Time to do some upgrades

[grom_e30]

idle control can use pwm, and boost control as well, im not sure you would be able to abuse either of those functions to do what you want though unless you could live with out 'warm up enrichment' and maybe use the open loop idle control pwm to drive your fan.

[euro2fast4u]

idle control can use pwm, and boost control as well, im not sure you would be able to abuse either of those functions to do what you want though unless you could live with out 'warm up enrichment' and maybe use the open loop idle control pwm to drive your fan.

I have no idle control valve and dont plan on using one. I usually do small adjustment to my throttle body but most times its pretty stable once its warmed up.

Given that how does the boost controller work? With the addition of a steady state relay i should be able to handle the load of the fan.

[grom_e30]

boost control has a pwm table based on tps and rpm

[euro2fast4u]

boost control has a pwm table based on tps and rpm

so then i could change the table to use time and clt.

220--0---0---0---100
210--0---0---0---90
200--0---0---0---75
190--0---0---0---50
180--0---0---0---30
170--0---0---0---10
------0---1---2---3

[grom_e30]

that will require modding the firmware

[euro2fast4u]

that will require modding the firmware

You mean recoding right?

[grom_e30]

yeah may be a case of bodging the existing code to look up clt instead of tps.

[euro2fast4u]

yeah may be a case of bodging the existing code to look up clt instead of tps.

I have done that before but it was combing a boost gauge and a vacuum gauge for tuner studio. again its been 8 years since i screwed with that.

[grom_e30]

http://www.msextra.com/forums/viewtopic ... 91&t=43601 may be worth a read

[euro2fast4u]

Capacitors should be in today, of course i found my old stash of MS parts last night.

What are the chances of this actually fixing the voltage spike?

[rickb794]

Poor grounding practices and dirty power sources are most often the cause. Unless you are dealing with USB noise.

[euro2fast4u]

Poor grounding practices and dirty power sources are most often the cause. Unless you are dealing with USB noise.

I previously added new ground wires and recently added new power sources and additional grounds. I also cleaned every ground and protected each one.

[rickb794]

Coil should be mounted on motor, sensor leads should not be run near the coil. Alternator and associated wiring? Low impedance injectors? Non stock spark plug wires, non-resistor plugs.

[euro2fast4u]

Coil should be mounted on motor, sensor leads should not be run near the coil. Alternator and associated wiring? Low impedance injectors? Non stock spark plug wires, non-resistor plugs.

May need more information. The engine is in a 1987 bmw.
Coil is mounted on the fender.
Sensor leads do not run near the coil.
associated wires and alternator are on other side of the engine bay.
Injectors are not oem. They are from a 2008 EVO 8 MR. They are low impedance injectors.
Spark plug wires are upgraded yellow ones lol dont remember the brand.
spark plugs are NGK BPR7ES

[rickb794]

You may need to run resistors with those injectors?

Also I believe someone did a mod to provide the flyback? attenuation circuit a better ground. You might search for that.

[euro2fast4u]

You may need to run resistors with those injectors?

Also I believe someone did a mod to provide the flyback? attenuation circuit a better ground. You might search for that.

Correct. that is one of the fixes that can possibly fix it. Both are actually however the links and photos are all broken.

[rickb794]

If you can be talked into trying a P&H board it may solve this issue.

jbperf.com

[euro2fast4u]

If you can be talked into trying a P&H board it may solve this issue.

jbperf.com

Dont think i need to be talked into, it wasnt proven to fix the issue.

BTW adding the .22uf cap has certainlty reduced the spikes all together and now have a relative small (low of 12.2) drop. over 25 minutes of driving i got 3 drops

battery spikes after adding .22 uf cap by euro2fast4u, on Flickr


One interesting thing i noticed was the afrs were off, which was expected but it no longer feels has happy as it was before. More delayed less rev happy, more pedal required to get it going kinda thing. with the cold night it should have felt similar as sunday.

[rickb794]

Ah, I see now! You were saying spikes, what I see in the log is not spiking.

I would track battery volts while doing a wiggle test and percussive maintenance and scope the alt output.

Drops are not noise (as I have experienced). A capacitor might help but it is a bandaid to the real issue.

Unstable power or a poor ground.

Have you discombobulated the alternator to see if it levels off? Although at low of 10v I don't think that is the cause. (that's cranking voltage on a good battery)(unless you have the lights, wipers and heater on...)

Solve this before chasing any operational (tuning) stuff, voltage changes that big are going to make the MS do crazy things.

Also noted in that log is a high of only 12.something volts, something is very no bueno. Running you should see over 13v.

You should also look at 5v Vref to be sure nothing is messing with it. The last place I can think to look is the voltage divider circuit that the MS uses to monitor supply voltage.

[euro2fast4u]

Yea, i tried 3 alts and all were low and high. if you see the most recent picture from the log i get 3 voltage drops to 12.2v. otherwise its around 13.0 volts.