Stutters on half tank

Keyride216

Hey guys, I hope you can help me out

I have an opel astra g convertible.
When I get around half a tank, my car starts to stutter, especially when asking for power, let's say from 2.5k RPM.
I have done a headgasket change and and timing chain change, that didn't change anything.
My mechanic told me it was probably something with the pump, but since it's only on half a tank I find this hard to believe.
Do you guys have any idea what this could be and how to fix it?

Cheers,
Max

corsaZ22se

It is quite possible your fuel pump is wearing out or has a blocked filter.
As it sits in the bottom of the fuel tank, when the tank is full there is more weight of fuel which will help push the fuel into the pump.
Does the fault get worse if you allow it to get even lower on fuel?

Keyride216

Yes, I once tried to get it lower and when I got from a 30km/h to 80km/hr road (so I had to accelerate, I thought it was done for. Only to start up again when it dropped to like 15km/h.
Sorry for the late reply I didn't see any email of replies.

Keyride216

Also when I bought car I changed the filter, the one that is under the car.

IDI_AMIN

Maybe the injectors could do with a clean out. worth a try, taking them out and check the spray pattern on them by running some carb cleaner through them. It's worth a go, especially if you have fitted a new fuel filter recently.

Assuming that it is a petrol car, try this one as well

https://z22se.co.uk/threads/fuel-pressure-mod-with-modified-inlet-systems.5580/

corsaZ22se

There is another filter on the bottom of the fuel pump.
What miles has the car done?
You may be in need of a new fuel pump?

Keyride216

@[deleted]
132600km, which is 82393 miles.

I took a pump from the junkyard. See if that helps any.
I've been tanking only 98 e5 in the car now last couple of weeks. I usually always filled up 95 e10, so did the previous owner I'm assuming.

@[deleted]
Yes it's petrol!
How would the injectors be the problem if its only at half a tank?

Cheers and thank you guys for still replying on here

corsaZ22se

I was told not long after I got my Vectra B to run it on 98/99 octane fuel by a main dealer and an independent tuner who specialised in the VX220's, been running that ever since. That was back in 2001. Also been told never to use e10 fuel in any Vauxhall made before 2010 by the main dealer without having it remapped, some older cars the e10 will eat away at the plastic/rubber parts of the fuel system causing leaks. Seen the same on older diesels with the latest bio fuel.
At that age and mileage it may be in need of a new fuel pump? Have you changed it yet and seen how the filter is/dirt in bottom of the tank?

Keyride216

That's a good tip! e5-98 it is.

I have not yet removed the old pump. I have gotten a new one, or old one really, at the local junkyard, previous owner of the car said there weren't any problems with the pump so lets see, will update.

Maybe good to mention: The person I bought my car from never had the stutters, the car was in a garage for about 8 months, when he took it out, the stutters came. Maybe because it was old fuel or whatever? I have also tried a fuel system cleaner additive. Didn't change a thing, needless to say.

Im placing my bets at the filter actually being blocked. I saw it at the junkyard and its a really fine filter, when I bought the car around the gas-cap was alot of crap, dirt and moss, some may fallen in.

If this doesn't change a thing I think im going to buy a new pump including swirlpot.

I have tried to order a new filter but couldn't find any for a decent price. I have ordered some carb cleaner which is arriving saturday. I will clean the filter then.
Until then, time to change the front brake pads.

corsaZ22se

the in tank filter can be cleaned with petrol or brake cleaner and low pressure air.

Keyride216

Oh well I have brake cleaner. Now I am going to have both. Ah well, finally got new brake pads on tho.
Anyway my plan is to clean it tomorrow. I don't have any pressured air tho, and since all of our country is on lockdown I can't get any either. But I'll just use alot of cloths, should be fine.
Thankyou Corsa, I will keep you updated!

Keyride216

@[deleted]
I cleaned the filter, did not manage to change the pump tho, seemed that it was stuck to the pump itself. At the junkyard I broke it while trying to get it loose atleast.

BUT
I cleaned it, got the crap out and went for a test drive, it still stutters but it seems like its alot less. I'm on 1/4th of a tank now and its 'driveable' while normally it would almost stall on 1/4th.

Now I didn't have the plastic cap on top while driving so I could hear the pump. It was whistling at about 4kRPM, weird I think.

Also there was this weird stuff in the tank. My brother called it kidneystones.

Maybe important to note:
One of the 2 hoses, the one that had an R with it, guessing 'return' had no pressure on it. While removing it nothing really happened, while removing the other one it squirted quite a bit.

Anyway I am having the assumption that it's the pump now. Maybe it's full of kidneystones?
Pictures:
kidneystones
before and after of the filter.
Very rusty locking-ring (white plastic is finger-condoms so nothing falls in them).

Cheers and thank you again!

IDI_AMIN

From the pictures , It looks like you should completely drain the tank and clean out as best you can if you have muck like that inside it. You say you put a new fuel filter in, that was why i suggested to clean out the injectors. You have probably shafted the new fuel filter as well, if that is what's in the tank.

Over a year ago i was working on a peugeot, the car was running but a bit erratic . And then another day it would not run at all. Turned out that 3 out of 4 injectors were not working properly. Completely shafted.

I would not have known that without removing them and testing how they were spraying.
There also was a good bit of water in the fuel tank as well. This could be what has caused what you are calling kidney stones if the car has been sitting for nearly a year unused.

Cleaning your injectors won't do any harm, and probably need done more now that you have discovered what is in the tank. Probably need to put clean fuel in as well, along with another new filter.

Keyride216

Thank you for your response @[deleted] Definetly will and kinda have to drain, and clean well.

Will be when the weather is nice, for now, full up more often.
But this crap has to be getting from somewhere right? The white stones are very fragile and pretty much break when you touch them, they remind me of chalk stones or something.
But if it would be the injectors, why only on half a tank? That makes no sense to me.

Cheers!

Keyride216

Keyride216 said:
Thank you for your response @[deleted] Definetly will and kinda have to drain, and clean well.

Will be when the weather is nice, for now, full up more often.
But this crap has to be getting from somewhere right? The white stones are very fragile and pretty much break when you touch them, they remind me of chalk stones or something.
But if it would be the injectors, why only on half a tank? That makes no sense to me.

Cheers!

Edit: after driving a bit more it is gradually less now tho.

corsaZ22se

The dirt on the fuel tank will most likely have come from filling stations over the years. Last spring I got some diesel and it was full of crap, ended up having to drain the fuel system and flush it out right up to the high pressure pump.
I would suggest you remove and flush the tank, get a brand new fuel pump and in tank filter as they are near on impossible to remove with out breaking, and a main fuel filter but start and run the car for a minute before depressurizing the fuel system and changing the main filter so to catch any dirt that may be in the pipes from the work.
Then test, add some injector as well.

Keyride216

@[deleted] Unfortunately I will have to get a new pump and clean the tank thoroughly.
Do you happen to know what intank filter I could use on the pump? The stock pump is an easy find online but the filter I can't find anywhere.
What do you mean by add some injector? Injector cleaning bottle?

corsaZ22se

Sorry i meant injector cleaner.
each time I have got a new pump it came with a filter but I only use OEM parts or better quality.

Keyride216

I'm always afraid to buy other things. Especially pumps, don't they pump out a different pressure or something?

corsaZ22se

So long as it is made for your car you will be ok. They are just a basic pump, more expensive ones may flow more fuel but it will only flow as much as the engine needs, the Fuel Pressure Regulator (FPR) on the fuel rail will sort the rest out.