87 951 VEMS Install
#541
Edit: yes, I took a look, it runs terrible on a NA
I figured it out I think. IAC was not set up correctly, will post solution later.
Sorry if this is inappropriate, being a solution for a NA 8V - But this thread is very active and there are some similarities between 8V NA & turbo, so it was my best shot.
Anyways, here's the solution: https://rennlist.com/forums/924-931-...l#post16296017
IAC was set up incorrectly. Changes I made in RED
Under Idle Ignition Advance:
Control Setting: disabled
Under PWM Idle Control:
IAC PWM Frequency: 200 Hz
Max PWM Duty: 100%
Min PWM Duty: 0%
IAC close delay: 1s
Power Off IAC after close delay: Enabled
Dual Solenoid:Enabled
Idle Solenoid Output: INJGroup
Idle Solenoid Channel dual: 6,i7
Under Idle Reference Curve / Idle Air valve reference position:
Deg C / RefDC %
-40 / 0
-15 / 3
-7 / 8
2 / 20
15 / 31
30 / 43
40 / 52
53 / 68
73 / 85
106 / 89
-> basically an ascending line from 0-90% RefDC. I think this should be the other way round and the solenoid channel further up should be inverted, but same difference, right?
Stock setting was a more or less flat line - so it was either not set up correctly at all or the early 2-wire ICV works very differently.
throttle is a bit jerky when cold, and it needs optimisation, but it's staying on when started cold, it's what's important!
Edit:
I would like to use different injectors in the future, could I use e.g. Bosch 0280155831 which have a 12 Ohm resistance vs. the stock 2.35 Ohm resistance with VEMS?
Sorry if this is inappropriate, being a solution for a NA 8V - But this thread is very active and there are some similarities between 8V NA & turbo, so it was my best shot.
Anyways, here's the solution: https://rennlist.com/forums/924-931-...l#post16296017
IAC was set up incorrectly. Changes I made in RED
Under Idle Ignition Advance:
Control Setting: disabled
Under PWM Idle Control:
IAC PWM Frequency: 200 Hz
Max PWM Duty: 100%
Min PWM Duty: 0%
IAC close delay: 1s
Power Off IAC after close delay: Enabled
Dual Solenoid:Enabled
Idle Solenoid Output: INJGroup
Idle Solenoid Channel dual: 6,i7
Under Idle Reference Curve / Idle Air valve reference position:
Deg C / RefDC %
-40 / 0
-15 / 3
-7 / 8
2 / 20
15 / 31
30 / 43
40 / 52
53 / 68
73 / 85
106 / 89
-> basically an ascending line from 0-90% RefDC. I think this should be the other way round and the solenoid channel further up should be inverted, but same difference, right?
Stock setting was a more or less flat line - so it was either not set up correctly at all or the early 2-wire ICV works very differently.
throttle is a bit jerky when cold, and it needs optimisation, but it's staying on when started cold, it's what's important!
Edit:
I would like to use different injectors in the future, could I use e.g. Bosch 0280155831 which have a 12 Ohm resistance vs. the stock 2.35 Ohm resistance with VEMS?
Last edited by chrsvo; 12-18-2019 at 05:22 AM.
#542
Edit: yes, I took a look, it runs terrible on a NA
I figured it out I think. IAC was not set up correctly, will post solution later.
Sorry if this is inappropriate, being a solution for a NA 8V - But this thread is very active and there are some similarities between 8V NA & turbo, so it was my best shot.
Anyways, here's the solution: https://rennlist.com/forums/924-931-...l#post16296017
.....
Sorry if this is inappropriate, being a solution for a NA 8V - But this thread is very active and there are some similarities between 8V NA & turbo, so it was my best shot.
Anyways, here's the solution: https://rennlist.com/forums/924-931-...l#post16296017
.....
#543
Rennlist Member
Okay I'm having a weird issue with the VEMS.
Car starts and runs fine for approximately 3 minutes then shuts off.
I can immediately restart the car,again it runs fine for a few minutes and then shuts off. I have replaced the DME relay with the same result. So what I did then I hooked up a test light to the fuel pump and verified that power is being interrupted to the fuel pump.The question is why?
Hoping the Brain trust here will have something else for me to try and diagnose what's going on here thanks
Car starts and runs fine for approximately 3 minutes then shuts off.
I can immediately restart the car,again it runs fine for a few minutes and then shuts off. I have replaced the DME relay with the same result. So what I did then I hooked up a test light to the fuel pump and verified that power is being interrupted to the fuel pump.The question is why?
Hoping the Brain trust here will have something else for me to try and diagnose what's going on here thanks
Last edited by gpr8er; 12-22-2019 at 08:08 PM.
#544
Three Wheelin'
Okay I'm having a weird issue with the VEMS.
Car starts and runs fine for approximately 3 minutes then shuts off.
I can immediately restart the car,again it runs fine for a few minutes and then shuts off. I have replaced the DME relay with the same result. So what I did then I hooked up a test light to the fuel pump and verified that power is being interrupted to the fuel pump.The question is why?
Hoping the Brain trust here will have something else for me to try and diagnose what's going on here thanks
Car starts and runs fine for approximately 3 minutes then shuts off.
I can immediately restart the car,again it runs fine for a few minutes and then shuts off. I have replaced the DME relay with the same result. So what I did then I hooked up a test light to the fuel pump and verified that power is being interrupted to the fuel pump.The question is why?
Hoping the Brain trust here will have something else for me to try and diagnose what's going on here thanks
It would be a good idea to make a log of this happening, and post a video of it here---- we might be able to see what is dropping out.
#545
Rennlist Member
Yeah it shuts off both driving and idling doesn't really matter.
It's it's definitely cutting power to the fuel pump and running out of gas but then it will start right back up I can hear the fuel pump spin up when I turn the key
It's it's definitely cutting power to the fuel pump and running out of gas but then it will start right back up I can hear the fuel pump spin up when I turn the key
#549
Rennlist Member
I've verified that the FP is losing power when the car shuts off with a test light at the terminals on the FP. Light solid then goes out, car shuts off.
I'm going to run a hot lead straight to the FP and try that.
#550
Three Wheelin'
Rippling at the end is the running out of fuel and car shutting off. It will immediately restart like nothing ever happened and repeat the same cycle. After I changed "pump off after inactivity" to 1.57 from 0.57 car seemed to run minutes longer.
I've verified that the FP is losing power when the car shuts off with a test light at the terminals on the FP. Light solid then goes out, car shuts off.
I'm going to run a hot lead straight to the FP and try that.
I've verified that the FP is losing power when the car shuts off with a test light at the terminals on the FP. Light solid then goes out, car shuts off.
I'm going to run a hot lead straight to the FP and try that.
Use a multimeter and switch it to the AC voltage setting. It is best to check voltage at the back of the alternator, but because this is difficult on a 951 with an A/C compressor and cooling shroud, you can check at the battery terminals. Normally, the AC voltage should be next to zero, but I suspect that you will find a volt or more.....
Last edited by Droops83; 12-23-2019 at 12:00 PM.
#551
Rennlist Member
It’s not normal for all of the signals to ripple like that. My gut feeling is that you are getting AC voltage out of the alternator due to a faulty diode, which can wreak havoc on DC electronics. The DME eventually shuts down, and because it controls the signal to the fuel pump side of the relay, the fuel pump also shuts down.
Use a multimeter and switch it to the AC voltage setting. It is best to check voltage at the back of the alternator, but because this is difficult on a 951 with an A/C compressor and cooling shroud, you can check at the battery terminals. Normally, the AC voltage should be next to zero, but I suspect that you will find a volt or more.....
Use a multimeter and switch it to the AC voltage setting. It is best to check voltage at the back of the alternator, but because this is difficult on a 951 with an A/C compressor and cooling shroud, you can check at the battery terminals. Normally, the AC voltage should be next to zero, but I suspect that you will find a volt or more.....
#552
Rennlist Member
Merry Christmas guys!
Spent a little time in the garage this morning and verified that the car will now run non stop with the FP wired directly. Obviously this is not a correct or permanent fix for safety reasons. So this confirms that for some reason the VEMS is stopping power to the FP. I'll poke around in the menus, but I'm the first to admit to being a NOOB
Spent a little time in the garage this morning and verified that the car will now run non stop with the FP wired directly. Obviously this is not a correct or permanent fix for safety reasons. So this confirms that for some reason the VEMS is stopping power to the FP. I'll poke around in the menus, but I'm the first to admit to being a NOOB
#553
Three Wheelin'
For anyone that has gotten wasted spark after going to VEMS, does the Bosch wasted spark (https://www.vems.com/ignition/bosch-motorsport-2x2.html) come with ignition wires? I have VEMS that did not come with wasted spark, and I'm looking into switching to wasted spark as well. I'm also doing a parts order, so I just need to know if I should include wires in that list or if the unit already covers that. Thanks.
#554
Three Wheelin'
I had to get custom leads made up as living down under and needing quickly was only option. The ends at the new Bosch ignition units lead connections are different to the old distributor. Rather than order the leads Peep sends, which I couldn't source locally quickly, I got a set made which he had ready next day and at lengths to suit my mounting of Bosch unit. I think I paid $100
#555
Rennlist Member
For anyone that has gotten wasted spark after going to VEMS, does the Bosch wasted spark (https://www.vems.com/ignition/bosch-motorsport-2x2.html) come with ignition wires? I have VEMS that did not come with wasted spark, and I'm looking into switching to wasted spark as well. I'm also doing a parts order, so I just need to know if I should include wires in that list or if the unit already covers that. Thanks.
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