Just had the fuel pump on my sei die again - that would be the third one the car has been through.

The blasted thing has been messing around the last couple of days and now won't make more than 1 bar pressure. Not so bad for a standard car but I use a Punto 75 pump which is supposed to work at 3.5 bar!

What I can't figure out is why they keep dying. At that pressure the injectors aren't working overtime and the pump isn't being stressed that badly. I avoid cheap, nasty fuel like the plague and the tank is wonderfully clean (having just inspected it).

Anyone know what the control voltages are? The only thing I can think of is that my ECU is pushing the pump too hard unnecessarily.

I've had the same problem with my ITB setup. Initially I thought my injectors were too powerful but they are right.

I'm still using the MPI 3bar pump, but thinking it's might be a good time to go overkill with a big pump.

Thanks

X

Having carried on reading through older posts (thanks to the associated topics links) I found a nice diagram showing the setup on the older rally spec 600's and it clearly shows a second fuel pump assisting the normal (standard) pump. I'm already using a few Supergara odds and ends in the engine as they had already solved the problems I was suffering from when the car was put together so a few more wouldn't go amiss.

Plumbing in a second pump wouldn't be difficult. Fuel pressure would stay the same as that is a limitation of the pump regardless of how many you have in parallel but it will definitely help with the flow rate. The problem I can see from it is that the extra pump doesn't sit in a trap like the standard one does so starvation going around corners at big throttle settings is a definite possibility.

I think I may have to invest in a swirl pot and a second in-line pump (actually I think I have both of these lying around unused from my race car) but I have no idea where to fit them as the engine bay is already rather full.... more so now that I am trying to get a proper airbox put together for the throttle bodies.

One last thought - how does the pick-up filter come off the pump? I can see how the pump comes out of the trap housing but the filter seems very firmly attached. Adding in an alternative pump would be relatively simple.

What regulator are you using? I'm still using the one built in the fuel pump housing. It's probably not helping with me using that method to be honest...

I know on turbo applications you some times have to use 2 pumps and a swirl. Surely we could get away with one strong pump with a resistor in the power feed?

Thanks

X

I'd forget about the resistor.

I've only experienced fuel surge on one cento -- a 1242 Cinq with sticky tyres and the stiffest suspension known to Centokind. Engine would cut dead when doing sharp turns with less than a quarter tank of gas. I remember someone (maybe Craig?) saying that it had to be down to an issue with the fuel pump as it had some kind of built in swirl. I didn't think this was the case until I stripped the tank much later -- one of the pipes at the very bottom was'nt clipped in right and pointed back to the tank, rather than into the pump.

One sprint Cinq (at least) has the tank foamed (for safety, but it would further prevent surge), but the Sei has that horrible ballcock fuel level thing, so that might present problems.

Webcon sell "in tank" pump/swirl units. They look a litttle like the Sei ones, but neater .

Important to remember that a pump must both deliver fuel (or be capable of delivering fuel) at a given pressure and a given rate.

Or these guys will cut you a good deal on an in tank pump to replace the stock unit, and give free advice.

Seriously considering using my current pump as a lifter to fill a proper swirlpot and an external pump to pressurise the fuel rail. It seems a shame to leave them sat in my garage doing nowt... problem is they were meant for a stupidly powerful turbo engine instead of a marginally insane na engine.

But you don't need the swirlpot, so why bother?

just buy my pump i have for sale in classified

Have you managed to come to a solution Jim?

I'm not going to think about buying a new pump until a solution can be conjured.

Talking to Kritip about the issue, and this has him scratching his head.

The idea I came to was to try the pump that came from the same model motorbike as the ITB's, but they mount completely differently.

Thanks

X

I have uprateds to a punto Mk2b sporting pump on my 16v cento. And it has been working great for the pass 3 months.

What is actually the problem here? Do people experience problem with a standard pump on a standard cent o ?

Ming

ycming said:

I
What is actually the problem here? Do people experience problem with a standard pump on a standard cent o ?

Ming

Click to expand...

Only if the pump goes wrong -- which is pretty rare.

What fuel pumps has the OP been purchasing? I really can't see why you should have had so many issues. There's alot of more powerful pumps that would fit, then just whack on an aftermarket fpr - should be fine.

Yep. I think they're suffering from the "lets stick a pump from the scrappy on" syndrome forgetting that the "new" pump has probably been abused for the best part of 100k miles already.

A new Wallbro or Webcon one can be picked up fot less than 80 quid.

:yeahthat: its one of those pieces of a car i would always buy new tbh

Neither of us would be the kind to fit a second hand pump to be honest.

Mine died after 300 miles and this is the first problem I've came across fueling wise. It could be that the ECU isn't setup properly in my case because it never had chance to hut a RR.

Either way it just seems coincidence that jim has also had problems.

Thanks

X

yeah i would just put it down to bad luck and just replace - sure it will be fine..

Actually it turned out that the pump wasn't the entirety of the problem.

I replaced it only to find the car still wouldn't start. Fuel pressure is good - reading 3.1bar at the regulator instead of 1.2bar which is what I was getting before, when the pump decided to kick in for a while.

I cleaned the crank trigger up and suddenly it worked up - I found a chunk of rusty metal had stuck to it. The engine was *much* smoother after this and it actually idles at 800rpm instead of 1200rpm when warm - one of the gripes I had with the engine builder so it looks like it wasn't actually his fault afterall.

Unfortunately that isn't the end of it - since then it has cut out a few times. When it does the pump has stopped. The remaining potential culprits are the ECU (unlikely as it is kept dry inside the cabin and tends to be an all or nothing affair), the fuel pump relay (currently residing just behind the passenger side headlamp) or some of the wiring joining it all together.

Last night I doused the connections in WD40 and it the engine cleaned itself up pretty quickly - although still running rich enough to spit flame on overrun, much to the delight of my wife and daughter who were behind the car when I revved it up.

This morning it started fine but a mile down the road the fuel pump stopped again. Checked all the connections and nothing much made any difference. Reset the alarm/immobiliser and it all started working again, whether this really proves the source of the latest facet of this fault I don't know but it is another lead (or wire rather) to follow.

What I did notice this morning is that there is a lot of grime on the fuel pump relay terminals and an equal amount of corrosion on the mounting block contacts so I'm going to see if I can clean them up tonight. I'm also going to see if I can find where the immobiliser interrupts the fuel pump signal from the ECU and see if I can get it exposed to test it next time things play up. I really don't want to have to pay an autoelectrician to sort it out...

ycming said:

I have uprateds to a punto Mk2b sporting pump on my 16v cento. And it has been working great for the pass 3 months.

What is actually the problem here? Do people experience problem with a standard pump on a standard cent o ?

Ming

Click to expand...

I don't think anyone posting on this thread has a standard cento...

Are you sure it's the fuel pump that's at the bottom of this?

Next time it cuts out, check for spark. No spark and no fuel always = TDC sensor.

But cleaning up all the terminals and coating them with silicone grease never did any harm.

when i first started i had a standard one

Give the pump a constant 12v see if it still cuts out?

surely once the car has started the immob does nothing.

Ming