Looking for help and support with EBL Flash system

[RF_Burns]

Here are some of the constraints for the knock sensor below. But from what I am seeing, idling at 800 rpm and a 0% tps the knock retard should not be included in the formula. Although if it was, the table shows a value of 4.92 degrees for 116 C, at 180 F it would make sense if it was effecting the timing which would give a total SA of 18.64. I'm sure it would immediately go back up when knocks aren't detected. I was seeing a few knock counts at idle, not many though. I think the whatsup app was showing about 40 counts at idle in about a 30 minute time frame though I didn't really pay much attention to them at the time, I was more listening to the engine and watching the timing light and SA values on the screen.

View attachment 17910

The knock sensor is basically a microphone which is then fed into a module which is basically an audio bandpass filter. The module then outputs a high (or low... can't remember which) to the ECM (EBL) to indicated that it "hears" knock.

Mine will hear "phantom knocks" from time to time. At first it was the exhaust pipes hitting the frame, but I have that pretty much fixed. So make sure you having nothing rattling that could trigger a phantom knock signal.

 

[tmsnyder]

The knock sensor is basically a microphone which is then fed into a module which is basically an audio bandpass filter. The module then outputs a high (or low... can't remember which) to the ECM (EBL) to indicated that it "hears" knock.

Mine will hear "phantom knocks" from time to time. At first it was the exhaust pipes hitting the frame, but I have that pretty much fixed. So make sure you having nothing rattling that could trigger a phantom knock signal.

Hi Bruce,

I believe the signal sent to the ECM is that the ESC pulls the signal to ground. IDK for how long but I've read that that is the signal.

Todd

 

[dbrannon79]

It appears you have the Idle spark advance set to "Fixed" at 20*, rather than using the table. this would account for your approx. 5* difference.

Option word 2, Bit 1 IdlSA is Set. Unclick this if you want the SA to follow the table while at Idle.

I have my motorhome set to a Fixed Idle SA as it seems to idle smoother, but the SA seen at the timing mark still moves around a bit.

your right, I forgot about that setting. Thank you.

as far as the main table goes. what's your (and others please chime in too) thoughts on it. and on the spreadsheet I used to build a table going off from what I found online for timing limits highs and lows. I feel like it has too much timing and might be where it's loosing power on the road.

I still have lots to to learn here

 

[dbrannon79]

I will look for rattles and see what might need to be addressed to help with the knock sensor.

If I try to use the table I created using the spreadsheet, I assume I will also need to adjust the maximum SA as well to the highest value on the main table. Hopefully I will have some time this weekend to play with it. I have a three day weekend!

 

[dbrannon79]

I have looked all over for rattles and can't see why the knock counts are so high. after loading the SA main table I made off the spread sheet knock counts climb rapidly around 2000 rpm but the engine sound fine. I don't hear any clattering or pinging at all.

Now given that the knock sensor is a microphone for the engine, it's location is questionable. the sensor is located about mid height on the block but at the very back near the bell housing area. I am curious if it's picking up noises from the trans, flywheel or clutch. will unplugging it retard timing or would that just disable it where the EBL wouldn't use it?

I want to take it out for a drive and see how it performs with the lower SA settings, it seems like it has more power as I set the park brake and put it into gear actuating the clutch some. it seems like it want to overcome the park brake quite easily now and wants to go!

 

[dbrannon79]

I also realized the tach in the dash (tach is from LMC) is off about 200-300 rpm depending on where I have the throttle. EBL shows 750 at idle and the tach sits right about 550. rev it up to around 2000 according to the EBL and the tach shows about 16-1700 ish. I wonder if there is a way to adjust the tach.

 

[RF_Burns]

It occured to me that you may have a miss-match between the EBL firmware and the WUD version. There was an EBL firmware update that required a change in the WUD version and something in the BIN file changed. It was a number of years ago, so I don't remember the details.

I wrote this in another thread about a year ago:

I've posted the final version (2.7) of the EBL Flash firmware which RobR released for the GM7747 ECM as used in our GMC motorhomes in the Resources > Chassis > Engine > Fuel and EFI section.

You need the What's Up Display (ver 3.1) for this version which is also included for download in the same Resource.

 

[dbrannon79]

I guess I need to figure out what version the firmware is and what WUD I have been using. I assume the WUD display will show the firmware version somewhere for what is on the ECM?

 

[RF_Burns]

Should show that info in the About tab I'm guessing. I'm about 4,500Kms away from my coach at the moment!

 

[dbrannon79]

This is what the WUD is showing.


would you know where I can see the firmware version for the ECM?

I guess it wouldn't hurt anything to just go through the update procedure?

 

[dbrannon79]

I went through following the instructions updating everything. in the instructions I assume I will now be using the WUD application that was installed using the setup app in the zip from your post in the resources? it looks like it installed EBL Flash II. does that make a difference since i was using the EBL Flash not the flash II before? the xdf that was I was using before was EBL_V31 in the newly created install for flash II it has EBL_V42.xdf

 

[dbrannon79]

All seems to be working with the update done. I connected using the WUD installed from the zip and it shows version 3.1. also took the time to go through and update each of the bins I had been working with so in case I need to go back and use one, i can. also reorganized my usb drive where i am keeping all of the files, I use the USB drive so I can go between my laptop and my desktop pc.

Thank you

 

[RF_Burns]

I left my old laptop which has all my EFI stuff on it back at home. So I don't have any of my info on which XDF file to use.

 

[dbrannon79]

No worries, enjoy your vacation! Heavy rain storms are supposed to be coming here. That might limit my play time LOL.

 

[dbrannon79]

Ok, the DRAC or VSSB arrived today so I attempted to wire it in like the diagram that the PO provided shows. I believe I have everything connected correctly but I am not getting any signal showing in the WUD.

Here is the vssb I have and the speed sensor that was on the trans. I have the sensor out where I can place my drill on it to spin it testing to signal. key on but engine is not running.






I have C7 & C12 wired to the speed sensor but have no idea which is + or - on the sensor.
C9 to keyed power. C8 to ground. and C11 connected to A10 on the EBL ECM.

I checked the VSS pulse per mile and the VSS filter in tuner pro, PPM is set at 1767 by the PO and the filter is at 75%. I know it should be more like 2000 PPM but idk what the PPM is for the speed sensor. Not even sure if this sensor will produce the type of signal needed. the markings on the sensor shows Masstech TR8-2525-2. I cannot find anything online about it.

Am I using the right type of VSSB? I know they are programmable just by changing the jumpers in them depending on what tire size and gear ratio you have. figured I would adjust that once I can get a signal to the ECM.

 

[dbrannon79]

Looking at the drawings on the old dynamicEFI site I am wondering if I even need the DRAC/VSSB module to get signal to the EBL ECM on pin A10. but I don't want to fry the EBL connecting it directly. I'm being very cautious about that.

Connection Drawings

 

[dbrannon79]

@RF_Burns I just ran across one of your posts from back in 2022 about you repairing your speed sensor. the photos look like it's exactly the same as the one I have. I have to ask, how did you connect it to the EBL? was a GM DRAC/VSSB needed? I think this uses a reed switch to send pulses and GM used a pulse generator and in a sense generated a square wave AC voltage to the DRAC. I don't think this type will generate "voltage" like the factory GM ones making it not work for the VSSB I ordered. Am I correct in my thinking?

Post in thread 'Speed sensor'

Jun 1, 2022

Here is several photos of replacing the reed switch in my Howell speed
sensor.
http://www.gmcmhphotos.com/photos/g7180-speed-sensor-repair.html
-------- Forwarded Message --------
Subject: Speed Sensor
Date: Wed, 1 Jun 2022 22:48:49 -0400
From: BruceHislop
To: GMC Motorhome EFI Group
I got my speed sensor from Howell.
I just looked and I don't see it listed separately, but it is shown in
the photos of some of their kits. I suspect if you called them they
would sell it separately.
It goes in line with the speedometer cable so the mechanical speedo
continues to work.
One...

• RF_Burns

 

[dbrannon79]

Well after reading more and searching, it seems this sensor is from a Howell EFI setup. looking at their diagrams the sensor is supposed to be connected to ground and to A10. so I tried it and I did get a signal showing up in WUD. only it was very sparatic. slowly turning it with my fingers I could get up to 3mph but with my drill spinning it at various speeds I would get no readings that is until I stopped turning it, the WUD would suddenly spike to max speed and then back to 0. connecting my ohm meter on it, it seems it's a one pulse per revolution reed switch.

If I read on another forum correctly, a standard speedo cable is setup 1000 revs per mile. that would equate to 1000 pulses per mile for this sensor. with the EBL set to 1767 I should have seen something spinning it with my drill, but I don't really know what the filter is for.

 

[RF_Burns]

The filter helps smooth out the "switch bounces". When a mechanical switch closes, it does not always make a perfect connection. The EBL may see several Open/Closes in a few milliseconds causing it to think the VSS is spinning faster than it is. The VSS filter negates the switch bounce.

On one trip, the engine started to cut-out, I hooked up my laptop to trouble shoot the issue and noticed the speed indicator would randomly jump up by 20,40 or more Kph. when it was hitting full scale on the speedometer. that's when the engine would cut-out. I pulled the VSS connector and that fixed the issue for the remainder of the trip.

I replaced the reed switch in the VSS and shortly after found out about this parameter and raised it from a low number to something like 70%.

I also discovered that Speed Limiting parameters were turned ON in the BIN. The switch bounce in the VSS was causing the speed limit parameters to be exceeded and the EBL would cut fuel and ignition to the engine.

You can read about switch bounce here:

Switch - Wikipedia

en.wikipedia.org

 

[dbrannon79]

Well, I did further diagnosing and discovered that if I cross pin A10 to ground just by touching on-off-on-off I get a constant signal pulse to the EBL. ground off the brass rivets and what do ya know, the reed switch is broken! it was still making contact using my ohm meter but picking at it with my fingernail I can plainly see the glass tube is shattered.

found a 5 pack on the jungle site (amazon) for $6. so I placed the order.