I've got a 1998 Jetta that I recently did some power upgrades to for power and mileage. Working to get it dialed in properly running as good as it can with new chip and injector nozzles.
Below is a listing of the car and upgrade components in the past 2-3 years
1998 Jetta A3 1.9L TDI 5spd Manual - 206k miles
- Straight Pipe, No Cat, No Muffler
- EGR Delete/Block Off
- Higher 5th Gear - 0.658
- South Bend Stage 2 Endurance Clutch
- New Drivelines, Wheel bearings, Motor mounts, Brakes Timing Belt etc
Just recently added:
- Malone Stage 2 Tune
- DLC 1019 Injector Nozzles and refurbed injectors
- NewSouth Boost and EGT gauge
I haven't checked mileage yet since the tune/injectors but I was getting a consistent 54-58 before. My goal was to add power/torque when needed and to improve on mileage if possible.
I'm struggling a bit with where the injection pump mechanical timing needs to be set and what the fuel IQ number needs to be set to.
The car has developed a slight shudder under load since the tune upgrade. I really only feel it at low RPMs under quite a bit of load, ie shifting into 4th or 5th a bit early. But it is shuddering when it didn't before the tune. I notice it particularly at 1400-1600 rpm in 5th gear, once my RPMs/boost pressure picks up the shudder goes away. Feels like an engine shudder, unless it was additonal torque straining something else. But most of my driveline is replaced/upgraded at this point.
Could this be caused by change to fueling? If so what should I have my IQ number at. Per the malone recommendation I did the hammer mod and currently have the IQ adjusted to around 5.8-6.0 for optimum mileage. Is that maybe too little fuel for the low end torque?
I currently have my injection pump set dead in the middle of the range in VCDS, is there any advantage to advancing mechanical timing as far as mileage? My car starts very good, no problems there. Seems to be conflicting opinions here regarding that... Thoughts?
The shudder isn't so bad I can't deal with it. But if possible I'd like to eliminate that. Any advice is appreciated!
Below is a listing of the car and upgrade components in the past 2-3 years
1998 Jetta A3 1.9L TDI 5spd Manual - 206k miles
- Straight Pipe, No Cat, No Muffler
- EGR Delete/Block Off
- Higher 5th Gear - 0.658
- South Bend Stage 2 Endurance Clutch
- New Drivelines, Wheel bearings, Motor mounts, Brakes Timing Belt etc
Just recently added:
- Malone Stage 2 Tune
- DLC 1019 Injector Nozzles and refurbed injectors
- NewSouth Boost and EGT gauge
I haven't checked mileage yet since the tune/injectors but I was getting a consistent 54-58 before. My goal was to add power/torque when needed and to improve on mileage if possible.
I'm struggling a bit with where the injection pump mechanical timing needs to be set and what the fuel IQ number needs to be set to.
The car has developed a slight shudder under load since the tune upgrade. I really only feel it at low RPMs under quite a bit of load, ie shifting into 4th or 5th a bit early. But it is shuddering when it didn't before the tune. I notice it particularly at 1400-1600 rpm in 5th gear, once my RPMs/boost pressure picks up the shudder goes away. Feels like an engine shudder, unless it was additonal torque straining something else. But most of my driveline is replaced/upgraded at this point.
Could this be caused by change to fueling? If so what should I have my IQ number at. Per the malone recommendation I did the hammer mod and currently have the IQ adjusted to around 5.8-6.0 for optimum mileage. Is that maybe too little fuel for the low end torque?
I currently have my injection pump set dead in the middle of the range in VCDS, is there any advantage to advancing mechanical timing as far as mileage? My car starts very good, no problems there. Seems to be conflicting opinions here regarding that... Thoughts?
The shudder isn't so bad I can't deal with it. But if possible I'd like to eliminate that. Any advice is appreciated!
98 A3 Jetta Upgrades/Adjustments for MPG
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