Car drives fine until about 4300 rpm...

Jon k · Post by **Jon k** » Wed Aug 23, 2006 7:19 am

I am running MSnS-E 029s ono a MS-1 v3 running 3 wasted spark to my BMW 24v inline 6. The car has a horribly rich tune right now (10:1 at some points, maybe even richer I dunno). It drives ok in the part throttle areas, still rich, but it goes. Then if I give it gas to try and get on boost a little bit, it straight up like freezes - it feels like the car shuts off for a moment and then clicks back on. In reality this is probably not the case. I have a feeling my aged plugs are fouled beyond oblivion, but I want more input. What would cause this sputter at 4400 rpm or so. Also, right around this engine speed I got a reset once... I am posting my MSQ and Datalog.

http://e34.digital7.com/initial%20setup.msq

http://e34.digital7.com/data1_long.xls

please help guys

Jon k · Post by **Jon k** » Fri Aug 25, 2006 12:57 pm

here is the datalog

http://e34.digital7.com/data1_long.xls

FoundSoul · Post by **FoundSoul** » Mon Aug 28, 2006 7:23 am

I'm having a hard time seeing anything that looks like it's popping/sputtering in that log, maybe someone else will see something I'm missing. All I see is that the sudden RPM drops are always just after you get out of the throttle, as would be expected really-- and I also noticed you're running almost no advance above 100kpa. 12 degrees everywhere it looks like. This can make for a super hot exhaust (glowing headers) and popping sounds as the combustion process may not be complete when the exhaust valves open.

I do see the tach signal dropping at idle a time or two, could be related to the coils be mounted on the tach wire as you mentioned in email. I don't see this at/around 4000+ rpms though.

Also it appears the TPSdot threshold may be a bit low as you're going into accell enrichments with little to no throttle input. That happened a couple of times near 4000rpm and could cause it to fall on it's face....

Jon k · Post by **Jon k** » Mon Aug 28, 2006 7:31 am

FoundSoul wrote:I'm having a hard time seeing anything that looks like it's popping/sputtering in that log, maybe someone else will see something I'm missing. All I see is that the sudden RPM drops are always just after you get out of the throttle, as would be expected really-- and I also noticed you're running almost no advance above 100kpa. 12 degrees everywhere it looks like. This can make for a super hot exhaust (glowing headers) and popping sounds as the combustion process may not be complete when the exhaust valves open.

I do see the tach signal dropping at idle a time or two, could be related to the coils be mounted on the tach wire as you mentioned in email. I don't see this at/around 4000+ rpms though.

Also it appears the TPSdot threshold may be a bit low as you're going into accell enrichments with little to no throttle input. That happened a couple of times near 4000rpm and could cause it to fall on it's face....

What would be a safe amount of timing to run on a 4v per cyl 6 cyl motor - I see a max of about 9.5 psi of boost - the CR is 10.0:1.

I haven't even tried to setup accel enrich... so maybe that's the issue?

Keithg · Post by **Keithg** » Mon Aug 28, 2006 12:38 pm

you do have caps from the coil 12V supply to ground, don't you? There was a post about that recently. I tried to run wasted spark and would get WOT misses as well. It was better with 025 style wheel decoder instead of 024 (36-1 wheel). I did not add the caps, but that would be a hlep. I am sure you are already running resistor plugs.

$0.02

KeithG

Posted by email.

sparkandfuel.com · Post by **sparkandfuel.com** » Mon Aug 28, 2006 1:03 pm

bcrx7 wrote:Make sure you have the VR+ and VR- signals connected the right way. Almost sounds like they might be reversed.

I was unaware that the VR sensor was polarized, evidently some are

renns · Post by **renns** » Mon Aug 28, 2006 1:17 pm

bcrx7 wrote:Make sure you have the VR+ and VR- signals connected the right way. Almost sounds like they might be reversed.

That'd be my first guess as well. I helped a guy out with his turbo rotary the other day. It would rev cleanly until about 4k, and then it stumbled and stuttered terribly. By swapping VR sensor leads, the problem was solved. Note that there is weak documentation in the build procedure in this area, as you have the option to jumper TSEL to VROUT, or TSEL to VROUTINV. This fellow's board was built with TSEL to VROUT, with VR sensor polarity correct according to the factory service manual. Apparently it should have been TSEL to VROUTINV, as the cpu triggers on falling edge rather than rising edge. In your case, swap the VR leads, or if the harness is all tucked away already, try moving the jumper on the board instead.

I was unaware that the VR sensor was polarized, evidently some are

Aren't they all? Seems inherent to their mode of operation.

Roger.

shaodome · Post by **shaodome** » Mon Aug 28, 2006 1:35 pm

Ion...so far in every KL powered car, the VR wires i've seen are solid green and blue coming out of the same black shield. Just to confirm, your using the green wire as the tach input and the blue to ground, correct?

Jon k · Post by **Jon k** » Mon Aug 28, 2006 2:39 pm

What are you guys talking about caps?

ion332 · Post by **ion332** » Mon Aug 28, 2006 2:46 pm

Jon k wrote:What are you guys talking about caps?

I don't think you have to worry about it if you are running the stock bmw coil-on-plugs. No big deal for you.

Jon k · Post by **Jon k** » Mon Aug 28, 2006 5:01 pm

ion332 wrote:
Jon k wrote:What are you guys talking about caps?
I don't think you have to worry about it if you are running the stock bmw coil-on-plugs. No big deal for you.

I am running GM coil packs (HEI) in wasted spark - the car seems so much better now it revs up to 6500 rpm. If I go WOT i get some hesitation but I think it's because the motor is piggly rich.

mkehler · Post by **mkehler** » Tue Aug 29, 2006 11:20 am

[quote="Jon k"
I am running GM coil packs (HEI) in wasted spark - the car seems so much better now it revs up to 6500 rpm. If I go WOT i get some hesitation but I think it's because the motor is piggly rich.[/quote]

What ended up fixing the issue?

thanks
Matt