Engine won't rev and hunts

[ANDTWENTY]

The garage I use doesn't have a fuel pressure tester. Thought I'd try clamping off the fuel pressure regulator, clamping it off increased the idle slightly and seemed to rev slightly higher but didn't cure the surging at all. I took off the vacuum hose and this had a similar effect but also saw no fuel leaking so I presume this is working okay.

I was thinking of getting a pressure test kit off Amazon, seem fairly cheap and it can be here tomorrow?

Went to feel the pump while it was running and noticed that the small line from the pump to filter is fairly kinked, could this be restricting the fuel enough to cause the issue? Going to pop the new filter on while it's off, should I renew this line or just straighten it? It's a plastic type of hose would rubber be okay?

[Laird Scooby]

Originally Posted by ANDTWENTY

The garage I use doesn't have a fuel pressure tester. Thought I'd try clamping off the fuel pressure regulator, clamping it off increased the idle slightly and seemed to rev slightly higher but didn't cure the surging at all. I took off the vacuum hose and this had a similar effect but also saw no fuel leaking so I presume this is working okay.

I was thinking of getting a pressure test kit off Amazon, seem fairly cheap and it can be here tomorrow?

Went to feel the pump while it was running and noticed that the small line from the pump to filter is fairly kinked, could this be restricting the fuel enough to cause the issue? Going to pop the new filter on while it's off, should I renew this line or just straighten it? It's a plastic type of hose would rubber be okay?

No wonder it won't rev!

You'll need some 6mm bore petrol hose and 2 hose clips (for petrol hose, different to Jubilee clips), i made a loop from my pump to the filter so there was added flexibility so the hose wouldn't get kinked, stretched or anything similar as the filter unions were tightened.

You can buy that short hose, complete with unions, from Volvo for about £50 and a 2 week wait - i'd go with the 6mm bore petrol hose!

*** EDIT *** i strongly suspect sorting that hose out will cure the problem, however you won't be able to carry out an effective fuel pressure test with the hose like that as it will almost certainly show enough pressure but it doesn't give an idea of the flow.
Fit a bit of 6mm hose and see what you've got.

[ANDTWENTY]

Originally Posted by Laird Scooby

No wonder it won't rev!

You'll need some 6mm bore petrol hose and 2 hose clips (for petrol hose, different to Jubilee clips), i made a loop from my pump to the filter so there was added flexibility so the hose wouldn't get kinked, stretched or anything similar as the filter unions were tightened.

You can buy that short hose, complete with unions, from Volvo for about £50 and a 2 week wait - i'd go with the 6mm bore petrol hose!

*** EDIT *** i strongly suspect sorting that hose out will cure the problem, however you won't be able to carry out an effective fuel pressure test with the hose like that as it will almost certainly show enough pressure but it doesn't give an idea of the flow.
Fit a bit of 6mm hose and see what you've got.

Think I'll go with the 6mm hose in that case haha. Fingers crossed it works, getting tired of this now haha. There also appears to be a 1 way valve fitted after the pump before the filter, this seems very stiff, I can't blow through it myself but does with compressed air, is this right, should it be this stiff?

[Clan]

Originally Posted by ANDTWENTY

Think I'll go with the 6mm hose in that case haha. Fingers crossed it works, getting tired of this now haha. There also appears to be a 1 way valve fitted after the pump before the filter, this seems very stiff, I can't blow through it myself but does with compressed air, is this right, should it be this stiff?

I think you will find it is 8mm bore hose , double check ... 6mm is for carburettor systems

[Laird Scooby]

Originally Posted by ANDTWENTY

Think I'll go with the 6mm hose in that case haha. Fingers crossed it works, getting tired of this now haha. There also appears to be a 1 way valve fitted after the pump before the filter, this seems very stiff, I can't blow through it myself but does with compressed air, is this right, should it be this stiff?

Yes, it should - it needs to hold a fair bit of pressure from running back to the tank.



Still available new from Volvo, can't remember the exact price but it was about £20 give or take, if yours is stiff to blow through one way and no flow the other, you probably have nothing to worry about on that NRV - the hose connecting between the fuel pump outlet banjo and the fuel filter inlet banjo is definitely 6mm, surprised me but the easy way to remove the old nylon tubing is to slit it lengthways with a Stanley knife then peel it off the hose barb underneath.

[ANDTWENTY]

Originally Posted by Laird Scooby

Yes, it should - it needs to hold a fair bit of pressure from running back to the tank.



Still available new from Volvo, can't remember the exact price but it was about £20 give or take, if yours is stiff to blow through one way and no flow the other, you probably have nothing to worry about on that NRV - the hose connecting between the fuel pump outlet banjo and the fuel filter inlet banjo is definitely 6mm, surprised me but the easy way to remove the old nylon tubing is to slit it lengthways with a Stanley knife then peel it off the hose barb underneath.

Normally the spring would go making them softer and not work but just seemed incredibly hard and I would have thought would reduce the flow.

It was 6mm as you said and I got a new bit, I didn't get a loop on it though as it would either rub the body or hang low and snag so just went straight. Sadly though this made no difference, engine still surges.

sometimes when it surges it'll backfire or pipe in the air filter box. sometimes it never does it sometimes it'll do it if I open the throttle for a long time, could this indicate anything?

[ANDTWENTY]

Was looking at getting one of these to test fuel pressure but noticed in the description it says not for jetronic or throttle body systems, any idea if this is okay? pretty sure mines jetronic?

https://www.amazon.co.uk/Noblik-Univ...9418129&sr=8-8

[Clan]

Originally Posted by ANDTWENTY

Normally the spring would go making them softer and not work but just seemed incredibly hard and I would have thought would reduce the flow.

It was 6mm as you said and I got a new bit, I didn't get a loop on it though as it would either rub the body or hang low and snag so just went straight. Sadly though this made no difference, engine still surges.

sometimes when it surges it'll backfire or pipe in the air filter box. sometimes it never does it sometimes it'll do it if I open the throttle for a long time, could this indicate anything?

Yes , that your fuel pressure is low !

[ANDTWENTY]

Originally Posted by Clan

Yes , that your fuel pressure is low !

Any ideas if that test kit is any good then? if I order it today I can get it tomorrow

[Clan]

Originally Posted by ANDTWENTY

Any ideas if that test kit is any good then? if I order it today I can get it tomorrow

well it has the T Piece to connect the gauge to like the volvo special tool , you don't have jetronic do you , you have 4 electric injectors surely ?

That kit is an absolute bargain they usually go for over £100 for a decent one