pistonpop

I have a 71 olds Cutlass S 350/350. I replaced the carb about 5 months ago, (the holly carb on it was shot) ,with a 4B, 650 CFM, Edlebrock 1806 and Edlebrock 7111 intake and fairly new HEI distributor from Summit. I purchased the car in October 2011.
The car ran much better with this new carb for some time, (for 4-5 months), About 4 weeks ago I was driving it and learched forward from a dead stop and hit the brakes hard and the car stalled. Then it started stalling frequently when I came to a stop that night. Then it seems now when I drive it runs fine but after about 30 min, when it gets around 195 it stalls every time I stop?
So I called Edlebrock and did some internet research and found others with this problem. I was given the below recommendations and did the following; I took off the air horn removed the needle and seats/springs and air mixture screws, adjusted the floats to top out at 7/16" and drop no more than 1", dried up all the bowls, cleaned everything with carb cleaner and blew it all out with a can of air, put it all back together with a new air horn gasket and new gas filter. The car started right up, waited until the stat opened and reset the mixture screws to its highest vacuum with a gauge and set the idle at 700 RPM.
After the car got hot the RPM dropped a bit and the car stalled!? I do not know the fuel PSI but intend to borrow my friends gauge tomorrow since these carbs like 5 to 5.5 PSI only. I did notice the fuel pump vent was capped and there is no vacuum hose from the vapor canister to the carb. I am not totally convinced it’s the cab. I might also change the fuel pump? And I am thinking of hooking back up the venting?
Any suggestions/coments? HELP!

MDchanic

I wouldn't worry about the fuel pump or the venting. Fuel pump problems first show up on hard acceleration, not at idle.

I think first you need to ascertain whether the stalling problem is caused by a momentary loss of spark or of fuel. This can be extremely difficult, as the problem only occurs for an instant.

Questions that may help you to figure it out are:
Is it hard or unusual to restart after it has stalled like this, or does it start right back up?
Does it run normally immediately afterward?
If you have a tachometer, does it do anything immediately before, or at the instant of stalling, such as jump, or drop to zero while the engine is still turning?
Can you induce any problems by wiggling the power wire to the carb?

Other options are to completely change out either the ignition or the carb -
either install a different distributor and coil, or a different carburetor (even if it's not really set up right). If one of those eliminated the stalling problem, then you know where you stand.

- Eric

pistonpop

It starts right back up and will keep running if I keep throttle 1000 rpms? otherwise it will keep stalling. It does drop in RPM's just before it stalls out. If I let it sit a while its fine until it heats up again!?

MDchanic

Mmmmmm... Makes me think about ignition.

Module, pickup, coil...

I'd consider reinstalling a points setup, just to see if it fixes it.

- Eric

Rickman48

Put a 3/8" carb insulating gasket under it, and forget about it!

pistonpop

I did that months ago when I did the carb.

pistonpop

I was thinking, I was over charging a few months ago, put in a new regulator and noticed after I drive a while it will drop a bit below 12V? You think that could have something to do with it?

I do have a spare GM HEI coil that I took out of a car some 25+ years ago :-) ?

MDchanic

I doubt it, but with an alternator charging system, you should never go that low.

For the ten minutes that it will take to bolt it in, why not?

- Eric

pistonpop

Thanks Eric

I am going to bed I'll let you know how I make out.

John.

pistonpop

Also I am looking at repair manual I can hardly read the wire diagram. Looking at the distributo and HEI coil that Ignition wire is the pink wire both the tack side correct?

TripDeuces

So you got an HEI. Did you replace the resistor wire to supply a full 12v? My bet is when it gets hot the resistance shoots up and and the HEI doesn't get enough voltage to run correctly.

Nasty455

Ignition module...common failure.
Be sure to use the correct grease under the module when re installing to prevent burning up the new one.
Easy and cheap to replace.

http://www.restorationperformance.co...ipment,/Detail

pistonpop

I bought the car with HEI already in it. I am not sure if the resistor wire was changed? It has a heavy gauge pinkish wire and a green wire which is the tach side I am guessing. So I need to check voltage. But car starts right back up and I need to hold the idle at 1k?

TripDeuces

The diagram I have shows a yellow wire (goes to starter solenoid) and a heavy cloth covered resistance wire that go to the + side of the original coil. I may be wrong but I would assume they would go to the + terminal on the HEI cap also. Someone correct me here if I'm wrong.
If you see a heavy cloth covered wire going to the HEI then you have the resistance wire attached to it and that is your problem. It reduces voltage and the HEI requires 12v at all times. If there is no resistance wire hooked up to your HEI then you'll have to look at the other suggestions here.

Nasty455

When the module starts going you get sporadic ignition spark.
Next time it may die completely...keep a tester handy and keep track of the no spark condition.
If you have a tach,watch it carefully,it will die a second or two before you notice the engine stall.

MDchanic

Guys, just so you know, he started two parallel threads with one identical question, and a lot of this has been addressed already on the other one.

Joining the two would save us a lot of hassle.

Here's the other one.

- Eric

pistonpop

Ok checking now. It does have a new connector attached to the distributor but it could have been spliced. I ran the car this morning it does have a slight miss but I did notice the volts read 13-14 at start up and as the car got warmer, (and battery got recharged), it dropped down to 12 started to stumble and it looked like volts were dropping just under 12 and it stalled. Started right back up! I did change the regulator a few months ago when I put a volt meeter in the car the old one was over charging to almost 16V! I wonder if that old regulator kept the car running?

TripDeuces

Where are you checking this voltage at? The battery or the coil?

droldsmorland

One thing a lot of folks miss is the need for good clean grounds. Especially with HEIs or MSDs. If the ground circuit(s) from the battery to the block and the block to the frame is not clean and tight it will cause high resistance in those circuits causing the system to seek grounds through other paths through the path of least resistance which is what electricity does. This will cause all sorts of transient volt/current spikes and other unwanted conditions. Digital electronics are more sensitive to this lack of ground compared to the stock analog points set up
Clean up all grounds. Spray ignition sealer on them to keep them good for a long time and possibly replace the HEI module and heat grease. Good insurance to carry a spare in glove box.

pistonpop

At the coil. I found that the new coil wire is in fact spliced into a small black wire that has the wording "resistance do not cut" so I am guessing this is the old type of wire from the old coil system that use to be in this car that needs to be replaced? If so what type of wire and gauge should I use?

pistonpop

Hi Eric.

At the coil. I found that the new coil wire is in fact spliced into a small black wire that has the wording "resistance do not cut" so I am guessing this is the old type of wire from the old coil system that use to be in this car that needs to be replaced? If so what type of wire and gauge should I use?

MDchanic

That would be a giveaway...

As I said in my response to you in the other thread:

- Eric

pistonpop

I would like to thank everyone for all the great advice. I found and replaced that resistor wire and the car has not stalled out! My USB port on my radio now works! I did introduce a hum in the radio but I have a filter and this will be corrected. I can now go to the car show this Sunday without looking like a fool! Thanks again all!

MDchanic

You're welcome!

Glad to help!

- Eric

TripDeuces

Just a word on Delco ignition modules. They rarely fail unlike the no name stuff out there. Like was stated earlier grounds can make them go bad early. Everything must be grounded.
I had this same problem with a Mallory Unilite that was double resisted. Removed one resistor and it runs great now. Glad things worked out for you.

George

pistonpop

Ok so i nipped my stalling problem in the bud, thanks to everyones advise. Running a new wire from the ignition to the HEI coil worked. So today I was in my local memorial day parade with my car club. Once the car got hot, (or fully charged?), I noticed my voltage went down to 11-11.5 at idle? It does go up when I excellrate? It also dives down when signaling or braking, could this just be a loose belt? I also replaced the regulator a few months ago. Any thoughts?

John NY

droldsmorland

Either that or a failing bridge diode? Just because the reg is new doesn’t mean it’s good. If in doubt have it tested. A good alternator/starter rebuild house should be able to test both the alt and the reg at the same time.
Are you sure all the electrical connections are clean & tight? This includes the alternator wiring as well as the battery and the horn relay etc...

pistonpop

Yes cleaned and tightened all connections. It just so happens I have a friend whom owns a local alternator/starter rebuild business mostly for marine but does cars also. I will stop by his shop. I am leaning towards a bad diode like you suggested. (I have seen bad diode's do some wacky things in the past!), It only happens at temps over 200 and it idle?! I'll keep you posted. Thanks for your help.

John NU

MDchanic

A bad diode with a heat intermittent does make sense.

As it heats up, the diode goes, reducing output.
Higher revs make up for the reduced output, but voltage is still too low at idle.

That wouldn't be Harbor Starter, would it?

- Eric

jag1886

I've not run into a diode being affected by heat. I've always found they where either good or bad and if one is bad the car will have problem with having a dead battery all the time because a diode's job is to stop the alternator form draining the battery when the car is off (it allows power to only go one direction).
If I'm wrong please explain way.

pistonpop

Thanks. Iteas was in the process of dressing up my engine anyway so I'll pick up a chrome one wire alternator and get rid of my regulator. I do have to tell yo,u back in the day when I was spinning wrenches for a livin,g I had seen a few dash boards lit up like Christmas trees due to bad diode's, and they were still charging?

John