sykosoft

I have just purchased a 1969 Oldsmobile Cutlass with a Rocket 350, and I suspect, a THM350. Car runs GREAT, but the transmission doesn't shift into 3rd (or at least, I can't tell that it does, 1 symptom being that the rev limiter won't allow the car to go past about 75mph).

In diagnosing, I've noticed that pretty much all the vacuum lines on top of the engine are cut, with screws stuffed in them. Additionally, the (I'm assuming) kickdown has no wires running from it. I'm attaching pictures, and am hoping the masters here can tell me what runs where.

There's a stack of 3 vacuum lines that are near the front of the engine (all cut), a line coming from the airbox (cut), and two lines that go into the engine behind the carb (also cut). Hopefully these are all clear in the pictures. Any and all help is greatly appreciated.

Michael

EDIT: Solved. See my post below. Plugged metal vacuum line.

joe_padavano

The biggest help we can give you is to suggest that you buy a factory service manual for your car. In the meantime:

The stack of three ports is a thermal vacuum switch (TVS). It is intended to switch the distributor vacuum advance between ported and manifold vacuum if the car starts to overheat. It appears that the distributor is currently running on manifold vacuum only. That's fine if the car runs correctly. Of course, since there is no vacuum in that TVS any more, there's really no need to cap the ports, either.

The thing you have labeled "kickdown" is the idle control solenoid. It was intended to prevent dieseling by retracting and letting the carb close fully when the engine was shut off. If you don't have a problem with dieseling and the car idles fine, don't worry about it.

Your car could have had either a Jetaway 2-spd trans or a TH350 three speed trans from the factory. What does the shift indicator say - PRNDL or PRNDSL? The former indicates the Jetaway, the latter the TH350 (assuming the original trans is still in place). If it really is a TH350, the kickdown is cable operated, not electric. If it's a Jetaway, the kickdown is electric and operated from a switch on the accelerator pedal under the dash. The wire goes from there to the trans.

Either trans uses a vacuum modulator. The modulator is located on the passenger side of the trans and there should be a metal pipe that runs from the modulator, up the bellhousing, and onto the intake manifold. This should be connected to manifold vacuum.

The metal vacuum line at the rear of the intake is for the power brake booster.

The small vacuum port in front of that fitting that's capped should have been connected to the hot air flapper on the air cleaner.

sykosoft

I will check out the things you have mentioned, and this is exactly the type of knowledge I was hoping for. The shifter says: PRNDSL. I do realize that it's possible the transmission was replaced post-factory, so I'll attempt identification according to: http://www.nastyz28.com/chevy-transm...tification.php

I've read that there could be basically 4 reasons for the transmission not going into 3rd:

1. Vacuum modulator problem (disconnected, leak, etc)
2. Kickdown problem (not properly adjusted tension-wise)
3. Governor problem
4. Truly bad transmission

Do these sound accurate?

Michael

joe_padavano

Yup, however if the vac modulator is bad, it won't shift from first to second either unless you're at wide open throttle. If it does shift 1-2 but not 2-3, it's unlikely to be the modulator.

sykosoft

I could have saved myself about a day and a half, and a lot of trouble, but wasn't really feeling so good, and made some silly decisions. Rather than ACTUALLY test vacuum on both sides of the modulator vacuum line, I went ahead and replaced the vacuum modulator and the governor (I had another th350 sitting here). Getting the governor cover off was practically impossible. We literally cut it off. While I was doing that, I decided to check vacuum levels at the modulator, and found none. Will need to replace the metal line at some point, but used the one I had from the other th350 on hand (from an S10 chevy). It doesn't even fit right, but now the transmission shifts pretty much perfectly, so that's the good news.

Solved.

Michael

rocketraider

I'd lay money that your heater control isn't working either.

Sounds like that car is a victim of an "amateur" desmogging by someone who really had no idea what he was doing, but subscribed to the "if it's got a vacuum line to it cut it, you don't need it" school of thought.

I've fixed many botch jobs like that over the years, sometimes over the loud protests of the owner. Then when the car finally ran right again he couldn't believe it.

All goes back to understanding how something works instead of automatically assuming the stuff you're disabling is somehow bad. I'll put a BB in an EGR vacuum line in a minute, but I've found the vast majority of other vacuum controlled components have no real ill effects on how a car runs and drives unless the vacuum line breaks and causes a vacuum leak. Exception being transmission controlled spark, which was one of the more ridiculous things they came up with to satisfy the EPA.

The one that always gets me is when somebody cuts, caps and disables a carb vapor canister. It takes no horsepower to operate it and recovers expensive fuel. Some later ones with vacuum switches and solenoids could cause problems, but for the most part all it does is take up a little space underhood.

sykosoft

I agree with you, to a point. My car is a 69, and I simply don't see any smog equipment on it (or any that was supposed to be installed on it). I do intend to try to fix the vacuum lines, I've just not been able to find a diagram for my 69.

Michael

rustyroger

I've come across a lot of American cars over here that have been worked on by so called experts brought to me because they couldn't get them running properly.
I have normally fixed them by resetting them to original factory spec, there seems to be a prevailing view of "if I cant work out what it does it shouldn't be there" and "all smog equipment does is hurt performance and mileage so discard it".
I'm not claiming know everything, but I have earned a living for over 30 years as a mechanic.
I subscribe to the view that the design engineers didn't get their degrees for nothing so unless I fully understand what the equipment does and what effect removing it will have I concede that I probably don't know better than the people who designed it in the first place.
Ask any mechanic which jobs give them the biggest headaches and they will probably say it's fixing a fault after someone who didn't know what they were doing has tried and failed.
Roger.

pac937drb

I've had my 86 Olds Supreme for about a month . Recently there was a big snow here and now i notice i have a big leak in the brake line on the drivers side rear tire . Now the brake light is coming on but it didn't until i took the cap off to check it ... now it's leaking worse . Can This lock up my back wheel ??? How much am i looking at ??? should it be fixed immeaditly ???

MDchanic

FIRST - How on Earth did you decide to hijack a two year old thread about a '69 Cutlass with a transmission problem with a new question about an '86 Cutlass with a brake problem?
Have you ever used the Internet before today?

Second - You have a leaky brake line, and your BRAKE light is on.
Have you noticed that this means that your rear brakes aren't working anymore?
Have you considered that the owner's manual of every car ever made says to stop driving immediately if the BRAKE light comes on?
Has it occurred to you that if your rear brake line has rusted through (steel brake lines + snowy environment + 27 years = rust), then the others are probably not far behind?
(It is also possible the you have blown a wheel cylinder, in which case the condition of the lines would not be directly related).

Third - STOP DRIVING THIS CAR RIGHT NOW BEFORE YOU GET KILLED.

Fourth - Welcome to ClassicOldsmobile.

- Eric

[fifth - would it be possible for a Mod to move this to a new thread?]

Paul Shaw

I have 74 cutlass 350 olds rocket" with a good shift kit changed to a edelbroc and realized the intake still had get on it they ran the hose to carb but the clicker the carbs not made for her plugged off it's like night and day