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Fuel filter priming bulb not staying hard

L

luke w

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Location
South Wales
Car
CN2
Been having slight running issues for a while now. The slight issue seems to match issues regarding either the EGR valve or fuel filter, ie, bit flat lower down the rev range, little bit of hesitation. Now the EGR valve has been deleted when it was remapped and has been blanked off and the fuel filter was changed not that long ago with a genuine Bosch filter. I've cleaned and replaced a few things but there's been no difference so thought I'd investigate the fuel filter to be on the safe side and upon giving the priming bulb a quick squeeze I could easily squeeze it to the point I could touch my thumb and fore finger. After a few squeezes it hardened (but never got fully hard, always about 5mm of give) but if then left for 5 minutes or so it was back to being easy to squeeze. I loosened the bleed bolt at the top of the filter and squeezed the bulb until firstly a few air bubbles came out then just diesel, nipped it back up a gave the bulb a few squeezes (at least 30 odd) again until as hard as before (still a bit of give). But, it's still going really easy to squeeze after a few minutes.

Now reading up on various threads on here, I get the impression that the bulb should be hard straight from the off and not need a few squeezes to become hard. So, any idea why I'm getting this problem? There are no fuel leaks so as far as I can see (all the hoses are dry and no puddles under the car or drips anywhere.
 
It's on the suction side of the fuel pump, so it won't stay hard. But air shouldn't be getting in. How old is the air filter?
 
So it is soft the first couple of squeezes no matter what?

Fuel filter is about 8k miles old now, but this issue has been around since it was remapped (with EGR delete) so probably for the last 5k miles odd.
 
Well when I first started squeezing it, it took a lot of squeezes to get it as hard as it would get, after I opened the bleed bolt and a few little bubbles came out it got harder a lot quicker. I'll put everything back together and take it for a little spin to see how it feels.

It was remapped by Fahad, I know there were a couple of issues which meant it needed a slightly different map, now that I've almost ruled out all the possible causes for the issues I'm experiencing I might have to call him back to have a look at it again.
 
Hello mate, have you run a scan on the car to see what dtc errors are in the ecu?

Your egr off was routine to be honest. Also I'm sure I asked before but not sure if I got an answer but have you blanked egr at both sides of the bypass pipe?

If possible for good measure can you also blank off at the actual valve itself. I had one a few weeks back where the guy had been trying to clean it and had actually damaged the internal plunger. It wasn't until we blanked it at the valve side itself that the car ran right.
 
Also low down hesitation can also be down to faulty imrc.
 
Hi Fahad

I did run a scan and the only fault code was P2008, but I had unplugged a few things previously to if it affected the running of the car. I've probably done almost 1k miles since and ran another scan today and no errors came up.

Both sides of the EGR pipe have been blanked. The IMRC has been replaced as it ran a little better with it unplugged, and it is a little better now the new one is fitted but not 100%

Next job then is to blank the actual valve as well and see how that goes. I'm sure it's something little that needs doing, the problem isn't so bad that it effects every day to day driving, but I'd like to get it running like I know it can.
 
Yep totally understand mate. If the valve is correctly blanked and there are no errors then it can't be the egr..
 
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