Severe misfire after revving

davudut5

Member
Joined
Oct 12, 2018
Location
Romania
TDI
mk2 jetta+mk3 tdi 1z+mk4 ecu
Hi.


We put in a jetta mk2 a 1z engine with a big turbo from a 2.5 v6 and some cheap 260 injector nozzles, after finding how difficult is to remap on a msa15 we put in a mk4 alh edc15vm ecu. The problem was from the begining even with 1z ecu. If floored in neutral and gets over 4k rpm the engine misfires badly and rpm drops and even stalls if not pushing accelerator pedal and still misfires bad like it runs on 2 cyl. After few seconds engine is running smooth again. Same happened with the msa15 ecu only when i gave the vnt turbo direct vacuum.
On the road from 1st to 5th is all good.

So if low boost is all ok, what happens, could the pump run dry or what, what do you guys think.



Timing is a bit on the low side, IQ is at 3,2 mg.
 

davudut5

Member
Joined
Oct 12, 2018
Location
Romania
TDI
mk2 jetta+mk3 tdi 1z+mk4 ecu
The pipe from turbo to resonator is 50mm and resonator and mufler are from the donnor mk3 2.0l gti. Could that be the problem?
Thanks.
 

davudut5

Member
Joined
Oct 12, 2018
Location
Romania
TDI
mk2 jetta+mk3 tdi 1z+mk4 ecu
Since on the road is all good up to redline is not a big deal. We put a mk4 used maf hoping to go crazy, turns out its wasted, reads 250 idle and full boost about 350. The car goes much faster on the 550 default value with it unplugged.
Well the ecu is in, next will be to remap. There is no dino in our town to make a custom map, hopping to make some power soon.


In vag com there is a button to measure the acceleration, did 11,5s 0-100km and 18s quarter mile, i guess its not making more than 100hp so really need the remap, hopping over 150hp from it. :)



Picture with old ecu and MAF
 
Last edited:

davudut5

Member
Joined
Oct 12, 2018
Location
Romania
TDI
mk2 jetta+mk3 tdi 1z+mk4 ecu
We upgraded to 11mm pump head, we kept the stock camplate as it had more lift than the one that came with the 11mm pump head. the 11mm camplate had less lift less duration and a bit less agressive.
Original was DE015 the 11 head had a DE604. The smoke increased and gave little power upgrade. Still not done with the remap, the boost gauge reads 1,2 bar full throttle for stock tune.

One more thing, past 4500rpm full throttle not even revs. Is it limited from ecu or it has something to do with exhaust pressure? Maxed out 4th, 160km/h at 4500rpm
 

davudut5

Member
Joined
Oct 12, 2018
Location
Romania
TDI
mk2 jetta+mk3 tdi 1z+mk4 ecu
It was not "emp" exhaust manifold pressure. After fitting a 11mm pump from auto trans mk4 what a change!! Pulls alot stronger up to 5300rpm, where is a hard cut rev limiter, very nice. Lift pump in the tank fitted also.
Combined with a CASA vacuum actuated turbocharger i believe it to be over 200hp. Custom map on dyno soon.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
I had a VERY similar problem with my 1z on my 762's, gt2052, and a custom stage 6 (all the fuel i can get all the time) tune from malone tuning at 32psi.
It would only happen when WOT before the car came up to nice hot operating temps. Turns out i was not getting enough pressure to the 764's to get a fully atomized spray pattern, not all the fuel would burn off and would essentially FILL THE PISTON BOWLS with liquid fuel. Once i installed my Walbro fuel boost pump the problem was MUCH less and nearly impossible to replicate.

Once the engine is nice and hot it was not an issue because the foul could burn better. Over all the power was much better with the boost pump, never got around to the 11mm pump but i'm sure it would have been a MUCH better result than the walbro pump. I plan on doing both though on my 944 build this fall.
 
Top