mk 1 16v fuel pump question

All aspects of tuning,modification and repairs to the BX 16valve.
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mac1776
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mk 1 16v fuel pump question

Post by mac1776 » Sat Apr 13, 2019 2:28 pm

Hi Guys, now the weather is allegedly improving it is time to make a start on getting the old girl to start !!
Compressions & sparks are good but no fuel is getting through to the injectors when the engine is cranked over.
Fuel is pumped as far as the fuel rail when the ign switch goes through to start but when the switch is released back to the run position the fuel stops flowing,is this normal?
Surely the pump should be running in the 'run' mode on the ign switch? Any ideas/pointers would be appreciated before I attempt to give it a go on Tuesday.
Many thanks in advance
Regards
Mac

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Vanny
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Re: mk 1 16v fuel pump question

Post by Vanny » Sun Apr 14, 2019 8:20 am

I think, and I'm afraid I'm no expert, that it primes when on ignition by running for a fixed time period (3s) then stops. On crank the pump doesn't start again until the ECU sees the engine running but I'm not sure of the criteria for this.

EDIT I've recently learned this is a load of horse manure for a 16v!

mac1776
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Re: mk 1 16v fuel pump question

Post by mac1776 » Sun Apr 14, 2019 1:41 pm

Hi Vanny
Thank you again, I will have a look on Tuesday.
Regards
Mac

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Dave
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Re: mk 1 16v fuel pump question

Post by Dave » Mon Apr 15, 2019 10:41 pm

You may have sorted this by now but if not you may want to check the relays located in the o/s wing. There are two, one deals with the pump and the other powers the injectors once it is provided with a signal. There could be a fault with the relay or the signal getting to it originating from the crank angle sensor. Fits in with what vanny said. Try disconnecting and connecting the relays a couple of times in the first instance, They can be seen when you lift the bonnet tucked up in front of the strut area.
Prefer it to the Lamborghini, like Signor Gandini!

mac1776
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Re: mk 1 16v fuel pump question

Post by mac1776 » Thu May 02, 2019 6:15 pm

Hi Dave,
many thanks, I have confirmed they both click when the ign is turned, which they do. I s there anything alse I should be looking for in that respect?
Cheers
Mac

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Dave
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Re: mk 1 16v fuel pump question

Post by Dave » Thu May 02, 2019 10:49 pm

Hi Mac,

It does not always follow that a clicking relay is good, it may still not be working. You can check by putting power to it then see it is activating fully across the other terminals with a multimeter by checking continuity. I think the injector relay also has a bit extra inside so perhaps not as easy to check. But assuming it works, there may be a problem with the tdc sensor which I believe is the trigger. Could be dirty or no use. Other than those items, something between or leaving the relay.

Just a thought, I don't suppose you have an immobiliser fitted which is not deactivating?

Also, have you enough fuel in, I guess so since you say it pumps at first but just to be sure, not low on a angle for example. Another thing, is the battery good, somewhere I have seen a poor battery cause starting problems on the 16v.
Prefer it to the Lamborghini, like Signor Gandini!

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Vanny
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Re: mk 1 16v fuel pump question

Post by Vanny » Thu May 09, 2019 5:40 pm

I've recently been educated that valver pumps only run when cranking out running. Confirmed by physical test on the ph2 sat outside (in the rain).

Can you put one of the see through filters in to give you a better idea of flow and content? Maybe there is air being drawn into the lines?

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