Siezed Fuel Pump - again

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kevp
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Siezed Fuel Pump - again

Post by kevp »

Im unsure if you can recall but last summer I had trouble with the engine cuting out after it had run for about 10 minutes, ie half a lap. When the engine cooled down the car would run again for 10mins.
It turned out to be the fuel pump was siezing up when it got hot. I fitted a new pump for the Llandow day (the management had not been adjusted for the new fuel pressure). Well that was the last time I used the car. It has been away waiting for the new garage. The car is back in its new garage, started it up & the usual spring check over, and the pumps gone the same way!.

The pump sits in a small swirl pot (VW) in the engine bay on the bulkhead under the pedal box. So not the hot side. I know the fuel keeps the pump cool & is constantly circulating. It has not run dry.

Any ideas as to why or how to overcome the problem, otherwise its a new pump every few drives!.

Hope you enjoy your easter eggs.
Schrodinger
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Re: Siezed Fuel Pump - again

Post by Schrodinger »

You are using a low pressure pump to feed this from the tank?
Keith
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kevp
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Re: Siezed Fuel Pump - again

Post by kevp »

Yes. I have a small feeder pump.
stylussprinter
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Re: Siezed Fuel Pump - again

Post by stylussprinter »

Kevin , try a PM to ''babybertha'' on this members list . He's a good engineer and if you give him all the info on past history (pipe size/pump psi/filter/layout) I'm sure he'll come up with an answer we all haven't thought of :wink:
I just love the Stylus but she keeps swallowing £££ !
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Schrodinger
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Re: Siezed Fuel Pump - again

Post by Schrodinger »

Do you have a photo of the accumulator in place?
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norma
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Re: Siezed Fuel Pump - again

Post by norma »

I had the same problem and had the swirl pot in the same place as you.
Fixed it by insulating the swirl pot with aluminium/glass fibre type material.
Nevr had a problem since.....
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kevp
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Re: Siezed Fuel Pump - again

Post by kevp »

Hi. Thanks for the comments so far.

Possible causes are;
Heat - insulate the swirl pot. I am unsure that this will help much. The pump is in the shade and the fuel is running around the injectors & back to the tank. This should keep the pump cool. Also the problem happens almost exactly after 10minutes, the engine has only just got to temp & the fuel temp would not have risen that much.

Pressure - perhaps the regulator is set to high & the pump is forcing against it. The injection timing is set at 2.05 m seconds on idle. This does seem to be a short duration looking at other maps suggesting a high pressure.

Incorrect plumbing - It’s a VW accumulator. From the pump the high pressure returns to the top of the swirl pot next to the pump. The low pressure feed enters the rear chamber & the return to the tank also runs from a rear connection.

Over voltage - I feel this is unlikely as the battery only ever gets up to a max of 13Volts. Also this would shop up as a blown fuse or melted pump.

Rob I will pm BB, Thanks
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kevp
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Re: Siezed Fuel Pump - again

Post by kevp »

An Update.

Today I have an expert (well it cost a lot so he must be) :( look at it.

The fuel regulator was all over the place, but mainly off the scale. So the pump was working at over 100psi (should be 40-45psi). 1 injector does not seem to be working correctly & the throttle linkage is not smooth at idle. He checked the ignition & cam timming - this was OK.
We tried a regulator from another car (Porsche 911) but the pressure was still 60psi. Its possible the injectors I have cannot run at that pressure & are having trouble closing.

I need to get the injectors flow tested & sort the regulator out. Then its back for another go.
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