87 951 VEMS Install
02-26-2023, 02:34 PM
#736
3rd Gear
Join Date: Nov 2020
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Thanks Chris,
I was able to solve the issue yesterday after Peep sent me instructions on how to upload the firmware again. Apparently I messed something during initial installation/setup. Now I working on learning how to modify configurations etc. as the car is good at idle but cuts when I try to accelerate.
Regards,
Rey
I was able to solve the issue yesterday after Peep sent me instructions on how to upload the firmware again. Apparently I messed something during initial installation/setup. Now I working on learning how to modify configurations etc. as the car is good at idle but cuts when I try to accelerate.
Regards,
Rey
02-27-2023, 04:13 PM
#737
3rd Gear
Join Date: Nov 2020
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Thanks Chris,
I was able to solve the issue yesterday after Peep sent me instructions on how to upload the firmware again. Apparently I messed something during initial installation/setup. Now I working on learning how to modify configurations etc. as the car is good at idle but cuts when I try to accelerate.
Regards,
Rey
I was able to solve the issue yesterday after Peep sent me instructions on how to upload the firmware again. Apparently I messed something during initial installation/setup. Now I working on learning how to modify configurations etc. as the car is good at idle but cuts when I try to accelerate.
Regards,
Rey
06-28-2023, 04:07 PM
#738
Advanced
Hey guys, I'm just starting my vems install and had a question regarding the optional oil temp sensor. It came with a harness but I couldn't find the pin outs on the pdf online. Does anyone know the pins for the vems harness? Thanks.
10-17-2023, 02:11 PM
#739
Hello,
Happy New Year to everyone,
I´m hoping someone can help me with some inside knowledge of vems.
I have a V3.3 (bought from Peep as a pnp as i really didn´t want to be going into the nittygritty diy of ecu´s at the mo) installed on a Porsche 944 turbo. It starts, idles and runs great on a good start BUT on about 50% of starts it is BAD and has a light misfire (like a vac leak or weak spark), almost dies on accel (like a carb accel pump not working) and has `hard´ backfires on rapid decels (like a bad vac leak).
Once started in this state it will not recover unless restarted (ecu reset ?) and is immediately obvious by the popping sounds at idle in the exhaust.
At idle (800rpm) The 02 is approx .05 higher than a good start (i presume unburnt fuel?) and very unstable as are the rpms & 02 with tps held at 4%.
Turn it off & on again and it will run perfect - 02 @ 99 or wherever it is set, no misfire, backfire etc.
I´ve tried all external troubleshooting i can find & think of, and am now wondering if its possible for Vems to initialise and latch in a state that can cause these issues until the power is cycled.
I was running WS with new leads (from Peep), but for t/s have put the orig stock coil n cap/leads back in, tried 3 new ws coils, deactivated and plugged the IAC, 2 new sets of plugs (resistor & non), checked for vac leaks, swapped inj, ign Channels & pins, jiggled harness´s conned out connectors, checked tps sweep, disabled inj cha´s during idle but cant find anything wrong.
Trigger logs look good, timing strobe looks good steady n solid also.
Cylinder head recon & turbo were replaced at the same time as installing vems.
Next thing i´m going to try is reinstalling the Motronic ecu but i was hoping for some ideas before doing that.
Logs & Trigger files attached. (Maps are untested at this time & idle is setup for t/s this problem - Idle EGO/Timing control deactivated)
Any advice appreciated,
Thanks !
Happy New Year to everyone,
I´m hoping someone can help me with some inside knowledge of vems.
I have a V3.3 (bought from Peep as a pnp as i really didn´t want to be going into the nittygritty diy of ecu´s at the mo) installed on a Porsche 944 turbo. It starts, idles and runs great on a good start BUT on about 50% of starts it is BAD and has a light misfire (like a vac leak or weak spark), almost dies on accel (like a carb accel pump not working) and has `hard´ backfires on rapid decels (like a bad vac leak).
Once started in this state it will not recover unless restarted (ecu reset ?) and is immediately obvious by the popping sounds at idle in the exhaust.
At idle (800rpm) The 02 is approx .05 higher than a good start (i presume unburnt fuel?) and very unstable as are the rpms & 02 with tps held at 4%.
Turn it off & on again and it will run perfect - 02 @ 99 or wherever it is set, no misfire, backfire etc.
I´ve tried all external troubleshooting i can find & think of, and am now wondering if its possible for Vems to initialise and latch in a state that can cause these issues until the power is cycled.
I was running WS with new leads (from Peep), but for t/s have put the orig stock coil n cap/leads back in, tried 3 new ws coils, deactivated and plugged the IAC, 2 new sets of plugs (resistor & non), checked for vac leaks, swapped inj, ign Channels & pins, jiggled harness´s conned out connectors, checked tps sweep, disabled inj cha´s during idle but cant find anything wrong.
Trigger logs look good, timing strobe looks good steady n solid also.
Cylinder head recon & turbo were replaced at the same time as installing vems.
Next thing i´m going to try is reinstalling the Motronic ecu but i was hoping for some ideas before doing that.
Logs & Trigger files attached. (Maps are untested at this time & idle is setup for t/s this problem - Idle EGO/Timing control deactivated)
Any advice appreciated,
Thanks !
I am now having the intermittent bad start issue as well. Like clockwork, on the 4th restart the issue is resolved and I have a normal idle. It doesn't appear to happen all the time but when it does I get a rough idle running .05-.10 lean , popping and misfiring. 4th restart I get a perfect rock solid .98.
We have no idea what's causing this still ?
05-27-2024, 09:03 PM
#740
Pro
I don't know what happened, but since last fall my 944 has been only running on two or three cylinders. I haven't had time to dig into it until the past month.
I've confirmed spark, compression, fuel pressure, and was in the middle of switching around injectors to see if one or two of them were clogged.... but now the car won't start at all.
The strange thing is that I can no longer connect to VEMS - bluetooth connection doesn't show up as discoverable on my laptop or phone.
I've tested the harness for power and grounds.
Is my VEMS dead? Are there any tests for this?
I've confirmed spark, compression, fuel pressure, and was in the middle of switching around injectors to see if one or two of them were clogged.... but now the car won't start at all.
The strange thing is that I can no longer connect to VEMS - bluetooth connection doesn't show up as discoverable on my laptop or phone.
I've tested the harness for power and grounds.
Is my VEMS dead? Are there any tests for this?
06-03-2024, 12:26 PM
#741
Pro
I don't know what happened, but since last fall my 944 has been only running on two or three cylinders. I haven't had time to dig into it until the past month.
I've confirmed spark, compression, fuel pressure, and was in the middle of switching around injectors to see if one or two of them were clogged.... but now the car won't start at all.
The strange thing is that I can no longer connect to VEMS - bluetooth connection doesn't show up as discoverable on my laptop or phone.
I've tested the harness for power and grounds.
Is my VEMS dead? Are there any tests for this?
I've confirmed spark, compression, fuel pressure, and was in the middle of switching around injectors to see if one or two of them were clogged.... but now the car won't start at all.
The strange thing is that I can no longer connect to VEMS - bluetooth connection doesn't show up as discoverable on my laptop or phone.
I've tested the harness for power and grounds.
Is my VEMS dead? Are there any tests for this?
Still chasing a no-start, but I'm putting the car back to stock for sale, so this will probably take care of itself (going with Focus 9 Tech DME).
06-15-2024, 04:35 PM
#742
Rennlist Member
Join Date: Sep 2023
Location: Prague, CZ
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Hi everyone, so I am finally putting my VEMS kit into my 86 951 but I am getting a crank/no start issue.
It looks like the ECU is not getting any trigger signals - the tach in VemsTune shows zero rpm. The trigger log chart is completely blank as well.
I have tried putting a multimeter on the primary trigger pin on the harness (EC36 pin 27 and 26) and I am getting ~5 Volts AC when cranking. The car also runs just fine when I switch back to the DME/KLR.
Another issue I've noticed is that I can't seem to be able to calibrate the TPS properly - I get 100% TPS at about 50% of pedal travel.
Any ideas?
It looks like the ECU is not getting any trigger signals - the tach in VemsTune shows zero rpm. The trigger log chart is completely blank as well.
I have tried putting a multimeter on the primary trigger pin on the harness (EC36 pin 27 and 26) and I am getting ~5 Volts AC when cranking. The car also runs just fine when I switch back to the DME/KLR.
Another issue I've noticed is that I can't seem to be able to calibrate the TPS properly - I get 100% TPS at about 50% of pedal travel.
Any ideas?
06-18-2024, 08:00 PM
#743
Instructor
Hi everyone, so I am finally putting my VEMS kit into my 86 951 but I am getting a crank/no start issue.
It looks like the ECU is not getting any trigger signals - the tach in VemsTune shows zero rpm. The trigger log chart is completely blank as well.
I have tried putting a multimeter on the primary trigger pin on the harness (EC36 pin 27 and 26) and I am getting ~5 Volts AC when cranking. The car also runs just fine when I switch back to the DME/KLR.
Another issue I've noticed is that I can't seem to be able to calibrate the TPS properly - I get 100% TPS at about 50% of pedal travel.
Any ideas?
It looks like the ECU is not getting any trigger signals - the tach in VemsTune shows zero rpm. The trigger log chart is completely blank as well.
I have tried putting a multimeter on the primary trigger pin on the harness (EC36 pin 27 and 26) and I am getting ~5 Volts AC when cranking. The car also runs just fine when I switch back to the DME/KLR.
Another issue I've noticed is that I can't seem to be able to calibrate the TPS properly - I get 100% TPS at about 50% of pedal travel.
Any ideas?
for triggers: that's a problem, but if VEMS isn't seeing anything it's got to be wiring. sanity check your harness and make sure that the speed/ref sensors make it thru to the correct pins: http://www.vems.hu/wiki/index.php?pa...Three%2FPinOut
06-19-2024, 04:06 AM
#744
Rennlist Member
Join Date: Sep 2023
Location: Prague, CZ
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for TPS: you mean even after doing the calibration in vemstune and burning the results? it seems to be you're probably missing a step.
for triggers: that's a problem, but if VEMS isn't seeing anything it's got to be wiring. sanity check your harness and make sure that the speed/ref sensors make it thru to the correct pins: http://www.vems.hu/wiki/index.php?pa...Three%2FPinOut
for triggers: that's a problem, but if VEMS isn't seeing anything it's got to be wiring. sanity check your harness and make sure that the speed/ref sensors make it thru to the correct pins: http://www.vems.hu/wiki/index.php?pa...Three%2FPinOut
It seems like the reference sensor signal shows up at the correct pin, I can see AC voltage on the primary trigger pin in the VEMS harness when cranking. I don't have an oscilloscope, but again - the car works just fine with the stock computer.
Honestly it looks like I just received a faulty ECU...
Last edited by mrazeja7; 06-19-2024 at 04:45 AM.
06-19-2024, 01:11 PM
#745
Instructor
Huh, usually I'd say that's unlikely but it kind of sounds like you did! The tps supply is fed by a basically-dedicated 5v linear regulator, so if +12v is there that's an issue.
If you got this from Peep, he's usually pretty good at bringup/install support! send him an email and I'm sure you'll be sorted
If you got this from Peep, he's usually pretty good at bringup/install support! send him an email and I'm sure you'll be sorted