Wednesday 30 March 2016

More Cooling System

Having 'fixed'? the cooling system I am now having trouble getting her up to temperature.   The gauge was hardly indicating and the ECU software thought she was running at only 73C.   I had been convinced by the other Rover chap that the temperature sensor was faulty and he sent me his spare to try out.   So I swapped them over at the weekend, I took her out yesterday and it had no effect except the ECU now thought it was running at 70C 

So hypothesis number 11 was that actually the radiator, contrary to everything I have ever said, is actually very efficient.   And although the thermostat is rated at 88C, that is fully open and it actually starts to open at 76C.   So the guess is that the moment the thermostat cracks open that allows enough water to flow through the radiator to keep the engine cool.   So I needed to make the radiator less efficient.

Decided it was time to fall back on the tried and trusted method we used when I was a 'lad' and partially block off the front grille.   So 2 roughly cut pieces of cardboard held on with cable ties was the 'Proof of Concept'.
Took her for a 35 min run and towards the end she stabilised at 84C  (the small rise at the end was me driving slowly through a village).  When I drove back home, scenic 20 min run, I didn't bother attaching the laptop but she warmed up to temperature much quicker and I got the impression she stabilised around 86-88C, which would be logical.

Plan now is to do a much longer trip tomorrow and see what happens.

Meanwhile, did a more permanent solution.   Two properly cut pieces of cardboard covered in baking foil.   Very Smoooooth :-)

Wednesday 16 March 2016

Idle Speed Changed

Ever since I have had the car she has happily idled at 1000 rpm.   I wasn't worried, but did wonder why everything I read said that the engine should normally idle at 850rpm.   But now I know how to reprogram the ECU I sent the appropriate code to drop it by 150 rpm.   It seems to have worked well and when the engine is warm it happily quietly burbles along at 850rpm with no hunting or surging.

What I found during the investigation is that the Rover engines normally leave the factory with a default idle speed set at 950 rpm but with a tuneable offset of -100 rpm.   For some reason the (my?) Superspec seems to have left the factory with the offset at +50 rpm.

Thursday 10 March 2016

Driver Seat Belt Extension Fitted

Ever since I have had the car, the seat harness has been a very 'snug' fit, but there was no adjustment left in the buckles.   And with having to wear bulky winter clothes it was getting a bit of a challenge.   And I also noticed that I was unable to get the buckle right in the middle, but it was offset to the outside of the car.    So time to fix that.

Seat out, bottom mounting removed, 3" extension strap fitted, seat back in and perfection.  I now have the buckle dead centre and about 1" adjustment either side.

Looks great, pity no-one will ever see.  

I then strapped in the passenger seat, for the first time ever, and found it was exactly the same, it is impossible to get the buckle centrally positioned on the body.  Obviously all my passengers have been too polite to point it out
So another extension piece on order so I can do that as well.

Later.  Belt arrived, fitted, so now passenger has full adjustment available and can centralise the buckle.


Tuesday 8 March 2016

Relays Revisited

When I first checked out the relays there were lots of questions left outstanding.   Since working on the lambda sensor change I have managed to answer most of them.   The original post is here, with the changes in Red.   Here are the specific updates:

 The 2 relays on the left appeared to be 2 of the 3 relays I could not find (ECU, Lambda & Fuel Pump).   While writing my software analysis program I found a way of testing the fuel pump relay while the engine was off.  And by holding it I was able to confirm that the one on the Right was the Fuel Pump.

Also, I had previously found that removing the one on the left stopped the Fuel Pump working so I think we can safely say that one is the main ECU relay as the first thing the ECU does when you turn on the ignition is prime the fuel pump for 2 seconds.

And it turns out the Lambda system relay actually controls the Sensor heater, not the sensor itself, as the heater is not switched on until the engine actually starts.   So removing it would not stop the Fuel Pump from priming.   The only problem is that I have absolutely no idea where it is in the car.   It must be well hidden.

And I have since been told that there are no headlight relays fitted to the car.  I find this odd, as the headlights are quite old and must have quite a heavy current drain and if there are no relays then all that current must go through the light switch.

So now just 2 outstanding questions:

1.  Where is the Lambda heater relay ? 
2.   Are there actually no Headlight relays ?

Clutch Revisited

Had a 'clutch' day today.    A couple of years ago I redesigned the pedal/cable join to eliminate the 'kink' that causes Superspec cables to break (described here).   That resulted in the cable being too long and I took up the slack with a piece of copper plumbing  pipe.

While I was underneath at the weekend securing the lambda sensor wiring I noticed that the pipe had actually settled at quite an angle, which was introducing a bend in the cable, the one thing I was trying to avoid.

So took it out and built a new spacer from a block of wood (more forgiving than copper) and a stainless steel bracket to mount to the bolt you can see (and covered it in black masking tape to disguise the fact it was wood ).    

So now the cable meets the hole at 90 degs, avoiding the bend I had before.

Took her for a drive and the clutch is silky-smooth    Bite point is a bit lower than I like so next time I have her on axle stands I'll wind it up a bit.

Wednesday 2 March 2016

Redesigned Exhaust System

For a long time I have thought I should fit a flexible joint into the exhaust system to isolate the engine vibration from the catalytic converter and silencer.   Now I had 3 complete exhaust systems
I felt now was the time.   So out came the angle grinder and the result is very good.

Ignore the reflection, I don't have twin exhausts :-)

So now the exhaust consists of the manifold, then a short length of pipe that mounts the lambda sensor, then a short flexible joint and finally the combined catalytic converter and heat shield.

It's a pity that it will all be hidden when I put the heat shield back on. Maybe I won't bother.

Tuesday 1 March 2016

Lambda Sensors

Having now proved that the lambda (O2) sensor was probably not working, it was time to do something about it.   I had a spare sensor, so the first thing to do was to remove the old one.  This turned out to be easier said than done, as it had been in the pipe for about 10 years and was corroded in.    So I took it to the local garage who managed to cut it out.  The sensor was wrecked in the process but that didn't matter.

While this was going on two things happened.   For some months I had been watching a Superspec exhaust, complete with lambda sensor, catalytic converter, silencer and heat shield that was on E-Bay.   The owner was gradually reducing the price and it was now down to £75.  As the RRP is about £500 I decided it would be a good buy.   At the same time someone I was working with on the software program said he had a spare sensor and would post it to me. 

So I suddenly found myself with 3 complete exhaust systems with sensors.

First thing to do was to mount the new exhaust pipe and sensor.  It looked good, but unfortuately when I took her for a run the sensor did not work at all.    That was rather worrying and I wondered if I had a more fundamantal problem.

But the next thing to try was to fit one of the new sensors instead.  I was actually quite pleased when I took the old sensor out and it was completely 'coked' up.  I suspect the previous owner ran it on his car without the heater connected and it just 'sooted' up.

So took her for a run with the new sensor fitted  (with the wires from the sensor and the loom simply twisted together) and this was the result (Shows before, with the original sensor, and after, with the new one):

So we can see the new sensor is working perfectly, rapidly switching between 0.1V-0.9V, which is how it is supposed to be.    And just as a check I tried the other sensor I had been given and got an identical result.

So I now have 3 complete exhaust systems, with 2 working sensors and possibly one more if it starts to work after I have cleaned it.