Fuel pressure
Printed From: The Brick-yard
Category: T5 Section
Forum Name: T5 Chat
Forum Description: Forum for T5 specific chat
URL: http://www.brick-yard.co.uk/forum/forum_posts.asp?TID=94330
Printed Date: 23 Apr 24 at 18:47
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: Fuel pressure
Posted By: Ynysmon
Subject: Fuel pressure
Date Posted: 02 Jan 20 at 11:04
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Hi, I’m new to the group and I’m Hopeful someone can help me with a problem that’s beaten two mechanics so far! I purchased a 2012 t28 102TDi swb van back in June. It had just under 100000 miles on the clock. The van soon went into limp mode and gave a fault code of low fuel pressure. I changed the filter etc but still the same. The van starts first time but doesn’t sound great with a hunting noise present and as soon as it hits around 30,000 revs it goes into limp again, we noticed that once the van had started if I unplugged the ecu connection off the fuel rail the engine tone changed and the engine sounded better. Soon as you try to move with it unplugged it went straight into limp mode again. Since then I’ve had the high pressure fuel pump checked ok, the ecu checked ok, two injectors changed, wiring harness checked fuel regulator changed and still have this fault. If anyone could Help in anyway it would be more than appreciated as I’m really at my wits end Thank you in advance |
Replies:
Posted By: Charlie Dog
Date Posted: 03 Jan 20 at 11:35
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Has anyone measured the pressure in the fuel rail yet? Plenty of kits on eBay if you wish to measure the actual fuel pressure in your injector rail. https://www.ebay.co.uk/sch/i.html?_from=R40&_nkw=fuel+pressure+tester&_sacat=0&_sop=15" rel="nofollow - https://www.ebay.co.uk/sch/i.html?_from=R40&_nkw=fuel+pressure+tester&_sacat=0&_sop=15
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Posted By: Ynysmon
Date Posted: 07 Jan 20 at 23:21
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Hi Charlie, I asked the mechanic had he checked this and he has. It’s showing fine on the manual gauge. He took the fuel rail off over the weekend and cleaned it and flushed it through. The engine does seem to tick over a little better without hunting not as evident but soon as you drive off and the revs increase it’s back into limp mode
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Posted By: Charlie Dog
Date Posted: 08 Jan 20 at 08:27
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I think you need to find a way to measure fuel pressure in the rail while you are driving. It's possible your pump can't keep up with higher fuel needs at higher loads. It's possible your filter can't keep up with higher fuel needs at higher loads. It's possible your fuel line can't keep up with higher fuel needs at higher loads. I daresay there are other options too.
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Posted By: Ynysmon
Date Posted: 08 Jan 20 at 08:40
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Thanks for your reply. I’ve had the hp pump tested and the in tank pump it’s come back fine, I’ve also replaced the following Fuel regulator 2 injectors Fuel filter A regulator on the hp pump Had the ecu checked, all ok I’ve thrown a lot of money at it now so I’m at the stage of no return 🤦🏻♂️ So have to keep ploughing money into it and get it sorted. I’m getting another auto elec to look at it next week as I fb the pressure isn’t fluctuating we’re thinking it’s maybe a wiring issue?? Have heard that a bad earth under the seat can cause all sorts of problems but not sure it would cause this. Thanks again for taking time to reply and I’m hoping someone will see this that can point me in a new direction to get it sorted
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Posted By: Charlie Dog
Date Posted: 08 Jan 20 at 09:19
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Were the pressure tests done under load? You go into limp mode under load so it's likely the load causes the problem. An ammeter in your pump circuit that you can read in the cab would indicate an electrical problem is one exists in that circuit. You can get easy access to the fuel pump circuit at the fuel pump fuse / relay. Aimless poking about with electrics can cause more problems than it solves. You may be able to find a faulty connection with a sensitive infra red thermometer. |
Posted By: Ynysmon
Date Posted: 10 Jan 20 at 17:44
| had the van back today and drove it fine until the revs picked up again. After what you’ve advised I checked and the van won’t rev pasT3,000 when stationary and out of gear. |
Posted By: Charlie Dog
Date Posted: 10 Jan 20 at 18:15
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If you wish to get any further yourself Ynysmon I think you need to invest in some software that will find out what you ECUs have got to say. https://www.ross-tech.com/vcds-lite/download/" rel="nofollow - https://www.ross-tech.com/vcds-lite/download/ And http://www.gendan.co.uk/faq/409_win7.php" rel="nofollow - http://www.gendan.co.uk/faq/409_win7.php Seem to be popular. As far as I know the software is free. You have to buy the kit to run it though. There are rip-off kits, which may or may not do the business. Gossip and rumour reckon rip offs can damage your van's health. |
Posted By: Ynysmon
Date Posted: 10 Jan 20 at 18:43
| I’ve had the ecu etc checked too🤦🏻♂️ The only fault we get is the low fuel pressure. Both mechanics have had it on their software and it tells them the same. It’s got everyone stumped at the moment |
Posted By: Charlie Dog
Date Posted: 10 Jan 20 at 19:02
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Some software, records what's happening as you drive. I expect both of those do. Probably best to ask first. Perhaps someone on this forum has the software and is prepared to help if you travel to them. You could also have you ECU examined and repaired is necessary. If you contact Honest John He may recommend someone VAG specific honestadvice@ He recommends a few ECU specialists here: - https://www.honestjohn.co.uk/faq/engine-electronics/" rel="nofollow - https://www.honestjohn.co.uk/faq/engine-electronics/ There no guarantee that it's the right place to look I'm afraid :-(
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Posted By: Ynysmon
Date Posted: 10 Jan 20 at 19:05
| thanks for the assistance Charlie. I’ll give him a try |
Posted By: Charlie Dog
Date Posted: 10 Jan 20 at 19:16
| Good luck :o) |
Posted By: Charlie Dog
Date Posted: 20 Jan 20 at 09:59
| Any joy yet Ynysmon? |
Posted By: Ynysmon
Date Posted: 20 Jan 20 at 11:57
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no it’s now with another auto electrician, who thinks it’s a ‘ghost Code and it might not be a fuel pressure issue? I drove it the other day a fair distance but kept it under 30,000 revs and it was drivable. I did notice on some occasions whilst stationary it wouldn’t rev pasT3,000 revs out of gear!
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Posted By: Charlie Dog
Date Posted: 20 Jan 20 at 12:30
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"Ghost code" is that a variation on "GOK?" https://www.internetslang.com/GOK-meaning-definition.asp" rel="nofollow - https://www.internetslang.com/GOK-meaning-definition.asp Must be costing you a fortune :-( How about asking this fella? honestadvice@
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Posted By: Ynysmon
Date Posted: 20 Jan 20 at 12:45
| I hope not🤞 Its a ******* nightmare though. It’s nearly beaten us at the moment. Not sure where to go if this ends up at a dead end again |
Posted By: Charlie Dog
Date Posted: 20 Jan 20 at 12:59
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How about asking this fella? honestadvice@ I've had a few chats with him, I reckon he knows his stuff despite that we don't always agree.
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Posted By: T5 TDI
Date Posted: 20 Jan 20 at 13:38
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I don't really know a lot about the common rail T5's but the exact code you got for 'Low Fuel Pressure' might give some better clues. Have you checked the low pressure pump in the tank? The high pressure pump expects fuel to be supplied at the correct pressure. If you can, try and find out what the exact code was and have a read of this in the mean time. http://wiki.ross-tech.com/wiki/index.php/16471/P0087/000135" rel="nofollow - http://wiki.ross-tech.com/wiki/index.php/16471/P0087/000135
Edit- 'Ghost code' I really doubt if it some kind of spurious code if it won't clear given your symptoms. ------------- 2004 2.5 174 |
Posted By: Charlie Dog
Date Posted: 24 Jan 20 at 09:55
From my end of the scope, if it both revs to 3k under load and then cops out and revs to 3k not load and then cops out then it's more likely to be summat limiting revs. Anyone know what could limit revs please?
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Ynysmon wrote:Posted By: fenwick458
Date Posted: 27 Jan 20 at 23:07
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I have just had what sounds like the same problem. was driving it for a year with it going into limp mode above 3000rpm, I was convinced it just needed calibrated after I had changed the pressure reg turns out the pressure reg was faulty. it cured the initial problem (rough idle) but would not rev above 3000rpm. I got the 1st one from ebay for £92, it said it was a bosch and it looked real and came i a bosch box...but who knows?? the second one was £310 plus VAT I think from TPS My advice would be take it to a VW specialist who has pressure regs to use for testing in the workshop, get them to try it with a new one and see if the fault remains. I have also heard other reports of these cheap ones being no good, not just mine also, when I was faultfinding on mine, I seem to remember trying to rev it up to 3000rpm whilst stationary to see if it went into limp mode, and mine didn't rev that high in neutral, it hit a limiter that was way lower. could be a software limiter, it knows the van isn't moving so limits the revs...? |
Posted By: Charlie Dog
Date Posted: 28 Jan 20 at 08:19
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also, when I was faultfinding on mine, I seem to remember trying to rev it up to 3000rpm whilst stationary to see if it went into limp mode, and mine didn't rev that high in neutral, it hit a limiter that was way lower. could be a software limiter, it knows the van isn't moving so limits the revs...? Wouldn't not being able to rev the nuts off the engine put the MOT man in a mardy?
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Posted By: fenwick458
Date Posted: 28 Jan 20 at 17:10
ah never thought of that. actually thinking about it mine would have been in P, never tried jumping in and putting it in N I guess it must rev to 3,000rpm for the MOT test
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Posted By: T5 TDI
Date Posted: 28 Jan 20 at 20:31
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It is correct that the 2.0 CR engines will not be able to rev fully when stationary. This is normal/ok on an MOT because it's behaviour agreed between the manufacturer and VOSA. I don't know if 3000 rpm is the actual limit but it is academic really because the UK diesel smoke/opacity test is laughable for a modern diesel unless there is something very wrong. My old bus is a 16 year old Euro 3 with just a CAT and no DPF and it easily passes every year. ------------- 2004 2.5 174 |
Posted By: Charlie Dog
Date Posted: 28 Jan 20 at 20:45
| Tempting fate there T5 TDi :o) |
Posted By: fenwick458
Date Posted: 28 Jan 20 at 23:48
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Yeah the mot smoke test is pointless and has been for ages. 10 years ago when re mapping PD engines everybody knew the limit for a clean burn, no smoke remap. But they also knew you could get more power if you just increase the injection duration so the nozzles pretty much constantly pour fuel in at entirely the wrong time But it makes an extra 15bhp... so what happened was every remapped TDI had a back bumper with thick layers of soot all over it But they all passef the smoke test no probs because the ECU only puts fuel in when the car is moving, so it was clean as a whistle during the test  Don't see that so much now that the pd engines have died out a bit. |
Posted By: Charlie Dog
Date Posted: 29 Jan 20 at 05:35
| That's very interesting Fenwick, thanks :o) |
Posted By: Ynysmon
Date Posted: 15 Feb 20 at 11:00
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the plot thickens with the van! They have drained the fuel and it’s definitely not just diesel in there! When t he van was delivered the delivery company said it was empty when they got the for the pick up and he had found some fuel in a can to drive it on the trailer. I then put £30 of fresh diesel when I first drove it. The diesel sample smelled of swarfeger hand wash stuff to me and was a funny colour. We’re now draining the whole fuel system to see if that’s it🤦🏻♂️
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Posted By: Charlie Dog
Date Posted: 15 Feb 20 at 12:38
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Oh dear, how very anger provoking :o( On the bright side, it's a not too expensive entirely nuts and bolts problem. What do think about adding an injector cleaner to your next lot of fuel :o)
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Posted By: Ynysmon
Date Posted: 21 Feb 20 at 18:07
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quick update, The fuel sample was a mix of petrol/kerosene and the diesel I put in. Mechanic has said the four injectors seals have gone and will need replacing (including the two new ones I’ve already put on it) He also said although the diesel pump has passed on a bench test it could also be effected once the new injectors are in. Not priced it up yet but I’m thinking it’s gonna cost me a fortune!
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Posted By: Charlie Dog
Date Posted: 21 Feb 20 at 19:08
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Nasty old kick in the gob there Ynysmon. How about asking whoever put the kero/petrol mix in for a lob. If you don't ask, you don't get. A solictor's letter might be worth pop. Except I don't know how much they cost.
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Posted By: Ynysmon
Date Posted: 21 Feb 20 at 19:39
| it was back in June I purchased it and have had countless jobs done on it now so not sure where I stand in terms of trying to get money back. |
Posted By: Charlie Dog
Date Posted: 21 Feb 20 at 19:57
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Can you finish this well known phrase or saying Ynysmon? "If you don't ask, . . . "
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Posted By: Charlie Dog
Date Posted: 21 Feb 20 at 20:02
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If they say "no", your next step is the Small Claims Court. The first step is simple, easy, and cheap. Many company's will offer money on the threat. If they don't, then things can get heavy. Another saying for you to finish. "Nothing ventured . . . "
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Posted By: Ynysmon
Date Posted: 19 Mar 20 at 19:36
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finally resolved the fault. Took it to someone else that a local guy recommended and it was sorted the same day! It cost me a new hp diesel pump but at least the injectors seem ok. I had the pump bench tested ok, but obviously not to the correct pressure by the looks of it. It’s not the first he’s had like this so hopefully this might help a member in future. Thanks to anyone that has taken the time to help, great forum and members.
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Posted By: Charlie Dog
Date Posted: 21 Mar 20 at 08:02
I bet you are well please aren't you Ynysmon?
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Posted By: Ynysmon
Date Posted: 21 Mar 20 at 12:22
| pleased it’s sorted, no so pleased at the cost of it all haha |
Posted By: T5 TDI
Date Posted: 21 Mar 20 at 20:23
The frailty of the high pressure pumps on the 2.0 CR engines makes me nervous about ever owning one. If you are unlucky, simply running out of fuel can wreck the pump leading to a £1500 + bill.  Mis-fueling could do the same.
------------- 2004 2.5 174 |
Posted By: Ynysmon
Date Posted: 21 Mar 20 at 21:31
| yeah as I’ve found out:( |
Posted By: Charlie Dog
Date Posted: 23 Mar 20 at 07:59
Which modern vans aren't monkey traps please T5
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Posted By: T5 TDI
Date Posted: 23 Mar 20 at 08:32
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T4! ------------- 2004 2.5 174 |
Posted By: Charlie Dog
Date Posted: 23 Mar 20 at 10:55
Thanks T5 :o)
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