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That little bucking (sometime called trailering ((like pulling a trailer)) is due to being to lean {EDIT} (or needing more ignition advance) at that spot on the map.

John
 

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Discussion Starter #22
MAP Plumbing and Injector Wiring update

Greetings:

The rear crank seal backed out and was nibbled at by the driveshaft yoke bolt heads. I took the opportunity during the R&R to attend to the MAP vacuum plumbing and the injector wiring.

The vacuum gauge showed a significant amount of pulsing at idle, and the GoTech load cell was bouncing over three cell ranges. Originally the idle balance fittings were simply siamesed together above each of the two throttle bodies and joined together below before running to the sensors in the dash.

Discussions here on the BB suggested that I build a small manifold and add restrictors to flatten the signal out. The photo shows how I used four MIG tips as restrictors and screwed them into a 1/4" brass nipple. Barb connectors on either end run to the instruments and to the fuel regulator.

The injector harness originally had a long run to a connector socket/plug, and then split out to four individual long wire runs, one to each cylinder. This effectively took the signals, passed them to the front of the engine bay, and then back along the top of the intake manifold as they were distributed.

In the GoTech design, all four injectors fire at the same rate continuously, so there is really no reason to wire all four injectors with an individual signal. The new harness joins the 2 pigtail wires for injectors 1&2 and for 3&4, each of which makes a direct 2-wire run back to the harness wiring junction near the firewall.

The GoTech supplies two ground-switching outputs for injectors via two wires - now those two wires run directly from the GoTech controller to the injectors without the original intervening connector up by the distributor. Each of the two paired injectors gets a +12v wire from the new relay/fuse box on the firewall.

Much cleaner, methinks, compared to what is shown in my 2nd post in this thread.

Hope it all works when
 

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Discussion Starter #23
On the Road again

Greetings:

The Alfetta has been out for three short jaunts this weekend, after finally sealing the back of the block and running leak-free.

I am very happy with the results so far. On this last trip, kathy drove and I manned the computer. I made a few minor adjustments to the ratios under heavy load, but mostly just sat back and watched out for flagrant violations of AFR.

Our most important goal has been reached. There is no longer an annoying bucking in the drive train at neutral throttle. That may be due to the engine rebuild, new driveshaft doughnuts, the EFI set-up, or a combination of the three.

One thing that will need attending to is the RPM readout on the GoTech's Dealer Tune dashboard. It bounces around considerably. It is unlikely that the engine, under heavy load climbing a hill in gear, would bounce around from 3700 to 4100 with abandon. No big deal, but it makes staying in the RPM band for cell tuning difficult. Obviously, the controller is getting a reliable signal to the coil.

I did reach an individual at the GoTEch EFI group down in FL. He is looking into how I can use the 0 ->5 v full Wide Band O2 sensor output. The unit seems to respond OK to the narrowband 1 -> 0 volt range and has a setting for wideband selection, but when I engage it with a target of 2300 millivolts, the AFR dives to 10. The Gotech Dealer Tune dashboard is reporting an AFR and millivolt reading that corresponds to what the AEM gauge is displaying at any given point, so it's not the connections.

= Michael
Now I need to get her to a dyno facility. I have a lead on one upstate in Danubry. Any suggestions in the NY metro area?
 

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Discussion Starter #24
Riteof Passage: 100MPH in a 20' x 40' Room

Greetings: The blue Alfetta was treated to a dyno session today. And I experienced a rite of passage - my first dyno run. Kids into autos today probably get on a dyno by age 17 ... I'm many decades late..

Danbury Chassis Dyno is run by Jeff Roell. We made about half a dozen runs from 3500 up to 6000 at full throttle. Magically, both the car and I held up. I kept thinking how embarrassing it would be if my newly rebuilt engine let go at 5 grand with the pedal to the floor.

After some fiddling with the midrange, which was too rich, and the high end, which was a bit too lean, we managed to record 120HP at 5700 rpm. Before the rebuild the engine was measured at 100 HP max in Seattle.

One last run was done for about 5 min at 60MPH in 4th, as the load was varied and the mixture was adjusted.

Drivability continues to be great, and I am much more comfortable running her hard now that I know I'm not likely to burn a hole in a piston :)

-- Michael
 

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Discussion Starter #25
Greetings Tuners!

The Alfetta has been driven a fair amount since my last post in May. Most successfully, completing the fast-paced 10 hour fall tour put on by the NJ AROC chapter. (BB Picture Forum post)

While I have been comfortable with the tuning level obtained from my self-adjusted maps, I have strived to get the close-loop feedback function, to no avail. The GoTech has all the control fields available, but when I engage it, it throws the mix way out of whack.

There is a control field to engage either a narrow-band or a wide-band, a setting for the target AFR, and settings for load start/stop range and what amount of correction to be allowed.

I tried both my wide-band with a real wide-band 0-5 v range, and also using an "emulated" narrowband output (0-1v), along with the appropriate DealTune parameter, but neither worked.

Has anyone encountered this issue?

- Michael
 

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I always worried about the engine blowing too. One time I had a coolant breach from the water jacket to the # 4 cylinder......WOW white smoke was everywhere.

Congrats on a job well done.

PS: I don't have a close-loop feedback function either...............That's where the A/F gauge comes in to let you know if something is out of the norm.
 

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From the edge of things:

Define 'way out of whack' mixture.

If the ECU is trying to correct during closed loop, it'll cause the mixture to fluctuate quite quickly and pretty radically from stupid lean to just a shade on the rich side in an effort to get a average mixture that equates to stoich.

EG: on an LED gauge, the lights will normally cycle almost continuously during closed loop, then fixate more or less around one point when in open loop.

If you're not getting any fluctuation at all during what should be closed loop, then yeah, you definitely got something goofy going on somewhere. Up to an including a poor to no connection from the O2 sensor to the ECU. (just because the gauge is hooked up right......)

Not being familiar with the GoTech, I dunno if it's a feature of it, but several aftermarket rigs have the option to turn off closed loop fucntion, and actually suggest doing so during initial tuning.

If GoTech can be turned off, you did turn it on again after didn't you?

Then there's the whole wideband vs narrowband output voltage and having to tell the ECU specifically which one you're using, and in some instances what converter box you've got a wideband running through.
 

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Discussion Starter #28
From the edge of things:

Define 'way out of whack' mixture.
...Then there's the whole wideband vs narrowband output voltage and having to tell the ECU specifically which one you're using...
Tifosi: Perhaps you did not read my text. I explained the settings being tried, (including NB/WB) and they conform to the suggestions you are making.

When the feature is engaged, the mixture immediately moves lean, and continues for a few moments until 17+ is reached and the car dies.

If someone has this feature actually working on a GoTech, I would be motivated to spend more time testing variations. As it is, I've put more time into it than should be necessary. I have been tempted to buy a newer "Pro" unit, but can't consider the $$$ unless I knew it would address the issue.
 

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Tifosi: Perhaps you did not read my text. I explained the settings being tried, (including NB/WB) and they conform to the suggestions you are making.

When the feature is engaged, the mixture immediately moves lean, and continues for a few moments until 17+ is reached and the car dies.

If someone has this feature actually working on a GoTech, I would be motivated to spend more time testing variations. As it is, I've put more time into it than should be necessary. I have been tempted to buy a newer "Pro" unit, but can't consider the $$$ unless I knew it would address the issue.
When you try it, how does the computer react to the sensor? It's almost as if it's reacting backwards. Also, most closed loops system allow you to bracket how rich and lean you go while using the sensor- so you should be able to keep correct.

So, when you had the basic EGO sensor in (the NB), when the sensor was <.5v according to the ECU, what did the fuelling do? And vice versa- although, with what you say, you are probably not seeing >.5 v.

Eric
 

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Discussion Starter #30
... It's almost as if it's reacting backwards. Also, most closed loops system allow you to bracket how rich and lean you go while using the sensor- so you should be able to keep correct.
Eric
Greetings Eric: Reacting backwards is my interpretation also.

The GoTech does have bracketing for how much to adjust, and those show up on the load graphs when running the software monitor. You are making a good suggestion - if I limit the bracket to a very small adjustment, the thing should still run regardless.

And yes, the WB and NB relationship to AFR are not only over a smaller range (5v, 1v), they are reversed direction. NB voltage goes down with increasing AFM, while WB goes up.

I know for certain that the GoTech controller is seeing the correct NB/WB value, since the AFM displayed on the GoTech tuning software panel tracks that shown on the meter itself. If that is set wrong, they don't agree.

The NB/WB digital output selection switch on my sensor is located on the back of the meter, which requires me to remove it to get it changed to any other mode. Did it twice, WB>NB>WB, and not really interesting in doing it again :)

- Michael
 

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Tifosi: Perhaps you did not read my text
I read the text, (otherwise I wouldn't have replied, or the reply woulda been so far off topic it wouldn't have funny), but didn't see any explination other than that you'd tried WB and NB and neither would allow proper closed loop function without making the mixture 'out of whack' :shrug:

Anyway..... Have you tried to get 'hold of JungleJustice?
He might have some better idea as to why your GoTech is doing what it is.
 

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Greetings Eric: Reacting backwards is my interpretation also.

The GoTech does have bracketing for how much to adjust, and those show up on the load graphs when running the software monitor. You are making a good suggestion - if I limit the bracket to a very small adjustment, the thing should still run regardless.

And yes, the WB and NB relationship to AFR are not only over a smaller range (5v, 1v), they are reversed direction. NB voltage goes down with increasing AFM, while WB goes up.

I know for certain that the GoTech controller is seeing the correct NB/WB value, since the AFM displayed on the GoTech tuning software panel tracks that shown on the meter itself. If that is set wrong, they don't agree.

The NB/WB digital output selection switch on my sensor is located on the back of the meter, which requires me to remove it to get it changed to any other mode. Did it twice, WB>NB>WB, and not really interesting in doing it again :)

- Michael
Michael
According to your calibration, how should the GoTech react to that voltage? It *should* add fuel once you get a calibrated voltage under .46, and should remove fuel once you get over .46. Each "step" should be calibratable.

Just turning it on probably wont work- you need to tell it the rate of increase/decrease of fuel, I would imagine. Is there a GoTech calibration guide somewhere? I know closed loop fuel pretty well- or at least how it should work, but I've not worked with a GoTech.
 

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I found the gotech site, and found the closed loop fuel guide.

Try two things- increase the lambda ramp interval and lower the lambda limit.

But I would suggest leaving it off. If all that can be documented for that is 5 parameters, and you have no idea how it's supposed to work... Oh, and there's no suggested values for the lean side. So when you are running lean, and the voltages are well below .65 (which is too rich for stoich, but it's not a big deal)- I don't think the system has any idea what to do.

Sadly, I'm not very impressed with the little I've read. Just leave it off.

Eric
 

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Discussion Starter #34
I found the gotech site, and found the closed loop fuel guide.
...Sadly, I'm not very impressed with the little I've read. Just leave it off.

Eric
Greetings Eric: Seems we reached the same conclusion. The guide you reference does not even mention the O2 sensor type selection, which is on the extended options screen (X)

I do hope to precipitate a solution from JungleJustice, or the folks in Miami who have these things on ebay , but have not answered my calls for help.

- Michael
 
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