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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
This morning, I discovered that the 1989 windshield wiper connection is different than the one on my 1984 Trans Am. I went ahead and started unraveling my '84 C100 harness. After reading all these threads, looking at wiring diagrams, and working with the '89 harness, the cluster of wires doesn't look so intimidating anymore.
Last edited by johnw999; 02-09-2017 at 01:51 PM.
Reason: Pic
Another member was selling an '89 harness that Pocket built, so I bought it. I tried to buy one from Pocket, but I could never catch him at the right time. He's quite busy. I'm not sure at this point if I'll modify the Pocket harness to work with my 1984 or if I'll continue to use the Speartech harness. If I use Pocket's harness, I'll have to get a Lingenfelter 58x to 24x converter box. For now, I took a picture of Pocket's harness and labeled the pic.
Second pic is the Speartech harness.
I've identified the connections on my Speartech harness near the ECM plugs.
Fan Relay
Fan Secondary Relay
Alternator Charge Light
Fuel Pump
Fuel Level
Fuel Tank Pressure
Evap Vent
Back-up Lights
Speedometer
Tachometer
ETC Pedal
A/C Compressor
These connections will be in the passenger side dash. I know that the A/C compressor wire doesn't go through the ECM. It's just for convenience to connect A/C on/off switch to the compressor.
I finished preparing my C100 and C207 plugs for connection to the Speartech harness. The wiring was overwhelming at first, but I eventually figured it out.
nice work so far! I feel the same way about the wiring. It was really intimidating at first, and I had to ask a ton of questions and read a bunch of threads, but once you understand whats going on its not all that bad.
I removed the old master cylinder which, by the way, was a total pain in the ***. Now I'm going to install the replacement MC. As I described earlier, I was able to find a connection that worked with a 3rd gen master cylinder and a 4th gen T56 slave cylinder. The new MC is a stock replacement, but the rockauto info advertised a 1" bore. Whether that's true or not is yet to be seen.
I spent some more quality time underneath my car's dash. Contorting myself so that I could look up at the steering column sucked. My ribs are killing me.
Anyway, I just removed the stock gas pedal and replaced it with a 2010 Camario DBW electric pedal. I used a mounting plate from Hawk's, and it definitely made things easier. The mounting holes on the plate were 1/4 inch off, but I was able to bend the two mounting points apart. The pedal is too close to a module under the dash. I don't know what that electric box does, but I'll have to move it a tad. The mounting plate from Hawk's has, otherwise, positioned the gas pedal perfectly.
Two charred and wet cars were in the middle of the street. The pavement had turned black from the intense heat. Firetrucks and police cars blocked traffic. I stood motionless...just staring at what was left...catatonic.
"Hey pal - is that your car?" I slowly nodded yes. "Do you know that you almost killed those guys? What do you have to say to that!!?? Driving daddy's car and didn't know how to handle it, huh?"
"Hi. Have you been drinking? Let's go talk it over with that police officer standing over there."
My friend's father had arrived, and he rescued me. My tormentor quickly vanished when he mentioned police officer.
Big day today. I had the Trans Am towed to ProTree Racing in Garland, TX. I called a towing company near Garland to come get my car. The tow truck driver used ProTree for one of his cars, and he had good things to say about the owner. I'm excited to finally finish the LSX swap. I just don't have the time or the experience to drop-in the engine and make the final connections. It's better for me to let a shop take it from here.
Later in the afternoon, I loaded the engine, transmission, and swap parts into my wife's minivan.
Perhaps it was a bit too much weight, but the minivan survived. I took it all to ProTree.
While my car is at Pro Tree, I replaced the insulation on my hood. It seems to be made of fiberglass (like attic insulation). I should have worn gloves. My hands and arms were itchy and irritated for hours.
Pro Tree Racing is almost finished with my car, and I'm looking forward to driving it with an LSX for the first time. There are lots of threads on LS1tech.com about 58x/E38 engines not starting after install. Well, my engine / ECM combo is now one of them. Daniel at Pro Tree really knows his stuff. The ECM wouldn't provide a spark signal or an injector pulse. Daniel checked all connections, crank signal, etc. He suspected the harness, and we both contacted Speartech. Justin at Speartech was very helpful, and he worked with Daniel to make sure nothing was overlooked. The engine still wouldn't start. I began to wonder if the ECM was programmed wrong. LS1tech also has many threads about E38 tune problems. It's not as easy to tune as a 411. VATS not being fully removed is a common problem.
Anyway, I should have bought my ECM from Speartech. Their harnesses and ECM services are priced a bit high, but they are a class act. I "overnight" shipped the harness and ECM to them for testing. The next day, Justin found the problem and called me. The ECM was programmed with the wrong MAP sensor. The tune parameters were way off. The guy I used to program the ECM even changed values that shouldn't be adjusted. The test engine at Speartech ran like crap (even with the correct MAP sensor). Justin fixed the ECM tune and overnighted the harness and ECM back to Pro Tree. I used a cheaper tuner, and that was an expensive mistake for me. I told him that my engine had a bosch sensor, and he couldn't even get that right. I edited my earlier posts and removed the name of that tuner. I wouldn't recommend him to anybody. Pics of my ECM and harness being tested at Speartech below.
You must have a lot of patience? I would have pulled all my hair out by now, lol.
Looking forward to updates and a video of it running when you get time.
Keep up the good work!
Thanks! It's going to be an interesting drive back home. The hood is in my garage, so I'll be driving an old car without a hood or current inspection sticker. As always, the constables will be patrolling the highway. I'll have to plan a low profile route home.
The overnight shipping expense was worth it. The harness and ECM were back at Pro Tree this afternoon, and I just got word...
This is gonna be so much fun!!
Exciting moment for sure when it first starts! I just reached that milestone on my build and it definitely gave me the extra push of motivation to get everything wrapped up. Look forward to seeing some driving or startup videos of your swap!
Son, have you been drinking?
No sir, I haven't.
Wait here.
Yes sir.
A few minutes later my father showed. "Go easy on the boy", the officer suggested. After a few words with my dad, the officer walked back over and gave me a ticket. He had to do it, and he was sympathetic. "This is a citation for failing to yield right of way on a left turn. It's just like running a stop sign, and it won't go on your permanent record." I nodded and took the ticket. It was my first one.
The driver of the VW bug was with his parents too. "You have a nice f**king day!" he said as they left. I just looked down. It was time to go home.
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Then engine is running, and the dyno/tune went well. All that's left now is the A/C. One of the 58X drawbacks is that the E38 won't control the A/C (clutch on, idle bump, electric fans). So, my A/C has to be set-up like the old carburetor engines. High RPM is apparently ok with the Sanden compressor. My stock A/C set-up is a self contained system for the A/C. The high pressure switch was on the stock compressor, though. The 4th gen high pressure switch is designed to work with the PCM.
The trinary switch from the vintage air systems looks like it will work. I just ordered one from Summit. It would be nice if it fits on the dryer where the low pressure switch is. I'll find out soon enough if the thread size matches the stock dryer.
I modified a diagram from Vintage Air. The green/black wire is 12v power which engages the A/C compressor. The blue wire is ground, and that completes the circuit for the radiator fans.
You don't want that AC compressor on at high rpm. Suggest you add an rpm window switch to your AC compressor circuit.
Even though you cannot send the AC request signal to the PCM it might be the case that the PCM reacts to the high pressure switch by triggering the idle bump and turning on fans anyway. In other words, wire the AC clutch in old school fashion, but let the PCM see the high pressure switch and just see how the PCM reacts. It's just an idea, I don't know if it will work.... but it sure would be nice if it did work!
Thanks - I'll look for the window switch and add it to my car when I get it back. There is lots of info on thirdgen and ls1tech about A/C without ECM, but opinions vary. Maybe someone will add a sticky thread for this type of A/C setup. More 58x engines will be on the market since 24x was discontinued in 2007. I don't know why, but the stock 58x ECM can't be programmed to control A/C for hotrod swaps.
Speartech recommended Vintage Air, but I read that Vintage Air HVAC controllers won't fit in a thirdgen dash. This is what Speartech sent me:
" However, we don't have any way to control A/C during a swap. That is the benefit of using vintage air. Vintage air is a standalone system and doesn't require any signal from the ECM. The V8 engine doesn't need an idle bump when compressor comes on and everything will work just fine for you. Our harnesses that contain A/C is simply a convenience wire to get a wire from the A/C clutch to inside the vehicle without the need of running a wire outside of our harness."
And Vintage Air's website says:
"The SD 508 Compressor is recommended for any Vintage Air System. It pumps 8.4 cubic inches per revolution with a maximum 6000 sustained RPM range."
I'd rather have the A/C clutch disconnected when I open up the throttle, though.
I don't know why, but the stock 58x ECM can't be programmed to control A/C for hotrod swaps.
I think the "AC request" now comes over a CAN network. You would need a device that can generate the needed CAN messages.
Originally Posted by johnw999
Vintage air is a standalone system and doesn't require any signal from the ECM.
Your car is old enough that it might have manual AC control anyway (stand alone). Not sure you're solving a problem that needs to be solved. Even if it doesn't, then you can make it manual AC control by moving a couple wires around in the engine bay.
Manual AC is just a matter of running the 12V "request signal" from the head unit in series thru the high and low pressure switch to the AC clutch. Use the 12V request signal to actuate the fan relay too. If you want to disconnect the AC compressor at high engine speed, then add an RPM window switch anywhere downstream of the fan relay interconnect. Basically, never interrupt the cooling fan circuit while the AC request is active (12V).
The assortment of relays in the diagram are specific to a situation where an ECM is controlling radiator fan(s) but you want to couple one of those fans with manual AC. The third relay (AC relay) is really just a third fan relay and has to have a current rating large enough for the fan.
The extra AC relay is needed because you want to avoid a situation where the ECM sees a relay signal that it did not generate on its own or else the ECM will throw diagnostic codes thinking something is wrong with the vehicle wiring. In other words, never hook anything to an ECM that isn't supposed to be.
Got the car back today, and Daniel did a great job. There was a last minute challenge with the alternator. It wasn't charging, but that was because I matched an f-body alternator with a E38 ECM. The E38 exciter wire signal wasn't engaging the alternator. The F-body type alternator has a single wire that goes to the lamp in the cluster. A workaround is to wire an in line resistor (to substitute for the lamp). That did the trick for my car, and a 13.8V charge was measured at the battery.
I had a long drive home, and I avoided the highways. The engine sounded great, the transmission shifted smooth, and the A/C worked fine. I got a check engine light half way home, and I'll have to pull the code soon. A lot of upgrades were made to the car, and these things are going to come up during the shakedown.
Here are some pictures. Looks like the new front springs will work. I like the way the car sits now.
The 3rd gen master cylinder works with the 4th gen slave cylinder. The clutch pedal is a little higher than the brake pedal. That's no big deal. The clutch has a rediculously long throw, however. I wonder if there is a bumper stop or an adjustment I can make on the pedal bracket. It's a bit uncomfortable waiting at a stop light with my left foot against the firewall. This crude pic shows my problem:
It's a bit uncomfortable waiting at a stop light with my left foot against the firewall.
Not a good idea for the sake of your throw-out bearing or crank thrust bearing to sit with the clutch disengaged. Put it in neutral and let the clutch out while you wait.
I too, just pop it into neutral when at a stoplight. I got spooked years ago when driving the Woodward dream cruise and spending five hours idling in traffic. When I got home, the old clutch master was almost empty and the slave had leaked it out under pressure.
I installed a brand new LT1 master and slave unit.
And that said, I run a fourth-gen brake and clutch pedal in my car. As I recall, I cut off the fourth-gen accelerator bracket, and retained my 3rd-gen accelerator pedal. I do not recall there being any fitment problems with the 4th-gen stuff.
I installed a new 3rd gen clutch master cylinder while the engine was out. I connected the 3rd gen MC to the 4th gen slave with a 4th gen McLeod clutch line (part #136.62011) and a Russell -4AN clutch hose fitting (part #641001).
Just replacing the stock master cylinder was a pain. I'm sure it's even worse if modifications are made. There was no room for my hand or fingers at the clutch pedal connection under the dash.
I took the car around the block again today. The fuel pressure seemed adequate while the car was idling. 80 psi almost seems too much. I reset the ECM, and I'll see if the fault occurs again.
Start at post #42 should give you some ideas. Im not that far along with mine yet but i have the same covers if Qwktrip jumps back in he might have a better way.
The port on the passenger side valve cover is the "clean side" (fresh air supply) of the PCV system. It draws filtered, fresh air from the ambient side of the throttle body or air intake tube. I have never seen an LS3 drive by wire throttle body but I have a Nick Williams LS3 cable throttle body and there was a port for connecting the hose. Just cap the driver side valve cover port, you want it closed off.
The "dirty side" (crankcase outlet) is the port on the valley cover just under the throttle body. Just loop a hose from that port to the throttle body again. This creates a natural air flow pattern from high pressure (intake tube) to low pressure (manifold that is normally in vacuum) to evacuate the crankcase.
If you have an oil catch can on a naturally aspirated engine, then the can goes on the "dirty side" between the valley cover and the throttle body.
I looked at the throttle body, and it doesn't have a connection like the cable TB's. I do have a connection on the Speartech intake tube. It's for sending fresh air to the crankcase. I'll look at the valley cover soon. Since I deleted the VVT and DOD features on my engine with a kit, the valley cover was replaced. I hope that didn't create another 58x DBW debacle.
I put the hood back on my car. I was relieved that the Speartech air intake fit under the hood. After the hood was installed, I drove the Trans Am around the block. The Texas Speed Cam and the Hedman Long Tube Headers sounded great. The idle was old school rough - glug glug glug glug. I dropped the hammer for the first time. The Trans Am launched and threw me back in the seat.
I was about to go get an inspection sticker. The car has been out of commission for a few years, and I'm sure I'll need to jump through some hoops to get a new inspection / registration sticker. The brakes don't feel right, though. I can see a brake fluid geyser in the master cylinder when the brake pedal is pushed. It's in the back of the master cylinder, so it has something to do with the rear brakes. I'll probably change the master cylinder and brake booster soon. Delays delays...
My trans am has been off the road for a few years and I find that the brakes are a little funny now. Brake fluid is hydrophilic though, so I think the system is due for a fluid change.
I am not saying that the E38 computer can control the fans and AC system but I can tell you that hptuners is showing me controls for them. My original plan when I got to this point was to try and use a mixture of stock parts but that will be considered when I get there so I don't say anything that might be wrong.
I figure running the clutch power wire through the low and high limits would be all that is really required. It looks like pin 63 from the J1 black connector has the A/C Compressor clutch relay control.
Next issue would be that since I do not have a BCM to sent a signal to engage the AC how do we suppose we could control the AC with the stock ecu?
02-09-2017, 01:36 PM
