Problem With Fuel Pump/system - R32 Gts25

[gts25]

Hi Guy's,

Wondering if anyone can lend any thoughts to a problem I am currently having.

I have an R32 GTS25 (RB25DE) standard with no mods.

A couple of months ago I had a problem with my fuel pump jamming. I purchased a new JECS fuel pump which is identical to the original one.

Since then I have had some intermittent problems with starting the car.

When the problem occurs, the pump primes on ignition but does not start. When the key is released, the pump primes again and the problem repeats itself in this manner (prime, not start, prime) until the car finally starts - it usually takes 6 - 8 attempts. Also on some occassions when the car finally starts the idle is very bad and the car will stall - pressing on the accelarator does not get any response from the engine (ie the engine does not rev).

I have noticed that when the car starts normally the priming sound is different to that of when I have the problem. I hear the normal priming sound but at the end of this I here a prime of a higher pitch. I take it this is when the pump is reaching the maximum required pressure

I take it I have a pressure issue.

So far I have done the following to troubleshoot:

- New fuel pump relay

- New battery

- New fuel filter

As yet I have not changed over the fuel regulator. From what I understand about fuel regulators, they are a vacum operated unit with a spring diaphram. Is it possible for it to occassionally to jam open stopping the right pressure from building. Has anyone seen this before?

I also have a R32 GTS-t (RB20DET) which I can swap parts over to test. Is the standard regulator from this the same as that of the RB25DE or is it of a higher pressure

If anyone has any suggestions/ideas it would be much appreciated as this is getting very frustrating....

Thanks

Jason

Edited November 23, 2005 by gts25

[Sydneykid]

Hi Guy's,

Wondering if anyone can lend any thoughts to a problem I am currently having.

I have an R32 GTS25 (RB25DE) standard with no mods.

A couple of months ago I had a problem with my fuel pump jamming. I purchased a new JECS fuel pump which is identical to the original one.

Since then I have had some intermittent problems with starting the car.

When the problem occurs, the pump primes on ignition but does not start. When the key is released, the pump primes again and the problem repeats itself in this manner (prime, not start, prime) until the car finally starts - it usually takes 6 - 8 attempts. Also on some occassions when the car finally starts the idle is very bad and the car will stall - pressing on the accelarator does not get any response from the engine (ie the engine does not rev).

I have noticed that when the car starts normally the priming sound is different to that of when I have the problem. I hear the normal priming sound but at the end of this I here a prime of a higher pitch. I take it this is when the pump is reaching the maximum required pressure

I take it I have a pressure issue.

So far I have done the following to troubleshoot:

- New fuel pump relay

- New battery

- New fuel filter

As yet I have not changed over the fuel regulator. From what I understand about fuel regulators, they are a vacum operated unit with a spring diaphram. Is it possible for it to occassionally to jam open stopping the right pressure from building. Has anyone seen this before?

I also have a R32 GTS-t (RB20DET) which I can swap parts over to test. Is the standard regulator from this the same as that of the RB25DE or is it of a higher pressure

If anyone has any suggestions/ideas it would be much appreciated as this is getting very frustrating....

Thanks

Jason

<{POST_SNAPBACK}>

My 20 cents.......

The standard fuel pump has a one way valve that stops the fuel draining back to the tank when the pump (engine) is turned off. It sounds to me like the replacement pump doesn't have the one way valve fitted and ALL of the fuel is draing back to the tank. This means the pump has to prime for quite a long time just to fill up the hoses, pipework, fuel filter, fuel rail, build up 36-38 psi of pressure and finally get to the injectors to squirt. The prime timing on the ECU isn't long enough for this to occur as it is designed for the standard pump with a one way valve, which take almost zero priming.

To fix it, take the one way valve off the standard pump and put it on the JECS pump.

One other thing to check. The standard fuel pump failing is most unusual, they are a very hardy device. It MAY be that something caused the pump to fail and is contributing to your problem. The most common I have seen lately is squashed fuel lines, where someone has lifted up the car on a hoist, or with a jack, and squashed the fuel lines against the floor pan. I would have a good look under the car, follow the fuel lines form back to front and make sure that they are in good condition.

Hope that helps

cheers

[gts25]

My 20 cents.......

The standard fuel pump has a one way valve that stops the fuel draining back to the tank when the pump (engine) is turned off.  It sounds to me like the replacement pump doesn't have the one way valve fitted and ALL of the fuel is draing back to the tank.  This means the pump has to prime for quite a long time just to fill up the hoses, pipework, fuel filter, fuel rail, build up 36-38 psi of pressure and finally get to the injectors to squirt.  The prime timing on the ECU isn't long enough for this to occur as it is designed for the standard pump with a one way valve, which take almost zero priming.

To fix it, take the one way valve off the standard pump and put it on the JECS pump.

One other thing to check.  The standard fuel pump failing is most unusual, they are a very hardy device.  It MAY be that something caused the pump to fail and is contributing to your problem.  The most common I have seen lately is squashed fuel lines, where someone has lifted up the car on a hoist, or with a jack, and squashed the fuel lines against the floor pan.  I would have a good look under the car, follow the fuel lines form back to front and make sure that they are in good condition.

Hope that helps

cheers

<{POST_SNAPBACK}>

Thanks Sydney Kid - that helps immensely.

I will check the fuel lines - I never thought about this. My original pump hasn't failed as such, it occassionally jams and doesn't pump. A knock on the fuel tank would get it going.....

I take it the one way valve is internal to the pump? I don't recall seeing a valve on the outside of the pump. The pumps are also sealed and not easily dissambled.

Would it be suitable to install a one-way valve in the fuel line close to the pump?

If so will any type be ok or do I require a specific valve?

Jason