engine surging
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engine surging
Hope someone can help. 351W 1984 F150 4 speed, Edlelbrock 1405 carb, performer manifold.
Starts and runs fine. After about 5 miles engine seems to surge for a few moments noticeable when coming down hill with foot off gas peddle. It has stopped running but starts right up and then runs fine. Damp/wet weather it seems tobe worse. Any suggestions on here I should look for solution.
Starts and runs fine. After about 5 miles engine seems to surge for a few moments noticeable when coming down hill with foot off gas peddle. It has stopped running but starts right up and then runs fine. Damp/wet weather it seems tobe worse. Any suggestions on here I should look for solution.
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From: Louisville,Ky.
Do you have the factory air cleaner on it? It may be icing up. You need the hot air intake from the exhaust manifold. I would try hooking the factory air cleaner assembly up and see how it does. Both of my Ford trucks do this when it is below 65 degrees or so.
The air bleeds in the carb ice up and it make itself flood out from lack of air. Once the thermostat opens and the fan blows heated air into the engine compartment, it will thaw out and run fine.
Jimmy
The air bleeds in the carb ice up and it make itself flood out from lack of air. Once the thermostat opens and the fan blows heated air into the engine compartment, it will thaw out and run fine.
Jimmy
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I have another Eldebrock air filter assembly and was wondering if running a air tube into the bottum from a heat box on the exhaust manifold might not do the same. My concern is the original air filter assembly would greatly restrict air flow. It was for a two barrel carb that was on the truck.
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From: Louisville,Ky.
Actually, you are better off with the stock unit. It will pull in warm air to aid in heat up and it pulls in cooler outside air from in front of the truck when it is warm. The cooler air in the summer will make morepower than drawing in hot air from under the hood.
My 460 runs better with the stocker year round than it does with a 14x4" open element breather. I don't think that just running a heat tube to the open element base will help much, because you are still pulling in cold air from everywhere else.
Jimmy
My 460 runs better with the stocker year round than it does with a 14x4" open element breather. I don't think that just running a heat tube to the open element base will help much, because you are still pulling in cold air from everywhere else.
Jimmy
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I installed origanal type air cleaner on engine. Still have a surging problem. Today it was damp and the engine stalled and started up right away. Idle went to normal after that. I drive about seven miles to work and it seems to do this about five miles into the trip. Could this be an igintion module problem that is the only thing that is the same before I rebuilt engine.
It is a F150 1984 351W with a 1976 Druaspark ignition all new plugs and wiring. Eledbrock 1405 carb, electric choke, new distributor. Complete engine rebuild, all was fine until cold damp weather arrived.
It is a F150 1984 351W with a 1976 Druaspark ignition all new plugs and wiring. Eledbrock 1405 carb, electric choke, new distributor. Complete engine rebuild, all was fine until cold damp weather arrived.
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I would just double check to make sure that your flap in the air cleaner is closing properly and that the hose is hooked up to it and the exhaust good.
Jimmy
Jimmy
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It does close, The hose goes right to the exhaust box which is in good shape. Should I keep the flap closed and let it run on heated air only? My question is why does it idle so well after stalling. I am idling around 1000 rpm.
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I still have the surging- bucking problem when I take foot off of gas pedal. Is it worth rebuild kit for carb. The truck runs great except for this. I brought idle up 1050 rpm's, so it does not die. Today weather was 40 degrees and damp. Ran fine but, still surged as I was coming down hill. You can feel the surging around 25-35 mph.
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Could a low engine temp contribute to this problem, ever since the rebuild the temp gauge reads very low, at bottom of gauge, installed new 190 thermostat on rebuild.
Gauge always ran higher before. I have researched this and come to the fact I have an icing situation.
I need to know what to do. Live in northern Michigan and winter is long.
Gauge always ran higher before. I have researched this and come to the fact I have an icing situation.
I need to know what to do. Live in northern Michigan and winter is long.
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From: Nova Scotia
You asked " My question is why does it idle so well after stalling."... that is because when it stalls, hot air rising from inside the intake manifold melts any ice built up in the carb. It only take a few seconds for this to happen.
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I have done everything concerning getting warm air into carb. Put truck on scope today, all is excellent, nothing is showing up. Mechanic said could be a coil going bad but not very sure. He did notice that I did not have my Duraspark module grounded. It is mounted on plastic inner fender. As could be metering rod or jet problem in Eldelbrock carb. I guess I will keep going until I find the problem. I don't want to rebuild carb, as it runs great except for this problem. Not sure if it carb or ignition. If anyone has any ideas I would welcome them.
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If it helps... my Duraspark module is mounted on the platic inner fender also. I believe it is grounded through onr of the wires. As for the coil... I profess to be an expert but I believe coils either work or they don't... no in between. If I am wrong, please correct me as I would like to know for sure.
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From: southern New Hampshire
I agree that it may be an iceing problem. I've seen air cooled engines with frost on the base of their carbs on a humid summer day. I get ice clogs in the air exhaust on my staight line sander on hot humid summer days.
As far as coils go, My wifes 87 T-Bird had a problem with stalling that kept getting more frequent. They guy at the parts store told me it was the module in the distributor because they sold a lot of those. I got it but also got a new coil just in case. Turned out to be the coil. You could see on the side mounted to the fender wall where it was arcing.
As far as coils go, My wifes 87 T-Bird had a problem with stalling that kept getting more frequent. They guy at the parts store told me it was the module in the distributor because they sold a lot of those. I got it but also got a new coil just in case. Turned out to be the coil. You could see on the side mounted to the fender wall where it was arcing.