nuc79

Have a proplem here. Just got the 94 Z conv't back from Kens Performance(aka Ken Wells) in Orlando with a fresh 4L60E rebuild. On the way down there to drop it off, SES light came on, and I began to notice hard starts at gas stations.

Since I didn't have my laptop and cable with me, I had Ken's shop diagnose it. Turned out to be a coolant sensor, and they only charged $30 to diagnose it, replace it, and refill the radiator.

So I went and picked up the car last weekend, was driving it back up north (well, 3 hrs north), and the converter unlocked at 80mph. It only did this a couple times, and it felt like the car lost power at the same time. Of course, the revs went up a bit because of the TC unlocking. Was worried it had something to do with the newly rebuilt tranny, but not likely given Ken's reputation. Also, wife was following and said she saw puff of grey/black stinky smoke when it happened(over-rich condition?).

So I got the car home, hadn't done it since, but I decide to run DataMaster on it. There was DTC 15 stored in memory, but the datarun looked normal when I took it for a 15mile drive. So I cleared the code.

Well, it hesitated on me once yesterday, and this morning it was really bad. Even felt the converter unlock again. This time SES came back on for a few minutes. So at lunch I plugged in the laptop, and the code 15 was back, with no other codes. Started the car(hard start again), and I could visually see (on the computer) the Engine temp jumping everywhere from -41 to the correct 204*F reading. Also, the cooling fans were cycling erratically.

So question is this:

It's obvious they replaced the sensor. The new one is very shiny brass, right on the front of the water pump. Could a new AC Delco sensor be bad and cause these readings? Or is it more likely the connection?

P.S., reason TC was unlocking (in case some didn't know), is that 4L60E/80E will only lock-up past a set eng. temp(don't know exactly which temp). This was a neat bit of trivia I learned from Ken.

nuc79

Also, bear with me, as I just ordered my cable and software from mastach.com last week, and have never datalogged before. Hope I explained everything correctly.

Additionally, want to make clear that I IN NO WAY fault Ken's shop for the problem i'm having. Those guys are great and their trannys are bad-as*.

I just figured they had forgot to erase the code from memory after they replaced the sensor...(not a big deal)

shoebox

Maybe the sensor is bad or the connection/circuit is. There is info on testing on my Tech Page (near the end of the "How-to" list). If the pcm sees the temp low, it is going to richen up the mixture.

nuc79

Thanks shoebox! That-> (http://shbox.com/1/4th_gen_tech2.html#ect) is exactly what I'll check tonight.

nuc79

UPDATE: well, turned out to be a pretty easy fix. The 2 wires coming out of the plug from the CTS were doing an immediate 90 degree bend, causing the one or the other to be pinched. That was causing a poor/intermittent connection. Fixed it in about 10 minutes. Just had to remove the intake elbow and donkey-dong. Then push the wires tight into the backside of the plug, and tape the wires to the plug with a couple wraps of hig-quality elec. tape.

Also, noticed that the dong brushes against the sensor and connection when re-installing. Maybe that's what caused it in the first place.(?) I know the sensor actually was bad when it was replaced last week, not just a bad connection. The poor connection happened immediately afterwards.

Cliff's notes: Be careful not to crimp or interfere with these two wires when installing intake elbow, or car might run like a$$.