[Yoder]

i have a 79 bronco with a 351m wen i open it up or put a load on her it dies after i let off the gas. for example i hooked up to a tree stump and put it in 4low and opened it up then after i let off the gas it dies. idk y i have a holly carb if that helps any..

[J&SBroncolvrs]

check your timing lately?

[clean 79]

Check your distrubor cap and rotor for corrosion and check plugs and wires while your at it. It might be as simple as a tune up to fix your problem..

[Yoder]

no i havent checked the timing i bought it and stuck a fuel pump in it. but wen there isnt a load on it it runs great and sits there and purrs like a kitten.

[J&SBroncolvrs]

It's quite possible it's fuel related, but I would check the timing on it anyways. Could be a bit retarded. Ever check it with a vacuum guage?

[Johnny Reb]

J&SBroncolvrs, on Feb 11 2009, 12:19 PM, said:

It's quite possible it's fuel related, but I would check the timing on it anyways. Could be a bit retarded. Ever check it with a vacuum guage?

For starters, I am just leanring about the 351-400. I myself am gonna junk my timeing and distributor set up and put in one that suit me. I have heard that Ford set the 400(I do not know if the 351 does or not-probably do) at 4 degrees BEFORE TOP DEAD CENTER---WHICH would set the power way off.I have had alot better luck with a point distributor and feel(myself) that the point has more power. I am looking forward to this summer to tear into the 400. I am sure it will run alot better and better gas mileage then what Ford has put in it.If Chevy got descent mileage out of a Blazer--I am sure us shade tree mechanics can do the same to the 3561 and 400. Take a good look at the distributor and look for a short also and the fuel system. For leaks,dirt in the lifuel filter,carb,the carb pump--The carb pump would be the first thing I would check . Take it and look for a leak before you take it off. If it leaks-maybe the screws are loose,maybe the little carb pump is bad. It copulkd be a bad carb gasketWrite the things down and as you check them-check them off
Good luck

[J&SBroncolvrs]

Johnny Reb, on Feb 11 2009, 04:52 PM, said:

For starters, I am just leanring about the 351-400. I myself am gonna junk my timeing and distributor set up and put in one that suit me. I have heard that Ford set the 400(I do not know if the 351 does or not-probably do) at 4 degrees BEFORE TOP DEAD CENTER---WHICH would set the power way off.I have had alot better luck with a point distributor and feel(myself) that the point has more power. I am looking forward to this summer to tear into the 400. I am sure it will run alot better and better gas mileage then what Ford has put in it.If Chevy got descent mileage out of a Blazer--I am sure us shade tree mechanics can do the same to the 3561 and 400. Take a good look at the distributor and look for a short also and the fuel system. For leaks,dirt in the lifuel filter,carb,the carb pump--The carb pump would be the first thing I would check . Take it and look for a leak before you take it off. If it leaks-maybe the screws are loose,maybe the little carb pump is bad. It copulkd be a bad carb gasketWrite the things down and as you check them-check them off
Good luck

I would not junk the distributor. The duraspark II system that Ford used in the Bronco is robust and reliable. The 4 degrees that you are talking about is built into the timing gears, not a setting on the distributor. New "zeroed" timing gears is the only way to fix this. A far better thing to do to your engine would be to get new double roller timing gears and a new cam. As far as the distributor and ignition, a better thing to do is get a high discharge coil. This allows you to gap the spark plugs wider, advance the timing more and get yourself more power and more gas mileage. After all this the distributor can be recurved so you bring in your total advance (32-34 degrees BTC) all in before 3000 RPM (this is really easy).

[Yoder]

i was thnking my self that i mite have a vacum port open somewhere but i dont no where. and i would love to but a cam in it but my dad wont let me. but i am going to drop the pan to put main bearings in or a oil pump i dont no which one yet. its not knocken or making bad noises so im thinking a oil pump but neways.ill pull the plugs a.s.a.p. and c wat i find.

[J&SBroncolvrs]

if you are dropping the pan, definitely check the main bearings. It's really easy to do if you have a torque wrench to retighten. And you can still check the timing with a vacuum gauge, it will tell you alot of things about your engine. if you can get it to read 22 hg at idle without bouncing around, your vacuum is good and your timing will be set right.
http://www.earlycuda...ech/vacuum2.htm

check that link out, you'll be surprised at what you can diagnose with a vacuum gauge.

[Yoder]

thanks you have been alot of help

[Johnny Reb]

Yoder, on Feb 12 2009, 07:11 AM, said:

thanks you have been alot of help

J&S ,you are right in about the timeing gear set(sorry I did not explain myself ) but as far as the electronic distributo goes. I will stick with points-because I have a 75 Ford dump truck that HAD THE DURASPARK. iT WENT OUT ONE DAY AND almost caused me to have a bad wreck. Since I have put in the point distributor I have had better power . Now I do have to put in a set of poitns once in awhile,but when it goes to missing---my engine does not quit and I loose everything. Thanks for claireing me up on my timeing gear and the knowledge on the distributor. I have thought about the high out put coil for awhile. I have been told it is hard on plugs. To correct this-couldn,t a person have a wider gap in the plug to extend the life of the plug?Like I said before-I am just learnig about the 350 and 400. All the personal knowledge I can learn will be appreciated.Thank you.

[J&SBroncolvrs]

Yes Johnny, a larger gap is the solution to plug life and also the main reason for the upgrade. Obviously you get a better burn and some more power. Now that I think about it I have a friend that upgraded his old chev and got rid of the points. He complained of a loss in power as well. I don't know if the high output coil and larger sparkplug gap would make up the difference in power, if you are happy with points i say stick with it.

[Yoder]

i bought plugs and wires im putting them in tonight ill let you know how it runs.

[Yoder]

i bought plugs and wires im putting them in tonight ill let you know how it runs.

[Johnny Reb]

Yoder, on Feb 19 2009, 08:15 AM, said:

i bought plugs and wires im putting them in tonight ill let you know how it runs.

You might want to check out your egr valve . My friend has a jeep and it was cutting out.(he had just re-built it and ut everything new on it-except the egr valve) When I drove up to him and heard it. I aske dhim did he check the egr and he hadn,t-but when he got home later on --he checked it and it was the egr valve.Good luck
Hope you got it fixed.