pw' spike to 0ms *update 2-11, switched to 1.0.2 code and...

jeffsnyder · Post by **jeffsnyder** » Thu Feb 07, 2008 4:01 pm

thought maybe I was getting a lean misfire in my car until I did some datalogging and saw that my pulse widths spike down to zero at some points, Ive looked through my MSQ and cant find a reason for this, only thing I can see that is an issue in my datalog is my MAP signal is all over the place

V3 MS2 using Extra 2.0 code...lastest beta realese
Car is a 92 Saturn with stock injectors and using HALL for a tach signal

any ideas ?

Maddog6961 · Post by **Maddog6961** » Thu Feb 07, 2008 8:03 pm

Looks like you might be having resets which is why everything drops to zero.

jeffsnyder · Post by **jeffsnyder** » Thu Feb 07, 2008 10:15 pm

The areas where things all drop to Zero are when im letting of the throttle....look at the TPS signal in the logs, you can see areas in the log were the PW drops to zero even though MAP/TPS and other valves are reading fine

Maddog6961 · Post by **Maddog6961** » Thu Feb 07, 2008 10:25 pm

Are you actually getting a misfire though and what makes you think that?

jeffsnyder · Post by **jeffsnyder** » Thu Feb 07, 2008 10:54 pm

I can feel the car jerk pretty hard,...I made a run and took note of were it would jerk...then looked at my datalog...the spots were my pulsewidth hit zero...it were I would feel it

hassmaschine · Post by **hassmaschine** » Thu Feb 07, 2008 11:40 pm

are you using high-z injectors? the settings you have look like they are for low-z.

otherwise, all your settings look ok - I personally wouldn't use multiply map (my mapdot is terrible).

jeffsnyder · Post by **jeffsnyder** » Fri Feb 08, 2008 12:12 am

Im using low indepedance injectors ( they are the stock injectors for my car) I didnt realize I had map multiply on....Im a little unclear on that setting, what does it do ?

md95 · Post by **md95** » Fri Feb 08, 2008 7:50 am

Are you saying that the ONLY time the PW goes to Oms is when you totally let off the throttle(engine braking)? If so, then do you have "over run fuel cut" activated? This cuts PW when you let off the gas to conserve fuel during decel when you let off the gas and are "coasting" in gear. This is how over run is supposed to work, but you may have to tweak the settings to get it to operate cleanly. If you are getting 0 PW drops while normal driving, then that is a different issue. I believe over run fuel cut works a bit better on a manual trans car, since it pulls a more consistant vacuum when you let off the gas, compared to an auto trans, which may not pull as much vacuum..kind of depends on how the transmission shifts on decel.

UnaClocker · Post by **UnaClocker** » Fri Feb 08, 2008 8:00 am

You using a V3 PCB? got the flyback section built on it? Low impedance injectors can really kick up some electrical noise if the flyback isn't working.
What wheel are you using? Are you using VR or Hall effect input? Maybe your VR circuit needs to be tuned better if you're using VR. Could be electrical noise on that sensor as well, causing the engine to lose sync.

hassmaschine · Post by **hassmaschine** » Fri Feb 08, 2008 10:44 am

jeffsnyder wrote:Im using low indepedance injectors ( they are the stock injectors for my car) I didnt realize I had map multiply on....Im a little unclear on that setting, what does it do ?

I don't really recall *exactly* what it does, but I know ken doesn't reccomend it, and my car runs better with it turned off (I have a noisy map signal though).

Post by **muythaibxr** » Fri Feb 08, 2008 10:51 am

multiply map comes from the original MS2 code that we started out with, and also the ms1 code.

It multiplies MAP into the final fuel equation, so even if you have the same VE in 2 load bins, (directly vertical of each other on the VE table), if you decrease MAP, the pulse-width will decrease. It tends to make the VE values vary a lot less, but at the same time map fluctuation tends to be more pronounced, especially on ms2 where we sense MAP to .1 kPa.

I added the option to turn off multiply MAP to enable better control of the pulse-width using the VE table, and to help negate the effects of a jumpy MAP signal.

Ken

jeffsnyder · Post by **jeffsnyder** » Fri Feb 08, 2008 12:00 pm

UnaClocker wrote:You using a V3 PCB? got the flyback section built on it? Low impedance injectors can really kick up some electrical noise if the flyback isn't working.
What wheel are you using? Are you using VR or Hall effect input? Maybe your VR circuit needs to be tuned better if you're using VR. Could be electrical noise on that sensor as well, causing the engine to lose sync.

Yes Im using the V3PCB and have the flyback section built, I have it setup to get a tach signal from a GM(Saturn)DIS module which uses the hall input

and no I dont have over run fuel cut on, and my decel fuel is 100% the Pw's spike to 0ms when im on the throttle and higher up in rpm

Maddog6961 · Post by **Maddog6961** » Fri Feb 08, 2008 2:21 pm

muythaibxr wrote:multiply map comes from the original MS2 code that we started out with, and also the ms1 code.

It multiplies MAP into the final fuel equation, so even if you have the same VE in 2 load bins, (directly vertical of each other on the VE table), if you decrease MAP, the pulse-width will decrease. It tends to make the VE values vary a lot less, but at the same time map fluctuation tends to be more pronounced, especially on ms2 where we sense MAP to .1 kPa.

I added the option to turn off multiply MAP to enable better control of the pulse-width using the VE table, and to help negate the effects of a jumpy MAP signal.

Ken

So what sort of behavior should you look for in determining whether or not to use map multiply? It you have a clean map signal without fluctuation problems, would you recommending using it?

jeffsnyder · Post by **jeffsnyder** » Fri Feb 08, 2008 2:26 pm

Could bad grounds cause the problem im having ? I have all my ground conections meet up about a foot away from the connector to a rather thick (think its about 12gauge) wire then its bolted to the side of the engine/tranny were the stock ground is

Maddog6961 · Post by **Maddog6961** » Fri Feb 08, 2008 4:24 pm

I am always hesistant to do that because I don't see automotive manufacturers doing it. They always seem to run lots of individual wires to a common grounding location and then joining them together with a connector. I don't know that that is your problem though.

If you have a way to probe your power supply on your injectors to verify that you have 12V at all times, that might be a good place to start. Also rechecking and jiggling all of the wiring might also be a good place to start.

md95 · Post by **md95** » Fri Feb 08, 2008 7:18 pm

Best bet is to run grounds right from the battery, and run a switched 12 volt power feed to the MS, from the pos battery terminal, switched through a relay. The battery acts as a natural noise filter, and takes any questionable grounds out of the mix. I saw similar behavior where PW goes to 0ms, but that was because of a lost wheel sync. If this is your problem, you can scroll through your datalog, and right at where it goes to 0, see if the "ASE" light comes on then off real quick. Mine did this upon a lost sync.

jeffsnyder · Post by **jeffsnyder** » Sat Feb 09, 2008 4:56 pm

Well I hooked it up to the Stim and im able to replicate the problem, so the issue is in my MS2. any ideas where I should start looking ?

jeffsnyder · Post by **jeffsnyder** » Sat Feb 09, 2008 5:52 pm

Interesting.....when im on the stim I put the PRM up to about 6.5k or so and can watch the PW's spike towards zero every couple seconds....but....

when I go into Tach/Input Ignition settings - and set my MS for "Fuel only" I no longer get spikes. so I take it something inside of my MS involving spark output is f**ked

Im using Js10 as a spark output and am setup for GMHEI/GMDIS as the manual shows

Xg1 jumpered to Xg2
JS10 jumpered to IGN
TSEL to OPTOOUT
OPTOIN to TACHSELECT

any ideas ?

jeffsnyder · Post by **jeffsnyder** » Sat Feb 09, 2008 8:03 pm

Interesting, looking at some of my data logs with PW spikes, there are also some Ign advance spikes that go to zero, but not in the same places as the PW spikes, something deffently wrong with my setup

jeffsnyder · Post by **jeffsnyder** » Mon Feb 11, 2008 4:39 am

PROGRESS !!! YAY !!

Reflashed MS2Extra2.0 to my MS a couple times to see if it could possibly be code curuption causeing my problem, didnt fix a thing

decieded to download MS2-Extra 1 realese code and my issues with the PW's dropping are gone (so far, atleast on the stim), even if im running spark control or not

So seems like my issues with Extra2.0 are just code related