jason's education thread

[larrym]

Well done!

[Scoobum]

Jason...you're into axle snapping territory with that short time. Time for some Mosers.

[good2win22]

Hey...congrats! Equates to an 11.91 at 108. PL log for the run?

Here's the log

[good2win22]

Jason...you're into axle snapping territory with that short time. Time for some Mosers.

Been thinking about that myself.  Was going to ask Santa for a rear dif cover.  Maybe I'll ask for the dif cover and axles

[Scoobum]

Your battery voltage is scaring me...go over it with Steve. Slight KR in 2nd gear...but it went away. 02's are rich in low/high gear. There's more in it with tuning.

[good2win22]

Your battery voltage is scaring me...go over it with Steve. Slight KR in 2nd gear...but it went away. 02's are rich in low/high gear. There's more in it with tuning.

KR was close to the shift and didn't rear its head on subsequent runs

Went through all grounds, cleaned and tightened.  Cleaned battery posts, all wires and terminal rings at starter and alternator.  Removed fuses and cleaned the fuse connectors and replaced fuses that looked aged.  Replaced alternator, replaced battery, repaired/cleaned both battery terminals. Getting 14.6 volts at the alternator, battery and back at the fuel pump hot wire when engine is cold.  Voltage drops to around 13.8 when things are at operating temps.  I'm at a loss.  I do have to run with headlights at this track as lighting is not optimal to run without.  About the only thing I haven't done is removed the insulation from the wiring to check for corrosion throughout the wires.  Volt booster from Caspers?  Alternator from powermaster?


Tuned for low gear fuel on last two runs as KR didn't show up on second run and ended up at 104 on the chip on the last run.  O2's were still in the 800-810 range.


How does overall fuel setting in the chip affect the low gear fuel?  On the few 3rd gear pulls that I've made on the highway, I'm getting into the 780's with the current setting at 144.  Dial back the alky?

[Steve Wood]

I would dial back the gas...hardly ever see one of Eric's chips that needs so much fuel added to get to 144.  Usually, that means something else is wrong.

The following is a cut and paste from my site....note that Parameter 1 controls wide open throttle in all gears.  Parameter 2 trims first gear fueling using parameter 1 as the input.  In other words, if you have set fueling using both parameter 1 and 2, and then you add fuel in parameter 1 because you were lean on top end, then you just added fuel to first gear as well so you may have to go adjust parameter 2 downward if it is now rich.

A caution!  If you optimize for 1/8mile racing, you may be too lean on top end when you go to a 1/4 mile track...maybe

From site......

Parameter 1 controls wide open fueling in all four gears.

Parameter 2 controls wide open fueling in FIRST gear and it is a trim factor based off Parameter 1.  In other words you first set Parameter 1, then you look at your low gear fueling.  If you want to lean it down some to improve turbo spool and get a quicker launch from a standing start, you can.  If you have too much wheel spin from too much turbo spool, you could make it richer and cool down the charge a bit to slow down the spool a bit.  It really depends on how good the traction is and how much boost you are trying to leave on.

Parameter 3 is the timing in first and second.  Normally you can run more timing in first and second at the strip if you can hook the tires because there is less load on the engine and combustion chamber temps are not as high.  This can be a bit more dangerous on the street when the engine is hot because excess timing might cause detonation in that case where it may not on the strip because the engine is cooler.

Parameter 4 is timing for 3rd gear and 4 gear.  Again on the strip you can usually get by with additional timing unless you are hot lapping the car and the engine is not cooled down between runs.

As a rule, I am much more conservative on the street because engine conditions are usually not optimum-particularly if you have been driving in traffic or pounding on the car at boost multiple times.

Okay, so that is what you can do with your chip.  If you had the SD chip you could adjust over 20 different things but there are only a few that I ever touch and seldom at that once I have things where I want them.

So what about fuel pressure?  It's something that can be adjusted.  When you adjust fuel pressure you adjust every facet of fueling from idle to wide open throttle.  A change in fuel pressure affects flow by taking the square root of the (new fuel pressure divided by the old fuel pressure).  Therefore a change in fuel pressure is a relative small change in the actual delivery but it is more obvious at idle and low rpm than it is at higher rpms because the percentage of change compared to the fueling is larger due to the small amount of fuel used at idle and low rpm.

This is what I do, I set the fueling to 43 (TT chips) and I drive the car until it is fully warmed up and I have done some stop and go driving, then I stop and look at the O2s in gear idling.  If they are 780-800 and the car is idling well, I call it good and forget it.  Note that the O2s will change when you stop and the O2 sensor starts cooling down so your 780 might increase to 810 in a short period of time.  Don't be confused because this is a function of the stock o2 sensor not a change in fueling.

If, when I first stop, the o2s read something like 820, then I reduce the fuel pressure 1-2 psi and try it again, until my first readings upon stopping are in that 780-800 range.  Remember that the TT chips are open loop at idle so that first blm cell is not adjusting the fueling like the factory chip.  It does have some learning capability, however, so that is what I like to drive the car for a bit before beginning to play with the adjustments.

If everything is right, the O2s should be pretty stable wherever you set them and they should not be jumping around at idle due to the open loop feature.  That is why the idle is normally smoother and better.

When you come off idle, then the chip goes to closed loop and the o2s will jump around a lot more as the ecm takes charge.

In essence, you can use the fuel pressure to set up your idle and low speed blms but I only look at the idle O2s first when I stop and the sensor is good and hot.

Now, remember that the fuel pressure affects the entire fueling range so the wot fueling will be a little leaner than what Eric put into his default  if you reduced fuel pressure at idle with the HOSE OFF so you need to look at the wot fueling to see if it needs adjusting.  Normally, it will probably not be noticeable because the chip was probably a bit rich to begin with for safety's sake.   Be sure to put the hose back on the regulator before you drive it again!

Now, having done this, I go to the wide open throttle setting and start dialing it in.  This needs to be done at the top of third gear so it will approximate what you will see at the finish line.  At this point, I am leaving the timing alone (using the default in the chip) and have the boost set for whatever Eric said the chip was burned for.

If the chip was burned for 25 psi, I would not be surprised to find that the chip was giving plenty of fuel for that boost level and no timing retard was being shown on Powerlogger.  If I am leaving the boost at 25 which is generally a good level for the street when using alky, I start removing a bit of fuel-say no more than two numbers at a time and making a run after each adjustment until I see the slightest hint of timing retard.  I then add about 3% of fuel back to the wot throttle setting and call it good.  I prefer to hae some margin of error-particularly on a street car where ambient conditions can vary widely.  This is done with Position 1 in the chip.

Spraying Methanol at 100%, I would expect my oem O2s to be around 780 on the street.  When at the track, I might lower my fueling a bit and look for something around 750-760 mv but in all cases, I am not going to accept any timing retard on PowerLogger.

Once I am happy with third gear fueling at the top end, I would look at the O2s in first and second from a launch.  Again I want to remove fuel until I am on the verge of timing retard and then add 2-3% back for some margin of safety.  I would guess the O2s will be close to 750 mv but the main thing is NO TIMING RETARD.

[good2win22]

I'll give it another shot at fuel pressure settings and let ya know.  Thanks Steve!

[Steve Wood]

okay, electrical side.

It's not simple. 

First remember that the voltage going to the fuel pump is not necessarily the voltage getting to the ecm as there is no common path between the two-particularly if you are using a hot wire.

Second, remember that the ground side of the circuitry is just as important as the plus side.

Third, the ecm has a voltage regulator in it.  One of it's jobs is to stabilize voltage to the injectors so that it adjusts injector pulse-widths to compensate from varying voltages.  I forget the range it can handle but this mean that 12.9 going into the ecm may provide the same fueling as would 13.8 volts because the injector drivers are compensating.

Okay, the voltage that we see on the scantool is routed something like this-

Alternator to battery to starter post to fusible link to bulkhead connector to ignition switch to ecm-ign fuse to ecm A6 terminal and then inside the ecm to an A-D converter and the output back to the scan tool.  Factory shows 13.6 at A6 engine running   http://www.vortexbuicks-etc.com/ecmwiring.htm

I have seen significant voltage drops going from the alternator to battery Plus terminal due to a problem in that cable internally.  I never cut it open to see if there is a connection inside the jacket but I have found some with big drops between the alternator and the battery that had a hot spot in the cable about a foot from the battery...repl acing the cable fixed that and provided more voltage to the battery.

Then, it used to be common to find the battery cable to the starter post was loose.

I have heard of one or two that had corroded terminals in the bulkhead connector but I have not seen that myself.

Inside, it is quite common to find a drop at the ignition switch...easy to find, drop the column and wiggle the connectors at the switch while watching the scantool voltage.  If it jumps around, you have a problem at the switch.  see http://www.vortexbuicks-etc.com/ignition_switch.htm

Next in line is the fuse block...more than once, I have seen corroded terminals on the ecm-ign fuse with significant voltage loss under load.

Then we can find corrosion at the ecm terminals/connectors.

We can also have a problem internally the ecm and the A-D conversion, I think.  I have changed ecm's and seen a different voltage being displayed on the scantool following the ecm swap...go figure.

Now, let's consider the ground side.

First, the ground side of the alternator goes from the case to the mounting bracket to the engine.  I found out the hard way what happens if you powder coat the case....you get a big drop on the ground side and an attendant voltage loss.

On both sides of the equation, check your voltage drops.  Put one probe of your meter on the alternator case and the other probe on the bolt going into the battery negative terminal...vol tage on the meter should read in the hundredths of a volt.

(do the same from the bat terminal on the back of the alternator and the other probe on the bolt going into the positive terminal of the battery.  Again the voltage on the meter should be in the hundredths.)

Okay, we have the ground side of the alternator going to the engine (does not hurt to add a ground cable from the back of the alternator to the engine using the threaded hole provided for such on the back of the alternator) and from the engine via the negative battery cable that connects to the turbo support bracket bolt  back to battery negative post.  How many times have we found the battery negative cable laying there not even connected to the turbo bracket or the bolt is loose?  A jillion times, or more!  When this happens, all the grounding of the electrical system is being handled by that little wire going to the inner fender sheet metal.  Strangely, most will start and run without the main cable being connected to the engine.

Then looking at the end of the ground cable at the battery, we see the small wire going to the inner fender sheet metal.  This wire is important as the factory wiring uses the sheet metal as the primary ground-not the frame.  I usually clean the connection up and use a 10 ga wire for this ground or a small ground strap.

Now, we have a couple of bundles of ground wires from the ecm and a couple of other places that are connected to the back of the passenger side cylinder head.  Often we will find a broken off wire or loose/corroded crimped on terminals.  The easiest fix is to take them loose, check the connectors for condition and move them to an intake stud.  The better fix is to cut the terminals off, extend the wires (solder, not crimp) and attach them to a terminal box on the firewall with a ground strap back to the coil bracket mount on the engine.  Caspers sells a kit with all the stuff needed if you don't want to go to the electronics parts store.  He also sells a fusible link relocation kit that moves the links to the inner fender which is much nicer.

A ground strap from the firewall to the engine never hurts.

Now, we depend upon two things which are not very dependable.

First is the alternator.  Alternators should increase current output as the load increases in order to maintain voltage at a steady state.  The only way to check this is under load.  Most places that check alternators these days don't put them under load...New alternators are just about as likely to be bad as old ones, it seems.

Jump a voltmeter directly off the back of the alternator and run it into the car.  Turn the headlights on High and go make a wide open throttle run under full boost.  The voltage at top end should be reading at least 13.5 or better.  If it is not, your alternator is not doing the job..new or not.  I have seen quite a few that drop well into the 12's.  That means your fuel pump is going to be struggling to pump enough fuel.

When replacing alternators, I am not big on 200 amp alternators, etc.  Most of them are using imported parts and they may not work as advertised when properly tested plus we don't that kind of amperage.  I like the second generation CS-144's that are rated at 140 amps....better built that our 120's.  I would prefer, myself, to find an original at the junk yard due to the quality of the original parts.

From my site-

This unit was installed on the following cars:

1996-94 Buick Roadmaster 5.7L, 1996-93 Cadillac Fleetwood Brougham (RWD) 5.7L, 1996-93 Chevrolet Caprice 4.3L& 5.7L, 1996-95 Chevrolet Impala 5.7L, 1995-92 Chevrolet Lumina APV Van 3.8L, 1995-92 Oldsmobile Silhouette 3.8L, and the 1995-92 Pontiac Trans Sport 3.8L
This alternator was also installed on police cars, and fleet vehicles such as taxis where normal operation may include lots of non-moving use with heavy radio traffic.
 It is listed as a Lester no. 8112 which may be helpful at wrecking yards, or such places.



The second undependable part is the fuel pump....new, old, guaranteed, gold plated, or whatever.  It is imperative that you know absolutely that it is delivering the correct pressure at full boost, top end, of the run every time, all night long.  I have seen as many new ones that start dropping pressure when the pump gets hot as I have seen old ones that failed.  I got home a couple of years ago pushing the alky test button and running on alky on a pump with couple of thousand miles on it.  It's not uncommon at all.

Now, you can log fp on the PL with a sender screwed on the rail or you can use a good quality (not cheap) gauge on a hose on the windshield.  This seems to be one of the more accurate transducers   http://www.motorsportsinnovations.com/wide_band_o2_files/WB_Pressure.htm

I think Motorhead Mike was the first to discover this one years ago.  I have seen many other brands fail.


I am sure this is a lot more than you want to read but...I am getting old and I may not remember this stuff much longer...

[good2win22]

Not sure if you've been told lately but I appreciate you Steve!

[Steve Wood]

and, I should have mentioned that fuel pump ground in the tank is often iffy after all these years....

[Scoobum]

Food for thot. The alky chip I received from Eric for this combination was so rich in low gear fuel...that pulling the full 20% of low gear fuel...only got the low gear 02's down to 780's.

If you had Eric burn your chip for your exact combination... and told him your max boost pressure was 25 lbs...then your fueling should be fine...or close to it...on the default setting for high gear fuel. I agree with Steve...adding that much high gear fuel...means there's something wrong.

I set my low gear fueling on the 1-2 and 2-3 shift points.

[good2win22]

Let's see if I can get all this stuff out there.
Chip was burned for a TA49 25 lbs boost with alky and I am now running a TE44
Fuel pump was a walbro.  Put in a racetronix pump along with sending unit which had AN fittings. -8 feed and -6 return.  Ran the bigger lines/inline fuel filter and ended up stripping out kirban's FPR.  Had another regulator from a dope deal I made for some champion fuel rails so I put it on and the pressure was set at 43 so I haven't touched it until yesterday.  The stock fuel rails are still on the engine.  Saving the champions for the engine build.  Pulled the vacuum line off the FPR yesterday and fuel pressure was sitting at a steady 46 psi.  Adjusted to 43 and with vacuum line back on pressure drops to 34ish. Reset the ECM, drove the car around town yesterday but was unable to get a good reading on the millivolts as it was jumping all over the place probably because I didn't get it hot enough.  BLM at idle was still at 128 after the around town run but I don't think I drove it around enough.  Pulled into the driveway and noticed fuel pressure was at 31ish. Popped the vacuum line and pressure was at 40.  Adjusted to 42ish, popped the vacuum line on.  Pressure was at 35ish but had to leave it. 
 
Drove the car to work this morning as it will be the last day of decent weather for a few days.  I can't get a "steady" O2 millivolt reading before it starts to jump around in gear at idle but it doesn't go any higher than 850s and no lower than 750s.  BLM at idle in park is now at 132. Seems to me that ECM is trying to richen at idle, should I turn down fuel pressure a bit to see if I can get BLM to 128?
 
Checked voltage at alternator output and + battery terminal, 0.04 volts with multimeter set at 20 volts.
Checked the voltage betweeen +battery terminal to the starter, 0.01
Not exactly sure where to probe between the 3 fusible links and the fuse block... help!
Haven't check the ignition switch.
Check the alternator case and the - battery terminal, 0.01 volts
The only ground that I haven't gotten cleaned is the firewall to the transmission mount bolt.  Otherwise, I have cleaned/removed paint and reinstalled grounds on the fender and fire wall.  No more powermaster, so that one is gone.  I did notice this morning that the blinkers were flashing a bit faster than normal.  Also, hot wire has ground clip on the relay.  No where can I find that it says to clip it to the tank or to the body.  Mine is currently clipped to the tank.
If I can't get the voltage drop figured out with shooting the wires.  I have another ECM but it will have to be modded for power logger.
Found 3 roadmasters at the salvage yard.  I'm off work tomorrow so I'm going to head over to see if the alternators are still there.
If I find one, does anyone have a part number for an overhaul kit for that alternator?
 
 

[Steve Wood]

I suggested a junk yard CS-144 140 amp alternator because it would have quality parts in it and you want to rebuild it with Chinese stuff?  anyway  http://alternatorparts.com/

You need to figure out whether you have a fuel pressure regulator problem or a fuel gauge problem.  Fuel pressure should stay where it is set.

Something is screwy because the O2s should not move much at idle after the first run following a chip reset.  If I understand correctly if the chip is reset, or the settings are lost due to a voltage drop out, then the chip will be in a closed loop mode the first time it is started which means the o2 values will be bouncing around.  After that, the chip will be open loop at idle (altho it will still learn) and the O2's will be pretty steady.  Does the battery voltage read above ten volts while you are cranking the car?

The ground clip on the hot wire relay should be connected to sheet metal.  I make my own hot wires but I connect the ground on the relay to the sheet metal by the tank hanger straps.  I also run a ground from the tank to the same spot.

[good2win22]

I was thinking of having a back up plan in case the junkyard alternator wasn't any good.  Are there not any US made alternator parts left?  Saw the alternator on fleebay and amazon, boy are they proud of it!

Perhaps I'm moving the fuel too fast with no time to cool down and the fuel is getting hot changing the specific gravity of the fuel thus making it less dense.  Besides voltage variances at the pump, that's all I can think about as to why the pressure changed.

Should I reset the chip and drive it around with idle in close loop before restarting and it goes to open loop?

I'll  check the firewall to tranny ground and install a separate ground as well as install a ground wire from the tank to the body and connect the ground from the fuel pump relay to the body.

BLM's at idle before this procedure was 119.  I was going with the +- 10 rule and now I want it to be exactly 128.  It's at 133 after the drive home from work this evening.