strange effects on a injecton quantity adjustment

[akal65]

I have a 96 Passat tdi that I have been working on and after installing new .205 nozzles I attempted to do a hammer mod to get rid of black smoke on hard acceleration , as I moved the top of the pump toward the fuel filter side I noticed my mg per stroke going up , I had thought the number would decline. I now have it at 2.8 what could be wrong ? the stock exhaust is still on the car perhaps the smoke is because I have high back pressure.

 

[garciapiano]

As far as I'm aware, lower IQ number = more fuel. so try increasing the IQ to around 5-6 mg/str and go from there.

Have you chip tuned the car? Because that will help with the smoke, if you haven't.

 

[akal65]

As far as I'm aware, lower IQ number = more fuel. so try increasing the IQ to around 5-6 mg/str and go from there.

Have you chip tuned the car? Because that will help with the smoke, if you haven't.

yes a rocket chip , I will try for 6. Thanks

 

[JETaah]

Yeah its 5 days later but if you check back...

I would check your injection timing with the new nozzles installed first before messing with the IQ. Get the timing to where it ought to be ( Green line or just below works well, i.e. 70/110. on the TDI graph when selecting AHU/1Z motor parameter)
Then set the fueling adaptation number to 32768 if it is not there already and then hammer mod it to 5 mg/str .

 

[akal65]

Yeah its 5 days later but if you check back...

I would check your injection timing with the new nozzles installed first before messing with the IQ. Get the timing to where it ought to be ( Green line or just below works well, i.e. 70/110. on the TDI graph when selecting AHU/1Z motor parameter)
Then set the fueling adaptation number to 32768 if it is not there already and then hammer mod it to 5 mg/str .

Thanks

 

[akal65]

Well sure enough despite the mechanic assuring me the timing was set right it is barely on the graph , very retarded. Thank you JETaah you were right on.

 

[Houpty GT]

Hammer mod is tricking the computer. For the engine to idle it requires a set amount of fuel. This amount of fuel needed is always the same no matter where you move the QA. As you bump the QA, the amount of fuel injected is physically changed and the idle speed changes up or down. The engine then adjusts the QA to bring the amount of actual fuel back to the proper level for idle. So, the ECU thinks it has cut or added fuel, but you have actually only snuck more or less fuel in without the computer knowing about it.