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Hi

I tried to start my TR5 which had been stood for a while and found whilst the battery was allowing the Bosch fuel pump to whir when I turned the key there wasn't enough juice in the battery to start the car - no surprises there.  However having removed the battery, charged it up etc I then turned the key to find that the fuel pump is silent and clearly not working so the starter motor is clicking away with no fuel coming through.  I have checked the fuses, I have checked all the wires connecting to the fuel pump but can't find any obvious issues.  Seems very strange when all I have done is remove and replace the battery after charging it up.  Any thoughts/assistance?

Thanks a lot

Best

Sean

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Sean,

welcome to the forum.

First thing to check is if there is 12.5 or so volts at the pump. If there is, check the earth, and this is where Neil (NTC) points you to.

I assume you have a TR5, which normally does not have an inertia switch. If it has, check this. Next suspect is the ignition lock, all current to the pump runs through this, if no relay is installed.

Waldi

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Thanks guys. I have checked the spade connector.  It is connected to the car body - not sure what else to check there.  It is a TR5 and all very original except for usual switch to Bosch pump so I don’t believe inertia switch (not sure what this would look like if it did have one).  I have called out the A.A. and will ask the mechanic to check the voltage at the pump and also the ignition lock - can you suggest how we check the ignition lock current functioning? 

Thanks once more for your patient guidance 

Best

Sean 

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Sean,

We assume this is electric failure, but give the pump body a couple of gentle taps. 

Good that the earth spade is ok, it could have been disturbed while replacing the battery while it is right next to it.

Now first measure the current at the pump terminal with ignition switched “on”. This should be a white wire. If the AA man arrives, it would be helpful to have a wiring diagram at hand, best A3 size.

So indicate the starter motor is “clicking”, do you mean it is working properly so turning the engine with normal cranking speed?

Waldi

Addition: 

The current to the pump runs via the ignition, the AA man will know where to look, a wiring diagram will help him a lot.

Edited by Waldi
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16 hours ago, Waldi said:

Sean,

welcome to the forum.

First thing to check is if there is 12.5 or so volts at the pump. If there is, check the earth, and this is where Neil (NTC) points you to.

I assume you have a TR5, which normally does not have an inertia switch. If it has, check this. Next suspect is the ignition lock, all current to the pump runs through this, if no relay is installed.

Waldi

Some did have one fitted ;)

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The pump could be jammed with some crud, but unlikely of you have a pre-filter

do you inow what ‘bosch’ pump you have Sean?

also whereabouts are you, someone local might help!

steve

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Hi Sean,

If the pump is not running at all, it could be defective. Have you tried an additional ground wire to the pump (a copper wire held to the pump negative terminal and the car body) ? 12 V at the other terminal is good, but the current needs to go back too. With ign on, tap it a bit harder, not much to loose, should dirt be the issue.

The PI system is not very easy to understand, especially when there are issues. There is a lot of information on this forum, especially in the TR6 section.

Filter type, pump location, earthing, best way to bring current to the pump, PRV issues, all is there. I recomment to start reading the wealth of info on here.

If someone near you can come and help you as Steve suggests, that would be great. I’m overseas, so not me, sorry.

Your pump could well be a Bosch ...996 pump, the filter housing looks original; the filter cartridge can best be sourced from one of the specialised TR businesses, because some, although they fit, are not correct. But before spending money on pump, filters, hoses, prv, it is better to first understand the issue.

And keep them coming, those questions.

Good luck,

Waldi

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That pump looks a lot like a bosch 996, fed through the original cav filter.

the 996 is the best bosch pump for the TR, and is no longer made.

the cav filter is ok but not ideal, and there have been cases of the ‘wrong type’ of replacement element breaking up

this could block and stall the pump?

my last tr6 had that exact setup, and ran fine for years.

i favour replacing the cav with a disposable sytec filter, and moving the bosch pump outside of the boot into the wheelarch area, and lower as Neil says is better.

i do have a known good spare 996 pump if you’d like to try that Sean?

i’m in Chertsey but only until midday Friday , back wednesday.

i would take the pump out and test it on the bench, the spade terminals are marked with polarity for testing, i’d try briefly reversing the polarity to see if it frees up.

be careful with electricity and petrol !!

steve

 

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Hi Sean,

12.15V at the pump, engine not cranking, is probably lower than at voltage at battery, so probably the pump was drawing some current. Did it get a bit warm? If so, this indicates pump is stalled.

If you disconnect the white (+) wire from the pump and measure again (then no current is flowing) is should be virtually the same as at the battery.

During this, it is best to disconnect the coil to avoid overheating. 

If all the above is the case and a bit more tapping does not work, I would replace pump and filter.

Waldi

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Thanks guys. I have checked the spade connector.  It is connected to the car body - not sure what else to check there.  It is a TR5 and all very original except for usual switch to Bosch pump so I don’t believe inertia switch (not sure what this would look like if it did have one).  I have called out the A.A. and will ask the mechanic to check the voltage at the pump and also the ignition lock - can you suggest how we check the ignition lock current functioning? 

Thanks once more for your patient guidance 

Best

Sean 

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Hi Sean,

you appear to have repeated (copied?) your yesterday’s post.

How are things going?

Cheers,

Waldi

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Hi All

Success!  Spurred on by comments here I whacked the pump a bit harder this morning with the rubber handle of a screwdriver and it came back to life - miracle!   Bruce from the Chiltern TR Group who has a 40 year old yellow TR6 he has had from new popped round to help and we went for a lovely spin. All good, fantastic to get the 5 back on the road.   Thank you all for your patient guidance.

Best

Sean 

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