Wobble on acceleration

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angeloc

Well-Known Member
Posts
1,012
Location
West Wales
I am still struggling to eliminate a low down miss - feels like a wobble on initial acceleration.

So here is a photo of my Leakback test - the car was run for a few minutes on tick over then a few blips of the accelerator were given. This is the result. Injector 1 on the left has just been reconditioned. Is this an acceptable amount of leak back - should I becoming elsewhere for my problem?

I am really pulling what hair I have left out on this one. All the usual other things either checked or done.
569cc310-7d93-b361.jpg
 
i should not pull to hard it does seem as though there is a slight problem with number 2 but I have never ever done this test doing tests like this can sometimes keep you awake at night about 40 years ago i use to look at mags like car mechanics and used to do test they had done only to upset the running of things
 
I was thinking there was a EML s/w d/l for Td4 to solve a problem of engine calibration not being restrictive enough on the EGR cycle. It would cause hesistation/flatspots when pulling away in low gears, but i was for the vin range i mentioned only. Also if you have an EGR bypass then it wouldnt be that either.


The only other thing to do with injectors i can think of is to check their numbers, to make sure they are correct.
 
I was thinking Injector numbers today - there are a couple of second hand ones on it but this model doesnt need coding. Also it has been doing it since I had it and the original injectors had never been out - I base this on the difficulty in getting them out last year.

I have had them all out recently and cut new seats and replaced sealing washers.

The car performed fantastically after this hesitation and honestly is faultless with 100mph easy - more with the synergy. I have even taken this off and gone back to the Bosch MAF in case but it's the same.

One thing that does happen is with the synergy and either Bosch or Piersburg if you turn up the power the hesitation gets worse but of course you then just power through it. It's quite a shake then though.

Do you think number 2 is leaking back enough to cause this? I am loathe to take it out and get it recon if it's something else - £115 for recon locally.
 
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Update

I took the photo of the Leakback into a local Electro Diesel place EGR did the recon on my last injector. He didn't think it was so bad that it would give my symptoms and didn't try and sell me another recon on this other injector so back to square one.
 
angelo...i think its time you now found a decent indie or diesel specialist with testbook and went for a run reading all the live data....you seem to be going round and round in circles with this and getting nowhere :( the only other thing to do is live with it!!!
 
I think you are right - problem is the nearest Test book is with a Main Dealer and an expensive full on one 32 miles away. I am going to pay my friendly guy a few pints to get it on the ramp with wheels in the air to absolutely eliminate any drive train stuff and then looks like its dealer time!

Anyone out there with Testbook who wants the money to do it - I don't mind a drive as long as its not too far.
 
Update - found a local guy via a garage owner mate. He looked at photo of leakback an said that looked like my problem - great I thought / then he said in his opinion all injectors should be changed at the same time and matched up !!!! Arrrghh!!! Anyhow I think as 3 look pretty good doing the one must be an improvement and less of a dent on the finances. Hopefully I will get it done before the end of next week.
 
I know that the injectors dont need coding, but when we sent our last injector out for referb, I waited while it was done and got to talking about problems and was told that they had once done a freelander with a problem that sounded the same as yours. The only way was to re-program the injectors/cpu, which cured the problem.
 
and if its not that injector........??? just keep thinking its time to put some money towards getting it diagnosed correctly instead of trying to cut corners that might end up costing you more in the long run....?
 
I am not trying to cut corners but find it very difficult to find people who really know what they are talking about.

It has been on a diagnostic a while ago and nothing showed up. It has just had a very rigorous MOT and a guy I trust said it was all ok in terms if suspension and other joints.

My leak back shows one injector out and one I had done last week now looks ok so it seems to me sensible to get this one done as well and at least they will all be the same.

When you say get it diagnosed - exactly what do you mean? Main dealer Testbook? I dont trust them.

If its not this injector it's only cost £114 - main dealer charges that for the coffee! At least by elimination I am improving other aspects of things. I am retired and do have a the time in the world to work on it and have the tools - its just this problem has got the better of me for the moment. When I sort it I will share the details - I was hoping that perhaps someone on here had some suggestions in terms of practical hands on - I have even offered to pay for diagnosis if someone is confident and has the kit.
 
Have you thoroughly investigated the possibility of engine hesitation caused by the hp fuel rail sensor?

Possible engine hesitation, poor idle, poor starting or all of the aforementioned, are listed as issues that can be caused by it.
 
That is a possibility but it's an expensive one to just buy to try in view of the leakback so I thought get the injectors equal first then go the rail pressure sensor - although if I put on the Synergy and turn it up the flutter gets worse - doesn't the synergy increase rail pressure?

Is there a way of testing the rail pressure sensor?

Cheers - suggestions always welcome.
 
angelo...please don't think im knocking what you are doing, i admire your dogged tenacity in trying to get it sorted mate!! when i say get it hooked up i don't just mean get the dtc's read as i doubt there will be anything stored. you need to get the computer plugged in and get the live data read, this will tell you what the ecu is doing, how much each injector is being fuelled, how much air is being let in etc etc etc anyone who knows what they are doing with this kit will often pinpoint a problem just by looking at the data. this may well cost you more than the 114 quid for a recon injector but it might just get it all sorted! appreciate it might be difficult finding someone suitable locally, whereabouts in west wales are you??
 
No offence taken honestly. I see where you are coming from but my experience do far is that most I speak with are to quick to go straight to the simplest problem ir get all new injectors - yeh right so that's £1000 then - the car is not valuable enough to do that!

I take the point about live data. I am in Carmarthen. I have seen an advert locally for an Independant in Whitland which is close.

I am happy to drive hundreds of miles if someone has the kit and won't rip me off.
 
Well I had hesitation, sluggish performance and a horrendous tick-over - but strangely enough quite good mid-top end performance - and didn't really know what to do either. After getting a quote from L/R on leak back tests/ injectors etc that made me go pale and queasy, decided to take the forum advice that made more sense than others and found a local self-proclaimed expert who worked in a garage that reeked suitably of old diesel. They carried out what I can see now was a thorough test - extracted all injectors onto the workbench and performed leak back and flow rate tests at various pressures up to 3,000 bar on all 4 injectors with print-outs as 'proof'. At this stage I was probably about 150 euros down if he'd put them all back in again, but his advice was to change the 2 he'd diagnosed as inoperative. So that added 200 euros each. He insisted on changing the filter (according to him the root of most problems and should be changed at 20,000km on any diesel) which added a chunk, and so I came out 800 euros down eventually. But what a difference! Will post pressure/ leakback results later in separate post (left them behind), and the detailed bill if that helps. One could just replace them all without testing obviously, but oddly enough full test not the most expensive part - and the test so fully explained all old engine characteristics (such as low speed roughness, high speed fine) that I can't see how anyone could diagnose anything much without this sort of full professional test - turns out he's one of only two centres in the department who can do it. I wonder if likes of L/R don't just take injectors to these sort of guys, and add on horrendous mark up - can't see them owning that sort of test-gear etc.
 
I have just cured a similar issue with mine more predominant when slowed down and stopped and accelerate away the car would hesitate almost stall and get an engine wobble.

I replaced the turbo filter which was only a couple of pounds, replaced the top turbo intercooler hose which had the tiniest leak where the hose rubbed against the inlet manifold securing bold and I took off the inlet manifold and cleaned the turbo boost sensor in the manifold - drives like a dream now (mines done 64k)
 
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