a multimeter checking continuity of the wiring ( and of course making sure you have good earth straps)

 

As Pops_Guild has written above having diagnostic kit can help but often the answer is more time consuming and tricky to solve.

 

I have also now had two cars in which the fault was the MEMS ECU itself which generally have lasted well.

 

FS

[RaLF020]

Thanks for the suggestions above.  

 

I fitted a new fuel pump in 2012 and cleaned out the tank, (the pre-filter had disintergrated on the old pump and while it worked, it was noisey).  I have checked the new pump is working on ignition now.  The engine bay earth strap was also replaced at that time and the contact is still clean and shinny.

 

I've printed sprokets instructions on how to test the lambda sensor and that is my next job.  I will spend some time buzzing out other wires for continuity and testing voltages as FlyingScot suggests.  PTC = manifold heater? 

 

@MatthewsDad, by "lost motion linkage" do you mean the throttle cable at the throttle body? If so, it's not be played with in the time I've had the car as it needs a diag terminal to set it up correctly. Do you think that could cause loss of power and revs hunting when the engine is warm/hot? 

[Pops_Guild]

I might be wrong but think FS meant the Potentiometer (TPS) which is black device on the left of the throttle body. If this is sending wrong info to the ECU that could affect fuelling. But he might mean PTC...

The PTC is the heater at the bottom of the manifold, it helps during the cold cycle fuelling.

Setting the lost motion gap doesn’t need a diagnostic tool, just a couple of spanners. It’s the adjustment of the accelerator cable so that the lost motion linkage has an even gap...follow the guide in the Haynes manual and apart from being in an awkward position to view the gap it’s straight forward. Setting this is is a good idea for the general health of the setup.

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Edited by Pops_Guild, 28 July 2020 - 09:33 PM.

[RaLF020]

Thanks for that Pops_Guild.  I managed to spend a bit of time on this yesterday & today...

 

Yesterday I set out to check the lambda (heater & sensor) functions with a DVM.  First thing I noticed was that one of the pins (grey wire) in the sensor connector was not fully inserted in the connector housing.  It must have been like that from new or got pushed out when the sensor was installed in 2012.  The pin is now clicked into place - an easy fix.  I had hoped this was the root of my issue so I fired him up and took him for a short drive to get the engine up to temperature.  He seemed to run a litter better but still lacked power and was hesitant in the mid rev range.

I got him back and for a long while he idled happily below 1000rpm.  I ran the engine at 2500 rpm for a few mins and the revs then started to drop out (down to maybe 500) without any change in accelerator pedal position from me.  Left to idle the revs continued to faulter until the engine died.  After that he would't run and that was my testing over for the day. Video here: https://drive.google...iew?usp=sharing

https://drive.google...iew?usp=sharing

 

Today, he fired up and ran happily so I set about the lambda checks intended yesterday.  With the lambda sensor disconnected I put a volt meter across the heater pins on the loom connector and got 14V.  With the DVM across the sensor pins and the sensor in circuit I could see the voltage sweeping between around 300mV and 900mV.  Is this upper value a bit on the high side?  I don't believe the car is running rich anymore but it was definitely before I found the previous 2 faults (split in injector housing gasket and faulty accelerator pedal switch) so even with these readings should I consider that the sensor has been wrecked by the rich mixture?

 

I have some videos including one of the lambda readings on the DVM when the revs are dropping out. Here:

https://drive.google...iew?usp=sharing

https://drive.google...iew?usp=sharing

 

I also checked out the stepper motor wiring. +12ve wire from the coil & 4 windings, each measuring between 15.3 & 15.6 Ohms.  All good?

 

Lastly i Looked at adjusting the lost motion gap. With the ignition off the throttle lever sits just below center but with a clear gap between it and both upper and lower arms.  With the ignition on, after operating the throttle linkage fully open and closed, the  throttle lever sits just above center, close to the upper arm but with a small gap between.  The cable adjustment nut is fairly ceased while the lock-nut is not.  Adjusting it further will probably end in a new cable as the cable outer is not in great shape. Do I need to address this?

 

There was a suggestion of testing the PTC.  Is this just a case of measuring for voltage at the connector which is not easy to get at!  I'm thinking the PTC is not a concern as the problems occur when the engine is warm, it runs fine when cold.  I had the inlet manifold out a couple of weeks back and flushed the coolant pipes. I wasn't specifically looking for it but i didn't notice a rattle from the PTC heater. 

 

Other things I'm wondering are...

Is the purge valve something to worry about with my symptoms? I checked the wiring is good and I can't see any obvious splits or cracks in the tubes. Is this something that needs further checking?

The Intake air sensor has been disconnected at various times when running the engine to get sight of the injector, as has the lambda sensor with the dodgy connector.  I am aware that the ECU will retain error codes until they are manually reset but am I right in thinking the ECU will use live data from sensors and not compensate for stale error codes? (ie. do i need to get the codes reset?)

and a random thought... I disconnect the battery every night / when the car is not in use (I have a battery eliminator).  Is this a bad for the ECU in terms of 'learning' the parameters of the engine or not a concern?

 

Thanks.

Edited by RaLF020, 31 July 2020 - 12:07 AM.

[RaLF020]

Bump (posted in Help - Several Spi Questions)

kkeith, My ebay diag cable arrived today and I spent a couple of hours pulling my hair out trying to get it to connect (looks like we have the same fate here too).  I'm using MEMS-ROSCO which as genpop says you need to unzip twice (extract the .zip file and then extract the .rar file)

 

Initially i ran mems-rosco.exe file and it auto found COM3.  However the USB serial port is did not seem to be associated with any COM port.  Later I discovered another .exe file hidden in the bin file (readmems.exe).  After running this file the USB serial port is recognised by windows as COM4.  I opened mems-rosco.exe again and it now sees COM4 but it still reports an error when I hit connect!  I've moved a step forward but am clearly still missing something.

 

If anyone can help further with this i think theres at least 2 of us here that would appreciate it.

[genpop]

Is the com port recogniced within the harware manager of the pc?

 

Have a look to the presentation or pdf and try again.

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[RaLF020]

Is the com port recogniced within the harware manager of the pc?

 

Have a look to the presentation or pdf and try again.

 

yep!  Still no joy here.  I can't run Rover-mems.com as i dont have an android phone and can't connect my old win7 laptop to the internet currently so I'm using mems-rosco.  My spi is a 1992 so running mems v1.3 i believe which is supported by mems-rosco.  I've no real reason to suspect the diag wiring in the loom as i've seen an ACR connected to it in the past, but i guess thats my next check.

 

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