38 replies to this topic

[Shep76S]

http://www.theminifo...-rally-mini-97/

[a13gpn]

the lambda readings are odd - the fluctuating is exactly how it should work, from lean to rich in milliseconds. but the dying when warm is odd but don't go splashing out just yet.

the sensors that you have checked, are they operating within the correct parameters from cold up to warm?

Does the throttle position sensor reading increase with revs?

do you have anything on the map sensor, the throttle switch?

did you do any of the suggestions I made in my first post? 

Today the lambda sensor was reading around 1v constantly with a very slight change every few seconds and then after 5minutes of running the sensor was at 0v. Heater circuit provides 12v correctly.

The other sensors all seem to be working correctly and show temperatures as you would expect. 

Throttle position sensor increases correctly with revs.

I cleaned the coolant but haven't checked compression or valve clearances. What should the spark gaps be set at? I can re check these.

Clamping the return fuel line or removing the lambda sensor all together has no effect in changing how rich it is running or clearing the massive hesitation before 2500rpm. 

[a13gpn]

Cool, the Plant brothers car?

I own both the Eddie Stobart sponsored A13 GPN Rally car and R13 GPN the Mini Magazine sponsored car. We are talking about R13 in this post.

Both cars were built and rallied by the Plant Brothers at some point, R13 was then handed over to West Midlands Motorsport who extensively re-prepped the car and it was rallied by Terry Colley. 

[a13gpn]

Just been researching a few things and looking over the engine bay in more detail. Bizarrely it turns out it seems to be running an SPI inlet manifold and K&N filter but has the MAP sensor pipes fitted but blocked off and sealed up as its running an aftermarket ECU. Also has a 52mm throttle body so a bit of a mix but the engine is definitely an MPI with front mounted rad/belt driven alternator. 

That information might help diagnosis? 

[Fast Ivan]

spark plugs should be 0.8 to 0.9mm

clamping the return line will increase fuel pressure, the system works on a restriction on the return line to create pressure

with no map reading the engine isn't going run right, fuel injection relies on information from all the sensors

sounds to me like its a bit of a bodge going on under that bonnet, are you certain its an mpi engine? front mounted radiator aside, the block should have the oil filter screwed directly in to the left hand side, the alternator should be mounted using the head

[a13gpn]

Ok I will check gaps tomorrow but I am pretty sure they are 0.8mm.

I tried clamping the return line, has no effect on the running at all.

I will agree that it is a bit of a bodge under the bonnet, but Ill keep working away at it until it is running correctly.

I am certain it is an MPI engine, just checked now and it has the screw in filter and the alternator mounted using the head.

I have ordered a new Lambda sensor anyway, so I can rule this out. The readings today from the sensor were a constant 1.2v and then after 2 minutes running 0.2v constant and then after 5minutes 0v. 

[Fast Ivan]

I hope you get it running as well and if we can help then that would be great.

 

Its clearly been modified, the question is did it ever run with this set up or is this something someone else has done prior to selling it to you?

What does the other mini, A13, look like under the bonnet? is it the same setup? does it run?

 

What I recon is that the engines been tuned a bit, the standard ecu may have been holding it back so an after market ecu was looked for, none existed that could replicate the complicated code for multi point injection so they switched to a single point injection setup.

 

I don't think the new lambda will solve your issues, (that isn't to say you don't need a new lambda though) I hope it does but I think your real issues are that there's no MAP, so engine load can not been calculated, there may be a default value for this in the ecu but its not going to give satisfactory running. 

No fuel regulator is also going to cause you problems.

 

If the new lambda doesn't solve your issues it might be worth taking it out again and keeping it for later, the over fuelling wont do it any good.

[a13gpn]

The engine is modified quite extensively. It must have ran in this configuration as it was MOT'd in 2006 then put away until I bought it. But clearly someone has been fiddling. 

A13 is a Grp N Spec 1275 SPI engine running on standard ECU. Runs perfectly. 

I think your idea of what happened and why it is running a SPI setup on MPI engine is possibly correct. But I do know this ECU was on the original build sheet so it must have been a planned change from the start.

I will try the Lambda sensor tomorrow and see where we are at. 

[Fast Ivan]

so was it running multi point injection when rallying?

what does the build sheet say about the injection set up?

what kind of mods have been done to the engine?

[a13gpn]

The only history I have of the engine build was when it was first built from a new engine block. (Same block now) It was running MPI at this point and rallied with this and standard ECU. Everything was brand new at the time.

Sometime in its life it has been changed to aftermarket Motorsport ECU and SPI injection but then rallied in this config I am sure. Build spec is below.
 

Group N spec with a brand new Rover 1275 engine and single point injection.

MBE engine management system 
Swift tune SW5i cam

Mini spares Hi lift roller rockers

HC water pump 

Straight cut gearbox & final drive of 3:44

Mini spares cross pin diff

[a13gpn]

Ok another update.

New Lamba sensor arrived but haven't had a chance to change yet, and I want to sort out the bigger problems first.

Decided to do a compression test.. 

1- 210 psi
2- 205 psi (Slowly falling over two minutes to around 190psi)
3- 215 psi
4- 215 psi

I added a tsp of oil into number 2, cleaned all spark plugs and started engine. For maybe 20seconds it ran much better without the hesitation but now running rough again with a few misfires and bangs from the inlet manifold. 

From this obviously think I need to strip the head down and take a look at gaskets and piston rings. 

Any other thoughts/Wise words/Diagnosis to what the cause could be?

Edited by a13gpn, 08 December 2013 - 02:15 PM.

[Fast Ivan]

the compression results don't look to bad, was it done on a warm engine with the throttle fully open?

Also the drop of oil added to the lower cylinder is supposed to be followed by another compression test to see if there is an improvement.

that said, even the drop to 190 isn't to bad really, a cylinder showing less than 10-15% than the others is normally considered ok

 

I think its all related to the injection/management setup, my advice would be to return it to the MPI setup and take it from there, then if you want to move away from the mpi setup to remove the restrictions then look at your options

[a13gpn]

Yes this was done with warm engine and throttle fully open. 

I forgot to write that after I added the oil I did the compression test again and number 2 stayed fixed at 205psi for over 10/15minutes whilst I cleaned the spark plugs up.

There was an immediate noticeable improvement in the running for around 20/30seconds but then I guess the oil burnt away.

Think I will check over the head and gasket and check the inlet manifold for leaks to rule out any problems here.

We will get there eventually!

[jamesmpi]

Kero us posted :)

[jamesmpi]

Keep us posted