Fuel pump's, is there any difference?

Post Thu Jul 27, 2006 7:55 pm

Hi all,

As you have all guessed by now i've done an M20 conversion on my pride and joy

I've got a feeling my fuel pressure is'nt upto scratch and want to know if anyone can tell me;

1. Do i need to install a 2.5 fuel pump?
2. Is there any difference between the 2 pump's?

Original engine was M40 1.8L
Conversion to M20 2.5L

Post Thu Jul 27, 2006 8:57 pm

i was told that all the e30's used the same pump but unfortunately i cant verify that.

Post Thu Jul 27, 2006 9:44 pm

Cheer's mate, that put's that out of the question then

Ok, i'm gonna tell you all what's happening

I put a FSE valve on the 1.8 M40 when it was in my motor so i did'nt see any reason, at the time, to change the mod.
I put the FSE valve on the 2.5 and all has been fine. Spoke to a few people and the FSE valve popped into convo and i was told to get rid of the wrongness by very well known mechanic's so the FSE valve has now been taken off.

I've now got a really shitty idle, like there's not enough fuel pressure.

The reason i ask is because it seem's to be leading this way through symptom's caused by me taking the FSE valve off.

What are your view's and do you know my problem?

Cheer's

Post Thu Jul 27, 2006 11:27 pm

My 318i touring is running the 2.5 M20 on the M40 fuel pump, no problems. All the fuel pumps are the same AFAIK.

Its possible that the FSE was masking an idle problem, so by taking the FSE off (good man) the idle probem has reappeared.

Post Thu Jul 27, 2006 11:55 pm

jmc330i wrote:My 318i touring is running the 2.5 M20 on the M40 fuel pump, no problems. All the fuel pumps are the same AFAIK.

Its possible that the FSE was masking an idle problem, so by taking the FSE off (good man) the idle probem has reappeared.

True.

It's not something drastic to worry about but it get's on my nerve's as i feel i'm not as such a novice mechanic but i can't get my head round it

I fitted a ported inlet manifold before putting it in (Done by Bexley's), would this course this?

If it is that then i won't bother worrying anymore

Post Fri Jul 28, 2006 6:46 pm

Problem solved, did the valve clearance's and she purr's now

Post Fri Jul 28, 2006 7:04 pm

Where did they port ?

Did they match it up to the head ports or inlet gasket ?

Post Fri Jul 28, 2006 7:13 pm

Andy335Touring wrote:Where did they port ?

Did they match it up to the head ports or inlet gasket ?

I'm not sure to be honest mate, i bought it from "ScottPlayer6" as it was and chucked it on before the engine went in.
As far as i could see, they've mainly just taken the sharp edge off so it should be fine???

Thank's for your reply Andy, much appreciated.

Post Fri Jul 28, 2006 7:23 pm

jonbuoy wrote: As far as i could see, they've mainly just taken the sharp edge off so it should be fine???

If it's just a mild tweak it should be ok, if they took off lots of metal from the inlet manifold ports but didn't touch the head ports then you will have a nasty flat edge which will hinder the air going in smoothly.

Post Fri Jul 28, 2006 7:59 pm

That is no doubt the case as the inlet was'nt designed for my head.
The head on mine is either reckon or new so it definately has'nt been matched

Would it be better to put the original back on?

Post Fri Jul 28, 2006 9:01 pm

I'd leave it on for now as i get the impresion from you that they haven't taken loads off and/or they just smoothed the rough edges off ?

May be they just matched the inlet manifold ports to the gaskets ?

If you ever need to take the manifold off eye up the ports of the head and manifold with an inlet gasket to compare them.

Post Sun Jul 30, 2006 1:43 pm

Cheer's Andy, thanx for your help

The edge's are just smoothed off so i think i should be safe with the size of the port's.

Thank's to the people who replyed to my thread

Jon