rhett838

Concerning my 68 Cutlass with a 350 Engine.

My Engine runs well at idle until it's warm - weird I know. Then when I'm at an intersection with the car in gear it just wants to die on me. It has died on me twice. I have to put gas directly in the carb to get it fired up again or else it won't start.

The carb also whistles when I press the gas. Not overwhelmingly, but it's there. I checked the hoses, but there doesn't seem to be a leak anywhere. Should I shoot some carb cleaner around the base and the back and see if it responds to that?

Then the car just won't accelerate. I'll punch it and it seems like it just won't take.

I think it's the carb. I took it off yesterday and cleaned it up and adjusted the floats, but that didn't help much...really it didn't help at all. It's an Edelbrock 1406 carb 600 CFM. The carb was put on 2 owners ago, so I'm not really familiar with it's history.

After I put it back on, it started. Idled fine. Got it up to 190 degrees. Took it for a spin and it didn't get pass my neighbor's house. It died. Got it going again and I just put it in my garage.

Just sitting there parked in my garage, I started it again. Idled fine. Got it warm again. Shifted through the gears and it would just want to die. But it would catch after a few revs. Then I'd rev it up while in park and it wouldn't get past 2000 RPMs unless I hit the accelerator a few times.

It's so strange

It could also be the fuel system. I got a clear fuel filter and fuel is flowing to the carb, so I'm not sure if that's the issue.

It could also be the timing, but it runs so well until it's really warm. It's not backfiring either.

I'm stumped b/c I'm not a mechanic, and I'm trying to avoid going back to a mechanic. I know it's something easy.

Thanks!

Rhett

joe_padavano

Points or electronic ignition? This may be a thermally-related ignition problem. Heat on the coil or ignition module (if electronic) can also cause the symptoms you list. Also, consider installing a fuel pressure gauge (even if only temporarily) to monitor what's going on when the car acts up.

rhett838

Thanks Joe!

I'm not real familiar with ignition systems and I've only had the car a few weeks. There isn't a coil, so I think it's an electronic system. I attached a pic I took yesterday with the carb off. It doesn't tell the whole story, but it's all I have right now and it'll probably give you a better idea.

If it is heat on the module. Do I need to shield it, get a new one that's more high temp friendly?

NHolds

Put a quadrajet back on it. I had a 1406 on mine once. Could never get it to run correctly. Found out later there was an obstruction in the fuel line, but I put my quadrajet back on, and never went back to the Edelbrock.

hookem horns

Maybe a vacuum leak? If staring cold the choke could mask the problem but then get worse as the choke opens up.

rhett838

This is a side note, but I really thought that square bore adapter was a 4bbl to 2bbl adapter before I took it off. I was really surprised this was a 4bbl intake manifold on a cutlass s 350. That's not common right?

I'm going to put a 7111 intake on it soon, but I want to figure out this darn sputtering before I muck it up even more.

NHolds

Could order either way.

MDchanic

You have a later GM HEI ignition system, with an integral coil in the distributor cap.

Among the many possible problems that have been posted here, you could have a bad HEI module - they often develop heat intermittents.

The next step, dare I say it, is diagnosis.
You have to determine what is wrong and what makes it better.
Get it hot, make it run crappy, then see if closing the choke a little smooths it out.
Next check the spark to see if it's bright white, or orangey and crappy.
Then go on from there.

- Eric

rhett838

Hmm - Changing out a HEI module sounds fun...doesn't look too difficult. Just don't want to screw up the timing.

However - I don't know how to close the choke on that carb. I noticed the "flap" over the 2 of the barrels is always open and difficult to close. Is that the what controls the choke?

I don't know anything about carbs, but I thought that flap was supposed to open up as you accelerated..

I'll have to download the edelbrock manual and read up on it.

rhett838

BTW Eric - You get a virtual High 5 for being to identify the ignition system I have using only a small picture that shows only 1/3 of my distributor cap.

RetroRanger

Choke adjusted ? I think the 1406 is e choke.

I have a 1405 on mine runs OK ...agreed the qjet may be better but it should run fine w the carb on there.

MDchanic

Thank you.

Here is a Carter AFB / Edelbrock (from here):



You push the throttle lever back to open the throttle and take the pressure of the pawl that rides on the fast idle cam, releasing the choke to move freely.

If the choke is closed when warm, then that is likely your problem.

If it is open al the way, then it is not.

- Eric

oldcutlass

You are going to have to do some troubleshooting when it starts running poorly and isolate whether it's a fuel or ignition issue. Joe's idea of putting a fuel pressure gauge on there is a good one because then you can monitor fuel pressure to the carb. People have been running that carb on these engines for years and years so that is not the issue. The suggestion to make sure the choke plate is opened all the way at warm up is a good place to start.

Eric's diagnosis of HEI issues are correct, so if you have access to a known good distributor that would be a perk. I'd also check to see if you have a full 12v to your distributor and not running through a resistor wire. Pop the cap and make sure it's seated squarely and firmly and in the notch, don't ask how I know.

Next time it stalls or starts to run poorly, monitor the fuel pressure gauge. If you have at least 6psi, check to see if you have fuel when you pump the gas by moving the throttle linkage and looking into the throat of the carb. If you have fuel check for spark, one of those spark testers work great.

rhett838

Ugh!!!! I just wrote a long reply on my phone bc my Internet is out and it didn't even post....aaarrgggghhh!

Bullet points:
Still sputtered

Choke plate closed at cold start, open as it got warmer...good

Didn't have time after work to buy and hookup fuel pressure gauge

Clear fuel filter looked dry. I'm leaning toward the fuel pump.

Took distributor cap off and hei module looks pretty new. Looks mean nothing I know, but I don't think it's the culprit

Issue seems to be getting progressively worse. Now it won't even start with gas in the carb

Very frustrated! Only had the car in my possession for 3 weeks!!!

oldcutlass

Did you check your spark?

rhett838

Didn't check the spark bc i forgot...and i didnt know how. But I watched a few you tube clips on how to do that just right now.

I didn't pull all the plugs. I used an extra plug I had laying around, but spark is coming from all of the spark plug wires...all blue. I guess I need to pull the plugs though to see if they're producing spark right?

I did get it started again though...I think bc the engine cooled down.

I have a pic of the fuel filter I want to share. Let me see if I can upload it from the phone and onto this site.

Basically the fuel filter isn't even a 1/3 full while the car is running.

Stand by for that

rhett838

Fuel filter while running...
The very bottom is all of the fuel in the filter

rhett838

Another view....of course it's upside down...damn iPhone!

oldcutlass

Put the fuel pressure gauge on it, and see what your pressure is. Also next time you get it started, have a timg light handy and let us know what your timing is set to with the vacuum advance disconnected and plugged.

rhett838

Thanks "oldcutlass" and "MDchanic"! I'm out of troubleshooting time until the weekend rolls around. I'll keep you posted when I get back on it with a timing light and fuel pressure gauge.

I was reading a post from 2 years ago that was similar to my issue. You 2 tried to help the guy, but he was just getting oil changes and hoping that would fix the the problem.

The runaround you guys were dragged into made me laugh out loud.

I'll try my best to listen and learn...thanks agin for your time and input! I'll get back at it this sat.

oldcutlass

No problem, let us know how it goes this weeknd.

MDchanic

Yeah - read through that thread. If it's the one I'm thinking of, we went through all the principles of auto mechanics, as well as the theories of gravity and General and Special Relativity and the Unified Field Theorem.

I still suspect spark, but it can be hard to describe a "good" spark versus a "bad" spark. The best way to be sure is to arrange it so that you can see how far the spark will jump - if memory serves, an HEI spark should get over ¾".
It is also possible to remove the module and bring it to any chain auto parts store, and they can check it (be sure to heat it up well first, like with a hair dryer).

As for the fuel filter, they never look full - that's normal.

- Eric

joe_padavano

Clear plastic fuel filters are probably responsible for more questions about fuel pressure and flow than anything else. It is normal for the filter NOT to be full of fuel. Pressure and flow rate are what matters.

1BOSS83

Pull the plugs. How long have you had the car? How often do you drive it? A lot of earlier carbs are having a hard time dealing with the "cleaner" gas in the pumps today. I've heard of some getting stuck open and overflowing. I'd spend some cash on a cap, rotor, coil and wires/plugs and see where you are from there. If the choke is open and there is fuel in the filter its either spark or the fuel pump.

hookem horns

[QUOTE=rhett838;535298]
Choke plate closed at cold start, open as it got warmer...good

QUOTE]

Sounds like the choke is working properly. Did it run better if you manually closed the choke plate after it warmed up? If it does help you have a vacuum leak somewhere. If so, try spraying a little carb cleaner at the base of the carb and other vac ports to see if you can find it. Idle will change when you hit the offending spot.

rhett838

So many ???s

I've had the car in my possession for about 3 weeks. I've owned it for over a year, but I'm not going to get into that here...I've posted on that scenario about a month ago.

If you read that scenario I wonder if my car has been messed with. Sugar or something in the gas tank has popped into my mind a lot lately, but I don't know the effects of that.

The owner before me said he never experienced this problem.

I've taken it out a few times. Each time the drive gets shorter and the sputtering gets worse. Now I go down the block and back. Anything over 7mph asks for a stall.

Joe said its normal for that filter to not be full o fuel, but did you guys see that pic? It's not even a 1//4 full. I'm going to check the gas pressure when I have time later this week.

rhett838

I hate posting w the phone...

Hookemhorns-sprayed carb cleaner around the carb while it was running. There was no reaction. I was hoping for a vacuum leak actually. However, there is a whistle that sounds like is coming from within the carb. I don't know what it is...bad gasket? Jet? I REALLY want to put a different carb on there just to see what happens, but I dot know anyone with extra carbs lying around

rhett838

You know, I just thought of this...see the pic I posted toward the top of this thread if my manifold minus the carb? That square bore adapter is covering up a lot or real estate. Could that be contributing to problems?

MDchanic

I really think you need to confirm whether this is a weak spark problem before you get much further.

- Eric

hullinger

Rhett, is it you that wrote about having your car at Desert Valley Auto Parts for a rest? If so, I'm glad you got your car back.

Rickman48

You do know that 'spacer/adapter' is supposed to have gaskets between them, don't you?
I didn't see any.
Heat might warp it, causing separation - hence, a vacuum leak!

Holiday350

what style of intake does it have and does it have egr?

Joffroi

I was the owner of the convertible before Rhett838 and never had any issues like that. Drove that car to and from work (15 miles each way) and never had a problem. Had to change the starter but I believe that was it. Its just very disappointing to hear a car you used to have giving so much trouble to a new owner. oldcutlass and MDchanic have helped me fix many problems with my cars and hopefully they can do the same here. If they are every in the KC area, I definitely owe them some goold KC BBQ and a couple beers! . I definitely appreciate being able to come here and ask even the simplest questions and getting help.

Couldn't help but noticed the location of rhett838 and oldcutlass (Granbury, Texas to Euless, TX = 1hr 5min drive). Is oldcutlass for hire? haha

oldcutlass

I noticed where he was also. There are a couple of other members much closer, lets see what progress he can make this weekend.

MDchanic

Thanks for the vote of support, Joffroi (and the offer ).

Usually, it's just a matter of needing to have someone force you to go through the problem systematically, until it's been narrowed down.

When we're wrapped up in it, it can be surprisingly difficult to look at a problem like this objectively, instead of just stabbing at random things, even for me. An outside person to keep us honest is often all that any of us needs.

- Eric

Greg Rogers

Could it be the "sock" in the tank? I spent a lot of dollars on unneeded parts years ago on a 73 Cadillac and it ran fine for a while then quit, after sitting a while would start and run then quit,etc etc.

rhett838

***UPDATE***

Welp - I finally got it going, with the help of my mechanic and the help of my $$$ of course.

The culprit??? The fuel pump. I actually put on a new mechanical fuel pump but it wasn't enough apparently. He put on an electric one and it idles fine now.

What a headache!

I also changed out the carb adapter. Originally a spread bore to square bore adapter was on it. I put on the opposite and guess what? That humming noise is gone. Maybe there was a vacuum leak too.

I also had the intake manifold taken off cleaned up and put back on. The plastic gaskets were used on the end seals...of course they were melted. So that's sealed up a little better.

And I changed out the plug wires.

Now I can drive it...FINALLY! But now my Tac and my other rally gauge doesn't work...who knows when I'm running low on fuel.

Also my Mechanic told me there's rust in the fuel tank and that I should change it out eventually. Anyone know where I can get one of those?

Mechanic also said I should get rid of it, but that's another story. He said if I keep it it'll keep him in business...lol.

On to the next thing...Thanks to everyone for your help!

oldcutlass

I was wondering what became of your issue? Glad you got it going.

MDchanic

A highly unexpected cause for the problem you described in the engine you described, but I'm glad you got it fixed!

- Eric

Fun71

I'm glad you got it running, but that isn't right. Over the years millions of Olds engines have run just fine with the mechanical fuel pump. I will tell you that I have run into more than one fuel pump that didn't work properly right out of the box. I went through three Carter M6109 pumps before I finally got one that didn't peg the fuel pressure gauge at 10 psi and flood the carburetor (max pressure for QJet operation is 7 psi). Apparently quality control has gone out the window as manufacturing has gone out of the country.