16 replies to this topic

[Shingler4596]

Ok so from start up when you rev the car it's not too bad but after warming up once it's revved it spews out black smoke. Any ideas? It's not an earth or fuse problem.

[Guess-Works.com]

Black smoke is soot, which usually means it's running very rich, take you spark plugs out and have a look, they should be light tan, but if black and sooty then it is definitely running rich, which means you have a problem with the injection/emission control system. Needs plugging in to a code reader/diagnostic machine for further investigation.

[Shingler4596]

How would an injection/emission control system problem be resolved, bearing in mind this all started when we replaced the pump with a replacement

[Shingler4596]

My idea is a problem with the injector as the mini was run dry not too long ago and it looks as if some crap got into the pump and packed it in so was wondering could the same have happened to the injector as we idling with the filter off it look like it's spraying way too much fuel for idle, an almost constant stream I'd say.

[Guess-Works.com]

Did you replace it with the right pump ?

Basically the SPi runs a different fuel pressure to the MPi, however, it seems sellers market the MPi pump for both and then states that the ECU should modulate ( not sure if that the right use of the word ) the fuel pressure accordingly. However, if the ECU is not doing this then the higher fuel pressure of the MPi pump would in theory push more fuel through the SPi injector...

 

So, first check to see if it's running rich by looking at the plugs, if it is then plug it into a diagnosis machine and find out what fuel pressure it is running at and also if there are any other diagnostic codes available.

 

[Guess-Works.com]

My idea is a problem with the injector as the mini was run dry not too long ago and it looks as if some crap got into the pump and packed it in so was wondering could the same have happened to the injector as we idling with the filter off it look like it's spraying way too much fuel for idle, an almost constant stream I'd say.

 

The spi always looks like its just pumping fuel into the throttle body, if you think about it, at 1000rpm that's over 30 pulses of fuel per second.

[Shingler4596]

It's deffinatley running rich, the pump we replaced it with as far as I was told is an OE syntec pump for SPI minis, problem is we don't have a diagnostic code reader for the mini so can't check it, the car was running great until the pump packed in

[Guess-Works.com]

I'd be finding a 2nd hand spi fuel pump ( or complete tank ) and trying that...

[Shingler4596]

Problem is you can't find any second hand pumps and the entire pump with pipes and tank top is about £170 and is rather not spend that money to fins out its not that which I doubt it is as the seller can good feedback on the pump I have

[Shingler4596]

I'd be finding a 2nd hand spi fuel pump ( or complete tank ) and trying that...

could it be a lambda sensor problem as the car was running poor before we had the problems with it running too rich and the had to cut this sensor out of the old manifold so it was bumped around alot

[Guess-Works.com]

So it's not just since the pump has been changed... You've also changed other things... ??

 

Rule 1 of diagnosis, if you've changed something and now it doesn't work, then it's a pretty good bet what you changed caused the problem.

 

Where possible, put things back to their, pre fault condition.

 

So between the car working properly and now, what have you changed ?

[Fast Ivan]

 

I'd be finding a 2nd hand spi fuel pump ( or complete tank ) and trying that...

could it be a lambda sensor problem as the car was running poor before we had the problems with it running too rich and the had to cut this sensor out of the old manifold so it was bumped around alot

 

it could be the lambda, it could be the coolant sensor, it could also be the air filter

point is it could be many things and just swapping out things is going to be hit and miss at best and very expensive

I always say start with the service condition of the car, oil, filters, valve clearances etc.etc. this also includes all the pipes and tubes that the spi has, make sure all the wires/loom are in good condition, check and clean all the sensors/connectors.

 

You say that all was well before the fuel pump change; this has to be checked out, make sure its the right one, as I said in your other thread; a higher pressure fuel pump could cause over fuelling.

 

owning or having access to diagnostics equipment is a must for the injection mini owner in my opinion, 150 - 200 on a code reader and a multimeter when costed next to a mini that could cost thousands doesn't seem to much to me.

 

There's a few pinned threads on the front page on the injection section that are very useful, I would start having a read through those, they are very informative and specific to the spi

[Shingler4596]

I won't be just randomly replacing parts, I will be testing each of the parts properly first.

[Guess-Works.com]

Catch 22, you can't test the parts properly without a diagnostic machine.

[FlyingScot]

Agree with the point on diagnostics, many many of the issues members post on here they could solve themselves with a check, yet they seem willing to spend on random parts without knowledge of what has gone wrong.

With regard to your query on fuel pumps, the SPi is designed to run 1 bar pressure. The fuel pressure is set by the mechanical regulator fitted in the main SPI unit and isn't adjusted at all by the MEMS ECU, if the regulator is faulty you will have an issue as the MEMS adjusts the injector pulse timing. Diagnostics will tell you nothing In this case as there is no measurement of, or control of the pressure.

You can however test the fuel pressure which is described in the workshop manual to confirm the pressure.
AFAIK the pumps are the same between SPi and MPi but the fuel pressure is different due to the regulator differences, SPi in the main body of the injection unit, MPi in the fuel rail.



FS