Mk7 2.2 - Acceleration issues after reconditioned engine

[TheChits]

Hi all,

I imagine you've all been match-sticking your eyes open and avoiding sleep in anticipation of this update...

I ended up getting a NEW turbo fitted. According to my local garage, there WAS play in the unit and the actuator. It was 120k+ miles old, survived an engine suicide etc so decided to go for it regardless. Was hoping it'd be the silver bullet, but I kind of knew it wouldn't be. Still peace of mind and worth the investment IMO after paying out for the recon engine.

Pretty convinced after reading lots of threads on here, chatting to transit owners and various mechanics that the DPF is blocked. But WHAT A CAN OF WORMS that is to open! Options seem to be:
1. Perform a static regen with forscan - Might burn off some soot but won't really 'clean' the dpf out to restore performance?
2. remove dpf and remap - Risky for MOT although every single person I've spoken to has never had or is directly aware of someone who's had an issue)
3. Book a DPF clean - Only a temporary fix?
4. get a new DPF fitted - Ridiculous money!

Still have no fault codes so I'm just basing my hypothesis on amateurish use of forscan live data and narrowing down the variables from my list:

- MAP - check and clean ✅
- MAF - check and clean ✅
- Fuel System & DPF 'snake oil' additive ✅
- Fuel filter ✅
- Throttle body check ✅
- EGR clean ✅
- Turbo replace ✅
- DPF (& vaporiser?) check...

Leaning towards having the thing removed and remapped. Is it a long-term solution?
As usual, any advice from you folks who have SO much knowledge is absolutely priceless...

TVM!

[gt_addict]

You can get the DPF cleaned off the van. If its blocked then its the best way to get it properly cleaned. Before that though you could try a static regen through forscan. If it fails then the Vapouriser is probably clogged which will prevent diesel being sprayed into the dpf which is used to get the temp high enough to burn the soot.

[TheChits]

Hi all.
I'm still working through this issue.
The latest is that I've had the dpf and egr removed and deleted and a stage 1 re map.
I've had two mechanics scratching their heads and me even more so as to why the acceleration is still sluggish at low revs.

The turbo (new) kicks in right around 2000rpm so was wondering if the settings can be adjusted to bring it in sooner?

Since the reconditioned engine was installed the performance just isn't what it was. Whether it's now 'normal' is by the by. It does drive fine, but it's driving me mental not knowing what to try:

- Could it possibly have had a stage 2 re map before? I'm told this would give it up to 200bhp but would it change when in the throttle sensor range the power was delivered?
- accelerator pedal unit on the way out? Is this common and could it be the culprit? Forscan data looks ok but I could be missing something obvious.

Thanks for any suggestions (if you're still with me..)

[gt_addict]

You ask if it had a remap before. So when the new engine was fitted they swapped the ECU etc aswell? That wasn’t mentioned before in the thread.

Map pressure in forscan should read around the 30psi full throttle. Mine peaks at around 34psi then holds at 29-31psi (mine is a 125ps eu5 though).

Turbo on mine does “kick in” around 1700-2000rpm but below that isn’t undrivable it’s still there and noticeably helps.

You’ve had the EGR and DPF deleted. Did they gut the dpf? If not they it will block again and never regen as its been mapped out.

[TheChits]

The ECU is the same as before.
Thank you for the map pressure guideline - I'll check that on live data.
Yes the dpf has been gutted properly now (before it just had a hole drilled in it.
Got a gut feeling that it had a (poss diy) stage 2 remap previously and the ecu was fully reset when the new engine was fitted. So my benchmark for performance is much better than stock.

But i don't want to get it remapped again before exhausting all the mechanical possibilities...

What about the throttle body? Are there obvious readings to check in forscan that would hint at a fault? Worth replacing as routine after xxxx miles?

[gt_addict]

Ok that makes sense now in regards to the old possible remap.Did they flash it with the correct map for your engine to return it back to stock? I’m a bit curious why they did that rather than just change the relevant codes for injectors etc.

Map pressures may be different if yours is a 100ps variant. But shouldn’t be that far off.

Throttle body at the bottom of the inlet I have no experience of. Technically it’s not need on a diesel but I suppose it may perform some sort of efficiency stuff in line with the EU5 regs. My van has done 158k and not replaced it yet. Inlet manifold has been changed though as I had to replace my EGR valve as I thought it was faulty.

Did you reset the adaptions when the new turbo was fitted? May be worth a try and take it for a drive for 50 miles or so to see if it helps.

[andz327]

If its a clogged dpf it's quite an easy fix on euro 5 engines, if it fails due to not reaching temp to regen then it's dow to a vaporiser problem, fit new vaporiser if its faulty , fix the dosing pump that feeds the vaporiser if it's faulty and clean out the dpf ( not by doing a regen) but by someone that knows what they're doing.... simples

Sent from my SM-G990B using Tapatalk

[TheChits]

Ok that makes sense now in regards to the old possible remap.Did they flash it with the correct map for your engine to return it back to stock? I’m a bit curious why they did that rather than just change the relevant codes for injectors etc.

Map pressures may be different if yours is a 100ps variant. But shouldn’t be that far off.

Throttle body at the bottom of the inlet I have no experience of. Technically it’s not need on a diesel but I suppose it may perform some sort of efficiency stuff in line with the EU5 regs. My van has done 158k and not replaced it yet. Inlet manifold has been changed though as I had to replace my EGR valve as I thought it was faulty.

Did you reset the adaptions when the new turbo was fitted? May be worth a try and take it for a drive for 50 miles or so to see if it helps.

THANKS GT
- As far as i know the ECU wasn't fiddled with BUT I reckon it was reset.
- Injectors were fine, but had new seals and washers fitted.
- Have done the 'reset all adaptations' in forscan. No result.
- will check out the inlet manifold. Is it a diy job? What are the common faults?

I'm now thinking it's a throttle issue - something between the pedal itself and the throttle body. I've found a couple of reset procedures that I'll try today and report back.
PRAY FOR ME...

[gt_addict]

Who “reset” the ecu? Can you ask them if they flashed a standard map?

The throttle pedal controls the injectors on a diesel not the throttle body. You could run livedata on the throttle position (pedal) and report back with readings for a more experienced member to look at.

Inlet manifold on a FWD is ten bolts and fairly easy to take off. Usually its just full of carbon etc. You’ll need new seals for it though. I just bought a complete new one to save all the cleaning.

Heres old vs new pictures:-

IMG_3682.jpeg

IMG_3683.jpeg

IMG_3681.jpeg

The throttle body was thoroughly cleaned and put back. It was still working fine.

[vansit1]

did you have issues with the old one or just replaced it?

[TheChits]

Thank you again for all the helpful advice.

Here's a snapshot of forscan data for anything with 'accelerator' or 'throttle' in the name, plus a couple with 'pressure' from a time when the van was tacking along on the school run this morn, but I don't know what the best criteria to load would be to unlock the secret formula... Any advice welcome.

forscan1.PNG

I've also attached the forscan data for the drive this morning in case anyone is feeling interested enough to have a look.

From my layman's perspective, the symptom I can most easily and obviously describe is a 'lag' when pressing the accelerator to when the engine responds. As a reminder I have recently replaced the MAF and MAP sensors (oem parts) and done a 'reset adaptations' in forscan.

[gt_addict]

Well the rhrottle is effectively 100% open and your manifold pressure works out as 36psi which would indicate the turbo and throttle position are well correlated.
As you said previously if the ECU was flashed with an original map then this may be it and previously it was remapped which is why it feels sluggish.
Thats the only thing it could be.
I know my van isn’t exactly sharp on the throttle and only comes “alive” around 1500-1700rpm.

[TheChits]

Well the rhrottle is effectively 100% open and your manifold pressure works out as 36psi which would indicate the turbo and throttle position are well correlated.
As you said previously if the ECU was flashed with an original map then this may be it and previously it was remapped which is why it feels sluggish.
Thats the only thing it could be.
I know my van isn’t exactly sharp on the throttle and only comes “alive” around 1500-1700rpm.

Thanks GT!
I'd said a few posts ago that I'd recently had a dpf and egr delete and a stage 1 re-map. So even if the ecu was flashed, the new map SHOULD have restored performance to what I was used to before the new engine. But it hasn't, which was leading me to suspect something else.
The engineer has said his tuner doesn't have a stage 2 re-map for the mk7 euro5... Surely there is one. As you suggest - if that's the likely fix then it makes me think more and more that it previously had a stage 2 map which was somehow deleted. Possible? Probable?

I've been really aware for a couple weeks now that the turbo doesn't kick in until 2000rpm in every gear. The van used to charge like a pack of wild dogs. Now it's like an old fat lab.

Anyone know if there is a stage 2 re-map available for a mk7 euro5?

[gt_addict]

Celtic tuning (i think) had a stage two. The stage one is usually just the standard 155ps map from the tranist. Same engine same gubbins etc. Stage 2 is something theyve developed I imagine.

[TheChits]

Nobody has mentioned this so I don't know if I'm barking up the wrong tree but could there be a fault with the turbo vacuum pump? The tuning guy has suggested I get it checked out before doing anything else.
1. Is it a separate component to the turbo itself? (looks like it from pics)
2. is it a DIY job to inspect and poss fit a replacement?
3. would a fault give any weird readings in forscan? If so, what should I check?
4. is it possible the hoses could have been put on the wrong way round and still work?

Thanks!