It's hot here...90+ in Colorado Springs, but lately I am experiencing what can only be initially described as vapor lock. It's bizarre, in the morning it's perfectly fine. Runs all the way to work with no issues. Yet after work (5am-3pm) I get maybe 5 minutes of driving and it starts losing power, backfiring then dies. If I get out and close the choke on the carb, I can get it fired back up for maybe 2 more minutes of driving. If push in the clutch and take the load off, the engine, it will stay running a bit longer. I can flutter the gas pedal and coax it along... I stalled out by my house this afternoon, gave it 5 hours to cool and went to drive it home, hard start and it stalled out 4 more times in the 3 minutes it should have taken to get home. Each time I got out and was able to restart it. I got it in the driveway and it idled just fine. Stayed running longer than it did when I was driving it. Things I know: I am not blowing any smoke out the exhaust pipe I get a bit of smoke out the breather in the valve cover when I try to start it. It feels hot, the radiator tank was hot to the touch I could hold it for maybe 4 to 5 seconds... The coolant appears to be clean, not muddy with oil. This problem has been getting progressively worse over the past three weeks. Meaning: It happened once then it was fine, a few days p***ed then it was fine, and now, it's after 4 minutes of driving...too frequent to count. Am I missing anything here? This is a bone stock car, with stock fuel pump.
My first thing to check would be fuel. Is it single carb? Have you taken the fuel line off and turned the engine with the fuel line in a clear plastic bottle? Also, is there a fuel filter that needs to be changed. Has it all been on the one tank of fuel? In order I would inspect/replace: Fuel filter Fuel line to carb Check carb for gunk Dump fuel and replace with better octane Fuel tank/fittings/blow out fuel line Hope that helps Damo
It is single 2 bbl carb. I drive it regularly (Every day) and just this morning put about ten gallons in it.The tank could need to be cleaned.. I will pull the line this weekend and check the fuel. The carb was spraying when I pulled the air cleaner to look things over when I messed with it on the side of the road. Air temp issue is the variable that gets me, in the morning, not a single issue. In the afternoon, you can tell it's going to die as when I let off the gas while driving it starts to cackle and sputter, then I have about 60 seconds before it straight out dies.
In addition to the above good advice, I suggest you also check fuel pressure coming off the pump to carb. Could be the pump is getting weak and unable to overcome the temp related vaporization you apprear to be experiencing. If everything checks out, you might consider adding an electric 'booster' pump for those occasions when this occurs. Ray
if the above doesnt work change the condensor , if you are still running points , had a chevy mill run like this once and then it just up and died one day , put a new condensor in it cleaned the points and vroom problem gone , a coil going out can act like this to , just something more to check
Chase all the above...but it does sound like vapor lock. Our Colorado fuels seem to be more volatile lately. Wondering if there was a formulation change? Noticing it in cars that didn't have an issue previously. As the boiling temperature decreases, the delta (difference in temperature) decreases relative to the ambient air temp. In other words, the 10 degree difference in temp from morning to afternoon is all you need to make that gas boil. It will bubble through the fuel line pretty heavily and a mechanical pump doesn't pump vapor too well. An electric pusher will help a lot. Then check for heat soak on the carburetor. You may also need to shield and insulate the carburetor to intake interface. This is only going to get worse in the future, unfortunately. I know a guy that is working on a fuel refrigeration system for the fuel inlet line to see if he can lower the temp in the bowl. It uses a 12v car plug-in cooler for its components. Jury is still out.
i had a similar problem with mine. i put on a electric fuel pump and ran new fuel lines then ran the line across the fire wall then turned it right to the carb.it should be cooler their and the electric pump will just push the vapor lock out. i did put on a fuel regulator you only need 3-4 psi for that carb. if you want to keep the stock look you could hook up the new line near the old pump and then to the carb use the old lines in the factory spot and see what happens. good luck
All of this is Very good advice and I will be into things heavy tomorrow. I am also going to get the radiator boiled out and flush the whole coolant system... This thing has never had a rebuild...the whole engine is original. I cannot imagine what is gummed up in the coolant p***ages. I will keep people posted and go about this systematically. But I hear what you are saying about Colorado fuel....I NEVER had vapor lock issues til about 3 weeks ago and I drive mine regularly.
i didnt think of this but buicks always seem to develope a sticky heat riser between the intake and exhaust manifolds , buick straight 8s are sensitive to this maybe it s rusted open and acts like its a cold motor and is over heating the fuel and causing vapor lock ,
Hopefully the ebay gods will smile on me and let me obtain the holy grail of Buick parts that 41-42 dual mani and carb set up I am bidding on
Ok this is not heat related. It is 60 out and the car did not drive for 5 minutes without dying. On the way home the stalling was more frequent. There is not fuel filter on this thing, all of the lines are steel.... I will keep going from there..
Sounds like a fuel delivery problem to me. I would suggest disconnecting fuel line from fuel tank to fuel pump, and blow it out..drop the fuel tank, and remove sending unit/pickup, and inspect clean or replace as necessary.
I am going to look at the carb too, the choke plate does not move to well. I am also searching for fuel pump specs to determine if it is working within specs
I can mimic the behavior of the car when I drive by closing the choke plate and throttling up.... I am going to wire the choke wide open and take a drive, I will keep you posted
please do im currious to know whats making it act up , the fuel pumps do need a rebuild on these mills from time to time to , ive read on buicks.net
Carb was REALLY gummed up at the choke plate...It was not operating properly. The plate was hanging up and not moving as it should. Did not open at all when you gave it some gas, was pretty much stuck closed. I shot a metric **** ton of carb cleaner in there to loosen things up. I let the car warm up till the tank on the radiator was hot, wired the choke wide open and buzzed around, no issues...I do think the engine might be running a bit warm as the air pulled off the radiator felt pretty damn hot. I want to get a laser thermometer on it to to get an accurate read..I was sweatin as I dialed in the carb.. I know 180 should be about right...and 180 is HOT but it felt warmer than I remember...I will keep updating this even if no other incidents happen this week...I am really tryin to keep this thing as stock as possible, it's still 6 volt and all that. I love these old engines, but sometimes they can throw you for a loop
Update, I took the Buick out to get doughnuts this morning and It had a slight stumble on the way to the store, almost dying, then I sat at the safeway and let it warm up, then mucked with the carb mixture a bit. When I was doing this I noticed some white smoke coming out of the breather on the valve cover.. I made sure the choke was open all the way. It had a bit of a cackle in the exhaust when I let off the gas on the way home, but no issues. I popped the hood at home and looked over everything and no more white smoke out of the breather... I would ***ume a complete carb rebuild is in order. And I am going to pop over to the buick guys and see what the specs are for the fuel pump as it's probably never been replaced.
Well, after a weekend of driving, back to square one.... I found this great resource http://www.teambuick.com/reference/fuel_vacuum_pump.html
I was having the same issue on my 50, I wired the heat riser open and no such problems "knock on wood" since. A rebuild of the carb and the fuel pump might also be a good idea just to be cautious! Chuck
Who has a good rebuild kit for the fuel pump....Kanter wants 130$ for a new fuel pump and you have to send in your old one?
I had a problem like this a month ago. I was 40 miles from home and my engine would only run when it was cold...as soon as it warmed up it died if it was running under 1500 rpm. Then it would not start again until it was cold, a half hour wait. I made it back 12 miles doing that and a friend towed me the rest of the way home. I checked its points and the points had worked loose from its breaker plate. Adjusted the points and all was well. Moral of the story: don't overlook the ignition system.
New fuel pump ordered from Bob's Automobilia.... They called to confirm that they were shipping the right one, literally 2 hours after I placed my order...pretty cool
Sorry I didn't get back to you sooner buddy, there is a guy in Minnesota who sells all of that stuff, at a great price! Here is his website http://www.oldtimeparts.com/ Chuck
Ok, Fuel pump is installed. When I pulled old pump, no dirty gas inside old pump. Damn thing will not run, still not getting fuel. When just turning over, it pumps air...When I dump gas down carb it starts gushing fuel inconsistently. Like it's pulsing.. I called Bob's they told me to check a rubber hose by the frame that can crack and rot.. I guess it is a tiny piece of rubber. I am on that next. IT will run when I dump fuel down carb. So I am/ must be ****ing air from somewhere.
Have you had the tank off? Might have a pickup tube thats rusted through. Try a gas can in between and see if that does it, that'll help narrow down the source of the problem.LB
Bob's suggested that I look at the tiny rubber line by the frame, there is about 6 inches of rubber line. Lo and behold it's rotted through and I found a rock in the metal tube from the rubber line to the fuel pump, it's a wonder it ran at all.
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