• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Sat for a couple months. Now multi-codes pending.

Gotcha. Suggestions on a replacement? I'm really green on these cars. I got my first good look at the U bend and understand the need to replace it. Don't want to spend dumb money on the car since the AC won't work.
I've got two engines that the cat was sheared off, so those would have a flex/flange that could be welded on to mine? Also, we don't have emissions testing. Not that I want to dirty the air, but seems I read you can run one O2?
 


depends on the year car you have. i fits 01-03 you'll have a cel and over fueling issues with out the cat.

a 97-00 you could still run the rear o2 and no cat and be ok pretty much.
 


3 is better then 2.5. if you had kr it might be gone with it. that u bend is a choke point. just removing that helps, so a larger pipe will be better.

be best to buy a new rear o2 sensor too, the old one will put up a damn good fight, and likely not come out. iirc them zzp dp's moved the o2 bung further away and you need a extension harness too.
 
The O2 harness is cooked anyway, so a new one has to be grafted in. Here's a couple of more cooked items I don't know where they go. What are they and where do they go so I can work on getting it back together now that I have a new 3" dp?

(1) The 1st issue is a vacuum hose that's burned. The circle is around the burned end I held near the port where it tees off. The arrow indicates the location on the port where it tees off.
(2) The 2nd is a circled electrical connector with one end cooked. For a location marker you can see the rear of the eng/trans and also the rear exhaust manifold. The spark plug wire seen is the rear pass side.

Thanks for any help.

Pics of both issues below. Trying to load pics on this site are very aggravating.

http://imgur.com/a/FscLh
http://imgur.com/SfOD2Ak
http://imgur.com/PrVfLfp

 
The burnt plugs, all thats back there is the trannys vss plug, the oil pressure sensor, and the rear knock sensor harness. the rear o2 wires run past all that.

pic one, the one of the top of the sc, the busted line are you saying the busted end leads to the top of the sc? if so that vac line leads down the fender with the washer fluid line under the fuse box, some one busted it changing the battery most likely.
 
Confirmed the vacuum line. Fire melted it in two back at the fire wall going where you said, I believe. That electrical connector isn't toasted as I thought. It only has a wire or two wires that are trained around the back side and appears to be at the back of the power steering reservoir.

However, one of the other connectors isn't in the best of condition. Think it's the VSS. Could a problem there cause my shifting down to 2nd issue? Because if you remember the car would drop to 2nd on the interstate after about 5 miles. Is 2nd gear limp home?
 
thin wire clipped to the p/s is the knock sensor harness.

any baked wires should be replaced.

the vac line, cut off the burnt ends, then patch it with new rubber vac line, just push the hard line into the rubber line.
 


Finally found the motivation to replace the oil pressure sender. What tool do you use to remove/replace it? And does anyone know the size of exhaust bolts for the flange from dp to muffler/resonator?
 
large channel locks work best, dont over tighten the new on, once its snug stop or you can break the housing, its a NPT thread, it gets fatter.
 
I used a 1-1/16" wrench and it took way longer than I wanted. I tightened it until I felt resistance but realized that was the sealant applied from the factory. So I continued and bit my fingernails hoping it wouldn't strip. Felt resistance again and just did a final snug.
I can't find what I did with the dp/muffler flange bolts. They need replacement but need them for example.

EDIT: just found the bolts.
 
Last edited:
Well the exhaust is quieter now, but the car has all the other running/driving problems it had when it quit. Idle starts at 1200 (lumpy) and increases to 1700 or so. Revving is anemic, as it starts good but breaks up half way up the tach read-out. Some fluid is burning continuously at the rear manifold. Looks like it'll catch on fire again if I run it long.

Only drove it up to 30 mph down the block and back and there was only one gear. No gear change, even when accelerating a good bit and letting off. And the exhaust is so rich it'll sicken you.
 


And maybe you should share your felonious nature on an aspiring rapper website.

A local mechanic gave me a couple of tidbits to work on saying there are multiple problems at work, one being the sensor in the coolant reservoir. Another being the VSS sensor and a probable bad wire.

This site doesn't seem to have much activity in this year range like I would expect. Is there a more active 3800SC website? Gonna try 60 degree V6 or whatever it's called.
 
you'd be hard pressed to find another forum thats 1/2 as active as this site. we are not there, anything we suggest is really a educated guess.

it might be time to seek a shop out. some times things are a bad wire or something dumb like that and if you dont know how to test it, your getting no where.

and i know of no sensor in the coolant res. theres one in the rad, but its worthless. you can unplug it and the car thinks nothing of it. mines unplugged for like 4 years now.
 
Interesting on the sensor info. Hmm. Maybe not so good of info from him then. The car has always had the LOW COOLANT warning come on and then go off (which I didn't mention before he said it), however it has always had what I ascertain as "enough". Previous owner said the light was reoccurring.

This shop owner heard "fire" and said no thanks even though it wasn't much of a fire. He has (2) SC cars he drives which is why I stopped. He also said check the ground under the rear seat until he heard I had the battery under the hood to which he said, "Oh, you have a Grand Prix then."

How hard is it to swap the wiring harness on these? Scottydoggs, your comment and the fire afterwards has me thinking I need to change it.

And who'd put full coverage on a borderline failing paint 4 dr with non-working ac, 199k miles and 17 yrs of age on it? Most of these cars this age are nearly throw away now.
 
Last edited:
i think you need to test it. you can cut off parts you need from a jy harness, solder them into yours.

that sensor gets dirty with dex sludge then shows the light when its full. if your coolant is always full, you can unplug it and the light never comes back on.
 
You must log in or register to reply here.
Back
Top