Intermittent fuel problem

[95-540iLE]

Have a problem with my H23 and hope you guys can help.

I have in the past noticed that the car starts to hesitate and run poorly - sort of like the first warning hesitation you feel if you run it completely out of fuel - when the tank gets down into its bottom 1/3rd or 1/4. When I noticed this, there was definitely plenty of fuel and filling it up removed the hesitation.

More recently, after having a set of headers fitted, I drove the car home - probably within the 1/4 to 1/3rd of a tank range - and the car hesitated big time, before feeling and sounding like it was running on partial cylinders and then completely stalling.

Not being able to work out why, I called our local AA. The first thing they did was put a couple of litres of petrol in and it started.

I have since filled the tank and in the limited driving done since, no problems.

As such, it appears the problem was fuel related, but I am not sure where to start looking for it.

Before I start removing and cleaning tanks/replacing fuel lines and pumps, are these symptoms a sign of a common problem?

Any suggestions that might short circuit my analyses of the fault?

Thanks in advance.

David

[Brianmoooore]

An E30 usually makes a good job of virtually completely emptying its fuel tank with no problems whatsoever. Start by taking out the fuel pump, and seeing if there is anything amiss with the pick up.
Is this car pre '88, with the two fuel pump set up?

[95-540iLE]

Thanks Brian. It is a 1985, based on a 323i.

[Brianmoooore]

In that case, check that the in tank pump is actually working.

[95-540iLE]

Again, thanks. I'm not really sure how to do that. Is there a relatively simple way of doing this?

Regards

[Brianmoooore]

Take the outlet pipe off and power it up! May be a good idea to fit a short length of alternative hose into a container of some kind.

[95-540iLE]

Got under my back seat today to check the fuel pump. Is anyone able to confirm what the part number is for the pump I have to order to replace it?

[95-540iLE]

Thanks Will - just checked the part number on realoem and it comes up as present on most E30's, but not the 323i.

323i comes up with a special part for Australian versions:

For vehicles with
National version Australia
and
Saudi Arabia version
L810A=Yes
10 SUCTION DEVICE WITH PRE-SUPPLY PUMP 1 09/1983 16141179415 $422.64 See SI 160287646


Not doubting your advice, but just checking ...

[Brianmoooore]

Given your symptoms, willnz's split pipe theory is quite likely correct!
If you have to renew the pump, get a second hand in tank high pressure pump, as fitted to E30's from '87 on. You need the two pipe version, from a small tank E30 (small engined saloons), remove the old high pressure pump completely, cut back and insulate its wiring, then run a pipe from the new pump outlet to the beginning of the steel fuel feed line under the car.

[95-540iLE]

Thanks guys. Will have a play around with it tomorrow.

[95-540iLE]

OK, it turned out to be the fuel pump. So I ordered a new one from BMA parts in the US using part number 16141184022. Cost US$195.

It arrived this week and I just had a look at it. And it is the wrong part. Only one pipe into it and the plugs for the electronic part is wrong. See pics.

Have I been sent the wrong part, or is the part number wrong? Comments and assistance greatly appreciated!

Regards
David

[Brianmoooore]

The easiest solution for you is probably to swap the actual pump into your old frame. Just requires soldering of the two pump wires.

[95-540iLE]

Will, the part number I ordered was the part number you gave me. That's why I was asking to see if they sent me the wrong one. Looks like they did.

I think I will have to try the soldering option suggested by Brianmoore ...

Thanks
David

That is the pump from the later tank with the fuel return built into the tank. Your tank does not have a return, it is the other pipe on your original pump.

The pic you posted of your pump top is identical to the 323 I have. It was NZ new. I would think the part number I gave you originally would be the one to suit your car.

Will

[95-540iLE]

OK, after spending months making sure I don't get below 1/2 a tank, I finally found time today to pull the fuel tank pump to attempt to change the new pump into the old frame (nice sunny 35C here today by the way!!)

But I have so far found it too challenging. There are a number of issues.

The new frame forms parts of what is needed to hold the much larger new pump - without it, the pump is flimsy and could fall off. Also, with the longer new pump, the assembled frame is too big for the tank. The wiring is an issue as there are two wires going to the plug in the new assembly, but only one in the old (it has another going to an earth) - I presume one of the wires on the new pump is also an earth wire.

Any helpful assistance out there? Or an alternative part number for another new pump that is the right part? Anyone have an old working one that they could sell me for a decent price? Anyone want to buy a cheap single pipe pump?

Pics below:

[95-540iLE]

Also, to what extent, if any, are these exposed wires an issue? I presume given that the connectors are also exposed, they don't pose a risk?

[Brianmoooore]

Only comment I can make about this is that the silver pump is the one I recognise as an E30 pump. Don't recognise the smaller one at all.
Exposed connections, and the sparks produced inside a pump as part of its normal running are no risk at all. Not enough oxygen present for anything nasty to happen.

[95-540iLE]

Thanks Brian. I have since sought a quote for pump part number 16141179415 from BMA in the US, who had one in stock. They were able to email me a pic which confirmed that this is actually the correct part to replace my in tank fuel pump.

Pic attached:

[95-540iLE]

Part number 16141179415 arrived today and now fitted. All good now!

Thanks for everyone's help!

regards

David