black smoke after egr blanking mod

hi all, long time lurker but first time poster on these boards and hoping for some help with a few of my 05 td4 hippos latest problems.
after reading alot of threads on here about lack of power i realised i was suffering from the old maf trouble (40k on the clock and getting progressively more sluggish) seeing as everyone here seemed to rave about the synergy2 and it worked out cheaper than buying a new maf with the added extra bhp i went ahead and fitted it a couple of weeks ago... instantly my power, torque and acceleration were returned to as good as the day i drove it out of the showroom the week after i decided to treat her to the egr bypass mod but this has resulted in clouds of black smoke when i accelerate (worse when towing and the more weight in the trailer the more smoke produced!) i checked all the hoses and cant find any holes or splits and its only a few weeks since i did a full service with the exception of fitting a new fuel filter. i then went thru the synergy2s intructions about issues relating to black smoke but none really seem right to me i've tried the box on every setting and the lower the setting the less smoke there is but still far more than im happy with a mechanic has told me all remapped diesels will smoke like this but that i should change the fuel filter and see if its helps, its due a change so thats next weekends project but we both doubt it will make much difference. the only other things that i can think of that might be contributing to the problem are a possible dodgy injector (idles erratically occasionally and takes an extra half second or so to fire up when i turn the key) although its been on the computer and no injector issues have shown up but i still have my doubts on this. the other issue relates to the fuel pressure sensor which gave endless trouble while still under warranty (cutting out at high speed then refusing to start!) but this was eventually fixed by the stealership after about the tenth time when i threatened to take them to court if there was an accident due to this problem
so where do you guys think the problem lies?? the synergy box, the bypass mod, maf, injectors or fps or something completely different??
thanks in advance

Hi,
Black smoke is either a lack of air or excess fuel.

The EGR bypass seems to be where the problem started. Did you block off the small diameter vac hose which originally connected to EGR?

Contact RoverRon he knows most about these systems and is happy to advise.D..

Perhaps the MAF wasn't as bad as you thought. Have you tried turning the MAFAM section off altogether?

no the maf was pretty badly gone and when i turn off the maf section its back to being completely lifeless again

Ok so with the MAFAM on what happens smoke wise if you use power setting 1 2 or 3?

on 1 and 2 its a bit sluggish on pulling away and a little smokey, on 3 it pulls away a little better and has good power but more smoke. i wouldnt mind spending the money on a new pierburgh maf if i thought it would cure the problem. o and i did block off the vaccum hose that went to the egr with a screw and its a good tight seal

For you to need the pierburg maf your maf signal would have be too high rather than too low, there would be heavy fuel consumption rather than no power. (this is before the synergy was fitted)
I'm not sure the pierburg maf will change anything. Your maf is responding to the signal amplification.

It not likely to be a sensor issue, if it was relatively smoke free before the egr was removed it should still be now.

I know you've checked already but be absolutely certain there are no air leaks from any of the induction hoses.

How long have you run the car since the egr mod?
It could be that you need to give it a bit of a caning and get some exhaust heat to burn off accumulated oil and crap.

I get a little smoke on setting 3 particularly under heavy load and when towing but nothing too embarrassing!

I don't think you should use anything higher than setting 3.

dearlander said:

the only other things that i can think of that might be contributing to the problem are a possible dodgy injector (idles erratically occasionally and takes an extra half second or so to fire up when i turn the key) although its been on the computer and no injector issues have shown up but i still have my doubts on this.

Click to expand...

My first Ron box installation led to erratic idle - after plenty of useful advice and twoing & froing Ron was happy to issue a replacement, solved the problem instantly! I'm not suggesting that's the case here, but might be an idea to check with Ron - go through all the checks he suggests and see where you go from there.
Did you keep the original EGR? is there a seal at the EGR valve body that maybe missing?

almost 100% sure theres no leaks from the hoses but i'll check again. have had the egr blank on for nearly a week now and have been for a few long runs without the trailer on so i would have thought most of the crap should have been blasted out by now although when i did the egr mod i didnt bother cleaning out the manifold as the egr didnt seem that dirty but maybe cleaning it might help, wont get a chance to do that til the weekend though. now that i think about it i didnt remove the old egr gasket and the blank had a cork gasket already on it, i wonder if that would make a difference??
prior to doing the blank i was using setting 6 which felt the best and there was no smoke
im certain the erratic idle has nothing to do with the synergy as the problem existed before i fitted it and it tends to happen more often in the morning when the engine is cold although it does sometimes occur even when the engine is warm although its nowhere near as bad since the fps problem was sorted out

Unless you have positively sealed the screw you used to blank the EGR vac pipe with gasket goo the screw may still leak. It might feel tight but the tube material may not flow into the core fillet radius.

dearlander said:

now that i think about it i didnt remove the old egr gasket and the blank had a cork gasket already on it, i wonder if that would make a difference??
prior to doing the blank i was using setting 6 which felt the best and there was no smoke

Click to expand...

Leaving the original o ring in place could be viewed as belt and braces and isn't going to cause this.

Strange that you had success on setting 6 initially as that setting amplifies the maf signal more and would produce more smoke than setting 3.

Try a road test with the maf disconnected altogether.

A long time ago (back in the '60's) when I did my first oilchange on my Mini I left the old gasket in the housing and put a new gasket on top of it. This resulted in serious oil leak, since then I learned that two gaskets one on top of the other is no good idea at all.

i'll investigate further at the weekend and let you know if i find the problem, until then i'll just have to ignore the smoke before i cause an accident.... am spending far too much time looking in my wing mirror trying to judge volume of smoke!

I take it you've already changed your crankcase breather filter/valve assy. Next, make sure you're using millers powersport 4 additive in your fuel & use at least double the stated dose every fillup.

chromiumuk said:

I take it you've already changed your crankcase breather filter/valve assy. Next, make sure you're using millers powersport 4 additive in your fuel & use at least double the stated dose every fillup.

Click to expand...

yep crankcase breather was changed... will give it a good dose of millers after i change the fuel filter this weekend

DearLander - is there any follow up to this thread. I am getting black smoke comming from my TD4 (like its under hard acceleration all the time). 30,000 miles only. Just changed Air Filter but have not yet changed Fuel Filter. I have the EGR blanking mod on order and will ensure the vac pipe is very well sealed. Really wanted to try to bottom out this issue before I fitted the EGR blank.

Would a dirty fuel filter cause smoking as was suggested in an earlier post on this thread ?

Have you checked for split or leaking intercooler pipes??

Thanks Chase - Will certainly check all hoses at the weekend. I had the 90 deg pipe to the EGR off at the weekend and maybe this split when I was putting it back on and I didnt notice.

I did notice a kind of "swoosh" noise from the turbo last time I drove it (its my wifes car ) which I hadnt heard before, but performance is not effected and economy is unchanged.

Thanks again.

It does sound like a boost leak then. It's a common cause of black smoke.

rouseslane said:

DearLander - is there any follow up to this thread. I am getting black smoke comming from my TD4 (like its under hard acceleration all the time). 30,000 miles only. Just changed Air Filter but have not yet changed Fuel Filter. I have the EGR blanking mod on order and will ensure the vac pipe is very well sealed. Really wanted to try to bottom out this issue before I fitted the EGR blank.

Would a dirty fuel filter cause smoking as was suggested in an earlier post on this thread ?

Click to expand...

Dont see why the fuel filter should cause excessive smoke. It will restrict fuel flow, but should not have any effect on performance until pressure falls so low that the low pressure sensor prevents the engine starting. This is because in a common rail engine the high pressure fuel pump delivers more fuel than is required at the injectors and the excess is spilled back to the tank. The electronically controlled injectors regulate the fuel to the cylinders.