Volvo S40 2.0d tuning project

I’m confused?..there is no pump in the tank I’m aware of?..I’ve changed the fuel gauge sender unit which involves removing the tank!..the series 1 S40’s had a removable inspection plate above the tank but the series 2 doesn’t! far as I’m aware the fuel is drawn from the tank and into the engine via the fuel pump in the engine bay?..that could possibly need a rebuild?..
Thanks - I stand corrected.. I have a S40 II so obviously won’t have this issue.

HP injector pump has been reconditioned (by the same guy that did yours) - as have injectors.

Fuel distribution line (from filter to injector pump) is original - so one scenario might be air bubbles being drawn through the O-ring seals (hard to see since the issue only arises under hard acceleration)..

It’s been suggested that I might need an inline LP assister pump - though don’t feel the engine is making enough power yet to hit that issue.

More likely - there may be a sensor issue (I’ve fitted a 4 bar MAP sensor and 2,000 bar fuel rail sensor as per HDI recommendation. Will know more when I have the logging files..
Air bubbles are present in the fuel line but that is normal..I can see them passing through the fuel line when we have been running it on the rolling road under hard acceleration..My car can produce well over 300BHP with the nitrous and water meth switched on!..I’ve obviously also fitted an uprated map sensor as it’s developing around 28PSI of boost but the fuel rail sensor is stock?..also believe it or not it still has a stock clutch!..I’ve experienced no slipping
Thanks Greg

Just come back after the logging run. Car was seriously black smoking under any power - plumes of it coming out when you floored it. Clearly an overfuelling (?) issue..

We did a couple of 3rd gear pulls with wide open throttle and repeatedly at about 3,100rpm the engine struggled to accelerate any further - almost as if the fuel is being cut.

I've attached the CSV log file - I used to view the data (link is here :

It shows the fuel rail pressure dropping significantly at around 2,800 rpm - safety cut off? Massive over feeling..?

Unless anyone can suggest anything obvious I think it's time to get someone with more experience to check it over.. :-)


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Oh mine black smokes under hard acceleration.James Bond would be proud of’s all down to the mapping..but not a whisper of smoke driving normally..and on the motorway I can get beyond 70+MPG…even around town it averages 45-50MPG..
I’d try another fuel would seam there is something amiss with yours?..or have yours said AP diesel’s had reconned your injectors and fuel pump so that can’t be the issue?..
Thats weird, their listed specifically the 3.1bar sensor which works on oem plug and a refurbished fuel pump, its so unfortunate that it doesnt seem to run good.
My suggestion is to try the oem rail sensor, delphi 3.1bar sensor, replace the maf and double check the flow of the injectors.
Usually if the fuel supply is at too little it would starve the engine and not run rich (black smoke). Hence i would predict that the map, injectors or the maf sensor is at fault.
Mine altough just a stage 2 from Hdi tuning is running fine on this application to 5.5k revs without a refurbed HP pump.
If this doesnt fix it, I would simply ask for a refund or a stage 2 map since that would work on the 1752 or 1756 too.
That’s what my map sensor is..3.1 bar and yes its a direct fit..It is actually a map sensor for a Ford Fiesta 1.6
Thanks Greg, Paskal. Still experiencing quite serious issues - to the extent that I may have to abandon my plans to take the car to Europe the week after next which is a real shame...

As a reminder :
- Fuel injection pump and fuel injectors completely refurbished by the same guy who did Greg's. Came back looking brand new.
- Turbo rebuilt and upgraded to hybrids by the same guy who did Greg's
- New Bosch MAF sensor fitted (genuine article, sourced from Autudoc)
- Bosch 3.1 bar MAP sensor fitted (supplied by Darkside Developments - so definitely genuine). This was a replacement for another Bosch 3.1 bar MAP sensor that I installed during the original rebuild to double check this was not the culprit.
- Bosch 4 bar fuel rail pressure sensor (again genuine)

Plus Do88 intercooler and associated upgraded pipework etc.

I have checked (and actually re-done) all of the upgraded sensor wiring. For the MAP and fuel pressure sensors I sourced new connectors with pigtail wiring and used heat shrink solder connectors to splice. Re-did these yesterday to make doubly sure the solder had correctly penetrated (it had).

I did notice that the turbo vacuum hoses are old - and in places, softened by oil. These may be collapsing under vacuum, though not sure if this would cause the issues I'm experiencing. Will renew with silicon replacements this weekend

I did another run last night and the car initially ran quite well - felt responsive under low throttle openings as I allowed it to warm up. Gradually increased the throttle openings once the car was warm and then did a hard pull in second. This resulted in similar symptoms - lots of black smoke, struggling to rev beyond about 3,200 rpm. From this point onwards, the engine struggled to rev beyond about 2,300rpm - and I took it easy from that point to nurse it home.

Checked for OBD errors and had two after this run :

- ECM-0002 Fuel volume control valve - Faulty signal
- ECM-089 Fuel pressure control valve : Faulty signal

The fuel volume control valve is new (replaced as part of the injection pump refurb). The wiring to the plug attached to it was (slightly) exposed at the point it entered the plug - though not shorting. I've tidied this up and insulated both wires - would ideally like to renew the plug but really struggling to locate it online.. Any suggestions?

Will take the car out again later today - though I'd be amazed if the fettling of the fuel valve made any difference..

Running out of ideas as to what to do next so any suggestions very welcome..
.. just been out on another test run - same symptoms and interestingly, same OBD error codes :

ECM-0002 Fuel volume control valve - Faulty signal
ECM-089 Fuel pressure control valve : Faulty signal

The fuel volume control valve is attached to the injector pump - though I'm struggling to find the fuel pressure control valve ..? Any ideas?
I can imagine your frustration!..I’ve not experienced any of your problems? car as done 168,000 miles..I’m still on the original stock clutch!..the only thing I’ve uprated is the map sensor ..still using the stock fuel pump and injectors although rebuilt..all my hoses are silicone and all the pipe work is custom made to fit around the uprated Nissan Skyline GTR intercooler..As I’ve said before the only issue I had was the car cutting out at around 3,800RPM and “engine system service required “ coming up on the dash..That would reset itself after around 10 seconds and normal driving would ensue..reconditioning the fuel pump and injectors solved that problem..My car runs sweet as a nut and dumping another 125BHP+ when I flick the nitrous and water meth doesn’t change that?..I don’t know what to suggest to you as my journey uprating my car has in itself been one of trail and error as nobody appeared to have done the modifications I was doing?..I hope you get to the bottom of your problems?..
Looks like I may have found the issue - air getting into the fuel line at the union with the injection pump. I’d re-used the fuel pipe from the filter to the IP when I refitted it after the recon work and it clearly wasn’t up to the job. Not bad enough to stop the car running and driving at low throttle openings, but anything more caused problems.

I reckon that air was being drawn in to the IP through the o-ring seal and causing massive fluctuations in the fuel volume sensor data from the LP side of the pump. This was then throwing out the fuelling - causing massive over- and then under-fuelling.

I replaced the pipe with a (bloody expensive) genuine Volvo one - and after a LOT of hassle bleeding the system managed to get it running (finally had to resort to Easy Start..). First run showed similar symptoms to those described earlier, but the motor then started pulling well all the way up to 5,500 rpm. We then did about 20 miles of hard driving with multiple pulls in all gears and it seemed to get stronger and stronger - with less and les black smoking (probably clearing out all the crap that had built up in the exhaust etc).

Might be premature to call success, but certainly feels much, much better..
These cars are an absolute bugger to bleed..even Volvo don’t like changing the fuel filter for that reason! man who does all my work on the car has found a very easy way to bleed the system whenever we’ve had to mess about with the fuelling side if things..he loosens the injectors off and the air bleeds off very easily then he just tightens them back up again..job you appear to be getting it sorted..
I thought I’d post an update on a few more snagging issues I’ve had whilst getting my engine to run properly. Much of this is obvious in hindsight but I thought it might help other diesel rookies like myself avoid them in the future !

After getting the car running with the replacement intake fuel pipe I did a few road tests and had each time the turbo boost rose above around 10psi experienced plumes of very sooty black exhaust pumping out from the exhaust. The max boost pressure that the ECU maps runs is 2.2 bar and it was pretty clear that at higher pressures I had air leaks and the engine was continuing to be over-fuelled.

I found two main causes of this :

- I pulled apart the custom intercooler pipework I’d made and found that the hose / adapter combination that joined the hard pipe that runs under the engine from the turbo feed to the intercooler was too short. This was flexing excessively due to the engine moving on its standard engine mounts creating high stress on one of the silicon hoses. This in turn was opening up a small leak around the union with the hard pipe (despite flanged unions being used throughout and high spec, bolted hose clamps). Lengthening this silicon pipe, sealing it with silicon instant gasket and installing updated (polybush) engine mounts addressed the issue.

- With the intercooler piping air tight, I did another run and was seeing 33psi at the boost gauge and hence the throttle body (the feed pipe was tapped into the hose that connects directly to the throttle body) - indicating that the intercooler pipework was holding the pressure OK.

However, I was still experiencing a lot of black smoke issues on hard pulls - and tracked the issue down to what in hindsight was a rookie mistake. I had installed an EGR delete plate that blocked off the EGR pipe where it connects to the EGR valve - but had fitted the pipe (at both ends) without using any sealant. It was clear when I removed it that large amounts of air had been leaking from the pipe unions - most notably around the face of the pipe flange and the blanking plate. I thoroughly sealed this using high temperature silicon gasket, allowed it to cure overnight and then road tested the car again. I have yet to really push the engine but this does seem to have sorted the issue - the engine runs much cleaner throughout the rev range, with only small amounts of paler exhaust smoke being seen on wide throttle openings and boost pressures greater than about 25psi.

When I get time, I’m going to make up a blanking plate to sit directly between the intake manifold and the EGR pipe - it’ll be a lot easier to seal the manifold at this end rather than rely on the EGR pipe holding pressure through it’s various unions.

I’m not going to call success quite yet but my experience highlights the importance of ensuring that entire intake system is fully sealed and can deal with the high pressures that the turbo produces..

As I said at the start of this post - obvious in hindsight..!
Wow!..I haven’t experienced any of your EGR is blanked off and there as been no concerns in that area..the only niggle I had was the boost pipes blowing off all the time!..we eventually sorted that by double clamping them…keep at it my friend..I’m sure you’ll get it sorted..
Were you using rubber pipes, silicone pipes or hard pipes? I've known a few people use a dob of GLUE but not sure I recommend that.
Great to hear that she is running alright. I blew up my engine sitting at 172k, surprised the engine went before the stock turbo lol. It is believed that my ebay special refurbished injectors was over fuelling cylinder 2 and 3. Should I buy another 2.0d engine or go with the 2.4d ?
Personally I’d look at getting a more modern D4 engine…they are near on 190BHP standard…the 2.4D is a big old lump and I’m not sure how tuneable they are?..
Personally I’d look at getting a more modern D4 engine…they are near on 190BHP standard…the 2.4D is a big old lump and I’m not sure how tuneable they are?..
Would be cool but needs a lot of custom fabrication, whereas with the old d5 its a straight engine and gearbox swap, also the wiring is way simpler. New D4 would probably require custom engine mounts, wiring, standalone ecu etc
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