VW T4 Forum - VW T5 Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
137 Posts
Discussion Starter #1
Hi all,

1.9 ABL 97 SWB

Recently I've had a few issues with the van ( draining battery) I've fixed this and started using the van again. Though I do have a whining starter motor which i address at the weekend

Anyway, I filled up £30 ( ~23 litres / 5 gallons) of diesel on Saturday, and I've done about 60 - 80 miles since and the tanks empty again. I wouldnt mind but my fuel gauge went down a quarter notch on a 4 mile run. I dont rev the engine of drive like a madman but its killing my wallet even more than usual. The cam belt was done 4k ago, along with glow plugs and when shes warm theres no problem with revs or power ( have to use the cold start to get her going in the mornings)

Calculating it Im getting at best 16 miles per gallon

My question is where should I look?

Steps I have taken:

1. inspect the engine bay, no sign of any fuel leaks
2. checked the cold start to see the cable isnt jamming up
3. checked my drive for leaking fuel

My steps I was thinking of taking so far are as follows:

1. Injector cleaner in the tank
2. Replace fuel filter.

Is the anything else I should check? I'll be going round my dads who's a fairly good mechanic ( used to own lorries etc), but would be great to have some suggestions of where to look.
 

·
Registered
Joined
·
191 Posts
Sounds like there may be a problem with the return fuel line from the engine to the fuel tank - without it the excess fuel that the injectors don't use can't flow back to the tank. If you take the van for a short run (~ 5 min) then leave it in on a flat bit on ground were there any perceptible leaks at all? I had something similar, but to get that sort of poor fuel mileage it must be leaking somewhere! Any black smoke on acceleration?
 

·
Registered
Joined
·
137 Posts
Discussion Starter #4
Hi, thanks for the reply, I shall take her out for a short run after work to see. Where abouts is the return in the engine bay? does it route past the fuel filter or is it behind the block?
 

·
Registered
Joined
·
47 Posts
Hi

I had a similar problem i thought, but when i dipped the fuel tank there was loads in there, my fuel gauge was faulty & still is, its drops down on its own all the time. i reset it with the ignition off & reads ok for a while then drops again. I will get a new one one day.
 

·
Registered
Joined
·
125 Posts
Hi all,


Is the anything else I should check? I'll be going round my dads who's a fairly good mechanic ( used to own lorries etc), but would be great to have some suggestions of where to look.
I'd check the lock on the filler cap - just in case, you never know these days.... some scrote might be draining small amounts at a time until you fill up again.
 

·
Registered
Joined
·
191 Posts
Hi, thanks for the reply, I shall take her out for a short run after work to see. Where abouts is the return in the engine bay? does it route past the fuel filter or is it behind the block?
The return is part of the filter, there are two lines running into it if you follow what goes in back to the bulkhead. One of these is from the fuel tank, drawing fuel, the other returns the unused back to the tank. Obviously there shouldn't be any leaks in either! It should be quite clear if there is a leak in the return, after a short while of running the engine, bring it back to idle and see if there are any pools forming under the van. The return at idle is quite significant, almost like a tap when you just open it past the dripping stage, and any revving at idle will only increase the flow. The fuel pump has to deliver the maximum amount of fuel for any specific load condition through the revving range, and at idle with no load, quite a lot has to be returned to the tank.
 

·
Registered
Joined
·
191 Posts
If there's loads of black smoke on acceleration, this could mean the engine is being overfuelled, the black smoke being the unburnt fuel exiting the exhaust. There will always be a little, but with around 20mpg, there will probably be clouds of it!
 
1 - 8 of 8 Posts
Top