[oldsevenfire]

Essentially, I am wondering if i can bypass all the sensors and emissions business (i live in the sticks, no inspections) on my car by slapping on headers, new carb with manual choke, maybe intake manifold, removing the emissions (i know it takes some time) and straight piping it. also, wondering how likely it is that this would solve all/any of my problems and if i can bypass the ecm without any headaches like i hope i can(heh). following, are the dirty details

have an 85 cutlass with a 3.8 v6. It was pretty dirty all around under the hood when i got it and I'm not sure where to start with helping it out. I gave it an ignition tune up and new filters and it ran alright but its got some issues. It doesn't shift right all the time... (won't go beyond 3rd when hot, shifts into 4th at 20 mph when cold)... its got BAD hesitation... usually idles at about 3500 most of the time when it starts and the fast idle won't come down even after its warm... sometimes when you hold the gas in one spot it will go back and forth between accelerating and decelerating like its trying to decide wether or not to shift... and its PAINFULLY slow.

...I suspect a combination of things may be going wrong (cat converter is OLD, probably plugged, some emissions stuff isnt hooked up right (ecm might be messing up the running due to false reading?) sensors might be bad, (temp, oil pressure, and voltage gauges don't work) there are a couple electrical connectors not hooked up or with wires missing under the hood...

(cheers to anybody who took the time to read all this and thanks for any input)

[DoubleVision]

These cars were mobbed with miles of vacuum line. Believe it or not, they also have a map sensor but it's not on the engine. It's in the interior. On the passengers side floorboard look to the panel to your right hand side. It's here you'll find the ECM and the map sensor. Just about willing to bet the map sensor has a broken vacuum line and likely many other vacuum leaks. You can either replace all the vacuum lines then adjust the choke or you can do as your speaking of. The trans likely doesn't want to shift from lack of vacuum.

[oldsevenfire]

map sensor INSIDE the car? interesting... I'll have to check that out tomorrow. So I think im going to cut off the catalytic converter asap. Is it a bad idea to drive it to the shop with no exhaust beyond where the cat is? people say it'll burn the exhaust valves with no back pressure but that also sounds like part urban legend. (ive never heard of that actually happening to anybody...)

[DoubleVision]

I've seen exhaust valves get burned many times from lack of back pressure. What happens is when the back pressure is reduced the mixture must be richened to compensate, otherwise the engine will run dead lean which causes the excessive hot exhaust. However, if you were to just "unplug" your converter it wouldn't hurt it as long as you focus on fixing the current vacuum leaks I'm sure it likely has. How do I know so much about these cars? I've built 4 of them, converted them all to sbc power. The Cutlass supreme 2 door in the 80's had a lovely body with very nice lines and when you apply things to them you can make them look really nice. What I did was turned them into half performance and half luxury, something you don't see often.
Even if I was starting out with a V6 car which 3 of them have been, a sbc swap is still a slam dunk as everything bolts in, the motor mount bolts are already pre drilled in the frame. Then you find a V8 donor car for the cross member. Then you write down the codes to 82 to 87 F bodies, the camaro and firebird, get the rear end codes for locking differentials and decent gears then hit the junkyard and find a unit and swap the guts in so in the process, I learned alot about these cars.

[oldsevenfire]

The cat is going to be a huge pain to get off without cutting it since the bolts are all severely rusted in. i'll figure something out... i have a 4 door though and kind of want to go the "performance luxury" route with it eventually. I've seen the potential of these v6 motors and nobody expects a turbo on a v6 sedan that looks like it wants to be a limo. haaaa. ...unfortunately, i have a ways to go before i start thinking about going that far with it. for now, ill be happy if i can get it above 15 mpg.

[oldsevenfire]

also... any ideas as to why the fast idle wouldn't come off? the choke pull off was just replaced. i hate putting it in gear when its revving like that...

[LATECH]

First I would pull trouble codes, write them all down in the order they appear.
Then unhook the battery for about a minute.Then reconnect it, turn on the Ignition dont start it though. Immediately recheck the codes that appear.
Then post back.
Oh read a little here to pull codes from your OBD 1 car.
http://www.aldlcable.com/

part way down the page it will explain how to get the codes. Pay close attention while retrieving codes and write the numbers down. We can help decipher them here.

[oldsevenfire]

The only reason I haven't done that is because the check engine light isn't on. Is it possible for there to be trouble codes without the light on? and i know its not just a burned bulb because it turns on when the car isnt running.

[LATECH]

Originally Posted by oldsevenfire

The only reason I haven't done that is because the check engine light isn't on. Is it possible for there to be trouble codes without the light on? and i know its not just a burned bulb because it turns on when the car isnt running.

Absolutely can and has happened.I have also had a few that have the light on and no codes stored as well.sometimes the lamp driver circuit fails,or other sections fail to communicate and the lamp doesnt work correctly
Also the MAP sensor wont be in the ECM on this one. That was actually used on oldsmobile and a few others, but last time I saw that was on a 1978 cadillac with an olds 403 fuel injected motor. Yep on a 1978, how bout that?

[cobalt327]

I agree- the idea of converting the whole engine and trans lock up over to non ECM is not what I would recommend doing first, when there's a distinct possibility that w/the replacement of the vacuum lines and a few bucks in replacement parts/sensors, that it will run as good as the engine's internal condition will let it.

Pulling the codes on a CCC (Computer Command Control, or OBD 1) equipped vehicle is uber-easy (can you bend a paper clip into a "U"?). Run the codes several times because you'll be counting flashes and pauses of the dash check engine light, and it's easy to get them wrong at first.

[oldsevenfire]

I stuck a paperclip in the connector and it just flashed code twelve, which according to my manual is no "distributor reference pulse". its supposed to flash 3 times then display other codes if there are any but no other codes came up...

pretty convenient setup though, not needing a scanner. ha

[cobalt327]

Originally Posted by oldsevenfire

I stuck a paperclip in the connector and it just flashed code twelve, which according to my manual is no "distributor reference pulse". its supposed to flash 3 times then display other codes if there are any but no other codes came up...

pretty convenient setup though, not needing a scanner. ha

That's good and bad- a code would have given you something to home in on, but a "12" is no codes, so in a way that's good, too.

[LATECH]

Driveability with No code takes you back to basic diagnostics.
You will need to look at the fact that the ECM could still be defective. The transmission may also have an issue.
First: observe the Idle speed control motor at the carburetor. Does it EVER move?
Second : Look at the fast idle and base Idle adjustments on the carb, Maybe someone cranked them up to keep it running.
If the Idle speed motor is moving out and in then it is trying to control the idle, maybe the base idle screw or fast idle is holding the engine speed up
Third: jump the connector under the dash, like when you were checking for codes. As soon as you turn on the key,listen to the carburetor, it should make a clicking sound for about 30 seconds.Also the Idle speed controller motor should extend and retract at the same time.
The idle speed control and the Mixture solenoid are both ECM outputs, meaning the ECM controls them. By determining if there working you can determine if the ECM has a problem it cant communicate for one reason or another. With all that is going on it should be trippin some code.


From what i can collect from what you said about its performance, and knowing what I know, I would have to say , the carb has been running rich for a long time, causing the cat to plug. The trans may have been damaged by dropping the shifter into gear at 3500 rpms once too often.
BUT lets not jump the gun, just check the 3 things I asked for and post back here.

[oldsevenfire]

the strange thing about the idle problem is that when i bought the car, it idled high (usually around 2700-3000). one day it wouldnt start so i did the tune up with plugs, wires, etc and it still wouldnt start. i towed it to a shop and they replaced the choke pull off. for about a month after that, it started right up and idled at a normal rpm. suddenly, one day it was back to idling high. (seems like it got even higher.) also, of you really stomp on the gas (close to redlining it) when its warm, the idle does come down to 1700 or 2000. ...usually. but anyway... i'll see what i can see with the idle control and such.

[oldsevenfire]

and i "fixed" the cat. it was definitely plugged pretty bad but didn't drastically improve the situation. seems to run a bit better though.