E38 - L77 conversion - No spark

They go by many names, P01, P59, VPW, '0411 etc . Circa 1999 to 2006. All VPW OBD2 PCMs.
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E38 - L77 conversion - No spark

Postby ben_att » Mon Aug 01, 2022 9:52 pm


I have got a VF Calais L77 6L with a 6L80E that I'm trying to get running. It came with the main engine loom which has the plugs to the E38 ECU along with 3 other plugs, one to fuse box, one for other various signals and a smaller one which is mainly for brake signals.
I have made up a wiring chart and pinned into these 3 plugs to try and get it started.
I have applied the VATS patch, and disabled the starter monitoring, I can make it crank and get no spark or fuel.
I've been searching for a few answers and can't seem to find what I'm after so was hoping someone can help.

Will P1682 - Driver 5 Line 2 (permanent) prevent the engine from running?
I have scoured through all the wiring and as far as I can see on the VF E38 drawings that I have, there are no ignition/acc feeds to X2, on X1 I have the following powered with 12V
X1 - 18 - Accessory wakeup serial data (without power on this the speedo reads 280km/h, seems I need this high as it also powers pin 9 on the auto for serial data wakeup
X1 - 19 - Run/Crank Ignition 1 voltage
X1 - 20 - Battery + voltage
X1 - 47 - Powertrain Main Relay Fused Supply (1)
What else is the ECU looking for that generates this error? Is it looking for serial data from a BCM for ignition voltages or have I missed a pin somewhere that needs voltage? I have wired a relay coil on X1-59 (Powertrain relay coil control) in case it was looking for a relay load (as well as the starter output and fuel pump relay output).

I also get U0109 - Lost communication with fuel pump controller. It looks like it's something in the OS that I can't delete. I don't mind if I have to install this module, but will this error prevent the ECU from allowing it to run? (I do have an operating pump and fuel pressure at the rail)

U0140 - Lost communication with BCM, this is expected with any 'stand alone' conversion I'm tipping and assume this shouldn't be a cause of no run provided the VATS is disabled?

Brake pedal position sensor circuit - I'll have to put a resistor across this, as open it generates a fault and shorting generates a fault, but will this prevent it from starting?

P0230 - Fuel pump primary circuit - Will this prevent it from running? I've got my own switch on the fuel pump temporarily, but can fiddle around and wire into the ECU, I've read on other forums that people have their car running but check engine light is on with this fault, so I'm guessing not the cause. Could it be that this fault may be generated as the ECU cannot see the FPCM and is looking for can bus data from the module saying it has power?

I have attached pdf's of the drawings I'm working with along with the tune I currently have in (and the original tune).
OS: 12656930 -> 1250242
Main operating system: 1250242

Any help to get this thing started is appreciated.

6L 19 July 2022 - modified.hpt
(731.5 KiB) Downloaded 7 times
x2 plug.pdf
(305.32 KiB) Downloaded 9 times
VF Engine loom to body plugs.pdf
(732.57 KiB) Downloaded 9 times
original vf 6l tune.hpt
(731.27 KiB) Downloaded 6 times
L77 engine schematics.pdf
(953.07 KiB) Downloaded 15 times
E38 VF X1.pdf
(502.47 KiB) Downloaded 11 times
Last edited by ben_att on Sat Aug 06, 2022 9:52 pm, edited 1 time in total.

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Re: E38 - L77 conversion - No fuel or spark

Postby ironduke » Mon Aug 01, 2022 11:45 pm

I am not experienced in stand alone, someone else will hopefully chime in.

Can you look in the data list for ignition voltages? See if one of them is low by 3 volts or so to set the code?

Are these ignition voltages staying powered during cranking? I am assuming your just using a toggle switch? if using an actual ignition switch some contacts(accessory) lose power during crank.

It sounds like your not using the engine controls ignition relay to switch the power on pin 47. Not sure if the ecm is seeing voltage on 47 before the relay is commanded and setting the code?

Are you seeing rpm in the data list while cranking?

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Re: E38 - L77 conversion - No fuel or spark

Postby Cincinnatus » Tue Aug 02, 2022 2:03 am

Vats patch? Hptuners? You can run standalone, but will be lots of codes unless you turn them off. I've done several standalone, but only gen3, not gen4. I would expect it will still want to use fpcm. Wouldn't expect bcm or other modules to be needed, though your source for vats patch should be your source for troubleshooting. Good luck!

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Re: E38 - L77 conversion - No fuel or spark

Postby hsv08 » Tue Aug 02, 2022 7:48 pm

Just a quick question, Did you do a write entire for the VATS patch?

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Re: E38 - L77 conversion - No fuel or spark

Postby ben_att » Sat Aug 06, 2022 5:33 pm

Thanks for the replies.

Yes, it is HP Tuners I was using and I did the write entire. When I do a read out of the ECU it shows that VATS has been disabled.

Next step is to fit a FPCM in and see if this makes a difference.

I can see all the voltages are good and I do get RPM when cranking.

You are right that I was not using the relay to control ignition feed, however I have since changed this so I apply power to the ECU and then it outputs a coil voltage to the relay and picks the ignition feed up and it seems happy.

So I was having a play again today and have got a log which I was going to attach (hp tuners but the site says extension hpl is not allowed when trying to upload) from when trying to crank, it looks like it's fueling but I get no spark (pulled lead and put plug on end of it so I could see).

The other weird thing is I have some faults which I don't think I should have.

P0122 - The ECM detects that the TP sensor 1 voltage is less than 0.325 volt for more than 200 milliseconds
-I have not seen the voltage drop to this level. It sits around 3.6V and goes to 0.8V with pedal fully pressed.

P0223 - The ECM detects that the TP sensor 2 voltage is more than 4.59 volts for more than 200 milliseconds
- This also does not happen as far as I can see. It sits around 1.1V and goes to around 4.2V with the pedal fully pressed.

P2122 - The ECM detects that the APP sensor 1 voltage is less than 0.325 volt for more than 0.4 second
Again, I have not seen this ever happen, it never goes below 0.9V, it normally sits on 1V and goes to 4.1V when pedal fully pressed.

I can verify this by moving very slowly through the log, none of the above conditions have ever been met on any of the log files, if I clear DTC's, and read DTC's 10 seconds later, they're still there.
Why would this be happening? Or am I interpreting this wrong and reading the wrong sensors? Pressing the Accelerator pedal has instant response on the throttle body and it appears to be doing exactly as commanded.
I have a VZ SS which has the L98 with the E38 ECU and the voltages are very similar. I have also compared the APP and TB voltages at idle and WOT on a VF SS and between all 3, they are all very similar which is what is throwing me off the most as there are no faults in the other two vehicles I compared to with the same voltages.


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Re: E38 - L77 conversion - No spark

Postby In-Tech » Sun Aug 07, 2022 2:17 am

HPT doesn't write the slave modules that control the pedal. If the E38 isn't from the same donor, you could have issues with that. I've done plenty of E38 transplants so I hope I can help. Also, most standalone transplants that I have seen have the cam sensor wired wrong. A and C are swapped and it will not fire the injectors. You don't need FPCM or BCM. They do need the network settings turned off for that. I rarely use HPT but I can program an e38 on the bench and read it out with HPT if you like, probably will cost you a license to use it though :rant:

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Re: E38 - L77 conversion - No spark

Postby ben_att » Sun Aug 07, 2022 9:25 am

Hi mate,

Thanks for the feedback. I didn’t think to give that info in the first post, my bad. The engine, loom, auto, ECU, pedal is all from the same car. It was all running prior to removal. The motor, auto and loom were all removed and transplanted in one piece. I’ve contacted the person I got it from and he’s still got the FPCM which I was going to grab from him and see if it makes a difference.
With the cam sensor, if I’m seeing the cam count increase as the motor cranks and the injectors are firing, I assume this would be ok? Mainly because it was all running in the car it was removed from with the same wiring too is why I would make that assumption.

Ah ok, so if those network settings are active, is it possible it won’t fire because it’s looking for data from the FPCM?
So you can disable these module with HP tuners or you just use that to pull the file and modify it using something else? I attached the hpt tune in the first post that I read out of it on the bench if that’s any good?


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Re: E38 - L77 conversion - No spark

Postby ironduke » Sun Aug 07, 2022 11:49 am

As far as I know you should always have spark.. Even if it was a theft/vats issue I believe that only fuel is cut.. If your seeing injector pulse then you should be seeing spark..
You do have power to the coils and no coil driver codes setting??

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Re: E38 - L77 conversion - No spark

Postby Tre-Cool » Sun Aug 07, 2022 11:55 am

(785.02 KiB) Downloaded 5 times

take a look at this file and compare dtc & options. this is in my turbo vy ute with a 6l80e.

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Re: E38 - L77 conversion - No spark

Postby ben_att » Sun Aug 07, 2022 6:29 pm

Thanks guys.

@Ironduke - Interesting, I haven't check with a multimeter but I can see the injector pulse on the hp tuners log and it looks similar to what other running cars logs look like when starting. I have power to A & D on each coil, I can't see anything happening on B & C with a multimeter but I would say this is because it's switching on and off too fast and the meter is too slow to see it, that's why I pulled a lead and connected to a plug in the open with a little lead wrapped out the thread to the ground and I don't see any spark.
The ECU is not throwing any codes related to the coils. The spark advance changes slightly while it's cracking but I can't see anywhere in hp tuners where I can actually see that the computer is outputting for each spark however when it is cranking there is a channel called current firing cylinder which counts through as expected. I can meter B of each coil to + which tells me the ground on pin 78 is good. I'm guessing I should see a fault if a coil was open or shorted? I might unplug one and see if the ECU throws a code, just to make sure it is actually seeing them connected. I'm not sure where to from there though why it's not triggering them.

@Tre-cool - Thanks for that. There is a lot of differences showing, but the OS numbers are all different also. Out of curiosity, is it running with this tune? The VATS is opposite to what my file is showing?
Mine shows both patches as disabled and when I hover the mouse over it, down the bottom it says
"[ECM] 105 - VATS Patch 1: OS Patch for VATS disable. To disable, select disable option then rewrite entire"
When I open your file they both show enabled?
Did you get the motor from a VE?
I'm pretty confident I can't load your file in because the all the system numbers are different? otherwise I'd try that.



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