cmexlr8

iTrader: (1)

I have used the wiring for dummies thread, Pocket's "start to finish" thread and the http://www.lt1swap.com/all_lt1.htm site to research how to wire in my LT1. I am not lengthening my harness at this time, but I still needed to know which external connections (power, ground and output) I needed to tie into the LT1 harness. I used tape to label all the external connections right off of the 4 ECM connectors and then I started looking at the c210, c230, and c220 connectors. It occured to me that the switched and constant power connections can be made to those connectors. I tested that buy supplying power to the purple, orange and pink wires and then checking all the individual wires on the ECM connectors and they all had corresponding power. So suffice to say the c210, c220 and c230 connectors are where you will make all of your power connections. I think a few of the guage and diagnostic connections are made there too.

Does this sound correct?

chevyowner02

iTrader: (3)

That sounds about the way it's done.

Z28ricer

iTrader: (2)

Yes, technically you could just get the other side of the connectors, put the appropriate power and chassis connections there, and have it run.

Of course then you still need all of the thirdgen harness cut up and engine side of it removed, as well as connecting everything between correctly, and you wont end up with too great of a fit.

I've done one harness like that, just a plug in harness that connected to the 4th gen engine harness with all of the thirdgen power and gauge wiring, but it really doesnt allow for a very good fit due to the layout of the LT1 harness.

89rs454

Let me say this, if you really want your lt1 swap done you will figure it out, google ect there is more threads out there on this subject don't just rely on one website. It's good to go in with an open mind and be smart. It's the best feeling when she is finally done and your on the road again, in the best small block Chevy them boys made.

Pocket

iTrader: (24)

You just described the 3 wire connection and it will get the engine running

Basically, all the pink wires get switched 12v, all the orange wires get constant 12v, the purple wire goes to your starter switch

However, none of those points will be fused, so its risky for more than a quick test fire

89rs454

Pocket is the man for wiring around here, lord knows he help walk me through mine. cheers

Z28ricer

iTrader: (2)

Less risky than eliminating the short circuit protection of the large wires feeding power into the car.

89rs454

Just have it all fused and your golden, If you happened to get the fuse box with the lt1 it's as simple as that.

Z28ricer

iTrader: (2)

I was referring to Pockets lack of knowledge about the fusible link protection of the power feed wiring, and extremely terrible and dangerous suggestion that people eliminate the fusible links because he doesnt understand their purpose.

89rs454

LOl this is a joke right?

Z28ricer

iTrader: (2)

Do you have the same misunderstanding of the fusible links as him, or do you know what they are for and are in disbelief that someone would suggest discarding them ?

89rs454

I know for a fact that he told me fusible links come first then you go from there, All of my wiring was done by his word. And i stand by that.

Z28ricer

iTrader: (2)

He has posted clearly on this board that he suggests discarding them and that they are redundant because there is a fuse block inside the car.

I had to openly argue the fact with him when he was insisting this was an OK practice and suggesting it to people in threads.

89rs454

I have a pm that says otherwise.

Z28ricer

iTrader: (2)

I see your PM and raise you posts on the forum, in plain sight:

https://www.thirdgen.org/forums/ltx-...harnesses.html



Theres more, but thats more than enough proof.

89rs454

Fair enough, it's just common knowledge to have all fusible links in between your hots. I have two blocks going just in case. I'm not throwing pocket under the bus but all he told me was fuse them off and that's what i did.

89rs454

So What's your problem with pocket?

Z28ricer

iTrader: (2)

The instructing people to ignore the advice that they needed fusible links on their long runs of large gauge wire that could lead to an electrical fire by following his instruction, and repetitively trying to argue with me about the fact, consistently insisting that they are "redundant" when they are nothing of the sort.

Its dangerous to do to someones harness, and dangerous to suggest such a thing, its one thing to do to your own car and put it at risk, its a whole different story putting others property at risk because you dont understand something.

89rs454

I hear you and you was a big part of my project, read all your threads listened learned everthing i could. Yall made it simple, My LT1 runs like a ******* top.

Z28ricer

iTrader: (2)

LTx and LSx swapped thirdgens make for awesome fun, I just really dont want to see anyone posting up pics of car-b-q's because of bad advice

89rs454

However, i do have this one little problem i don't mean to highjack this dudes thread but my converter is not locking and she is reving high and it's killing gas milage?

cmexlr8

iTrader: (1)

I pulled the v6 harness out and have been using it for some connectors and some of the wire to lengthen things I needed to be longer( o2 sensors). I put a an 86 or 87 engine harness in place of the 92 v6 harness because I had it and it was much simpler. I pruned out the wires I did not need from the 87 firewall connector earlier when I had a carb'd motor in this car. So it is pretty straight forward to tie in the switched and constant power wires to where I think they need to go in the 4th gen harness. I am just kind of relieved that I don't have to splice in power in multiple places. Nothing I read ever comes out and says anything otherwise. I do realize that the gauge or "output" connections will be a little less straightforward.

I will be running a fuse block for the power connections.

Z28ricer

iTrader: (2)

Operation:
The TCC system uses a solenoid operated valve to couple the engine flywheel to the output shaft of the transmission through the torque converter. This reduces the slippage losses in the converter, which increases fuel economy. For the converter clutch to apply, at least two conditions must be met:


•Internal transmission fluid pressure must be correct.
•The PCM completes a ground circuit to energize the TCC solenoid in the transmission, which moves a check ball in the fluid line and allows the converter clutch to apply.

The PCM controls the TCC apply solenoid by looking at several sensors.


•Engine must be in closed loop operation.
•Vehicle Speed Sensor (VSS). Speed must be above a certain value before the clutch can apply.
•Coolant Temperature Sensor (CTS). Engine must be warmed up before the clutch can apply.
•Throttle Position Sensor (TPS). After the converter clutch applies, the PCM uses the information from the TPS to release the clutch when the car is accelerating or decelerating at a certain rate.
•Another switch used in the TCC circuit is a brake switch which opens the 12 volt supply to the TCC solenoid when the brake is depressed.

Location:
The TCC solenoid is located inside the transmission.



Also, i'm not certain but i'd think the Park/Neutral position switch not being hooked up or not working might also cause an issue with it.

Edit: Yup it does, first thing to check is to make sure you've got it setup:

Purpose:
The PARK/NEUTRAL switch indicates to the computer when the transmission is in PARK or NEUTRAL.

Operation:
This information is used by the computer for Idle Air Control (IAC) operation, EGR operation as well as transmission Torque Converter Clutch (TCC) operation. DO NOT drive the vehicle with the PARK/NEUTRAL switch disconnected, since idle quality may be affected.

Location:
The Park/Neutral switch is located on the base of the shifter in the center console.

89rs454

Right on so i'm just going to wire my own switch temp to see whats up, can anyone tell me what that sport mode meant on the formula firebird trannys? lol was it a tcc lock on off switch because i left it own when i got it? eaither way I'm saving up for a T56 but would love to know.

Z28ricer

iTrader: (2)

The listed operation does not say it effects the tcc, and unless you've hardwired it to ground, it doesnt matter what position the switch was in when you took it out of the vehicle, its in normal mode unless the input to the performance mode is grounded.



When the performance mode is selected, the B+ performance mode input signal is momentarily toggled to zero volts. The PCM enters performance mode and turns on the performance mode indicator lamp (within the switch). While in performance mode, shifts will be firmer and delayed 1-3 mph upshifts or 1-3 mph downshifts. Normal operation is obtained by toggling the performance mode switch again, or when the ignition switch is cycled "OFF" then "ON".

89rs454

well i know for a fact my tcc is not locking and it's not trowing any codes? I will just live with it untill i can get a M6 or t56 i guess. I hate this fuc*** auto it's no fun.

Z28ricer

iTrader: (2)

It shouldnt be too hard to troubleshoot it and get it fixed so long as its not the converter itself. I'd troubleshoot it.

89rs454

Will do but your T56 is lookin to good, so i plan to run her till she drops lol.

Z28ricer

iTrader: (2)

T56=win

But I still wouldnt put off fixing the issue unless you've got the T56 sitting beside you

89rs454

Yeah i know man i'm gonna wire up a switch and see's what happens. but book it when i say i geeting a stick. An auto is no fun..... even with a high reeving lt1 lol

John in RI

iTrader: (167)

Smart,.... I too started with an early ThirdGen harness and would recomend it to everyone doing this swap. For 88+ cars it's probably easier to simply convert to the 84-87 wiper motor rather than dealing with hacking apart an 88+ harness. (Firebird 86-87 should have VSS wires too.) Since the Fusable links (& all required "HOT" wires) are already present in the Thirdgen C100 harness to the starter - why remove them ? Why use the purple soleniod wire on the LT1 harness rather than the Purple Soleniod wire on the ThirdGen C100 ? ( plan on using VATS ??) The ThirdGen C100 distributor wire is the perfect "swithed" power source too...... Doesn't sing the original ThirdGen C100 wires means stuff is using the "properly" fused power - correct ?

I used 95 LT1 PCM harness and ended up with a 4th gen underhood fuse/relay box to run all the stuff I didn't have ( Fuel pump relay/fuse, Fans relays/fuse, Fog Light relay/fuse, PCM fuses). If you do get a 4th gen underhood relay center, be sure to get the one from the same year car as the LT1 harness your using. 94-95 fan systems are very different for example, (same is true for changes from v6 vs v8 cars).

Using the 4th gen Relay center allowed me to simply feed switched power to the Relay Center, connect it's red "HOT" wires to a junction block (like the 4th gen) & plug into the LT1 harness's C100. Not the final version, but you get the idea !



My LT1 C210 and C105 were eliminated, LT1 C230 runs thru the firewall and connects mostly to the 95 type ALDL, My LT1 C220 connection (gauge wiring) connects @ the ThirdGen C100; and my Relay Center C100 plug runs directly to the PCM C100 plug. (PCM mounted near heater box in engine bay. ) Lot's of re-pinning and cutting of the custom Relay Center wires to length, but I cut them LONG from the donor car so it was cut to fit in most cases - not adding wire. (my 4th gen Relay center is mounted on the drivers side "battery" tray.)

By the way,..... T56 FTW !!

Z28ricer

iTrader: (2)

I'm not sure where you come up with the earlier harness being a good idea for the 88+ cars, there are no advantages to it, other than if you had one sitting, and didnt have the correct harness for your car it would be free.

The wiper stuff makes no sense, the wiper wiring is on the earlier harness to the c100, of course its in the wrong half of the connector, it doesnt connect to the engine side of the C100, not to mention going backwards from the newer wiper motor doesnt make any sense.

As far as using the 4th gen fuse/relay box, I just see a lot of doubling up by putting fuses in place that are already inside the car.

John in RI

iTrader: (167)

No Advantage The early Thirdgen C100 harness has only Engine, gauge, and wiper wiring. It takes about 2 minutes to figure out where the wiring is that's needed for the swap,... about as simple as it gets. Not sure why you would think that an 88+ harness that's got the ECM and Engine harnesses integrated together into one monstrous harness is a better option ?? Snip a few wires from the 84-87 C100 or hack 40-50 wires out of the 88+,... what sounds easier/faster ??

Going 'backwards' by using a using a 84-87 wiper motor means; What ?? What's "wrong" with the 84-87 style wiper motors ?? When the early C100 harness is used, the 84-87 wiper motor is a 'plug-&-play' install. Why deal with splicing it into the 88+ wiper system ?? From 84-90 the wiper wiring is located at the same C5-6-7 & D5 C100 pins. IIRC only the 91-92 uses wiper wiring that's run thru the headlight harness so Yes,...your partially correct, for the 91-92 sticking with the original wiper motor makes sense; but that's not true for the 88-89-90 cars when using an 84-87 C100 ThirdGen harness.

** 82-83 wiper wiring is "special" !!

There is ZERO redundancy in my 4th Gen Relay center and there will always be ZERO redundancy in the earlier cars. Early cars didn't have the stuff that the LT1 conversion needs & the relay center provides. My 84 (or most early ThirdGens for that matter) do not have any relays or fuses for fog lights, an electric fan, electric fuel pump, or any injector fuses. Lets not forget that all those things require relays and relays can't be mounted to the fusebox. IMO The 4th gen relay center is the perfect way to run all this stuff to 1 location and to make a direct connection to the LT1 C100 plug.

cmexlr8

iTrader: (1)

Yes, you and I are on the same page. I used the c100 diagrams from the 91-92 cars and the one from the 87 cars to match up the wires I needed. The ones I cared about were in the right place. I think the only special thing I had to do was with the fuel pump wire. I am also with you on the purple starter wire. I am unsure of how that is going to work out though. I will deal with that if there is a problem. I know I used it when I had the carb'd setup in there without issue.

I don't have the relay center so I will be using my third gen wiring for my fuel pump. Again, I was already doing this when the carb setup was in there. I will need to steal a couple of relays from the 92 harness I pulled out to setup the fans. I am going to use the 4th gen main power junction block because I have a remote mounted battery.


I will probably do something similar for my ALDL

Z28ricer

iTrader: (2)

Again, you seem to be confused here, there are 18 TOTAL wires in the 88+ C100, and thats duplicate counting the tcc wire, and the reverse light wires, so you are either actually going to end up with 17, or 16.

As far as duplicates and stuff you dont need, if you did go doing something silly like using an early C100 on the 90-92 cars you'll have quite a few things assbackwards:

Pay attention here, I know this two halves of the C100 thing get tricky, there are again TWO parts to the C100

The wiper wiring is part of the Headlight harness on the newer underhood wiring. This means that first off your wiring in the early engine side of the C100 now connects to nowhere

Next up if you are starting with a manual 88+ car and have a T56, now you just lost your reverse light wires.

Your connection for the fuel pump relay output, well thats now gone too.


Alternator and power for the fan relays ? Nah we dont need those either as those are gone.

Yes indeed it takes a few minutes to seperate the C100 wiring from the C230 and ecm wiring.

Of course its going to take a lot longer for all of this nonsensical reworking of a early harness.


Again you are wrong here, the wiper wiring is routed through the headlight harness in every single 88+ you just suggested use the earlier harness. So going to the early motor that is going to be much older and more worn out, and less plentiful is also going to take a good bit of rewiring, which is not even related to the swap.

See, you are trying to suggest something wiring wise, yet you are completely confused and turned around backwards as to whats what, this is why I said, its not something everyone should be doing.


You are suggesting that people do this with 88+ cars, yes on an early car without any of the correct wiring it is a good idea, however I am referring to your suggestion that people with newer cars do the same, and in that case it is extremely redundant, the only thing that a stock 88+ harness needs added in that isnt present is a fuse for the reverse lockout, anything beyond that is redundant.

John in RI

iTrader: (167)

Tommy - You sure came off like a snot. Relax, installing a early thirdgen C100 causes ZERO redundancy. There's almost nothing to an early C100 other than hot, switched, and gauge wires so,............ what's redundant ?? He used an early harness, I think that was a good idea.

I'd rather start with this:


Rather than start with this,........ when 85-90% of it is not needed:


Bye the way; this was an 89 TA Engine/ECM harness,.... you can clealy see the wiper plug - but no headlight harness in sight.

"completely confused and turned around backwards as to whats what" Come on dude - For real !?!? If it makes you feel better, your right !?!? Feel better ?

Let's not take a very specifically applied system (the wipers) and preach about right/wrong because each and every variable is not covered, in fine detail. Wiper systems were 82-83, 84-87, 88-92, If your not using the original C100 harness from the car than there's a very high probability that you will need to re-wire ( or re-pin ) the 4 wiper wires. Not rocket science here. You got condescending and all "holier than thou" there like you know everything and that our collective knowledge don't mean ****. You did read my post right ?? I did mention that there was re-pinning done to my stuff, right ?? Do you think I got rid of my LT1 C105 or C210 by just cutting off the plug and hoping for the best ??

Installing an LT1 is a custom swap, anyone attempting it expecting plug and play from out of the box is in for a surprise !

86 FIREBIRD

87

89

90

91 CAMARO




Opps,.... looks like the wiper C100 pins changed in 90, not 91 as I posted earlier. 88 & 89 shop manuals show the wiper wiring in the same Dash C100 pin locations as the 84-87 cars Could the book be wrong; sure,... I don't sell custom harnesses so I don't know every circuit by heart for every year, every motor, every tranny, and every option combination available. Sure seems like the 88 and 84 wiper wiring leads to the same place on dash harness C100 to me. Lets not forget the 82-83 cars or the 84-86 Digital Camaros; the wiper systems in those models are completely different than other thirdgens.

All the ThirdGen C100 connector is good for is tapping into the dash wiring thru an existing hole. Basic connections are for the gauges, Switched Power, HOT power, Wipers and VSS ( in some cases. ) Any / ALL of theses wires can be run ANYWHERE / ANYHOW. ( re-pin, splice in a new harness, whatever you like.)

Tommy - quit being a snot & tell the dude what his 92 V6 Dash C100 needs because it's not on the his 86 engine C100.

cmexlr8

( see the Pics above for 86 Firebird and 91 Camaro C100 schematics. 91-92 cars should be very similar. )

When using the early harness I've found that it's good to use a 4th gen relay center ( matching the year of the PCM ) so that all the fuses / relays the LT1 needs are already correctly placed in a central location & plugs directly it into the PCM C100. You could also cut the thirdgen relays off the thirdgen ECM harness and tap into your fusebox and splice into the LT1 C100 to recover many of those things. It's a custom job - expect a 1 of a kind !

Also; If you plan to use the PCM to control duel fans be sure of the year you LT1 stuff is from. The 94 PMC uses 2 relays to control duel fans - but the 95 system uses 3. Each and every install is different is be sure that you know exactly what harnesses your working with. (My LT1/T56 harness was different than the LT1/auto information I was finding ! )

Z28ricer

iTrader: (2)

I come off as a "snot", well i'll take that over suggesting that someone use a harness that is completely wrong for the application.

Use a early harness on a 88-92 car and as I already stated you are missing all of the above wiring, fuel pump, brake warn, alternator/fan relay power.

So for all of the cars without the wiper wiring as part of the engine harness,you just removed several needed wires, the correct wires, they were all there in the original harness, yet disconnecting each of those 16/17 wires is an issue, compared to chasing down an early harness, and then trying to add them back in.

You need all of them, you want to suggest a harness that is missing half of what is needed, instead of the original harness which has all of it. Again there are NO, NONE, ZIP, ZILCH wires that can be just done away with from the newer car C100, to make using the early C100 a good idea.

The ONLY case where this is a good idea is early cars without original EFI, as i've already stated.

As I already said, with an original EFI car ( read 85+ efi cars) all of the fuses are there, injector power, ecm power, etc, making the car use the 4th gen fuse block is redundant (not the early part of the harness, that just leaves you without needed wires, that were there in the correct harness)

With reference to the fans, it doesnt matter what the original fans were, there are two outputs from the pcm, high and low, whether you do it thirdgen style left and right, or wire them series/parallel for high/low does not matter.