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  #781  
Old 02-26-2017, 01:47 PM
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another option
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  #782  
Old 03-07-2017, 01:28 PM
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I have been wanting to get out in the car and finally had a morning open to join a local cars & coffee. So Friday night I figured out how to get two child seats in the back. This was a pain because the buckles on these old lap belts are in the center, while newer belts put them on the sides. This means the buckles are buried somewhere in the child seat so they are hard to access for tightening and release. I have several different child seats for my wife and my daily drivers and fortunately a couple of them worked out.





This was the first trip out with the whole family: my wife, my 6yo son, and my 3yo daughter. My wife hasn't been in the car other than a very brief jaunt up the street and back, so this was her first time experiencing any town or freeway driving. She was nervous, especially when the transmission started doing it's voodoo shifting going down the freeway. I finally had to slow down and just lock it in 2nd gear when it started bucking between 2nd and 3rd going up a grade. It's a mess, but I just wanted to drive the damn car regardless. Maybe I'll get "lucky" and the stupid transmission will blow up on it's own.

Anyway, we managed to get to the cars and coffee and the kids had a good time looking at all the cars. To them every classic car is a Nova just like daddy's. I enjoyed talking to a couple people that were interested in the swap. One in particular complemented where I put the ignition coils, which I thought was cool given all the effort I put into that. But my car overall is just a mess - lots of patina, bad fitment of panels, loose ends that need to be cleaned up - it's not nearly as nice as it looks in the photos.













I noticed a few things on this trip that were troubling. One is that the idle oil pressure became lower than what I have been seeing on earlier drives. On previous drives, it tends to be around 30psi cold idle dropping to low 20s warm idle, but this trip it steadied out around 15psi warm. I am not sure how much stock I put in that number though, because at the same time on this trip the coolant gauge remained stuck at 200F, even when I first started the car and it was definitely cold. I need to confirm my gauges are setup and working properly - the pegging of the coolant gauge doesn't give me confidence. The gauges are Speedtech CAN-bus operated and depend on the signal from the ECM. I think I will try checking with the OBDII reader to see if they match. Maybe something is awry with the wiring of the gauges or the sensors themselves.

If the oil pressure is actually dropping, that is clearly a concern. It might be time to drain and check the oil, slice open the filter, and see if anything is going on.
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  #783  
Old 03-07-2017, 02:05 PM
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CarterKraft CarterKraft is offline
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Sometimes multiple gauges going nuts is a ground problem. Most of these gauges are ground referenced so a grounding issue will show up with high coolant temp readings.

Congrats on the drive and remember "you know whats worse than a ratty hot rod?"

NO hot rod...
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  #784  
Old 03-07-2017, 02:12 PM
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From a lesson I learned a long time ago with just electric gauges:
Medium quality Mechanical Gauges (Oil and Temp) under the hood.
Also a mechanical pressure switched Oil, & Temp idiot light in the cockpit.

I run only build with analog gauges, however I would run the under-hood (and have) parallel to ANY digital systems.
I only put the oil pressure gauge on my 75, but the electric (OEM) dash gauge is nearest the pump and the under-hood gauge is as far away as I had a port.

The other gauge that I have often put under the hood is a simple vacuum; that one can save you on the side of the road!

E
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  #785  
Old 03-07-2017, 03:09 PM
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Quote:
Originally Posted by CarterKraft View Post
Sometimes multiple gauges going nuts is a ground problem. Most of these gauges are ground referenced so a grounding issue will show up with high coolant temp readings.
That's a good point and probably worth chasing. I found it odd that the coolant gauge was stuck on 200F while the oil pressure responded to engine RPM. Maybe the two issues are related.

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Originally Posted by entropy View Post
From a lesson I learned a long time ago with just electric gauges:
Medium quality Mechanical Gauges (Oil and Temp) under the hood.
Also a mechanical pressure switched Oil, & Temp idiot light in the cockpit.
I like your thinking. I have half a mind to put the console and all the mechanical gauges I already have back in from the previous engine: oil pressure, coolant temp, voltage, and vacuum. They are 2-5/8" Autogage. I sprung for the CAN-bus gauges because they were simple to hook up and included idiot lights, but you can't beat the simplicity and trustworthy performance of mechanical gauges. I just hate running the required capillary tubes through the firewall and the required fittings/adapters. I would also like to have the original temp/oil idiot lights working, but those require bulky switches to be adapted onto the engine. I'll have to think about where/how to do this.
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  #786  
Old 03-07-2017, 03:30 PM
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For pressure gauges I only use those that have an actual transducer (3 wire) sensor. Anything that is one wire and relying on the block / ground wire/ chassis / ground wire path never work well.

Dan
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  #787  
Old 03-07-2017, 03:49 PM
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The OEM oil sensor is a 3 wire labeled lo ref, +5v, and EOP.

The OEM coolant sensor is 2 wire labeled lo ref and ECT; I assume it is a thermistor sensor.

I assume neither is relying on the block for ground, but the lo ref might be connected inside the ECM and run to one of the grounds on the block. I'll check over the wiring after I see if the OBD2 and guages match.
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  #788  
Old 03-14-2017, 04:19 PM
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Yesterday I had an opportunity to drive the Nova to take my son to baseball practice. Before I left, I checked over my guage wiring and found the coolant temp gauge had disconnected, which is why it was stuck previously. With that resolved I attempted to setup my OBD2 WiFi dongle and Torque app to do data logging. I was unsuccessful on the drive to practice, but I was able to get it working for the 7 minute drive back. Here is some data.

First, oil pressure. The horizontal axis is time in MM:SS.S, starting at 19min 35sec and ending around 26min 51sec. The vertical axis is the oil pressure in psi, as logged by the computer. The drive started with the engine cooled off and I encountered lots of stop signs on the way home. You can see the idle oil pressure started out around 28psi cold and as the engine warmed up it eventually settled to around 20psi. It never got as low as what I saw on the gauge the other day, but with only 7 minutes to warm up, I don't know how warm the oil was for this drive.



The next graphs show both engine RPM and speed (in mph) over the same 7 minute drive. I have put boxes around the RPM fluctuations where the transmission was shifting back and forth rapidly between 2nd and 3rd gear. The farthest right box is a good example where I was going a steady 40mph and was able to hold 3rd gear for a bit. With a little bit of throttle the transmission shifted down to 2nd.



In the next image, I've added a 3rd graph showing the manifold absolute pressure in psia. 14.7psia would be wide open throttle (no vacuum at all) and 0psia would be absolute vacuum, so think of this chart as flipped from what you would get out of a vacuum gauge.



I was hoping to get an idea of what speed and vacuum levels corresponded to gear shifts, but it's really hard to tell from this data. You can't even discern the 1-2 shift and the 2-3 shift happens so rapidly back and forth that it's hard to pinpoint what's going on. Anyway if any of you see something interesting in this data, please let me know.
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Last edited by TheBandit; 03-14-2017 at 04:49 PM.
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  #789  
Old 03-20-2017, 11:35 PM
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My garage is a 3 door 20x30. The 20ft depth does not leave much room in front of a car for a workbench and room to stand, so I need to pull the car in just far enough to close the door and no more. Instead of dangling a tennis ball, I picked up parking laser pointer that activates with motion. I have it pointing to the transition between the hood and cowl panel so all I have to do is watch it as I pull in. This gets the back of the car as close as possible to the roll-up door so I have a couple feet in front to work.



I've decided to take the car out at least once a week, weather permitting, when I take my son to baseball practice. I love that I can fire it up and drive off immediately, without waiting for things to warm up, and it runs without stumbling to wherever I need to go. Of course it runs better as it warms up, but the fact that I can get out of the driveway with it cold is a huge improvement over my old carbed setup, which had no choke/fast idle and needed to run a few minutes before throwing into gear.

Here's a photo of the car at the baseball fields a couple weeks ago.



It occurred to me that a long time ago during the swap I had found the vacuum modulator screw was adjusted all the way out loose and I had turned it in about 1.5 revolutions because I read somewhere that was a good base line. Since getting the swap running and having the transmission problems, I've tried disconnecting vacuum and adjusting the screw in tighter, but I hadn't tried backing the screw out to loose again. So before a drove to practice yesterday, I loosened the screw and what do you know, it now will shift into 3rd and usually hold it there under part throttle. Something tells me I'm back to where the transmission was before the swap. I'm wondering now if maybe the line pressure or governor pressure is too low, requiring a loose modulator screw plus vacuum to allow the governor pressure to overcome the modulator and cause a shift. Maybe that would explain why the transmission is acting oddly with engine load / vacuum. At any rate it does seem to at least shift more normally now.

On the way to practice, I stopped at the pharmacy to pick up some albuterol for my daughter. She has breathing problems when she gets sick, so we have to treat her with a nebulizer. It sucks when she's sick.



When I got to practice, I had to parallel park and the power steering was just awful. That's when I discovered the fluid level had dropped to just the tip of the dipstick. After topping it off it started working more like it should. I'm guessing the system previously had some air that wouldn't burp. Good news there!



After practice, we drove over to one of our favorite sandwich shops where I took this framer photo of my boy. He always asks to take the Nova everywhere we go - I hate to turn him down.



Here is a picture of my happy place - "the office". I still have a few dangling wires that I need to do something with, but I just can't find time to get any real work done on the car right now. I've had a recently family loss, and I'm contending with my job, unexpected house repairs, and all the demands of parenting. Anyway, near the parking brake I have rolled up the tach wires that need to be connected still and all the gauge wiring under the dash needs to be tied up or replaced with mechanical gear.



I read the oil pressure after warmup with the OBD2 reader and found it was showing a hair over 20psi while the gauge read about 15psi. I trust the obd2 over the gauge, but I still want to confirm with a mechanical gauge.

Looking forward to a lot more driving and buttoning up some loose ends!
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Last edited by TheBandit; 03-21-2017 at 06:41 PM.
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  #790  
Old 03-21-2017, 03:38 PM
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Excellent news. At least some improvement has been made in shifting. Hopefully you can toss that boat anchor in favor of a T56 in the near future and put all this nonsense in the rear view.



Dan
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  #791  
Old 03-30-2017, 11:58 AM
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I took the Nova to work this morning and logged the drive w/ the OBD2/Torque App. The idle oil pressure started at 25psi cold and eventually settled to 17psi warm. The Speedhut CAN-bus gauge was reading a few PSI lower than what I pulled off OBD2; I trust the OBD2 over the gauge, but I need to add a mechanical gauge and see how it compares.

Unfortunately the transmission problem still isn't resolved. At freeway speeds it's still shuffling between 2nd and 3rd. Still odd that it never did this before the swap. I must be missing something.
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  #792  
Old 03-30-2017, 05:40 PM
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Hey Clint,

I've been a long time reader of your project. I know nothing useful about TH400's, but I did a little searching and found someone that had a similar problem. His issue turned out to be a loose downshift solenoid in the valve body. This might be worth looking into. Post 28 and 30 have the solution to his problems.

http://67-72chevytrucks.com/vboard/s...=621560&page=2

Hopefully I can post the link. I'm not trying to break any forum rules...

-Jim
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  #793  
Old 03-30-2017, 05:54 PM
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Thanks for the idea Jim! I didn't mess with the kickdown solenoid as far as I can remember, but it might be worth checking into. I don't have the solenoid connected at the moment, maybe I should try powering it to see if it "clicks" on and off normally. I'll see what I can do to troubleshoot.

AFAIK there are no OFN rules against linking to other forums, especially when the info is relevant!
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  #794  
Old 03-31-2017, 12:37 PM
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I pulled the governor last night and it looks fine. The valve and weights move freely. It appears to be a stock/unmodified governor, although one of the two springs is much heavier than the other. I will probably want to re-calibrate this after I get my issue sorted out, but I don't think it's the source of my woes. Here is a video on Instagram of my governor functioning: https://www.instagram.com/p/BSSfDoDhJJh/

I also tried powering the kickdown solenoid and got the expected "click" each time +12v was applied. The solenoid is probably not stuck or at least if it was, it freed up as soon as power was applied. I can't confirm the solenoid or valve are attached properly without pulling the transmission pan, though.

Once I put the governor back in, I will test drive to see if anything changed before I move to the next troubleshooting step. I think I am going try to running it without the vacuum line connected and see what happens. Theoretically it should shift firmly at fixed driveshaft speeds and it should not hunt between 2-3-2.
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Last edited by TheBandit; 03-31-2017 at 01:20 PM.
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  #795  
Old 04-01-2017, 09:16 PM
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Put the governor back in and took a test drive. There was no change, which is what I expected.

Next I disconnected vacuum from the modulator, simulating WOT. I found a good straight on ramp to the highway to see where it would shift. 1-2 shift is at about 10mph and soft. I ran second gear all the way to the rev limiter 6,250rpm and it never shifted 2-3. It just stayed in 2nd.

I'm thinking about cleaning out the valve body and installing a transgo reprogramming kit so I can establish a new baseline. I think something is wrong with the 2-3 shift valve. It could also have something to do with the detent valve if it's stuck or leaking. I don't think is the direct clutch because reverse is working fine.
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  #796  
Old 04-03-2017, 12:35 PM
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I got the car in the air last night, drained the transmission and dropped the pan.





I didn't find any broken bits in the pan. The filter was still attached at the o-ring/pickup tube (obviously I took it off before taking the photo above). The detent solenoid was bolted down tight.

I decided to drop the valve body. This is the furthest I've ever explored the internals of an automatic transmission. I don't expect I'll be going any further than this.



I checked each valve and they all seemed to move freely with a flathead screwdriver. I was hoping to find something obviously wrong, but no dice.

So my plan now is to start fresh on a few parts. I ordered a Transgo 400-PRO reprogramming kit, which includes new shift valves and springs, pressure regulator spring, accumulator piston, separator plate that dual feeds the direct clutch, governor springs, gaskets etc. I figure rebuilding the valvebody with this stuff will establish a fresh a baseline. I also ordered a new vacuum modulator in case something is screwy there and got a switch for the gas pedal so I can get the kickdown/detent system working.

I am hoping this is the last $100 I throw at this automagic and if it doesn't shift properly after this, I am going to live with it until I can find a suitable 6spd.
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  #797  
Old 04-03-2017, 04:49 PM
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That sounds about as good a plan you can hope.
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  #798  
Old 04-03-2017, 07:38 PM
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Originally Posted by TheBandit View Post
I am not planning to use the ECM to control or respond to the AC compressor because the E38 ECM is designed to perform that function via the BCM and GMLAN communication. I don't want to have to add a BCM or deal with programming it or adding I/O, so I am going to make the systems blind to eachother. I plan to use a trinary switch to override the ECM high speed fan relay control. The ECM will not know when the AC is on or off. I was a bit worried about idle response, but I have heard of folks implementing Vintage Air systems this way without any issues - the ECM is apparently able to adjust for the load quickly enough.

FYI this is what I did for the Vintage Air Gen4, I don't like it.
The idle RPM drop during clutch activation is too low for my taste, it sounds like it's going to stall, once its engaged its fine.

It looks like if I add a wire to the PCM @ pin 17 wire 762 it will allow the PCM a better response.

This is also in a un-tuned as of yet setup.

I'll report back after adding the wire.
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  #799  
Old 04-04-2017, 07:12 PM
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You're in a very different situation using the LS1 type PCM and (I assume) a DBC / IAC valve setup. You should definitely wire up pin 17 so the ECM will command the IAC valve and bump the idle up right away when you run the clutch. There is some more info and wiring diagrams in this thread: http://ls1tech.com/forums/conversion...does-work.html

On my E38 ECM there are no discrete inputs for AC - everything is communicated over GMLAN in the OEM setup. I've heard my DBW setup can react fast enough to maintain idle when the ac clutch is applied, but I honestly don't know. With a looser stall and a good tune, I think it's less likely to fall on its face, but we'll see. I think it helps that I will not be running a clutch cycling setup - I plan to use the original POA valve setup.
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Old 04-05-2017, 09:28 AM
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Yes you are right and again a valuable resource for me on this swap.

I originally wanted the PCM to control the compressor activation but switched to a trinary switch for ease of wiring. I might have to go back that way if I can't get this operating to my liking.
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