If you searched an EDC17 CP44 file for pre-injection maps and the 16×16 shape from your training doesn’t appear, you’re not searching wrong. In this ECU pre-injection is stored as 8-bit values with 16-bit axes. A default 16-bit scan can’t render them. Switch to 8-bit, set a reference line around 15, and walk the file from the start. There are few 8-bit maps in this ECU, so the candidates surface quickly.
This is the text summary. Members at our May 2026 Q&A live saw me find these maps on Marek’s actual binary in WinOLS — opening properties, switching bit-width, setting the help line, and walking through the candidates. For the full Bosch EDC17 context, see our Bosch EDC17 tuning guide →. Register free for our next Open Q&A → — live with me, agenda forming.
The question — from Q&A live 2026-05-05
Marek asked, sharing his binary file:
“In the last meeting on Teams you talked about the maps Pre Injection, Main Injection, Post Injection — in that file it is clear as you showed it. But when I try to find those maps in the EDC17 CP44 file I am not sure if those maps are correct. Can they have slightly higher values, for example, or maps of a different size than 16×16?”
The expectation that pre-injection is 16×16 is the source of the trouble. In EDC17 CP44 the bit-level shape is different.
Why 16-bit search doesn’t find them
In EDC17 CP44, pre-injection quantity maps are stored as 8-bit values with 16-bit axes. Scan the binary in 16-bit and the values just won’t read as anything logical:
“If we do not see anything logical [in 16-bit view] — this is too small. Then we are just told that they are coded 8-bit.” (~40:08)
This is not a bug. It’s how this ECU stores pre-injection. Switch the search to 8-bit and the maps surface.
The 8-bit walkthrough
The workflow I ran on Marek’s file:
1. Go to the beginning of the file, switch to 8-bit view
“Go to the beginning of the file, switch to 8-bit. The values should be about 14 to 20.” (~40:18)
When stored 8-bit, pre-injection quantity values sit in the range 14–20.
2. Set a help line (reference line) around 15
In WinOLS: right-click → Properties → check the help line option → set to ~15. The reference line gives a visual anchor while scrolling through the 8-bit zone.
3. Walk the file — look for 8-bit values with 16-bit axes
“The axes are always 16-bit and the values are 8-bit. There are not many maps with 8-bit values, so I simply go through the file and look for occurrence of the 8-bit maps with 16-bit axes.” (~40:39)
This combination — 8-bit values, 16-bit axes — is uncommon in EDC17 CP44. Few other map types share that profile, so candidates are easy to spot.
4. Confirm with the conversion factor
“And the conversion factor is 0.08 — so now you have milligram per cycle for the pre-injection.” (~41:14)
In WinOLS Properties → Conversion, factor 0.08 converts the raw 8-bit value to milligram per cycle. A raw 15 becomes 1.2 mg/cyc — the unit and order of magnitude expected for pre-injection quantity.
Two groups, sometimes more — always check
“There are two of them. Usually there are more than two — so you should always check if there are more. In this particular car we have two groups.” (~41:30)
Marek’s binary had two pre-injection groups. Other applications of EDC17 CP44 can ship more. Always check the full 8-bit zone before deciding the search is done.
Tuning: +20% across all groups
“I will do all of them by adding 20% to that 8-bit. Add 20% — that will be absolutely enough. Or you can try more, of course it will probably be even better.” (~41:50)
Edit every group by the same percentage — that’s what “do all of them” means in practice. +20% is the starting point Thomas demonstrated; he noted you can push further if needed.
The same %-scaling principle applies on Delphi DCM 6.2 (see KB-09 →) and on EDC17C46 driver-wish pairs (see KB-08 →). It’s not CP44-specific — it’s the same rule whenever a map family ships in multiple copies.
What this means for tuning
Pre-injection maps in EDC17 CP44 aren’t hidden — they’re stored in a bit-width that 16-bit default search can’t render. Knowing the layout (8-bit values + 16-bit axes, factor 0.08, range 14–20) is what makes the search work. The tuning rule on top is unchanged: identify all groups, scale the whole family by the same percentage.
Related on Tuners Guild
- The same +% rule on Delphi: KB-09 Why does my Peugeot HDI with DCM 6.2 ECU have 100+ duplicate maps? — synchronous percentage scaling on a different platform
- How pre-injection sits in the 4-tell method: KB-01 How do I distinguish pre-injection from post-injection maps in EDC17? — distinguishing pre vs post once you’ve found the maps
- Bosch EDC17 generic context: Bosch EDC17 tuning guide →
- DCM 6.2a pre-injection community thread (different ECU, similar question): DCM6.2a pre-injection maps — C4 Grand Picasso FL
- EGR off and the DPF stops regenerating: The +20% post-injection rule — full article on the blog — the post-injection side of the same map family
- Full diesel calibration workflow: Chip Tuning Diesel — Practice course
Want the full EDC17 family workflow?
EDC17 CP44 is one variant in a wide family — CP01, CP02, CP14, CP44, CP46, CP74 each ship slightly different bit-widths and map layouts for the injection chain. Our Chip Tuning Diesel Practice course covers the search workflow for the most common variants, including which maps are 16×16, which are 16×8, and which need the 8-bit trick from this post.
See the Chip Tuning Diesel course →
Your turn
Found pre-injection maps in a different EDC17 variant (CP02, CP14, CP46, CP74) or a non-Bosch diesel ECU that needed an 8-bit (or other unusual bit-width) trick? Post your case:
- ECU variant + car
- Bit-width of values vs axes
- Conversion factor that produced sane mg/cycle numbers
- How many groups you found
Cross-variant comparisons help everyone build a faster mental map of where bit-widths shift across the EDC17 family.