LHU starts but thinks it's in Park

[marksawatsky]

I now have a running, driving race car (YAY!!) but the ECM thinks the car is not moving so it only permits 68% throttle opening briefly then pulls back to 30%. I can adjust the RPM it will rev to through Engine>Cutoff DFCO>Extreme cutoff and Cutoff RPM vs gear but the engine still will not make boost or get full throttle. Many people say it's because the ECM is not getting a speed reading from a VSS and this could be, but how do I get around that or how do I get a VSS signal to the ECM? I have a wheel speed sensor sending 6 pulses per revolution to a Dakota Digital SGI-5E converter box which then sends a signal to X2 pin 8 (output speed digital signal) on the ECM. Do any of the smart people on this forum know how to convince ECM that car is moving or make it not care and provide full power? See the race car build here: https://www.youtube.com/channel/UCe5...G1KogAVpWraiIw

[sprinto7]

So, question to all the experts. Just what does it take to get a current ECM/VCM to think the vehicle is moving so it will go to full RPM?

I think I know the answer for a GM 1.4 Turbo engine with an E78 VCM, but Marks LHU baffles me.

Should we be able to make all this work by disabling the VSS?
It appears Trifecta can make the LHU, and LNF run at full power without and external VSS.

I "THINK" there could be a monetary award for the first person that comes up with an HPtuners solution.

Right Mark?
Del

[marksawatsky]

Yes, I'm willing to compensate anybody who solves this riddle

[marksawatsky]

Checked DTC's today
Here they are:
P018B
P0520
P057C
P0621
P0645
P0686
Then I cleared them and started engine, here are new ones:
P018B
P0520
P057C
P0621
P0645
U0140
U18A2

[sprinto7]

Checked DTC's today
Here they are:
P018B
P0520
P057C
P0621
P0645
P0686
Then I cleared them and started engine, here are new ones:
P018B
P0520
P057C
P0621
P0645
U0140
U18A2

IMO: 18b is fuel pressure. you need to find out if it high or low pressure. High=fix, lo=delete
520 oil pressure, you need to find out truth about that.
57c delete
621 generator lamp? find out and fix.
645 delete
u0140 delete
u18a2 ?????????????????? IDK what it is.

Del

[marksawatsky]

I had to disconnect one oil sensor to install mechanical gauge, fuel pressure is the sensor in the tank, which I don't have but I have another one inline and the computer does read that one.

[sprinto7]

Too many lines of communication going on. :-))
Del

[marksawatsky]

When I first started car, it showed no oil pressure on the HPT scan screen. Everything was hooked up and I couldn't resolve it so I got the AutoMeter adapter and installed a mechanical gauge. It was a single wire gauge/switch and grounding it resulted in nothing so I haven't worried about it. My engine has a variable oil pressure pump but HPT doesn't provide a way to adjust that (that I could find) and GM's own install manual for the LTG says you don't have to run variable pump, it's ok to leave it pumping maximum pressure.

[marksawatsky]

Does anybody know if there is an operating system difference between the Regal GS Auto and Manual trans cars?

[TurboCobalt]

marksawatsky, please share more details about the setup.
what year, model, did the engine / ECM come out of?
what trans are you running? (manual? im guessing, otherwise you'd just use the output speed sensor in the trans)

how did you configure the Dakota Digital SGI-5E converter box, which output are you using.

Do you have an oscilloscope to look at the output of the converter box?

to test the OSS: it says to output 5V, 300Hz, 50% duty cycle signal to the TCM, and the ECM will interpret that as OSS output of 745-825 RPM.
That however doesn't say what the signal looks like that the TCM will output for the ECM which is what you need.

if you want me to calculate some unit conversions, give me info like tire radius or diameter, and details on your wheel sensor and i'll try to figure out how to configure that converter box.

EDIT: im reading the instructions for that converter box and it's just a pull down, it will not generate 5V, so unless the ECM is generating 5V then i dont see it working.

EDIT2: i kept thinking about your problem and i think i have a solution: your problem is that the coverter box you are using is only a current sink, not a voltage source, and the ECM is expecting a voltage. i would try this. First check to see that the ECM x2-5 to ground is 5V when the ECM is awake. If it is 5V, then put a 2200 ohm resistor (1/4 watt) (even radioshack should have it) from x2-5 to X2-8 on the ECM, this will provide a pullup voltage. also connect X2-8 to your converter, you will want to use OUT2 eventually to fine tune it, I would try to get a 3x multiplier configured in your converter box as a start. this is using a lot of guessing on how the real VSS really works, and the assumption that your tires are 20inch tall. If you get any sort of speed output, than its up to you to dial in your converter box configuration. in your HP tune, make sure the VSS sensor is used.
Disclaimer: this is a lot of guessing, if this damages your ECM or converter box i am not responsible. I don't know how much current the converter box can carry, so i made a guess, it should be able to sink 2.3 mA just fine.

[TurboCobalt]

Here they are:
P018B - fuel pressure performance (seems to be the low pressure side)
P0520 - oild pressure indicator
P057C - ummmmmm, not a regal code, cruze forums say brake pedal position.... is your ECM not out of a regal?
P0621 - generator control circuit shorted high (um... i would fix this)
P0645 - HVAC, AC clutch relay circuit
P0686 - not a regal code, google says voltage error low (low 12v at some point?)
Then I cleared them and started engine, here are new ones:
P018B
P0520
P057C
P0621
P0645
U0140 - communication code, you either didn't wire one of the CAN bus or it's shorted somewhere.
U18A2 - communication code, CAN bus is either not wired or shorted somewhere.

I never did an engine swap, never tried to run a standalone ECM, so i don't know what's the norm, however your whole electrical system seems ... questionable ...

[marksawatsky]

Thanks for your input, I will answer the best I can:
-Engine is out of 2013 Buick Regal Turbo with auto trans and has the ECM, sensors and electronic pedal out of same car (but no TCM,BCM)
-I am running a Borg-Warner Super T-10
-The Dakota Digital SGI-5-E box has been tried on Hi-Hi, Hi-lo, lo-hi and lo-lo and tested on all 5 outputs. The test mode has also been tested where the DD box produces a steady 33hz or 66hz output. The sensor used for all these was a Dakota Digital 128K sensor part #SEN-01-128. Note that this sensor was found to be defective and they have since sent a new one that appears to work but I have not retested in all those modes because I used a proximity sensor on a front wheel that pulses 6 times per wheel revolution and tested using that.
-I have just purchased an oscilloscope but have not used it yet and don't know what I'm supposed to look for
-Front tire is 21.5" tall and the wheel speed sensor produces 6 pulses per revolution
-The DD box is producing 5V when I spin the front wheel

[TurboCobalt]

could you elaborate on this: -The DD box is producing 5V when I spin the front wheel
Which pin has 5v, are you talking about the sensor 5v power?
you are using the 6 pulse per rev, and that's fine, but were you able to verify that your DD box can read that in?
i think that the config you'll want is L-L with your 6 pulse sensor.

with no connection on any of OUTx lines coming out of the DD box, when you spin the wheel im guessing you will see 0V on output pins: OUT2,4 and 5.
if you do get 0V on output 2,4,5 with nothing connected, then i think my previous edit was right.

Since i did my edit very late, you may have missed it, i'll re-paste here

EDIT2: i kept thinking about your problem and i think i have a solution: your problem is that the coverter box you are using is only a current sink, not a voltage source, and the ECM is expecting a voltage. i would try this. First check to see that the ECM x2-5 to ground is 5V when the ECM is awake. If it is 5V, then put a 2200 ohm resistor (1/4 watt) (even radioshack should have it) from x2-5 to X2-8 on the ECM, this will provide a pullup voltage. also connect X2-8 to your converter, you will want to use OUT2 eventually to fine tune it, I would try to get a 3x multiplier configured in your converter box as a start. this is using a lot of guessing on how the real VSS really works, and the assumption that your tires are 20inch tall. If you get any sort of speed output, than its up to you to dial in your converter box configuration. in your HP tune, make sure the VSS sensor is used.
Disclaimer: this is a lot of guessing, if this damages your ECM or converter box i am not responsible. I don't know how much current the converter box can carry, so i made a guess, it should be able to sink 2.3 mA just fine.

more Edits: i think the ECM is expecting a 50% dutycycle signal, i dont know how you have your 6 pulse sensor wired, but if it's something along the lines of: it catches 6 spokes on the wheel, and the dutycyle is more like 10pct, that might not work, but we'll get to that later.

[marksawatsky]

Thank you TurboCobalt. I have great news!! Bad News Racing sent me a tune today and I loaded it and the car was on jackstands so I started it, put it in 3rd gear and pushed the gas and brake at the same time-it pulled all the way to redline and made boost! Before I would just rev up then drop, rev up then drop. I put the car on the ground and took it for a drive and the power would overwhelm the brakes and just pushed the locked up front tires along the track. Then I looked at the vehicle speed through the OBD2 port and at it was clearly not accurate but was working! It would go from 30 mph to 158 mph in 1st gear. I changed the Dakota Digital box settings from Hi-Lo to Lo-Lo (just like you said) and made some little adjustments and I think it's accurate. I put a piece of tape on a front tire and spun the tire with a drill and timed how long to make 10 revolutions. Then did some calculations and figured the tire was spinning at 7 mph, and the speedo on the HPT Scanner said 7 mph!! I have to drive it again and check throttle openings and boost, etc but so far it looks like BNR has solved my problem.

[ecotecjohn]

Marksawatsky I just built a airboat with a 2013 lhu and I'm having same issue only getting 30% throttle I would really like to talk to you. If you can email me at [email protected] thanks john