Today I decided to do some tuning in the idle area. With no electrical load the car idles at 13.0 to 13.7. Turning on the heater and the blower fans, the AFRs go to 14.5 to 15.5. I also have an issue of when my SPAL fan comes on, the car basically shuts down and I either have to catch it by loading fuel into the idle cells in the map or just let it die because it leans out too far. I'm at a loss as to what could be causing this issue.

I never had an issue with my car like this before and I didn't add anything to the car that would cause this, well other than the AEM EMS v2. I'm reading the AFR with my AEM UEGO gauge.

Any advice here? I'm getting fed up with this car. I'm almost thinking I should have got that Z06 when I had the chance.

 

Anyone have the correct battery offset tables for DW1300 injectors? I've used the included papers that I got with them and also DWs wizard on their website. I'm thinking this is where my issue is at.

 

It's pretty easy to play with. Knowing that Latency/Battery Offset mostly affect idle and low load cruise, and scalars affect high load/WOT, you can sit and play with offset while idling in your driveway until you get it right.

Assuming the latency/offset curve is correct, you can start by moving the entire table in the same direction until you have the car running stoich like you want. At that point, you can vary electrical loads to see how the car reacts. From there, you can focus on the voltage range that shows the most issue with loads/voltage dropping. You'll mostly be balancing between two different cells of battery voltage. It sounds like you have it running rich with virtually no additional electrical load and not enough adder for the voltage seen with electrical load.

FWIW, I've never found DeathWerks data sheets to be accurate.

 

Yeah, I am starting to wonder about the data sheet. Their site is giving me different values than the sheet for the battery offset.

I've been subtracting from the battery offset table when there is no load, and adding when there is load, but it eventually starts doing it's own thing. I can go from .74 (random value) idling fine just a tad rich, to .73 (random value) and it'll go almost full lean. Literally .1 and it makes a huge difference.

 

When you get values that are in between cells, you'll have to balance between them to get them to run correctly (adjusting both cells on each side of the value you're having issues).


The last set of DW 1300's I tuned were a little difficult to control. Eventually, one stuck open so bad that it started leaking fuel out of the uppipe gasket on a Subaru. Later, on the dyno an injector totally gave out and this was on a sponsored car...

With that said, if you want an easier time tuning, I would consider going to ID injectors. They really do make dialing in the minor things seem... minor.

 

I have had no luck with DW injectors. I have purchased about 4-5 sets in various sizes for customers.. their info always feels wrong and I have had to send 3 sets back due to a bad injector or 2

 

what if... my battery offset tables are correct, but my alternator is going out, would that cause this issue? Maybe a grounding issue? The fan isn't drawing that much voltage when seen in AEMtuner.

Would increasing/decreasing fuel pressure help to tune them at idle?

I'm basically just spit balling now. I can't think of what could be the issue. I'm hoping its not the injectors cause they have 0 miles on them and maybe an hours worth of idling.

Why are ID1000s so much "better"?

 

If your battery offset is truly correct, it will make up for any voltage variations, to include a failing alternator. In fact, that's exactly what that table is for, to account for how long it takes the injector to open based of the voltage it is being fed.

Increasing pressure would actually require the offset to be raised as well as the scalar, but you'd likely still be fighting the same issues. Lowering it would likely give poorer performance from those injectors on top of inaccurate injector issues.

ID1000's are so much better because they are truly a matched set of injectors, starting with a very good core. Most DW injectors are hacked injectors. I've never been impressed with a DW injector and my original DW fuel pump in my STi failed on the first drive. It's not that your injectors are going bad, they're just not good injectors from the start. I've gotten 2200cc (ID2000's) to idle better than DW1300's.

FWIW, in the middle of tuning some DW13000's on a customers built motor WRX, I had the shop replace them with ID1000's in the middle of the tune because I could not get them to idle nicely without making the car run rich. Upon first start, with ID's generic numbers found on the website, the car fired up and idled like stock before I even started tweaking. Upon driving the car, after the tune, the owner commented on lower EGT's just putting around on the freeway. My only theory was that the fuel was actually combusting when it is supposed to vs an injector that was sloppy. I previously had spent time with the DW injectors he had so the comparison was useful.

 

I honestly appreciate the help here guys. I live in Oklahoma so DW is close by. I'm going there with the injectors to see if there are any issues with them. I'll update the thread when I know something.

Also, I think I'm going to go ahead and buy a set of ID1000s (or maybe ID2000s) to have as just incase replacments.

Any info you could give me on the ID2000s? You think they idle just as good as everyone says the ID1000s do?

I'm planning on eventually switching from 93 to E85 and I'm sure I'll need all the injector I can get.

 

ID2000's take a little work to idle nicely, but it can be done. They are actually 2,200cc injectors, so they're very capable of providing lots of fuel. If people need more than what an ID1000 can provide, I generally recommend backing it with a big fuel pump and bumping the pressure, or just wait it out for the up and coming ID1300's. On my STi, I have ID1000's and run a higher base fuel pressure as running ID2000's required a bit more work with this car and didn't see the need to spend $1,000 on injector when I just didn't need that kind of flow.

When you do make the switch, you wish you had much earlier.