AZX1308 Fuel Pump

[kingroon]

Hi,

I have a failed Fuel Pump on my 69 Series II 2+2, which looked to be a new unit a few years ago, but having sat for some time has [I'm guessing] gummed up with Old Fuel.. I used a Persuader to try and waken the Motor, which worked feebly when disconnected from the Mechanical Unit, but ultimately would not push the Fuel up to the Carbs when connected.. In fact, the pressure at the Carb end of the Hose was non-existent.. So, new Pump..

I see that the AZX1308 has been superseded by the AZX1308U Dual Polarity model; is this the go to replacement..? Or is there a more modern solution to what appears to be [from Googling etc.] a common issue for Motors that aren't used every day..?

I can't imagine I'll be driving mine to the Train Station as part of my Daily Commute, so would prefer something a little more robust and that doesn't mind sitting for a week/fortnight/month or so..

Any help, guidance or advice greatly appreciated..
Matt

[Gfhug]

Matt, have you asked SNG Barratt and Burlen (sucarb.co.uk) what they advise?
Remember a member of the JEC or JDC gets a discount from SNGB which easily pays for the cost of membership with the savings made. But always worth checking the prices they charge in case eg Burlen are cheaper or vice versa.

Geoff

[mgcjag]

The 1308 is standard points and still available the 1308en(sngb 1308u) is the electronic version..and is the way to go in my opinion..Steve

[caveman]

Part Number: AZX1308EN for Electronic Neg Earth
https://sucarb.co.uk/su-fuel-pumps-spar ... ive-2.html
I’ve recently fitted one and so far so good.

[kingroon]

..have you asked SNG Barratt and Burlen (sucarb.co.uk) what they advise?
Remember a member of the JEC or JDC gets a discount from SNGB which easily pays for the cost of membership with the savings made.

Hi Geoff, thanks for the advice, I guess I should have gone straight to the Mfr off the bat..

I haven't joined up to the JEC yet..

..the 1308en(sngb 1308u) is the electronic version..and is the way to go in my opinion..

Great, thanks Steve, I did wonder that the newer model might be the Pump of Choice..

Of course, once I have installed the new Fuel Pump, the next logical step is a Triple SU Carb Upgrade, right..?!

[kingroon]

Well, that didn't exactly go as intended..



Plan was to fit the new Fuel Pump, fire her up, and then hit the Kent B Roads..! Of course, that was a Pipe Dream..

I ordered a new Fuel Pump, and set this Saturday aside to fit it, along with flushing the Fuel Hoses and Pipes to get rid of any Gunk that would just foul the new Pump as it had the old.. However, removing the seized Fuel Gauge Sender Unit [that wasn't a good sign], and looking into the Fuel Tank, it became obvious that in fact the Tank needed replacing; at the very least reconditioning..

So, removing the Tank.. Once drained of Fuel via the Sump, and all hoses labelled and disconnected, removing the Tank is straight forward in a wiggly kind of way.. Held in place with three securing bolts, one of which mounts to a Bracket the retaining Nuts of which can be removed from underneath the Car..





..then remove the Sump Tower and wiggle.. Looks like a PO had a minor disagreement with a Speed Bump, the collateral damage being a Bent Sump Tower.. Pretty lucky the damage was cosmetic.. Nonetheless, new Tank is the way to go..

[kingroon]

To Do List:

• Clean Pump Pipes, soak in a Petrol Cleaner

Shopping List:

• Fuel Tank

• New Banjo Bolts [4] and Seals [8]

• Sender Gauge

• Fuel Filter [4]

• Fuel Hose 3-4mm Internal [check Tank Outlets] 2 Metres

• Cork Seal Rings

Wish List:

• Additional Inline Filter..?

• Shorter Drainage Tower..?

[caveman]

When your fuel pump is fitted, check the fuel pressure figure as mine was 3.8 psi at the filter (ignition only) and too high for the triple carburettor recommended pressure of 2psi.
You may want to add a Malpassi Filter King pressure regulator to your list to keep the pressure under check. More info on the forum:
viewtopic.php?f=3&t=14130

[kingroon]

When your fuel pump is fitted, check the fuel pressure figure as mine was 3.8 psi at the filter (ignition only) and too high for the triple carburettor recommended pressure of 2psi.

Thanks for the Tip..

I am running Dual Stranglebergers, will this still be applicable..?

[caveman]

For both cars the fuel pressure is the same and should be around the 1-2 psi mark. Up to 3 psi for a modified engine.
Some great tuning tips in the knowledge base:
https://www.dropbox.com/s/6pmcaqykapw7n ... e.pdf?dl=1

[kingroon]

Trial fitted the new Petrol Tank successfully, just waiting for a few ancillaries to arrive, then I can fit in earnest..

[caveman]

A quick update on my AZX1308EN Electronic Neg Earth SU pump recent experiences.
First one ordered in Jan 2024 failed after no more than 3hrs use. It failed to deliver fuel on its final run out after 1.5hrs continued use, leaving me to finish my trip away on a spare Facet. Both utilising filter king fuel regulator. It was too hot to touch when I tried to remove on the side of the road! It was despatched back to Burlen via supplier.
The replacement SU, fitted early August and again the electronic version, failed straight out of the box and couldn’t fill the fuel bowl! I’m now in a quandary and am wondering if the points version is more robust or maybe this was a bad batch I also know of an S3 variant failing out of the box

[MarekH]

The original setup is extremely simple. I'd suggest that newer "upgrades" have a smaller operating window, i.e. a lower amount of headroom for when the pump is asked to do more work than a normally functioning system does and that they are thus less tolerant of poorly maintained or ageing cars.

kind regards
Marek

[caveman]

Both cars in question are well maintained but on these occasions 2 out of 3 failed straight out of the box, go figger. I personally suspect lower quality circuit boards/electronics, post Covid shortfalls etc.

[MarekH]

Indeed, but the old points style system has very few drawbacks that need upgrading. If, for argument's sake, the pump draws 5 amps instead of 3amps, the points continue working (albeit now ageing prematurely) and the wiring isn't going to be anywhere near melting below 10amps,..... but the upgraded super duper complicated circuit may not like to work at 5amps because some of the components on there are spec'd without an overhead, whereas the simple workhorse just plods through anyway.

Essentially, the old style brute force circuits have a 30 year track record behind them but the new circuits won't have that safety record until another 20-25 years have come and gone. That's why my points saver circuit is simple - it solves the one problem the conventional SU pump circuit has and doesn't introduce any new unknowns.

You can of course take the contrary view and thank the new circuit for failing - there may be something badly "wrong" and the circuit board is acting like a very expensive fuse. Thank your lucky stars it is failing and stopping something even more serious from happening. Or there may indeed be some duff components on there - without testing it, I don't know - the jury is out as one or two failures from thousands of sales is not really more conclusive than it being anecdotal - imho.

kind regards
Marek

[caveman]

Interesting reading Marek and thankyou for your input. Having also been reading Jag Lovers these past few days, others have had similar failures so I think the issue maybe bigger than first thought. What I omitted to say was that all 3 units came from the same independent supplier so maybe bad batch?? As there’s not too much to get wrong when fitting i.e. a good ignition feed and a good earth point, there was definitely something internally amiss, the excessive heat of the SU pump body tells me things weren’t correct with any of these pumps, thankfully my S1 doesn’t have the covering around it like the S3 variant as I know that would have melted in situ.
I’m at a loss as to which variant to purchase now, having literally been ‘burnt’ with the electronic versions. Part of me thinks to go full old style points and convert later. In 20 odd years, my Facet pump never let me down once and is currently refitted to at least get me through the final weeks of summer.

[MarekH]

If you want to send me the old stuff, plus any points or spares, I can look at it and deduce what has failed. I'll PM you my details.
kind regards
Marek

[mgcjag]

Hi Steve..Marek hasent really promoted that he makes a small circuit board that fits into a standard points pump and it uses low current through the points to switch high current through the cct board...thus saving the points..
.I would go for a new points pump and fit one of Mareks circuit boards....Steve

[MarekH]

I'm happy to send Steve one of my boards for the cost of just the postage if it means I get to learn "why what doesn't work" from being able to examine his old board. It's called education I suppose.

kind regards
Marek

[caveman]

Steve, Marek, many thanks for the information and kind offer Marek. I was aware of the conversion and may well look to convert an older points style pump as a spare, in the near future. My recent electronic pumps, being new, have been returned under guarantee otherwise I would have jumped at the chance to upgrade. Having read more posts here promoting the electronic versions I have since ordered another solid state version and should take delivery tomorrow so will see how that goes.