Davegsm82
Veteran Member
I have an AFN engine in my T3/T25 and decided after 7 years that I should substitute in the 520 injectors that I had removed from my ASV engine to see if there was any difference. The AFN has 520's in it but they are about 200k miles old.
First problem was that injectors 3 and 4 were stuck, I managed to get #3 out with an improvised slide hammer but #4 wouldn't budge. Took it for a drive to get it as hot as possible, doused it with diesel and penetrant etc but it wouldn't move.
So now I have 3x replaced injectors and one original stuck in the head.
Which leads me to a question about injector 'wear', the new injectors have made a noticeable difference to the driveability of the vehicle, which is a large heavy high-top van shaped like a brick and with the aerodynamic qualities to match. The engine previously wouldn't pull very well below around 1800-1900rpm and boost seemed to come as a sharp spike sometime after that which rapidly tails off above 2700rpm.
On the flip side, with 3/4 new injectors installed, there is less noise, both in the transmission and overall engine drone while driving, this was probably the most surprising result. Probably more predicatbly I noted a slight improvement on fuel economy in the short drive since replacement and there's usable power in the higher gears right from 1500rpm all the way up to 4000.
So the question really is, how do you tell when your injectors are shot, and what differences to worn injectors make to the power and torque delivery of an engine?
First problem was that injectors 3 and 4 were stuck, I managed to get #3 out with an improvised slide hammer but #4 wouldn't budge. Took it for a drive to get it as hot as possible, doused it with diesel and penetrant etc but it wouldn't move.
So now I have 3x replaced injectors and one original stuck in the head.
Which leads me to a question about injector 'wear', the new injectors have made a noticeable difference to the driveability of the vehicle, which is a large heavy high-top van shaped like a brick and with the aerodynamic qualities to match. The engine previously wouldn't pull very well below around 1800-1900rpm and boost seemed to come as a sharp spike sometime after that which rapidly tails off above 2700rpm.
On the flip side, with 3/4 new injectors installed, there is less noise, both in the transmission and overall engine drone while driving, this was probably the most surprising result. Probably more predicatbly I noted a slight improvement on fuel economy in the short drive since replacement and there's usable power in the higher gears right from 1500rpm all the way up to 4000.
So the question really is, how do you tell when your injectors are shot, and what differences to worn injectors make to the power and torque delivery of an engine?