Twins with Twins, Anyone?
- Thread starter kidturbo
- Start date
Which is why I want to know how many teeth it needs. There may be other solutions out there as well.
Thing is, according to all my research and Speedo calculaor values, that 40 tooth wheel on output shaft is correct. In pic above I switched the pickup to Input Shaft for comparison. Which could be different tooth count. Doesn't explain why my output speeds are off by like 3.8x.. Unless it's related to transaxle vs RWD or something. More digging required here.
I was able to do a calc pid with (input shaft speed) / 1.6 ; and gives me relevant # to engine RPM on my laptop. So for short term, I can use that while figuring out the output shaft error.
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I was able to do a calc pid with (input shaft speed) / 1.6 ; and gives me relevant # to engine RPM on my laptop. So for short term, I can use that while figuring out the output shaft error.
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No I just ran both shaft speed sensor wires back to the pickup so could use either. Plan was to put the DD GPS to pulse output unit IN on both T42 VSS lines so can log actual boat speed vs prop shaft speed. And for that I can fudge the Speedo calc tables to get a match. But doesn't explain output shaft speed RPM being way off. Ya would think it should read spot on..
I'm hooking up the second TCM on the bench to test this transaxle theory..
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I'm hooking up the second TCM on the bench to test this transaxle theory..
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Found it.
Seem the 07 FWD Impala must measure the output-shaft speed down wind of the transmission. So the H0103 table is actually used to calculate the shaft speed off a 40 tooth ring somewhere in the system, maybe... Found that by looking at a tune from a RWD 4L80. Switched these to 1.00, and on the bench it's much closer. However it reads double what my pulse generator says it's outputting. Going to load in the boat now and see..
Also found the VSS is simply a combination Axle Ratio and TRPM. Which I recalled from earlier VSS experiments. Second pic is a comparison of 1.00 and 1.16 axle ratio agains VSS with same output shaft speed..
Seem the 07 FWD Impala must measure the output-shaft speed down wind of the transmission. So the H0103 table is actually used to calculate the shaft speed off a 40 tooth ring somewhere in the system, maybe... Found that by looking at a tune from a RWD 4L80. Switched these to 1.00, and on the bench it's much closer. However it reads double what my pulse generator says it's outputting. Going to load in the boat now and see..
Also found the VSS is simply a combination Axle Ratio and TRPM. Which I recalled from earlier VSS experiments. Second pic is a comparison of 1.00 and 1.16 axle ratio agains VSS with same output shaft speed..
While the H0103 table is the key to output-shaft tooth count, I'm affraid the FWD Impala OS has got me stumped. There is only like a dozen T42 OS out there. More ya read, more differences you find. With the Final Drive Ratio set at 1.00, I'm now reading off by a factor of 1.3 on the output sensor RPM. The lowest acceptable field value is 1.00. Looks like I need 0.70.. Or better yet, flash a truck OS onto these puppies.
The Speedo Calculator in EFIlive won't allow me fudge that H0103 lower constraint. Nor will it allow me to check Transaxle box, or adjust the tooth count field to other factory option of 7.. So for now, switching back to the input shaft sensor and my calculated pid which seems to do the trick for logging. Bolting port side turbo on now. Hope to hit the water for the weekend.
The Speedo Calculator in EFIlive won't allow me fudge that H0103 lower constraint. Nor will it allow me to check Transaxle box, or adjust the tooth count field to other factory option of 7.. So for now, switching back to the input shaft sensor and my calculated pid which seems to do the trick for logging. Bolting port side turbo on now. Hope to hit the water for the weekend.
I Wonder if a RWD OS will do the same or be different.
What gear does the TCM think its in? Maybe you can change it there? D7001-D7004
D7004 is 4th which is .750 on the one I am looking at. Which had a 4L80E transmission
What gear does the TCM think its in? Maybe you can change it there? D7001-D7004
D7004 is 4th which is .750 on the one I am looking at. Which had a 4L80E transmission
I'd say a truck OS would probably do the trick. The ring is out of a OEM transfer case, basically identical layout.. Far as gears, I have them setup as a 2spd, and 0.00 out 3 & 4 gear ratios. However sometimes it shows 3rd for current gear position.. Who knows, I hacked up the stock file pretty good.
Both engines / trans checked out and ready to go.
Antizize on V-band clamps is the bomb. Thanks..
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Both engines / trans checked out and ready to go.
Antizize on V-band clamps is the bomb. Thanks..
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I learned a hard lesson with those low temp self soldering connectors. They're awesome for radios and lights. Not so much for under hood stuff. Constant engine compartment temps will eventually turn the "solder" to powder and cause connection issues. Cost me a couple tow bills back to back a few months after I made the repairs using them under the hood.
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Good to know on those connectors. So far I've used one on a stereo amp relay, wire and about 10 on this TCM harness hack job. I would definitely agree the solder melting point could become an issue if laying near anything 200F..
PS. But still handy as he)) in tight spots where you don't want crimp connector.
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PS. But still handy as he)) in tight spots where you don't want crimp connector.
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I don't think the issue with those solder connectors is the heat re-melting them. It is more likely, depending on the solder alloy, the tin in the solder crystalizing and falling apart. Lower temps and heat cycles hasten the process. As what's happening in this photo. Beta tin turning into alfha tin.
Wikipedia article about tin pest: Wiki tin pest
Wikipedia article about tin pest: Wiki tin pest
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The weather slowed progress over the weekend. But did manage to at least back it into the water and test of few things.
TCMs both work fine for the job at hand.
Port engine still had a misfire, so tore into the harness and cut out an old repair where one of my helpers had crushed the crank pickup wires behind PS pump. Hoping that was the issue..
Found a broken oil line on gear reduction box, no way to repair.. Wonder if thats where all the oil kept going?? Waiting for local speedshop to open, then once oil line fixed, I'm off to boat or float whichever is least stressful..
What ya think of these recycled catch cans??
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TCMs both work fine for the job at hand.
Port engine still had a misfire, so tore into the harness and cut out an old repair where one of my helpers had crushed the crank pickup wires behind PS pump. Hoping that was the issue..
Found a broken oil line on gear reduction box, no way to repair.. Wonder if thats where all the oil kept going?? Waiting for local speedshop to open, then once oil line fixed, I'm off to boat or float whichever is least stressful..
What ya think of these recycled catch cans??
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I'm a big fan of using food containers as catch cans. Had an old Jeep J20 with a Mountain Dew 2L bottle as the radiator fluid overflow bottle. Always amused me.
Hopefully that sorts out the misfire. I'm looking forward to videos of it running around again!
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Hopefully that sorts out the misfire. I'm looking forward to videos of it running around again!
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Lol all the money in this boat and those Are the current catch cans?
Yep 2 liter bottles make great reservoirs. I had a 20 ounce bottle attached to the overflow on my reservoir my Duramax when I blew my head gasket’s. So I didn’t lose so much coolant. I would just dump it back in the reservoir every time I put fuel in it. I took a 3000 mile vacation pulling a 10,000 pound camper and never had to buy any coolant.
Yep 2 liter bottles make great reservoirs. I had a 20 ounce bottle attached to the overflow on my reservoir my Duramax when I blew my head gasket’s. So I didn’t lose so much coolant. I would just dump it back in the reservoir every time I put fuel in it. I took a 3000 mile vacation pulling a 10,000 pound camper and never had to buy any coolant.
Got a few hour out on the water couple days ago. Transmission issues looks to be resolved. No more flaring or slipping, but at their current 300psi line pressure setting, I doubt we have enough HP power to slip anything yet. But test we did, and added a second camera to monitor the engines.
Which by chance did find one problem I'd forgot to address from our last runs. How quickly can you spot it??
Source: https://youtu.be/WNp4ZiuWZLo
Which by chance did find one problem I'd forgot to address from our last runs. How quickly can you spot it??