Opinions Please

Opinions Please

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Dodgy Dave

Original Poster:

810 posts

252 months

Saturday 3rd April 2004
quotequote all
I know the best way to check the health of ur engine is to look at ur pistons!
And as you will be able to tell my engine must be running very rich.
Its an SPI so all fuel is controlled by ECU.
The engine is far from standard and wondering if anyone has any ideas on what mod may have a bad effect on the fuel mapping or maybe my ECU has just gone nuts and thinks its american!!!

What makes it worse is it seems some cylinders are worse than others!!

And another bloody annoying thing is i only run it on optimax "The engine cleaning fuel"!!!!







>>> Edited by Dodgy Dave on Saturday 3rd April 21:13

TVR SLag's BiL

5,281 posts

247 months

Sunday 4th April 2004
quotequote all
What state was the head gasket? It looks as if it could have been sucking water/oil in. Did it use alot of water??? Did it burn any oil? Did you have the car tuned on a RR???? Anyone check the CO?

MR2Mike

20,143 posts

256 months

Sunday 4th April 2004
quotequote all
Dodgy Dave said:

Its an SPI so all fuel is controlled by ECU.
The engine is far from standard and wondering if anyone has any ideas on what mod may have a bad effect on the fuel mapping


So you have a very modified engine running with the stock injection and ECU? It's not at all suprising it's not running correctly tbh.

What exactly has been modified? Wild cams can cause all sorts of problems do to the wildy changing vacuum in the inlet manfold and very strong pulses gebnerated by the faster opening and closing of the valves.

phil hill

433 posts

277 months

Sunday 4th April 2004
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Hmmmm, OK I'll bite.......

Block's been "decked" (no engine number !!).
No heater tap on cylinder head (hence cylinder 4 has run hot, as evidenced by clean exhaust valve and back half of piston crown).

Other than that, looks rich, really rich. Is the O2 (Lambda sensor) lying to the ECU ?? Has you even got an O2 sensor in that Maniflow LCB ?? Do you do lots of short trips ?? How many miles has it done since it was built ??

Dodgy Dave

Original Poster:

810 posts

252 months

Monday 5th April 2004
quotequote all
Thanks for the replies
Ok
Nick, The head gasket didnt look in a bad state. Interesting you think it may have been sucking oil and water in as I thought maybe it looked like the cylinders were leaking but looking at it again after what you said i do agree. Never burnt oil or used any water though.

Mike, The cam i put in was designed for the SPI engine. Ive never upgraded the ECU and injector as costs are more than the cars value and would rather put that money towards a kit
For a full spec (dont think i forgot anything) please have a look at my profile as it takes me ages to type out the list!!!

Phil, The reason the block has no number is because i bought it from mini sport.
Can i add a heater tap to the head?
I do have the Lambda sensor installed correctly as maniflow do a lcb for injector cars and puts it in same place as standard exhaust.
It done loads of miles since build which consist of driving the 40 mile round trip to work at mainly motorway speeds if i get up early enough!!
And it is driven fairly hard.
Think its done 10000 miles since i built it.
I was going to change the lambda sensor before as I have had the problem of over fuelling for some time but thought it was cured by a incorrect Thermostat.
Is there anyway you can check the sensor?

phil hill

433 posts

277 months

Monday 5th April 2004
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Dave

I don't think there is a problem with the head gasket, the contact areas of the "fire rings" look bright on both the head and the block. Also if it wasn't loosing water or burning or leaking oil, then I don't think that's the problem. Were the plugs clean or similarly covered ??

Most engine "rebuilders" wouldn't bother removing the engine number unless they have "decked" the block.

Another thought, did MiniSport change the injector ?? Or does the car have a "rising rate" fuel pressure reg ?? These are both ways of increasing the fuel without reprogramming the ECU. If either have been done you may have a lumpy idle and a petroly smell at idle as it could be a touch rich at idle. I'm not sure what the ICON does in this situation, does it mess about with ignition, fuel, or both do we know ??

The old favourite of checking tail pipe colour for state of tune has been largely negated by low-lead fuel, although if it was really rich you would expect the tail pipe to be black and sooty, a petroly smell all the time, and ultimately premature engine wear due to excessive petrol washing the bores clean of oil. As you have got 10K so far without it becoming "smokey joe" and consuming oil at a frightening rate, I guess it can't be too far from right.

You can fit the original heater tap on the head. Checking the picture on your profile it looks like you'll have to drill out the membrain which blanks off the hole, then fit the original heater tap and re-plumb. One thing to bear in mind is it will work backwards compared to the later style valve, pushed in for heat and pulled out for off. It's always a good idea to have some water flowing out of the tap, I never close the heater valve, I close the heater flap in the car.

Dodgy Dave

Original Poster:

810 posts

252 months

Monday 5th April 2004
quotequote all
Cheers for your help so far Phil

In the order you asked :
The plugs were also dirty, but again like the valves/cylinders some were worse than others

Whats involved in having a block decked and why?

Minisport never saw my car, I purchased the "Short Engine Kit" and did it all myself.

Its the std injector still on there and as far as i know there is no fuel pressure regulator and if there is one its never been touched!

All the ICON does is change the ignition timing.
I thought the only way to adjust fuel on injection mini's was to chuck ECU and Injector body and purchase adjustable ones.
The car was running fine before i took it apart.
The guy at MiniSpeed was impressed how much torque i had when setting up the chip!!

"Checking the picture on your profile it looks like you'll have to drill out the membrane which blanks off the hole"
Ahh i wondered what that was for!!
Is this something which is highly recommended as it can have a bad effect on valves/rings or something other?

Cooperman

4,428 posts

251 months

Monday 5th April 2004
quotequote all
Hi Dave,
Can I jump in here. I'm not an injection expert, but I do re-build quite a few engines.
Decking the block is done for either or both of two reasons. The first is to ensure the block in absolutely smooth and level, thus ensuring good gasket sealing. The second is to ensure the piston crowns come right to the top of the block.
When re-building an engine and after the crank is ground and the block re-bored, you do a 'trial build' (or 'dummy build' as some call it) using linished down gudgeon pins and with the piston rings removed. Then bring the pistons at 1 & 4 to TDC and measure how far down the bore the highest one is. Don't be surprised if there is a few thou difference in this dimension, BMC/BLMC/Rover tolerances were never that good. Repeat for 2 & 3 pistons, again taking the two measurements. Strip it all down and have the minimum of the 4 measurements taken machined from the deck of the block, using a tolerance of -0.001" to - 0.003".
Even if the pistons stick a few thou over the top of the block deck in practice, it won't matter. This can happen if the block has previously been decked and needs a light 'clean-up'. If the piostons are more than about 0.007" proud of the deck you should machine the piston tops down to get parity.
When you have finally assembled the block, crank & pistons you can calculate the volume needed in the head combustion chambers. It's a bit long winded, but if anyone wants the calculations let me know and I'll post the method and numbers on here separately.
It looks like a mixture problem on your engine, Dave, and when it's all back together I suggest you take it to Peter Baldwin's rolling road near Cambridge (01223 207217). Those injection ECU's are a black art to me. Give me a couple of HS4's anyday.

I hope this helps,

Peter

Dodgy Dave

Original Poster:

810 posts

252 months

Monday 5th April 2004
quotequote all
Cheers Peter
Beginning to think know I probably could of saved money and time on the mods by binning the ECU and Injector at the start and fitting a Super-Charger with Nitrous!!!
But hey ho you gotta make the best of what you got!!

Im thinking there is something defiantly at fault here, either ECU, Lambda Sensor or injector itself!
I need to find a way of testing each of them separately.

phil hill

433 posts

277 months

Tuesday 6th April 2004
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Hi Dave

Thanks to Coop's for explaining "Decking", I do tend to assume people know what I'm on about sometimes !! Most good engine builders will deck the block during a build, but a reason why decking has become more sort after in mini circles was an article by a certain D.Vizzard in one of the 'Keep you mini alive' mags from MiniWorld. The article goes into one of tuning's more difficult concepts, that of "squish". As far as I can make out it's all about concentrating the fuel mixture in the optimum position in the combustion chamber for the fullest possible burn.

The ECU can be sent away for testing, but I doubt it will have anything wrong. The injector has to be tested in a special high pressure rig, things like the open/close times can be checked, as can spray paternation. There will be a pressure regulator somewhere, I think they look a bit like a metal in-line fuel filter, about 25mm in diameter, 35mm long, fuel hose in and out top and bottom, and a central seam ?? The pressure regulator can be checked with a gauge, something of the order of 100~150psi. I'm not sure what pressure the mini runs at, but it's likely to be anywhere from 40 to 100psi. Lambda sensor ?? Not sure how you test, but it should give out a voltage in the range of 0.8 to 1.2 volts from memory.

Another "quick and dirty" trick some people try to increase fueling is to gently crush the body of the pressure regulator in a vice. This puts an unidentified amount of extra pre-load on the spring inside the regulator, which increases the set pressure. Very imperical, but if the fueling has been checked on the dyno. and it's ok over the whole load and speed range, then what can you say ??

Plotloss

67,280 posts

271 months

Tuesday 6th April 2004
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Lamda or air flow meter maybe?

Seems like something is misreading and consequently overfuelling...

Dodgy Dave

Original Poster:

810 posts

252 months

Tuesday 6th April 2004
quotequote all
Cheers Guys
I think i gotta start with the cheap fixes and work my way along the list in the hope that one of them will solve it.
Saying that though its gonna be very difficult to know if its solved because the car was running fine before I dismantled it.

Maybe regular checks of the plugs and the MPG I get will be the best way to know.

The "Airflow Meter" is the part that resides in the air-filter isnt it?
I think that first then the fuel pressure regulator then the lambda.
I think your right about the ECU phil, They either work or they dont!

Cant I put bigger plugs in with a really high output Coil to help burn the extra fuel!! Ill get a bigger bang then!!!!

Mr2Mike

20,143 posts

256 months

Tuesday 6th April 2004
quotequote all
Dodgy Dave said:
Cheers Guys
Cant I put bigger plugs in with a really high output Coil to help burn the extra fuel!! Ill get a bigger bang then!!!!


Only if you can jam some extra air in as well

Dodgy Dave

Original Poster:

810 posts

252 months

Wednesday 7th April 2004
quotequote all
Mr2Mike said:

Only if you can jam some extra air in as well



So if i charge up the compressor and buckle it up into the passenger seat, feed the hose out of the window and under the bonnet.
Cut a hole in my filter and run it into the intake, your saying thats all my problems solved!!!

Cooperman1

116 posts

244 months

Wednesday 7th April 2004
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Dave,
I can't remember what year your car is, but could you fit a pair of 1.5" SU's on a really nice manifold?

Dodgy Dave

Original Poster:

810 posts

252 months

Thursday 8th April 2004
quotequote all
Its a 95 Peter
Uses the same block as any older mini so I can turn it into any type.
To fit SU's i think id need to remove ecu, throttle body and fuel tank. Not to sure what i would have to do about all the wires which would be left hanging but it can be done with out to much trouble.

Thought and asked about this before but was thinking forced induction!

Cheers