I have a 74 Delta 88 with the 350 olds non ac car. 71k on it. Been driving it for a year now with no issues at all. It is all orig motor.
I recently had my WP rebuilt and when I put it back on I went from a 180 Tstat to a 195 Tstat for better heat this winter (convert car).
Now since that tstst change when the car is at running temp and it is sitting for a bit at a light or like today in a parking lot running for a bit while I talked to dude to replace my top. It is dieing out. At that light the other day it was cutting out but got it home. Today it was sitting, running idle for about 10 minutes, when I came back out it was not running (never has done this). It would try to start but sputter a tiny bit then just turn over. Sprayed a little starting fluid in it and it would run a hair then just turn over. It is getting spark.
Could it be as simple as changing to that hotter Tstat that what I am pretty sure is the orig carb can not handle that hotter running motor?
It was running fine at any temp before the tstat change and now RIGHT AFTER the change it acts like it has vapor lock or the carb just wont run, too hot and too old??? Before the stat change this car ran well under all temps, on choke, off choke, etc.

 

The thermostat change isn't causing your problem. I would look at your choke/vacuum. Even if you didn't get the airlock out of the rad it wouldn't cause the problems you mentioned unless your temps went sky high 240 +

 

It may be as simple as readjusting your carbs a/f mixture. When was the last time it was tuned up?

 

Vapor lock? How's your fuel pump working? Does your fuel pump have a return line?

- Eric

 

The car was tuned up right before I got it. Was the carb messed with I do not know and it appears from looking at it that it has not been touched in ages if at all.
I am not getting sky high temps, no "hot" light is coming on.
The Fuel pump is new, installed before I got the car a year ago. I have put about 2500 trouble free miles on the car since I got it. Just odd that it is doing this all the sudden after the tstat being the only change. It is cool here in Cincy, 60, so it is not hot out. I
I don't recall a return fuel line.
I guess I can take off the breather and check the few vac lines I pulled off and see it they worked back off.
She fires up and the choke sets and it runs fine (always has), no hesitation when first driving from stops, etc, but after she gets to temp this new "event" is happening.
Could it be just happen chance that the carb is just puking out now and has nothing to do with my tstat change?
Maybe the carb just is saying it is time for a rebuild of which I have NO CLUE on how to do.
It is sitting at the top shop now. Once it is cooled off it will run fine to get it home them prob do this all over again.

 

Airlock in the radiator? I thought I burped the system. How is it done in a car like this.

 

If it is a choke issue, is there a way to disconnect it to see if that is it?
Could my EGR system be causing issue?

 

If you seen a good flow going through the tubes before finally topping off the rad then you should be good. You EGR could cause what your experiencing, you may want to try and pinch it off and see if any changes occur. As Eric & Eric mentioned is sounds like a fuel/carb/issue among other vacuum related problems.

 

I don't think you folks were on the same page. The vapor lock issue is not related to the radiator itself. The air in the radiator and or motor will work it's way out over time. Just check you fluid level occasionally.

 

since the tstat is not it you all say I will back track my work I dealt with when I pulled the pump, check vac lines, etc. see what happens. Just odd it runs great till at running temp then a no go.

 

is the EGR always working? I don't know if it worked when I got the car but while WP was out I fiddled with the diaphram and it was moving. Maybe I broke it, or fixed it and it causing running issues at running temp?

 

went to get it just now after sitting 3 hours cooling off in 50 degree weather. I hit the gas once and tried to start, tried for a moment to run but did not. After that nothing. tried starting fluid and it tried but stumbled and then nothing. Starting fluid again, stumbled then nothing, starting fluid again and I kept my foot on the gas and it ran rough then was ok, was able to drive it 4 min to home. Ran fine. ODD.

 

Is the choke open when hot? If choke was sticking closed you now have fouled the plugs and it will do what you describe.

 

Did you recently fill the tank with gas?

 

I assume you mean the FLAP on top front of carb? If so yes that is working as it should. Open when hot, various close to closed based on how cold the car is when I have happened to being looking at it for any reason.
It was open fully when it got was sitting yesterday and shut off after running idle for about 10 min.

 

No, has half tank, but it's been a week or more since fill.

 

I will go over everything vac wise, maybe even go ahead and replace all the vac lines since they are old. My car just to the left of the Tstat housing has a black cover over some vacuum stuff, I will make sure non of the lines came off in there.

 

So there is NO way that this old carb sitting up on top of that motor all these years, is worn down to run one way and that is with a 180 tstat and then I introduce a 195 stat to it and it is like, NO way man, this is to warm and when it warms up it just ***** the brick on me? It running well when cold, it is the running temp thing that gets me.

 

No.

- Eric

 

So I then just have soemthing that I disturbed when I had the the Tstat stuff off? Again there are several vac lines that come and go to the left of it under a black cover.
It was said to pinch the ERG off, meaning then vac line to it? Block that line? Does the EGR work once it is hot doesn't it? Could it be causing vac issues?
Should I rebuild this carb just in geberal due to it's age though before this issue it ran rather good?

 

I would change your fuel filter and check for vacuum leaks as in spray carb cleaner around the carb. The bolts and screws on the carb work loose over time and can cause a vacuum leak. I periodically tighten mine.

 

Yea I will look at the filter at the Carb. I actually recently lightly snugged down some of the bolts on the Carb for the reason you state.

 

Most likely.


That is probably the EGR delay valve.


Worth a try. Takes a second.


Could be. But you probably just knocked off a vacuum line.


I've heard of putting a Tiger in your Tank, but not a Gerbil in your Carb.

You haven't had good luck with simple repairs thus far. I'd keep it simple and avoid fixing what ain't broke for now.

- Eric

 

If I plug the EGR vav line, does that EGR valve delay (as i call it is looks a small ball) thin cause issues with other things since the line going into it is plugged?

 

You need to read chapter 6C of your Chassis Service Manual, especially the section on EGR, and the descriptions of the operation of the different components.

I was wrong about the component I think you are talking about - it is not a delay, it is a thermal valve that opens at 61°F.

One of these vacuum diagrams probably applies to your car:



- Eric

 

I have a serv manual for 1974 olds cars. I will look at it. I jsut don't get how many of these things work. Beyond my pay grade.
Looks like the one on the right is my set up. I do not think have the DTVS listed on the lower right on the pic on the left.

 

The manual will tell you. Better than I can, since I don't mess with EGR and emission controls.

- Eric

 

well tonight I let it get hot and it shut off again would not start and run worth a **** at all. She was nice and hot. I went over all the vac lines, everything snug, no tears or holes.
While I had the WP (weeks ago) off I looked at the bolts on the carb and thought they prob are lose, they were. So I snug them down. Tonight after it was very hot I poured some gas directly into the front barrels (and to the prev questions the choke is setting right, flap closed when choke set cold, opened when hot) and noticed wet gas on the intake. So I poured a LITTLE more in and on both front sides of the carb as fast as I put the gas in it leaked right out I think the bottom carb gasket to the intake.
So would this be my issue? Sucking in that much or little air to make it not want to run when at running temp? I assume the gasket is changing seal as it gets cold to hot??
I guess I should but the carb repair kit I found on ebay and replace the gaskets?

 

You could just put some sealant on the gasket surfaces - RTV would work, but I personally have a thing for Hylomar.

- Eric

 

if I am pulling the thing I may as well put fresh gasket in there I would think.
I assume this is my running issue?

 

You should be able to get a carb base gasket at your local auto parts store. In the past I got them from NAPA and O'reilly's.

 

so this decent gas leak is the problem? When it is hot it is sucking air IN and not allowing it to run/start?

 

We can't tell you what the problem is.

You have to diagnose it and figure it out.

- Eric

 

To answer some of your egr questions; the egr valve only opens under light throttle/cruise speeds. The valve remains closed at idle and WOT. It is possible that the valve was stuck closed until you tested it. It could be that there is some carbon chunks stuck in the valve and holding it open at idle. An easy way to check for this is to check the temp of the valve at idle, if it is as hot as an exhaust manifold; it is stuck open. This may lead to having to clean out the egr passages to prevent more carbon from getting lodged in the valve. I don't know how this system is configured, but the ones I have experience with had an egr adapter plate under the carb the could be removed and cleaned out. Other wise the intake will need to come off to clean out the passages if this ends up being the problem.

 

GM used a lot of plastic 'tees' in the vacuum lines. I've had them hairline crack before and you can barely notice them visually. Besides the obvious cracked hoses check them.

I doubt your car is running hotter with the new thermostat. More likely it is just taking longer to open the thermostat with the 195 in it. The overall temperature probably remained the same which I'm guessing is in the 200-210 range. The efficiency of your cooling system dictates overall temp not the thermostat.

 

good test I don't know, but when hot and is idling well, if I manually push on the diaphram in it the car wants to stall out, when I let go it runs fine.

 

well I have not went through replacing all the vac lines and the like. If you all are saying on little leak can make it not run when hot then why is no one saying anything to what I see as a HUGE air leak when hot and that is my gas leaking from under the carb. If gas can get out that means in a closed system (air cleaner and all is attached)it is sucking in air. Is that air going to make it not run?? I am surprised no one has said anything about that pretty good gas leak I mentioned.

 

I believe Kenneth chimed in on where to get your new gasket. Yes it can cause your issue.

 

I am trying to get estimates to replace my top and now I can't drive the car far at all with this current issue right out of the blue. ha ha ha

 

Next time you start it, try to hook up a vacuum gauge to it and see what its doing.