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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.
It requires Spectre 4932 Water Neck and a themostat to use that hose. There are even better options out there I just couldn't see paying so much for them.
The tach will lag some at the top but not by much. If you need something super precise you may need to go aftermarket. I just ordered a new old stock 1990 v6 tach to put in. The v6 tach has the right redline for the ls1. I'll have to tweak the pcm output to drive it.
Use a multi meter on your tach line and see how much voltage you see. I ended up going lower on the resistor to get the voltage closer to 12. With the higher ohms I was only seeing 9v. Also I'm considering putting a diode on the line to the pcm to prevent back flow of electricity into the pcm.
I also considered this or the msd version. https://www.autometer.com/ls-plug-play-harness-with-tach-adapter.html however the resistor was much cheaper
Allan, my tach doesn't act odd but it definitely does not keep up at high rpm (89 Firebird). I never noticed for a year driving around town where I don't have traction to drive 100%. But it became obvious at the drag strip when I was able to bury the throttle and the engine kept hitting the 7000 rpm rev limiter with tach reading somewhere around 6200 - 6400 rpm.
My tach is driven by a Holley HP EFI engine controller. I have observed the signal with an oscilloscope and the waveform was well defined and just under 13V (nearly system voltage). I know very little about electronics but I'm guessing the RC constant of the tach circuit causes the lag at high rpm. It seems to act okay when snapping the throttle at lower rpm's.
Allan, my tach doesn't act odd but it definitely does not keep up at high rpm (89 Firebird). I never noticed for a year driving around town where I don't have traction to drive 100%. But it became obvious at the drag strip when I was able to bury the throttle and the engine kept hitting the 7000 rpm rev limiter with tach reading somewhere around 6200 - 6400 rpm.
My tach is driven by a Holley HP EFI engine controller. I have observed the signal with an oscilloscope and the waveform was well defined and just under 13V (nearly system voltage). I know very little about electronics but I'm guessing the RC constant of the tach circuit causes the lag at high rpm. It seems to act okay when snapping the throttle at lower rpm's.
Yes guys i appreciate these responses... my son's is strange in that it normally works, but if you really get on it WOT, like a street / drag launch from stop, first and second will result in the tach starting to rapidly follow the engine speed but then collapsing to zero/bouncing until you let off the throttle... an aftermarket autometer tach wired up i put just for a quick test tracks without issue. yes the circuit time constant is a question and i haven't taken the tach apart to look at it... interestingly the stock tach on my iroc with an ls3 with the tvs2300 which is crazy compared to the stock crate ls3 tracks it great and i use it to shift and rarely hit the limiter. (compared to HP tuners it looks like the tach at the top end (or at least how i see it!) is about 150-200 rpm higher then when i think i am shifting at 7000, ie my shift is usually actually around 6850.
i will also investigate the pull up resistor lowered below what i have of around 2.5K
of course the formula and camaro tachs are different to some degree, but i haven't looked too hard yet. this experience is with GM E38 / E67 ECMs... i did buy a holley HP that i am now using in my current project build with Ramjet type SBC as the holley software looks very nice and i like the fact you can control basically any engine so if it works out i may eventually switch the LS swaps to it... i wish they gave an option of running a mixed MAF / SD vs just the SD wideband o2, but all the optionality looks great
Has anyone used the 4th gen cruise control? This is my last known unknown... I'm sure I can muddle my way through the wiring but there has to be a write up somewhere on using it... I've seen fleeting mentions of it but nothing in detail.
Yes guys i appreciate these responses... my son's is strange in that it normally works, but if you really get on it WOT, like a street / drag launch from stop, first and second will result in the tach starting to rapidly follow the engine speed but then collapsing to zero/bouncing until you let off the throttle... an aftermarket autometer tach wired up i put just for a quick test tracks without issue. yes the circuit time constant is a question and i haven't taken the tach apart to look at it... interestingly the stock tach on my iroc with an ls3 with the tvs2300 which is crazy compared to the stock crate ls3 tracks it great and i use it to shift and rarely hit the limiter. (compared to HP tuners it looks like the tach at the top end (or at least how i see it!) is about 150-200 rpm higher then when i think i am shifting at 7000, ie my shift is usually actually around 6850.
i will also investigate the pull up resistor lowered below what i have of around 2.5K
of course the formula and camaro tachs are different to some degree, but i haven't looked too hard yet. this experience is with GM E38 / E67 ECMs... i did buy a holley HP that i am now using in my current project build with Ramjet type SBC as the holley software looks very nice and i like the fact you can control basically any engine so if it works out i may eventually switch the LS swaps to it... i wish they gave an option of running a mixed MAF / SD vs just the SD wideband o2, but all the optionality looks great
https://www.thirdgen.org/forums/elec...ach-fixed.html take a look at this, your son's tach may have bad capacitors in it. There are companies you can send it to and they will rebuild it or for a few bucks you can do it yourself. However it could still be low voltage to the tach, the firebird version is more sensitive than the camaro to voltage on the signal wire.
Oh one other question the scan tool port, is the 12v switched 12v with ignition or is it constant 12v. Right now that is rigged I need to finalize the wiring and mount it.
I've decided I'm building a custom radio pod, I want to use a proper 2 din radio as no one makes a nice 1.5 din and single din's are limited in features.
Got in new door sills, inner fenders, and the dash pad. The first two I recomend the latter well it's good but at the price they sell for I really wanted perfect. I think some of the imperfections will soften once it sits in the hot car a few days during summer. It looks better than the big crack, I may experiment with the old dash pad try recovering it.
I've gotten rid of all the rattles and noise from the drive accessories (easy to solve all it takes is more money LOL) the Water pump was 90% of the noise. The Alternator was doing a random noise that took me for ever to find I thought my exhaust was tapping on something as it sounded like that type of rattle. So now my front drive accessories are 100% new except for the power steering pump. I'm not sold on the factory 2k exhaust though, I have a magnaflow muffler I need to weld in. Though just listening to it you wouldn't expect it to be what it is... right now its in the sleeper mode... maybe I should keep the 2k stock muffler and add electric cut outs
So I'm 99% sure I have the cruise wired right but its not working.... it was the one electronic part that was below the water line on the donor car so I'm rolling the dice and bought a couple off ebay. I've gone through the 2k schematics 4 times and the wiring matches the pin out on the module. The only other thing I can think of is a slim possibility that the PCM isn't sending the signal on the engage wire, I don't have a good way to test that as I believe its a pulse signal not a constant. Does anyone have the parameters of the Pin H and J going to the PCM R13 and R37?
So I bought a GM cruise module tester off ebay. The module is good. I also picked up a truck and another fbody cruise module. The truck one seems to work as wired (testing on jack stands so it reves and shuts off because the speed increases too rapidly). Neither Fbody unit works off the controls (I can set them using the tester box so they function)
The tester also shows the VSS pulse as good.
So this leaves me with the wires going to the computer, will have to get HPTunners back out and see what the inhibit signal is doing. And look at the tester to see if it tests for that. The tester does show the on/off, accel/resume, set/coast, brake etc function as expected.
Who would of thought the cruise module was the thing that would cause issue... all the other wiring fell in place like the engine was built for this car Though with the money I have in the cruise control I should of just bought the Dakota digital one.
Though with the money I have in the cruise control I should of just bought the Dakota digital one.
I have that, but I have issues with it. When I was using the GPS module for my DD gauges the cruise worked flawlessly, but when the GPS speedo stopped working (I think I had a ground issue, maybe) and switched the input to the VSS on the trans, the cruise would surge under some conditions but the speedo needle was rock solid in the cluster before it would start surging. I called DD and they didn't have any input on it, so far that is the only problem I have had with my DD stuff, just the support staff isn't great.
Err so I had grounded the clutch switch with a gator clip jumper wire to test and even though I "always" ohm those out I didn't this time ... So with that fixed the fbody module works now.
moral of the story is hook it up right before testing...or at least verify the wire.
So I did this today. I had it painted in 2001 ish at macco and it started pealing in the same spot as the factory paint. After testing I decided everything reacts with the macco paint and it's pealed twice in the same spot so I took it down o metal. Etched it and primed it in PPG epoxy primer. Still need to work he few dings and then I spraying it in PPG single stage that I had mixed to match the macco color.
Ok so my speedometer works spot on but noticed today the odometer isn't ticking up. I've only done about 50 miles since the swap and I didn't notice. Did my odometer just break or is the speedometer and odometer two different circuits?
Took a snapshot of the bird out in the wild. Yeah I know time to paint the spoiler it's been in primer for like 16 years. Ignore the yellow tape it was rattling so quick temp fix.
At the quarry up the road from my house, they have on overlook deck. Hawks 17 inch repainted by me in gunmetal/graphite and 1970's chrome center caps.
So after dragging the BMR trans cross member over every bump I drove over and there not being one that would work with my sub frame connectors I built my own from the BMR. Gained about 2.5 inches of ground clearance. Goes above the exhaust which gave me some additional room so now my tunnel doesn't get as hot.
A few updates I put the posi and gears from the 2000 donor into the thirdgen housing. And the rear disc brakes. First time ever setting up gears so far so good. The 3.42 gears are much better with the T56. Ignore the grime it's not rust just a combination of old under coating and dirt.
... So with that fixed the fbody module works now.
