would a remap affect injector readings, and would a faulty injector affect a remap

[will-crowe]

hi all

As some people on here know i have been having trouble for the past few months with my 1.9 cdti 150. on cold start it gives off blue smoke and a judder or 2.

8 times i have sent the car back to the dealer and each time a fault has been diognosed with injectors wether it be cylinder 1,2,3,4 but yet each time i get it back ITS STILL THE SAME!!! i have taken in to vauxhall today who tell me the injectors are over compensating for a faulty injector ( the dealer asked vauxhall to look at it a month ago who diognosed cylinder 3 and the dealer replaced and reproggramed which vauxhall confirmed today, but vauxhall did not complete this, the dealer has his own mechanics). 1 has been replaced and 1 refurbed in the 8 times its been back. so i rang the dealer to have it back.

my main question is would a remap affect the readings or alter them as the last time i took it in they said there was no fault to be found ( one week ago) and once i got it back i had it remapped ( 3 days ago) unfortunatly my remap isnt working as much as it should, would a faulty injector cause a remap to hold back its potential?

please help someone lol iv posted a few posts on here and had some great feedback i just cant seem to get to the end of my problems

[paulvectrac]

Yes a map alter the reading mate and yes of an injector was down the car would run ruff but I don't think it would cause a massive power Loss

[nutron]

I presume they changed the glow plaugs if it is only on cold start.

[will-crowe]

yes glow plugs changed before. full set. so your saying a remap would cause injector readings to be out of sync with each other and cause an injector to play up? if it was a bad map?

[paulvectrac]

yes it will mate as the timing of the injectors is altered as in the amount of fuel going in

[lee52]

I presume they changed the glow plaugs if it is only on cold start.

am more into old school dervs not these new fangled things lol but if its only when cold are the glow plugs getting power is the glow plug light coming on etc...
i know with the old school stuff the glow plug light is timed by temp basically telling you when to turn the key the glow plugs stay on for a set time regardless of temp (they stay on after the engine has started to help running until engine has so temp in it

had them in the past where the light goes off to quick so basiclly ignore light count to 15 then crank

[nutron]

The glow plug operation would not be changed. Most places grab the duration map and crank it up, which could cause starting issues and I have in fact seen this effect myself on RS Tuning maps. Timing is effectively reduced once running but on start up the car cranks to a specific IQ (injection quantity) that it draws from the map tables.

[Teapot]

Its not clear from your original post whether the issue began before it was remapped or immediately after. You don't say what firm did the remap but it is possible that if it has been done very badly this could cause starting and idling issues.

You say that the performance is not as you expect following remapping. This is unlikely to be caused by an injector fault - you would experience vibration during accelleration if one or more injectors was not spraying properly under load.

[lee52]

Its not clear from your original post whether the issue began before it was remapped or immediately after. You don't say what firm did the remap but it is possible that if it has been done very badly this could cause starting and idling issues.

You say that the performance is not as you expect following remapping. This is unlikely to be caused by an injector fault - you would experience vibration during accelleration if one or more injectors was not spraying properly under load.

just a quick hyjack my 150 starts runs idle underload etc.. spot on no vibrtion or lumpyness etc.. but i tried a crd-t box and dtuk red and must admit i was very disapointed in the gains was expecting more. pulled better top end. i have looked at the injector quanity deflection values and 2 of the injectors are a + number eg 0.36 and 2 of them are a neg eg -0.41 is that a sign of injectors not been as good as they should be

[Teapot]

It is only cause for concern if an injector deviation figure is more than +/-2.5 mm3. Note that a bad deviation figure doesn't necessarily indicate a faulty injector - it could be that more fuel is required on that cylinder due to low compression caused for example by a damaged valve/seat or piston/cylnder damage.

The way to verify whether the fault is the injector or mechanical is to swap injectors between two cylinders and re-code appropriatily. If the bad deviation value follows the injector then its the injector. But if the bad deviation value stays on the same cylinder, then its a mechanical fault.