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-   -   Loosing RPM 5.7 EFI (https://www.offshoreonly.com/forums/general-q/376403-loosing-rpm-5-7-efi.html)

SB 08-23-2022 12:49 PM

On many of these engines, The ecu and techmate assume you did initial timing correctly and show values timing should be if you did. It does not show you actual because it doesn’t know. This is why as you advanced distributor, it showed at timing mark with timing light, but not on the techmate.

So, now knowing this, is you total wide open advance actually wrong ?

DrFeelgood 08-23-2022 12:58 PM

The techmate should have a setting that does the same thing as the jumper plug, putting timing into base mode just like the jumper did.

Ryanw10 08-23-2022 03:08 PM


Originally Posted by SB (Post 4842488)
On many of these engines, The ecu and techmate assume you did initial timing correctly and show values timing should be if you did. It does not show you actual because it doesn’t know. This is why as you advanced distributor, it showed at timing mark with timing light, but not on the techmate.

So, now knowing this, is you total wide open advance actually wrong ?

I still think so as the timing drops from 2200-2400 rpms and then never increases again and only reaches a max RPM of around 3500. I drew a line on this graph to show what the timing is doing based on what I see on the techmate.
https://cimg7.ibsrv.net/gimg/www.off...25059e34ac.jpg

DrFeelgood 08-23-2022 03:24 PM


Originally Posted by Ryanw10 (Post 4842510)
I still think so as the timing drops from 2200-2400 rpms and then never increases again and only reaches a max RPM of around 3500. I drew a line on this graph to show what the timing is doing based on what I see on the techmate.
https://cimg7.ibsrv.net/gimg/www.off...25059e34ac.jpg

Is there any knock retard showing up? I think up to 9 degrees can be taken out when knock is detected.

AllDodge 08-23-2022 03:59 PM

Knock will take out timing but will also throw a code 43

Ryanw10 08-24-2022 06:04 AM


Originally Posted by DrFeelgood (Post 4842514)
Is there any knock retard showing up? I think up to 9 degrees can be taken out when knock is detected.

The techmate showed zero knock retard the whole time

Ryanw10 08-24-2022 06:05 AM


Originally Posted by AllDodge (Post 4842520)
Knock will take out timing but will also throw a code 43

I did have a "general warning #2 telltale sign" at the beginning of the day, and no other codes. After erasing the code, none came back the rest of the day.

Ryanw10 09-23-2022 05:44 AM

Still fighting this issue. My latest find is I think there is an issue with my sensor grounds. On the ECM connectors I have good continuity for both ecm grounds. On the sensor grounds I have no continuity, but when I check at the actually sensor plugs I have continuity to ground on the TPS, but there is resistance on the ECT, MAP, and IAT sensors, I should be seeing continuity to ground at all these pins correct?

DrFeelgood 09-23-2022 06:05 AM

Generally speaking, sensor grounds should run to the ECM, and then the ECM is grounded to chassis (or engine block, in boats), rather than running the sensor ground directly to chassis ground.

Some good reading if you're bored:

https://www.haltech.com/news-events/...dos-and-donts/

Ryanw10 09-23-2022 12:01 PM


Originally Posted by DrFeelgood (Post 4845920)
Generally speaking, sensor grounds should run to the ECM, and then the ECM is grounded to chassis (or engine block, in boats), rather than running the sensor ground directly to chassis ground.

Some good reading if you're bored:

https://www.haltech.com/news-events/...dos-and-donts/

That makes sense, thank you for the reply


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