LM-2 OBD connection intermittent?

[Pete102580]

At first I thought the OBD connector was loose, so I snugly zip tied the LM-2 plug to the port. It seems that after a few minutes, the LM-2 can't read the the PCM & all OBD inputs fall dead. Checking via the menu, it indeed shows "pcm not connected" & I can't figure out how to reconnect it without cycling the truck off/on- or unplugging the OBD port & replugging.

The wideband never ever loses power, nor does the unit if just plugged into the OBD port. So, I'm not losing power- but I am losing the PCM. Occasionally, the PCM will just show up after several minutes of being lost.

Just for shits my friend and I took it out in his mazda speed 3, and there were no problems what-so-ever....

So, the LM-2 is fine..... but my truck is not. Anyone else run into this?

pete

[emwhiteR/T]

I've never lost connectivity to my PCM before with my LM2. I've had it lockup with the OBD & Wideband plugged in at the same time.

Do you have yours set to auto for OBD? That's what I leave mine on and it comes up as a GM something or other.

[Pete102580]

ya, it's set for auto detect. when it connects, iirc it says ISO 9421 or something real close to that. just strange... every time at startup it's fine. then about a block or two later it loses everything. i thought maybe the sample rate was too high or something, I'm really not sure. I've seen a couple different settings for that but haven't played around much.

not losing the wideband reading makes sense, as it's powered off the cigarette lighter. what's strange is OBD power is good, just the readings drop out.

i guess ill just have to figure out exactly what conditions cause the drop-out, then start troubleshooting. maybe a loose wire somewhere because after a while, sometimes it will come back. but, if that were the case, a loose wire would account for a sensor or 2 dropping out, not everything.


you know -talking myself in circles here-..... what could very well be the culprit is my PCM is not grounded to the chassis at the PCM. it has it's grounds through the PCM plugs, but the PCM itself is mounted to the inner glove box skin... i think i should add a grounding strap and go from there.


pete

[bfranzel]

ya, it's set for auto detect. when it connects, iirc it says ISO 9421 or something real close to that. just strange... every time at startup it's fine. then about a block or two later it loses everything. i thought maybe the sample rate was too high or something, I'm really not sure. I've seen a couple different settings for that but haven't played around much.

not losing the wideband reading makes sense, as it's powered off the cigarette lighter. what's strange is OBD power is good, just the readings drop out.

i guess ill just have to figure out exactly what conditions cause the drop-out, then start troubleshooting. maybe a loose wire somewhere because after a while, sometimes it will come back. but, if that were the case, a loose wire would account for a sensor or 2 dropping out, not everything.


you know -talking myself in circles here-..... what could very well be the culprit is my PCM is not grounded to the chassis at the PCM. it has it's grounds through the PCM plugs, but the PCM itself is mounted to the inner glove box skin... i think i should add a grounding strap and go from there.


pete

you relocated the pcm right. im not 100% where the output wires on your obd port comes from but id be looking in that direction.

[Pete102580]

im going to ground it first, then a multimeter on a couple pins should tell me fairly quick if that doesn't work.

pete

[BryanRT360]

my freezes up ever now and than. it is a little tricky to get it working right though. I plug into the ciglighter first wait till it starts reading A/F(after o2 warm up) than I plug in the obdII port. if i plug the obd in first I'll get and error code on the lm2 for the wideband

[Pete102580]

I've noticed that too.... sometimes the wideband will stick at "W69". I'll try that too.

you'd think for $4xx bucks they'd make something that wasn't finicky....

pete

[emwhiteR/T]

Good luck!

I've noticed that too.... sometimes the wideband will stick at "W69". I'll try that too.

you'd think for $4xx bucks they'd make something that wasn't finicky....

pete

I know! Mines out of warranty but they don't seem to answer anything on their forums. My call to them was to "upgrade" to the latest version to fix everything.

[mtlcafan79]

Weren't people having problems with those if you logged more than a few channels at a time?

[Pete102580]

ya i think so.. i think most of us stick to 4 or less channels. it's "capable" of like 11 i think.

pete

[emwhiteR/T]

I log like 6 or 7 but I set the non essentials to "low priority".

[Aves]

I log 5 on mine. I had that problem wit it loosing pcm when I first got it. Then upgraded software and have not had problem again. But then again that has been overwhen a year ago so I would think your software is current might try to reload it.

I hate not being able to keep obd connected without erroring. Sometimes forget in staging lanes and all I get looking at log is AFR.


Troy

[emwhiteR/T]

Bump, fix it yet?

[Pete102580]

nah, had a lot going on lately with exams.. and packing for Mexico

[Pete102580]

well, no luck yet... key on/engine off- i can pick up the PCM via the OBD port all day long. right after i start the truck, it will pick up whatever values i set it to for a few seconds then it drops out. sometimes it comes back for a second, sometimes it doesn't.

Turn the engine off and then key back to run and it connects back up after a few seconds just fine. it will sit there connected all day long until i start the truck.

i updated to the latest firmware, no luck there either.

i quit for the night... im getting pissed.

pete

[BryanRT360]

try waiting till the o2 warms up and starts reading. than plug in the obd port

edit: already posted that a while ago in this thread..

[Pete102580]

ya, i was sure to go back and re-try the previous suggestions.

can't find anyone else on google with this problem either... gonna start poking the trucks port with a multimeter tomorrow... unfortunately its too damn loud to sit out in the driveway and troubleshoot all night, lol.

pete

[emwhiteR/T]

Leave the O2 out. Unplug the power wire and leave the OBD II plugged in and run it that way. See if it will stay connected with just the OBD II powering the unit.

I know they can be real sensitive to electronic fluctuations. Innovate closed down their forum and quit helping with the LM2 a long time ago.

[Pete102580]

that doesn't work either

[Pete102580]

Just for the sake of logging my troubleshooting steps...

pin 27 on the forward most PCM connector is the SCI Transmit port, I checked continuity between that and pin 7 (ISO 9141) on the OBD connector and it was good... After work I'm going to jumper straight from the PCM to the OBD port to bypass any crap that may have gone wrong when I lengthened all those cables.. i did catch one mistake i made right after i moved the PCM... i had the TC lockup wired into the air conditioning. both were brown wires, same size, so i'm not above second guessing myself on the wiring, regardless of how careful i was.

just for shits i ordered an inductive clamp so i can at least log a/f & rpm. if all else fails at least i have that.

pete

[BryanRT360]

Just for the sake of logging my troubleshooting steps...

pin 27 on the forward most PCM connector is the SCI Transmit port, I checked continuity between that and pin 7 (ISO 9141) on the OBD connector and it was good... After work I'm going to jumper straight from the PCM to the OBD port to bypass any crap that may have gone wrong when I lengthened all those cables.. i did catch one mistake i made right after i moved the PCM... i had the TC lockup wired into the air conditioning. both were brown wires, same size, so i'm not above second guessing myself on the wiring, regardless of how careful i was.

just for shits i ordered an inductive clamp so i can at least log a/f & rpm. if all else fails at least i have that.

pete

you shouldn't need the clamp. did your's come with the 14 wire analog cable? there is a wire you can use for rpm..

chapter 5.1 of the lm2 manual page 29
the black/white wire is + and the blue wire is -

[Pete102580]

ya i have that cable... wires to the coil right?

that's kind of a pain, my coil is stuffed under the metal wiper cowl wayyyyy deep in there. have to take it out to mess with it. i already ordered the clamp, & it's easy so i guess i'll stick with that.
pete

[Pete102580]

well, i'm at the end of my rope...

i hard wired the pcm I/O to the LM2, along with power and ground.... does the same thing: reads fine in the accessory position, but as soon as i start the truck, the OBD sensor info drops offline.

i have another PCM on the way to test out just to see if i need a new one.. if that doesn't work, i'm done fucking with it... RPM & A/F will have to suffice for a tune.

pete

[emwhiteR/T]

Good luck with the clamp on the RPM's. When the forums were open, there was complaint after complaint of how shitty the LM2 was with it. Apparently the signal is all over the place and nobody got a perfect read of the RPMs.

[Pete102580]

you shouldn't need the clamp. did your's come with the 14 wire analog cable? there is a wire you can use for rpm..

chapter 5.1 of the lm2 manual page 29
the black/white wire is + and the blue wire is -

well... i tried it anway.. it picks up rpm but i have to mess with the settings more, it was all over the place.
pete

[Pete102580]

you know- there is one last ditch option aside from switching PCM's... i'm wondering if there's too much noise in the system & the LM-2 disconnects because of it... i'll pick up an RFI filter from work and see what happens with that.

pete

[Intense RT]

Still does it logging 2 channels? Per instructions (which I have to read every time because I mess with it rarely and forget) you connected the laptop to the lm-2 etc etc , set it all up. No offense..This stuff is not my deal so I read it every time.

Either way, while the concept of the LM-2 is excellent, the delivered product leaves a lot to be desired as far as "finicky" errors, not getting data after a pass. Gotta get the ritual down in the staging lanes while you are two or three cars behind. To a layman, as far as electrical/pcm stuff it seems the way to go if you can get it for a screamin' deal...if it has been shown to function..

[Pete102580]

you shouldn't need the clamp. did your's come with the 14 wire analog cable? there is a wire you can use for rpm..

chapter 5.1 of the lm2 manual page 29
the black/white wire is + and the blue wire is -


it didn't like the coil, but it loves the tach output on the MSD.

I've fucked around with this thing so much the past few days, ive uncovered 10 years worth of rats nested wires.... now i've got shaved wires & alligator clips to clean up & i'm ready to at least start logging a/f & rpm.... maybe tomorrow. trying to put it on the track this sunday.

pete

[Pete102580]

Still does it logging 2 channels? Per instructions (which I have to read every time because I mess with it rarely and forget) you connected the laptop to the lm-2 etc etc , set it all up. No offense..This stuff is not my deal so I read it every time.

Either way, while the concept of the LM-2 is excellent, the delivered product leaves a lot to be desired as far as "finicky" errors, not getting data after a pass. Gotta get the ritual down in the staging lanes while you are two or three cars behind. To a layman, as far as electrical/pcm stuff it seems the way to go if you can get it for a screamin' deal...if it has been shown to function..

i ditched everything except OBD rpm and it still drops it. i'm pretty impressed with the unit itself, i just cant get it to work on my truck.. i've had it in the wifes TL, my trailblazer, and a mazdaspeed3... works awesome in everyhthing but my truck, so as much as id like to blame the LM-2 I just cant.

I've ruled out everything except a bad PCM... I hard wired the the LM-2 and i still cant get it to stay connected. i was pretty surprised to find that there's only one pin on the PCM & OBD port that sends/receives data.
pete

[mtlcafan79]

I tuned on my TKO truck and the R/T with LM-1's. All they recorded was RPM and AFR. ODBII data is just a bonus.

[Pete102580]

ya i know... it's a real nice bonus to have though.. it would help immensely in troubleshooting various issues as they arise over the years.
pete

[Five9Dak]

it didn't like the coil, but it loves the tach output on the MSD.

I've fucked around with this thing so much the past few days, ive uncovered 10 years worth of rats nested wires.... now i've got shaved wires & alligator clips to clean up & i'm ready to at least start logging a/f & rpm.... maybe tomorrow. trying to put it on the track this sunday.

pete

An interesting note, I've had RPM input devices that like the coil(-) more than the MSD out.

Did you perchance tap coil(-) AFTER the MSD instead of before it?

[Pete102580]

at first i wired up to the coil, both + and -, then i played with those for a bit, disconnecting one and grounding the other.... it registered, but was wayyy off.

then i tapped the msd output and watched it for a bit, seemed fine in the driveway- have yet to clean up and take her out. my clamp came in today so if the msd ends up not working at least i have another option.

pete

[RTchas]

Okay I am in the same Boat with my LM-2 ! I got good A/F but no OBD reading?? I got power when I plug it in just OBD no Cig. Lighter, but it reads nothing and says " Not Connected". I have MP PCM did not try software update yet but WTF this thing wasnt cheap and my 50 Autozone code reader works better with the OBD than it dose! So I dont think its the OBD in the truck? Any Luck with yours Pete ?

[Pete102580]

nope. i blame the truck, not the lm-2.... the lm-2 works flawlessly in all my other vehicles and a couple of my friends cars, it just doesn't like my truck

i don't get it.... i gave up for now.... got bigger fish to fry.

pete

[emwhiteR/T]

Okay I am in the same Boat with my LM-2 ! I got good A/F but no OBD reading?? I got power when I plug it in just OBD no Cig. Lighter, but it reads nothing and says " Not Connected". I have MP PCM did not try software update yet but WTF this thing wasnt cheap and my 50 Autozone code reader works better with the OBD than it dose! So I dont think its the OBD in the truck? Any Luck with yours Pete ?

Are you leaving the OBD II set to auto, so it can find the OBD II parameters on it's own? If not, give that a try.