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"Jerk" when under acceleration

2v50

2v50

Member
Messages
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14
Location
Edinburgh
Car
Mk7 Tourer 2.2 I-CDT
Hi all
So the new car has already started to give issues... Power steering cooling line burst (fixed that with a universal oil cooler from amazon - thanks for the idea ;) ) , and the clutch master cylinder is on its way out.
It's a 2008 i-cdti tourer - 162k miles.
The current issue is a " jerk" when flooring it, almost always in 3rd, around 3500rpm. I've only had it happen in 4th once, and it was right after changing up. I was ***uming it was VSA - as one of the times I caught the VSA light flashing up, but since then it hasn't come on for this. It certainly feels a fair bit like the brakes suddenly engaged and then let off, very quickly. The revs hang for a second then it picks up and right up to speed - no more issues.
I have done some searching but I can't find anything that matches up - maybe the fuel filter? I have no service history whatsoever, just a promise from a dealer - who are useless...!
Any thoughts are much appreciated!

(Not sure if this belongs in Diesel faults - I kinda suspect it might. )
 
Possibly egr but if you’ve seen you vsa light then more likely a failing accelerator pedal position sensor, or an abs sensor. Have the abs module scanned to see if any errors have been registered. Alternatively you can drop me a line and book for a session.
 
Thank you to both of you !
The car goes in to Honda tomorrow for the pass airbag inflator recall - I've been ***ured they do a through inspection there and check for any problems in the hope of making some money. The car is currently under a ( mostly useless ) 3 month warranty so I'm trying to get everything done via that -but with it being the height of mot season just now that is not proving easy
. 1-2 weeks to get it diag'd for the warranty co, then a further 6 weeks to even think about getting work done!

I'll see what Honda pull up - if anything, otherwise I'll see if a friend's snap-on diag unit can pull up anything.

F6HAD - I'll likely drop you a line sometime further down the line... Once out of warranty and money is a little less tight. The forum has certainly hyped up your skills and a wee tune for economy and EGR off sound like an excellent idea.... I gather you are Leeds based? If so a bit far for just diag - a good 450 mile round trip. ( Plus the warranty co. won't pay more than £50 an hour! )
Thanks again - I'll see what the findings are and post my results.
 
Well, Honda western did... uh... nothing good. Damaged my dashboard, scratched my glovebox, left the car half a mess - they hoovered the passenger carpet and dressed the tyres though. Random, and very annoying.
Checked via the snap-on unit - couple of random faults showed up. Intermittent crankshaft sensor reading, ultrasonic unit, rain sensor.. I forgot to take a picture and I've forgotten what else! Nothing particularly obvious anyway.
Cleared the lot and will see what reappears.
Got my dad to have a wee spin in it - he feels like it's driving fine other than a little hesitation and a very small flat spot where it feels to be doing nothing. Leaning toward accelerator position sensor now, but I'll see what comes up in a couple days ( or after some decent driving, as planning on doing the clutch master cyl tomorrow!)
 
If it’s your APPS then you’ll see the VSA light come on when it hesitates, if not then chances are it’s the egr valve.
 
Thank you - the VSA light doesn't come on with the slight hesitation - the clutch master cyc is still making my life difficult right now but it's seeming like there's often hesitation that I was putting down to that. Car drops to <600 rpm when pulling off sometimes. No VSA light with that though. Only time I've seen the vsa light without loss of traction ( or taking a roundabout too fast...) is when the car felt to jerk under heavy acceleration - I've not managed to reproduce this in my limited time with the engine actually up to temp in the last few days. Seems a little erratic!
 
450 quid lighter - car serviced. Fuel filter was done in - this was the apparent cause, took it to Bonnington Mill Garage , Edinburgh. Clutch pressure plate has failed now.... does it ever end?
Onto that job next week. Back to the Peugeot 206SW for a while. That sweet 1.4 petrol power... or lack of it!
 
Did the fuel filter solve the jerking?
 
Just tested - nope! Annoyingly the guys at bonnington were 100% insisting it would be the fuel filter - can't say I'm too happy now. It's been less common since a while back, it did it 7 times in a row pulling off from a lay by on the a77.
The revs drop dramatically then shoot back.hp to 3k, I'm going to ***ume that it's definitely an EGR issue and not related to the clutch - doing the clutch next week, so I'll check once ive put a few miles on the new clutch. It no longer seems to do it in 3rd gear flat out - smooth as butter 30mph shifting at 4k ... But from 10mph in 2nd , single hard jerk at around 35-40. Need a co-pilot, or something to monitor and record what's happening, as I'm awful at describing it
 
Did they use a genuine or aftermarket filter?
 
They claim to use only genuine - fitted Bosch everything, fuel, air, pollen and oil filters!
 
Bosch only do the fuel filter (pre facelift cars). The rest is all Honda marked oem. Sounds like there is indeed a different issue, possibly egr
 
I had an issue that turned out to be the throttle position sensor. It had not failed but there was dirt/wear on the carbon track of the variable resistor inside.
Sometimes it would go into limp mode with the lights on the dashboard, but most of the time there would be a momentary drop in power, sometimes on a level road when I coasting, foot just resting on the pedal.

A good dose of switch cleaner in the vicinity of the TPS , a minute or two of moving the lever and two years later it is still working well, with just the odd hesitation once or twice a month.
 
Totally forgot to reply there - sorry Channel Hopper. Think the tps does need a good clean - dip in power, that I tend to call a flat spot, right around 1k rpm, just as pushing pedal that tiny bit down to bring up to speed from a standstill or close to it. Either pull away very slow, or it stalls, or give it too much and jolt forward as boost hits. Will definitely give it a go. No dash lights or limp mode though!

Starting on the clutch tomorrow - I've done around 400 miles almost entirely cruising on motorway where the clutch does not pose issues due to lack of use...
Had just over 3/4 of a tank - usually that's around 600 miles fuel for me. Car burnt the entire lot on the second trip - range was showing around 300 when I left - 90 miles later fuel light was on . Tyres at pressure as per door sticker , cruise control at aprox 70 80% of the journey , remainder was almost all motorway with speed restrictions, so still on cruise control in 6th gear. Freaked out when the fuel light came on - I've never risked running out of fuel before, always have more than I need for the trip!
Managed to run it back down the road to an asda for fuel , 178.7p / l ... painful! 40 quid in got me the 80 miles home with 274 miles range on the trip computer. The car held its own figures of 50mpg avg over the trip , but a quick calculation shows it was getting less than 20mpg prior to the fresh fuel.

Coming through the lit sections around Ayr, I notice the car throws out a pile of smoke while under heavy load - looks white/grey in colour.
Checked the oil filler cap with engine off - white/grey vapour, smells mostly of hot oil to me though.
Would it be practical to try and deal with this at same time as the clutch - I'm ***uming the smoking and to some degree the fuel consumption is going to be a failed or failing EGR valve? , plus possibly some bad fuel from Tesco? Though the latter seems unlikely. I've really not much idea when it comes to diesels and their emissions control systems, starting to wish I'd gotten a petrol!

Thoughts much appreciated - I'm totally out of cash to throw at this car since the service!
 
2v50 said:
Totally forgot to reply there - sorry Channel Hopper. Think the tps does need a good clean - dip in power, that I tend to call a flat spot, right around 1k rpm, just as pushing pedal that tiny bit down to bring up to speed from a standstill or close to it. Either pull away very slow, or it stalls, or give it too much and jolt forward as boost hits. Will definitely give it a go. No dash lights or limp mode though!

Starting on the clutch tomorrow - I've done around 400 miles almost entirely cruising on motorway where the clutch does not pose issues due to lack of use...
Had just over 3/4 of a tank - usually that's around 600 miles fuel for me. Car burnt the entire lot on the second trip - range was showing around 300 when I left - 90 miles later fuel light was on . Tyres at pressure as per door sticker , cruise control at aprox 70 80% of the journey , remainder was almost all motorway with speed restrictions, so still on cruise control in 6th gear. Freaked out when the fuel light came on - I've never risked running out of fuel before, always have more than I need for the trip!
Managed to run it back down the road to an asda for fuel , 178.7p / l ... painful! 40 quid in got me the 80 miles home with 274 miles range on the trip computer. The car held its own figures of 50mpg avg over the trip , but a quick calculation shows it was getting less than 20mpg prior to the fresh fuel.

Coming through the lit sections around Ayr, I notice the car throws out a pile of smoke while under heavy load - looks white/grey in colour.
Checked the oil filler cap with engine off - white/grey vapour, smells mostly of hot oil to me though.
Would it be practical to try and deal with this at same time as the clutch - I'm ***uming the smoking and to some degree the fuel consumption is going to be a failed or failing EGR valve? , plus possibly some bad fuel from Tesco? Though the latter seems unlikely. I've really not much idea when it comes to diesels and their emissions control systems, starting to wish I'd gotten a petrol!

Thoughts much appreciated - I'm totally out of cash to throw at this car since the service!
Click to expand...



No worries, you have a lot of more pressing issues.

Before you start on the TPS (it doesn't need dismantling, just spraying of Servisol close the box and inside the connector block and engage the pedal a number of times before it evaporates.

As for the heavy fuel use, if there are no leaks under the car or around the engine, you may just have a leaky injector (or two).

Fresh fuel in the tank is always good, moreso if it was near empty. You could try dropping a full can of Redex or similar in next time you are close to empty, thrash it for five minutes and then leave overnight before topping up again.
 
Channel Hopper said:
No worries, you have a lot of more pressing issues.

Before you start on the TPS (it doesn't need dismantling, just spraying of Servisol close the box and inside the connector block and engage the pedal a number of times before it evaporates.

As for the heavy fuel use, if there are no leaks under the car or around the engine, you may just have a leaky injector (or two).

Fresh fuel in the tank is always good, moreso if it was near empty. You could try dropping a full can of Redex or similar in next time you are close to empty, thrash it for five minutes and then leave overnight before topping up again.
Click to expand...


Well, that's the pressing issues done, 2pm - 5pm yesterday and 10am-5pm today, and that's it back on the road. The clutch was both rather well worn and burnt, adjuster maxed out and the pressure plate springs weak, along with a buggered release bearing running on a dry shaft... and of course, the DMF, was done in, far too much play!- ( thanks to honda specialist's garage who were very confident that it was fine....sigh! Can't go just by noise it seems.) Dingbro's had one in stock, along with new bolts.
Cleaned up and fitted the lot, car is running again - feels like it has a chunk more power, though I think that's just from driving a 75hp 206 about again.
Actually got a fright when boost kicked in trying to take it easy driving home.

Leaving the probable EGR issue till another time for now, don't want to be messing about while the clutch beds in.
Going to spray down the TPS just now, if I can find my contact cleaner. The flat spot is very, very obvious now that the car doesn't immediately attempt to stall as the clutch engages!

I'll see how the fuel remaining lasts - I should see at least 250 miles from it, anything much less than that and I'll be investigating injectors ect, otherwise I'll give just that a go , and avoid Tesco for diesel, even if it is a full penny cheaper than asda! Maybe time to invest in a costco card, just for fuel...

Many thanks!
 
Well, I've taken off the EGR, cleaned it out, tested it works.
Took the car a run - still jerking! I kept the throttle to the floor and the car lost power, and the glow plug light starts flashing - right into limp mode. Cheapo code reader confirms P1065 active + pending fault. Clear the code, give it a good rev up and down, pretty smokey looking behind - can't tell the colour but lovely reek of fuel. Seems to stop... Took it back on the B road, 2nd gear up to 5k and held no issue. On the A1, tried same again, fine.
About 15 miles down the road, pull over to check on someone broken down - water pump exploded, ow! - Leave the car idling for aprox half an hour. As I pull away, foot not quite to the floor but close... jerk in first and twice and second, then stops as I let off slightly and go into fourth. No Limp mode.. Fine cruise back home, try both 1st and 2nd to redline again and totally smooth.
So, a totally intermittent fuel pressure issue, with a oem fuel filter used!

Any suggestions before I start checking the garage actually fitted an oem filter ?

On a side note - what a massive difference clearing the EGR, the intake will 100% be coming off for a clean as well!
 
You might have an airlock after fitting the fuel filter, if it doesn’t bleed out itself then try priming the bulb and bleeding from the 10mm bolt on top of the filter a few times. That code is nearly always attributed to a fuel filter issue on these cars.
 
Leaky injector on cylinder four....!
Certainly doesn't appear to be an airlock from the fuel filter, though I'll bleed it again if the injector doesn't appear to fix the issue. Right now she's burning fuel like there's no tomorrow - by my calculations I'm getting at best 17mpg just now! A far cry from the 60+ I was getting to start with. Tested refurbished injector set me back 75 - and saved a very expensive drive out to the breakers yard.

Current ***umption with the jerking is the injector is leaking extremely badly above idle speed, causing a drop in pressure at the rail under load, causing jerking followed by limp mode if pushed.
Fuel issues have to arise when it's so expensive I can't afford to waste fuel!
Lovely sooty exhaust at the moment - Starting to invoke one of the local Fabia's that leaves clouds of reek wherever it goes. Plus side the graphite paint hides whatever gets on the boot!:cool:
 
If it’s leaking that bad I’m surprised you didn’t hear it ‘chuffing’ or at least smell it.
 
Not leaking from the top seal it seems. just dumping fuel into the cylinder all the time! ( I'll take the mechanic's word for it considering he fitted it for free.. or well, an owed favour! )
Replacing injector 4 mostly fixed the fuel consumption, car reported 53.7MPG over 700+ miles of motorway. Aprox total distance (including remaining trip computer estimate 800 miles on £154 of diesel at 195.7 - still much lower economy than it was getting to start with., but at least not bankrupting me entirely!
Seemed to loose boost at one point - after an hour or so of driving the car lost power. Can usually feel boost come in just below 2000rpm , instead slow and steady acceleration without much power, even if dropping a gear. Seemed normal on the return journey - maybe due to he heat? return journey was at night thankfully. Probably because of my cardinal sin of taking things off and reusing gaskets... !

Still smoking a pile, nothing while not under load though - but the other day I left such a large cloud of smoke behind that the car behind slowed down on the slip road. Fuel pressure issue still present and causing jerking, had it happen at 2500rpm working through the gears up to 70. Going to leave it to sit a few days, managed to catch covid, typical!


edit - yet another unrelated issue found, after taking great effort to try and get the intake off, i was foiled by two entirely seized nuts. both center nuts would not budge, spanner was starting to cut into them! After this i felt the need to check the exhaust manifold, apparently the reek I've been smelling has been that, cracked at the weld on cyc no.4. here was me putting that down to the EGR or being stuck behind buses. I'm suddenly rather glad I usually have the windows open for ventilation.
 
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Finally got the fuel filter off - they had fitted a Bosch fuel filter. Using an impact by the feel of it - required a scaffy bar to be removed. Bosch filter has a totally different design to the genuine article. Lesson learned there, I'll only ever be going to the mechanic I know. Jerking issues gone, and with another full service done she now runs like a dream again. Fuel economy seems to still be fairly poor compared to when I got the car, but it seems to be idling that drives it down rapdily. Around 40-42 around the town, not exactly being nice to her with acceleration.

F6HAD, thank you for all the information you gave me, I'm unsurprised it was the fuel filter to blame, though rather annoyed that a ex honda master tech fitted a part that caused a problem - I guess no one knows it all but a quick google of fuel filter on these engines would have gone a long way. Thankfully she only cut out due to it once and no damage was done.

Things are awfully busy just now but I'll be wanting EGR off and depending on conversation with my insurance, a remap, sometime next year. Seems worthwhile at this point!
 
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