When BS3 doesn't stand for Big Stuff

[MY3TTYPES]

When does the BS3 NOT stand for Big Stuff?! My saga:

When I itched for a t-top GN, I searched. After 6 months, I found what I thought was a good one. An 86 with mild parts, and only a few of them. New posi, wired Walbro with adjustable regulator, stainless exhaust, K&N filter, boost/knock gauge, new TE44 ball bearing turbo...added a set of 16" GNX wheels. I’m set! A good, basic combo with a solid, unopened motor owned by mature (and experienced) individual. And I’m not new to used cars. I know there will be things. There always is, right? Right.

So when the car arrives (6 weeks after purchase) I take delivery. At the depot, the folks ask me “Where is the flat bed?” Huh? “Ya, that car has no brakes! You can’t drive it.” So I look around under-hood, see it’s out of fluid. Strange. Seller drove it 45+ miles to the depot for drop-off. Well, I topped off the brake fluid and had enough to get my 50+ miles home. Car doesn’t run as well as I would’ve thought, but well enough for me to get home (almost). At 3/8 fuel in the tank, the car stalls and won’t start. Hmm, “Hey Bud, bring me some GAS!” Car fires but runs a little worse. But I fill the tank, (takes 10.6 gals., about right for 3/8) and get home. Must meed some fuel gauge work. No biggy. Closer inspection shows need for a new Power Master.

Well, at least now I know the brakes are ok, though at a price (you know what I mean). Do the other basic things; plugs, tranny service, fuel filter, oil change to Royal Purple with correct filter, install the GNX wheels, and a thorough cleaning and a CD player with fresh speakers. I’m ready for summer fun!! “Commuter Special, coming through!” Shinin’ bright and getting looks and thumbs up everywhere. People wanting to play, I just smile (no need for tickets). Not yet, still to new.

Front vibrates a little and, after a look-see, notice the sad bushings in the front A-ams. I’ll get to those soon enough. Ride to work a few days, happy with myself and new ride, but it still runs rough here and there with bad mileage. Around 15! But it passes CA smog test ok. But it stalls and won’t start 5 or 6 times now. So I set the TPS and IAC after a thorough cleaning. No change. Wires seem ok, but will soon be replaced. Fuel pressure was at 35 psi, so I bump it up to 39-40. Seems the same. Still haven’t goosed it, not yet familiar enough yet.

I start looking closer at the programming in the BS3. Get some help from PTE with the settings, but still not happy. I figure there is a parameter/combination at fault. I’m learning. Play with the maps some (fuel only) and it seems to help overall, until the stall happens. And a program that makes the car happy one day doesn’t mean it’s happy another day. But I keep trying little changes. Make progress, then WHAM! Bad running. Have gone back to original program several times but car has never liked it much. But it’s my base line.

So this week, I go for a longer ride, about 150 miles round trip, for work. Beautiful day. 84*, sunny, tops in the trunk. Lovin’ it! This is what it’s about! Until the stall. Well today, I’ve got laptop, fuel pressure gauge and a few basic tools. Fuel pressure is good, but the BS3 dash is saying very high AF ratio. Like 15.9:1! Uh-oh! So, I fatten the map in all non-boost range by 25%! Also, open the O2 Correction (+ and -) to 25%! Well, it runs again. Cautiously, I motor home, trying to watch the laptop while running. In case something bad changes. It’s seems low on power, but otherwise, not bad. Even the O2 Correction seems kinda happy with only minimal adjustment around 2% - 3% overall.

Next day, it’s running so fat that I think I killed the plugs. I’ll check them this weekend. I dropped the map back towards “normal” but something isn’t right. I checked all electrical connections and they “seem” to be ok. Cleaned up a little anyway. I’m gonna check the EGR valve (though not in operation) and plugs, looks for vacuum leaks, etc. I’m thinking maybe the O2 sensor may be at fault, but I really don’t know.

So, that’s my story. Any ideas?

TIA, Ed

[Grumpy]

convert it back to a chip in the car and ENJOY it

[Old Buzzard]

program that was in the car when you got it. Then, switch to open loop, and see what happens. Could be the sensor took a dump. If the car ran well, to begin with, adding 25% fuel, and allowing big correction limits, is only covering up the original problem.
Have you confirmed that the sensors are all working?
A bad temp sensor can put the ECM into cold start. Depending on where the car came from, that parameter could have more/less fuel commanded, than you need for your climate....

Where is the O2 sensor mounted??
The usual problems, such as exh leaks, bad coilpacks/modules, etc, will affect this system, just like a stock ECM....
I'd suggest you do some data logs, for a good look see at how "stuff" is working.
Good luck.

[87gnjoe]

Does the car still have a MAF sensor on it? A bad one will cause your stall condition as well as a host of other things. Gotta love when the seller leaves out just a few things that are wrong with the car

[MY3TTYPES]

Originally Posted by Grumpy

convert it back to a chip in the car and ENJOY it

I've considered this approach, but I don't thik it's neccesay. Plus it's become a mission now!

[MY3TTYPES]

Originally Posted by Old Buzzard

program that was in the car when you got it. Then, switch to open loop, and see what happens. Could be the sensor took a dump. If the car ran well, to begin with, adding 25% fuel, and allowing big correction limits, is only covering up the original problem.
Have you confirmed that the sensors are all working?
A bad temp sensor can put the ECM into cold start. Depending on where the car came from, that parameter could have more/less fuel commanded, than you need for your climate....

Where is the O2 sensor mounted??
The usual problems, such as exh leaks, bad coilpacks/modules, etc, will affect this system, just like a stock ECM....
I'd suggest you do some data logs, for a good look see at how "stuff" is working.
Good luck.

"...have gone back to original program several times but car has never liked it much. But it’s my base line." Tried open loop once and don't remember it helping. The "big fat" has been temporary fix. I'm looking for the original problem. When i find it, I'm sure things will staighen out.

Temp sensor seems ok. O2 sensor is wide band iand is in stock location (just before turbo).

Exhaust is leak free, and logs change depending on what stage the intermitent problem is at, at that particular time. Ignition seems ok as well.

Thanks, Ed

[MY3TTYPES]

Originally Posted by 87gnjoe

Does the car still have a MAF sensor on it? A bad one will cause your stall condition as well as a host of other things. Gotta love when the seller leaves out just a few things that are wrong with the car

Sorry, no MAF, which I'd need to replace if I go back to OEM ECU. And ya, "Love" that's what I'm feeling. I didn't even mention the rust! Neither did they in an honest sense. "...just starting...", "...started to leak..." yada yada. And yes, I did ask, just to be informed.

Thanks, Ed

[Old Buzzard]

Originally Posted by MY3TTYPES

"...have gone back to original program several times but car has never liked it much. But it’s my base line." Tried open loop once and don't remember it helping. The "big fat" has been temporary fix. I'm looking for the original problem. When i find it, I'm sure things will staighen out.

Temp sensor seems ok. O2 sensor is wide band iand is in stock location (just before turbo).

Exhaust is leak free, and logs change depending on what stage the intermitent problem is at, at that particular time. Ignition seems ok as well.

Thanks, Ed

If the problem isn't at the same "place", when you log a run, then I'd be looking at something other than the programming.IE:
A. Loose, bad connections.
B. Bad grounds. Is the ecm grounded, and powered directly to the batt?
C. Inconsistent fuel pressure.
D. Just because the ign "seems" to be good, does not mean it's ok. I suggest you have it tested, especially, when hot.
E. TPS is represented as the same value, both on the BS3 dashboard, and the DVOM?
TPS values good, when doing a sweep?

As for the O2 location. That current location is:
A. Too hot for a WB sensor.
B. The exh gas pressure is too high.

The sensor will live longer, and be more accurate, if it's down stream in the DP.. Say at least 12"...

Back under my HEMI!

[MY3TTYPES]

Originally Posted by Old Buzzard

If the problem isn't at the same "place", when you log a run, then I'd be looking at something other than the programming.IE:
A. Loose, bad connections.
B. Bad grounds. Is the ecm grounded, and powered directly to the batt?
C. Inconsistent fuel pressure.
D. Just because the ign "seems" to be good, does not mean it's ok. I suggest you have it tested, especially, when hot.
E. TPS is represented as the same value, both on the BS3 dashboard, and the DVOM?
TPS values good, when doing a sweep?

As for the O2 location. That current location is:
A. Too hot for a WB sensor.
B. The exh gas pressure is too high.

The sensor will live longer, and be more accurate, if it's down stream in the DP.. Say at least 12"...

Back under my HEMI!

I've been checking connections and all seem fine so far. Wil be checking engine grounds, etc.

Have checked ECM connections, also seem fine.

Fuel pressure is good. set at 40 psi.

Good thought foor the widwband. Will look into moving it further downstream. That has been my theory for the problem. System was installed at PTE. Figure they wouldn't miss a step like this, but who know?

Also, by intermitent, I mean it's not a static problem and the fuel MAP changes aren't the same at each occurance. Hence, I'm baffled!

Thanks for the input. Hats off to the HEMI! Ed

[Orlando_87GN]

Unless you are building an all out race car I would ditch the aftermarket ECM in favor for a Translator+, Extender chip and LS1 MAF which uses the factory ECM. Sometimes having the ability to tweak every last parameter with an aftermarket ECM can cause more harm than good. With a new car and unknown combo the last thing you need is to do is futz with a problematic ECU. Before anyone blasts me for suggesting a 'downgrade', think about things like TCC, fast spool, lean cruise mode and open loop idle which probably aren't available in BS.

[MY3TTYPES]

Originally Posted by Orlando_87GN

Unless you are building an all out race car I would ditch the aftermarket ECM in favor for a Translator+, Extender chip and LS1 MAF which uses the factory ECM. Sometimes having the ability to tweak every last parameter with an aftermarket ECM can cause more harm than good. With a new car and unknown combo the last thing you need is to do is futz with a problematic ECU. Before anyone blasts me for suggesting a 'downgrade', think about things like TCC, fast spool, lean cruise mode and open loop idle which probably aren't available in BS.

Whether or not it's a race car, if it's something mechanical (or something other than the computer), changing the ECM back won't do anything but cost more money (to replace missing components or new parts).

Not to mention the future mods I might make someday, should I decide to be heavier into racing. I have suffered from that (check my sig) before!

Actually, TTC, lean cruise and open loop idle are a part of BS3 (if set up that way) as far as I know.

Not sure what you mean by "fast spool". Is that a tranlator +, Extender chip option?

My problem is odd and unpredictable. BS3 isn't hard to set up, I'm just having some "issues" that are being caused by "something". I just have to figure out what "it/they" is/are!

My combo is not unknown (check my sig).

I am very suspisious of the wideband O2. It's mounted in the stock O2 location and I am feeling that isn't where it should be. Probably have to remount it (a new one) farther down stream. (Do I hear 3" DP in my future?) I'm hearing they aren't real happy in the factory spot (due to heat and pressure).

I also need to move up to bigger injectors, though I'm not boosting past 5 or 6 psi until I get it functioning all the time. Those boosts are only for 1 or 2 seconds, by the way (don't get distracted).

Thanks for the input though, Orlando 87. Ed