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carrpet

Getting the fuel pumps running for pressure testing

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My car is a 1989 G50 66

I have a problem getting my fuel pumps to run in order to measure cold pressure, warm pressure etc
I have removed the plug from the WUR and the air flow meter plug, but when I turn the ignition on (and energise the Hamilton Palmer original immobilser) the pumps don't run. However the pumps do run when I run the engine (I have to turn the engine over for 8-10 seconds before it starts hence me investigating my cold pressure).
I must be missing something to get the pumps to run, without jumping the fuel pump relays.
Your help would be appreciated !

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The fuel pump, 1 only,  is controlled by the DME relay.There is no WUR on a 3.2 Carrera but there is an ICU, Idle Control Unit. Unplugging this and the AFM has no effect on the pump. Turning on the ignition does not run the pump. Rather the DME, or ECU if you prefer, needs to see the signals from the crank speed and reference sensors to activate the DME relay. The delayed start you are getting does sound like the fuel pressure issues but could also be a number of other problems. The Bently manual lists a logical sequence of actions for chasing down starting issues.

 You can run the fuel pump by jumping it at fuse 6 (when counting from the left). A fused live wire directly from the +ve battery post to the fuse 6 terminal should make the fuel pump run.

HTH

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Pretty sure the OP has a 930?

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1 hour ago, NigelJ said:

The fuel pump, 1 only,  is controlled by the DME relay.There is no WUR on a 3.2 Carrera but there is an ICU, Idle Control Unit. Unplugging this and the AFM has no effect on the pump. Turning on the ignition does not run the pump. Rather the DME, or ECU if you prefer, needs to see the signals from the crank speed and reference sensors to activate the DME relay. The delayed start you are getting does sound like the fuel pressure issues but could also be a number of other problems. The Bently manual lists a logical sequence of actions for chasing down starting issues.

 You can run the fuel pump by jumping it at fuse 6 (when counting from the left). A fused live wire directly from the +ve battery post to the fuse 6 terminal should make the fuel pump run.

HTH

Thanks for your help Nigel.

Will give jumping a go this afternoon

Peter

 

1 hour ago, NigelJ said:

The fuel pump, 1 only,  is controlled by the DME relay.There is no WUR on a 3.2 Carrera but there is an ICU, Idle Control Unit. Unplugging this and the AFM has no effect on the pump. Turning on the ignition does not run the pump. Rather the DME, or ECU if you prefer, needs to see the signals from the crank speed and reference sensors to activate the DME relay. The delayed start you are getting does sound like the fuel pressure issues but could also be a number of other problems. The Bently manual lists a logical sequence of actions for chasing down starting issues.

 You can run the fuel pump by jumping it at fuse 6 (when counting from the left). A fused live wire directly from the +ve battery post to the fuse 6 terminal should make the fuel pump run.

HTH

I definitely have 2 fuel pumps though as do all 930's

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27 minutes ago, sopor said:

Pretty sure the OP has a 930?

Don't know who OP is ?

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That would be you! 😀

OP=original poster

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32 minutes ago, sopor said:
2 minutes ago, sopor said:

That would be you! 😀

OP=original poster

Thanks you are absolutely right !

2 minutes ago, sopor said:

That would be you! 😀

OP=original poster

Pretty sure the OP has a 930?

Don't know who OP is ?

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Ran the engine this afternoon with the pressure gauge attached. Cold pressure was 18 psi, warm pressure was 54 psi. It was about 8C when I carried out the checks. The WUR is working !

Pressure gradually dropped to zero over the next 5 hours. How do these numbers sound ?

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I used to have the shop manual supplement for the 930 but lent it to a friend and he sold it with his car!

A google search brings up https://www.manualslib.com/manual/392505/Porsche-911-Turbo-1989.html?page=112#manual

which suggests your control pressures are too high. The pressure you need to measure once the pump is shut off is the overall system pressure; not the control pressure.

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It depends on which 930 you have but I think a 930/66 motor has a cold control pressure between 0.8 and 1.2 bar at 10 degrees C and warm control pressure between 3.45 and 3.85 bar. Your measurements are 1.25 and 3.72, so probably in spec if you measured ambient temperature accurate. The spec also has data at 25 and 35 degrees. 

System pressure needs to be 6 to 6.7 bar; you need to measure this too.

System pressure should be above 1.4 bar after 20 mins. I imagine that this is OK if it took 5 hours to drop to zero but best to measure properly. 

The easiest way way to get the pumps running without cranking is to disconnect the safety switch connector on the metering head (reach around the back under the air filter housing - it’s a brown plastic connector). Take 2 seconds and avoids messing with the relays. 

Cheers

David 

 

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31 minutes ago, sopor said:

I used to have the shop manual supplement for the 930 but lent it to a friend and he sold it with his car!

A google search brings up https://www.manualslib.com/manual/392505/Porsche-911-Turbo-1989.html?page=112#manual

which suggests your control pressures are too high. The pressure you need to measure once the pump is shut off is the overall system pressure; not the control pressure.

Thanks the model designation is quite confusing, mine is a 66 and was one of the last made/ sold but there is a 68 model which appears to be an older model.

The spec differences between the 66 and 68 are quite significant particularly the CO levels at tick over.

Thanks for the link to the manual. Will measure system pressure tomorrow afternoon.

 

 

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28 minutes ago, flatsix777 said:

It depends on which 930 you have but I think a 930/66 motor has a cold control pressure between 0.8 and 1.2 bar at 10 degrees C and warm control pressure between 3.45 and 3.85 bar. Your measurements are 1.25 and 3.72, so probably in spec if you measured ambient temperature accurate. The spec also has data at 25 and 35 degrees. 

System pressure needs to be 6 to 6.7 bar; you need to measure this too.

System pressure should be above 1.4 bar after 20 mins. I imagine that this is OK if it took 5 hours to drop to zero but best to measure properly. 

The easiest way way to get the pumps running without cranking is to disconnect the safety switch connector on the metering head (reach around the back under the air filter housing - it’s a brown plastic connector). Take 2 seconds and avoids messing with the relays. 

Cheers

David 

Thanks David

I will have another go tomorrow afternoon and include system pressure. I need to be more precise about the ambient temperature. The removal  of the connector on the metering head doesn't seem to work for me to get the pumps running. I have always tried with the ignition on but I am getting feedback from the Pelican forum that the ignition switch just needs to be in the ON position. What is your view on this ?

Peter

 

 

 

 

 

 

 

 

 

 

 

 

 

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Hi Peter, 

That information from Pelican is wrong. The pumps shouldn’t run with just the ignition on; the engine needs to be turning over. It’s a safety feature to shut the pumps down in the event of an accident when the motor stops with the ignition still on. It’s done with a switch on the sensor plate that detects displacement as air is pull through. It’s this connector that can be disconnected . The other ways to make the pumps run is to bypass the pump relays or physically displace the sensor plate (air cleaner renoved). 

Ate you just checking or do you have a running problem?

David 

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10 hours ago, carrpet said:

Thanks the model designation is quite confusing, mine is a 66 and was one of the last made/ sold but there is a 68 model which appears to be an older model. 

From memory the 66 motor was in all Euro 930’s from, I think, around 83/84 to the end with the 68 being for the US/Can market following its reintroduction in the mid-late 80s. The manual linked above doesn’t look to include the 66. 

My 84 Euro 930 runs a 930/66. 

David 

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Hi David,

The Pelican information is consistent with yours in that the air flow meter connection needs to be removed from the rear of the flow meter, but that you just have to have the ignition key in its first position (ie. auxiliary equipment on but not ignition on) for the pumps to run. I have been unable to get the pumps to run by doing this although I have had the ignition on when I tried previously.

I have a poor cold starting problem where the car often fires half heartedly immediately but does not fire up until the engine has been turned over for 10 seconds ish. That is why I was checking cold pressure which I thought may be high. Doesn't appear that is the case though !

Peter

 

 

1 minute ago, flatsix777 said:

From memory the 66 motor was in all Euro 930’s from, I think, around 83/84 to the end with the 68 being for the US/Can market following its reintroduction in the mid-late 80s. The manual linked above doesn’t look to include the 66. 

My 84 Euro 930 runs a 930/66. 

David 

I think that means you can be a great help to me in resolving this David, thankyou for your help ! Much appreciated.

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As David says the 930/68 engine is USA only (1986-89)

ROW is a 930/66 from 1984-89, before that is was a 930/60 or 930/62

930/63 is a California car

930/65 is a Japan car

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carrpet..have you installed the fuel pres gauges??? In order to check your fuel press.you have to have them in the system then you do not need to worry about jumping the fuse for the pump running.

 

like these

 

Ivanm

fuel pres gauges.jpg

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2 hours ago, proporsche said:

carrpet..have you installed the fuel pres gauges??? In order to check your fuel press.you have to have them in the system then you do not need to worry about jumping the fuse for the pump running.

 

like these

 

Ivanm

fuel pres gauges.jpg

Hi Ivan

Yes I do thanks !

Peter

2 hours ago, proporsche said:

carrpet..have you installed the fuel pres gauges??? In order to check your fuel press.you have to have them in the system then you do not need to worry about jumping the fuse for the pump running.

 

like these

 

Ivanm

fuel pres gauges.jpg

Ivan,

How do you get your joints to handle 95psi system pressure without any pipe clips ? What kind of fuel pipe are you using ?

Peter

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Got the fuel pumps running without the engine running. The issue was my good old Hamilton Palmer immobiliser which was immobilising the fuel pumps for me !

Now to test the system pressure without any leaks !

Peter

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it is actually not too good to run the fuel into the engine...

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12 minutes ago, proporsche said:

it is actually not too good to run the fuel into the engine...

I agree, ok for a couple of secs for a quick test but leaving the fuel pumps running without the engine running is a bit of a risk because if you have a leaky or failed injector it can fill a cylinder with fuel which wont compress like air does when you try to start your engine and bend some very expensive parts that are impossible to un-bend :)

 

hqdefault.jpg

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2 minutes ago, jevvy said:

a bit of a risk because if you have a leaky or failed injector

Don't need leaky or failed injectors on a CIS engine, all the injectors squirt all the time there is pressure in the system.

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2 minutes ago, SilverWT said:

Don't need leaky or failed injectors on a CIS engine, all the injectors squirt all the time there is pressure in the system.

Even if the flap isn't lifted?

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the only way -really - is to instal the fuel press.gauges and go from there ..other tacktick i do not recommend..

if the flap is not adjusted properly the injectors will leak...too

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