rrwebster

1994 Firebird Formula LT1, 4l60e



Just picked it up for a song because fuse 11 keeps blowing. Picked up a cheapo manual, ordered a full service manual. looking at the cheapo manual that circuit goes from the fuse block to the coil, to the TCC Solinoid.



Put a multimeter on the coil, set a larger fuse on it so i could get a reading and there is voltage to the coil. next point is the TCC Solenoid.



tried to remove the plug from the trans but it's not moving. figured if I could unplug it and the fuse didn't blow then it's something in the transmission.



the kid that owned the car said he was driving down the road and it just died.



This fuse will blow the second the key is put into the run position.



History as I know it....



kid bought the car, the engine was trash, paid to have a new engine installed, also paid to have a shift kit installed. Drove it around 2000 miles since the work was done, last week it died... last night I bought it and brought it home today.



I've read on some other forums where people stuck a larger fuse in and it would run but I'm not into frying wires so I thought I'd post here.



I've read a couple of other solutions...



the ground from around the coil area.

wires laying on the headers/exhaust manifold



Haven't checked the ground but did check the manifolds, no wire... plus I've moved all the wiring around and tried it and no change.



As fast as this blows the fuse there is a direct short someplace.



would it make sense that the trans kit guy pinched a wire?



to replace the TCC solenoid and wiring harness you just drop the pan?



I'm new to the LT1 and 4l60e.



thanks in advance to any and all help.



Robert

Paul Bell

iTrader: (9)

You gotta get that plug outta the transmission. With it out, if the fuse does NOT blow, you'll be dropping the transmission pan next to find a pinched wire. This fuse feeds five of six transmission solenoids, not just the TCC. These solenoids get full time 12 volt positive via your fuse 11 with the PCM applying ground as needed to energize them.

A bad ground will not blow a fuse. If a ground connection (AKA negative return path) is bad, whatever circuit it's grounding will not function.

rrwebster

Thanks Paul... if I can't get it out I'm going to pull the pan anyhow. I figure since someone has been in there recently there must be a pinched wire somewhere in there. Thank you for the schematic... since I'm sure it will be a day or two until I get my manual it will come in handy.

Robert

Paul Bell

iTrader: (9)

BTW welcome to the forums. Setup a signature that says "94 Formula A4" so people will know what car you have as well as some of your mods.

The reason solenoids and relays get full power and the PCM switches the ground is to allow the PCM to monitor the health of the item. E.G. If a solenoid goes bad, the PCM will see a loss of available positive voltage coming into the PCM from it and set a code. The fuel injectors also work in this way.

rrwebster

Paul... thanks for the welcome!

Okay, got the plug off... no more blown fuse.

pulled the pan. no obvious pinched wires... actually all looks good except the plastic harness frame is broken. there is also a spot where it looks like there are two pinks into a single with a connector. Is tranny fluid conductive?

I also noticed that the plug had fluid in it when I disconnected it.

with the pan off I'm going to plug the plug back and see if there is still a short.

If the solenoid was bad would it cause a short? doesn't seem like it should. Oh and the tranny fluid smelled burn when I first pulled the pan.

Robert

rrwebster

Well... not sure what the problem was. Blew out both halfs of the Connector, checked for a short... no short. Used a tie strap to hold up the wiring harness that was laying on the filter, buttoned everything up.. no short.. no problem with the fuse... everything is fine..

ya know... I thought my 88 GTA with a 305 and TPI ran good... OMG I'm in love!!!!

This isn't just a stock LT1 it's got a hypertech chip in it and a B&M shift kit. I can't believe how well this runs... a 15 mph roll nailing it breaks both tires loose... amazing...

My original plan buying this car was for the wiring harness and transmission as I have another LT1 that had 70,000 miles on it. I got to hear it run before the engine was cut out of it. Anyhow was going to pull the TPI out of my GTA and put the LT1 in it. How close to 88 WS6 handling are the 94's? because I can't hardly notice the difference excpt maybe my GTA is a little tighter.

Paul, thanks for your input in my problem.

Robert

Paul Bell

iTrader: (9)

Glad you’ve eliminated the short.

It’s rare that the transmission solenoids go bad. If you need to remove them, be careful as some of them have a spring loaded thing behind them.

Transmission fluid does not conduct 12 volts.

If the fluid smells burned, assume it’s been beaten on. Flush through a few gallons, get on a fresh filter and figure there’s a transmission in your future.

I’d say the ‘93 and up cars will handle better as they have a better front suspension design.

You can’t have a "chip" as these cars did not have a removable chip. It’s probably been tuned.

Make yourself familiar with LT1 section. That’s where the LT1 die-hard guys are.

https://ls1tech.com/forums/lt1-lt4-modifications-31/

Paul Bell

iTrader: (9)

That's quite a list of cars in your sig!

To swap a LT1 into a non-LT1 car, you'll need to install the entire fuel injection system with wiring harnesses and PCM. Not a small/easy job.

rrwebster

yeah... tell me about it.. my 88 gta didn't come with an engine a wiring harness or a trans... stuck a 87 version in it... nothing matched.. had many wires to figure out and run. I've already put toether all the connection difference from the LT1 to a third gen. Not rushing into it....

Robert