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I have a 1987 460 with carburator. I am having problems with it losing power under acceleration and on hills. It sputters and backfires. If I run it easy, it will hold its speed. I recently had the exhaust redone - installed 2-1/2" into 3" with hi flow muffler - old system blew apart from the manifold - flared pipe slipped out of flange. This seems to have made the problem worse. Previously, it would backfire under compression - coasting down hills but I had occasional power loss on acceleration/hill climbing. I have replaced the plugs, wires, air filter, fuel filter, distributer cap, rotor button and pcv valve. I have not had it properly tuned. I have found an airleak under the carb but have not had time to search any further into it (plenum between carb and intake manifold?) A friend suggested the plug wires are shorting out but the local auto shop guy disagreed. Any suggestions of what to try would be appreciated.
The problem is when you mash on the gas, it will send one big distinct ""backfire"" or in my case "frontfire" out the carb... one big pop.... nothing more or less. If you slowly ride p the throttle, it won't "frontfire" unless you mash it.
My grandfather's motorhome has a Ford 460 in it, I believe it has the duraspark IGN.
The plugs were replaced a little bit ago, and I just finished replacing the header gaskets due to a leak.
I have yet to check the carb bolts for tighness, I will do that first thing in the morning.
I was told by a V8 mechanic I know that it is possible the power valve could have gone out... If so what is the case on this? I am normally a honda guy and got into V8's about 2 yrs ago so I am new to diagnosis on these puppies =)
Cap and rotor get replaced tomorrow, and maybe a baseplate gasket would be cheap insurance. Does this motor take points?
FYI: the ignition module is remotely mounted to the front of the engine bay st the passenger side wheelwell and I remember it saying duraspark II or something similar.
The motor/trans itself were replaced 40K ago so it should be ok still... but not being run much in the last year or so might point twards the gaskets going out.
Idle is lumpy.. and irregular... the lump jumps around a little... but anything above 1.3K is smooth as glass.
my net connection out here in the desert is kinda shotty at best so an E-mail reply along with the web reply would make my day =)
I have a 1987 460 with carburator. I am having problems with it losing power under acceleration and on hills. It sputters and backfires. If I run it easy, it will hold its speed. I recently had the exhaust redone - installed 2-1/2" into 3" with hi flow muffler - old system blew apart from the manifold - flared pipe slipped out of flange. This seems to have made the problem worse. Previously, it would backfire under compression - coasting down hills but I had occasional power loss on acceleration/hill climbing. I have replaced the plugs, wires, air filter, fuel filter, distributer cap, rotor button and pcv valve. I have not had it properly tuned. I have found an airleak under the carb but have not had time to search any further into it (plenum between carb and intake manifold?) A friend suggested the plug wires are shorting out but the local auto shop guy disagreed. Any suggestions of what to try would be appreciated.
If you have a vacuum leak under under the carb that is definitely going to cause problems. When you say propoerly tuned I think you mean timed, right? If the timing is off that will cause problems too. Without the vacuum problem fixed and the engine timing it is going to be hard to solve. How many miles on the engine? Have the timing chain and gears been replaced? The chain and gears are usually only good for about 80K but my father-in-laws jumped at 70K. If the chain is stretched enough and the gears worn that can cause a variation in cam to crank realtionship by as much as 10+ degrees. Hopefully the chain hasn't jumped a tooth, but that usually shuts you down.
I'm sorry I don't have details, but Ford has a recall regarding a lot of cars and trucks for ignition module problems. There is a class action suit that requires them to fix it no matter how many miles are on the engine. I believe you might qualify. I don't know if a dealer would tell you the details. I'm sorry to just give you what I read about, but it might explain the problem?? good luck
Believe it or not, if you have electonic ignition, you may have a bad "MODULE". I had the same problem on my 440 and after changing what was everything "fuel" related, I had this $80 module replaced and frankly, I'd have paid 3X that if I had known.....check it out! Roger
I have a 1987 460 with carburator. I am having problems with it losing power under acceleration and on hills.
How long is your wheelbase? Class C or class A ? First, get the vacuum leak under the carburator fixed. Then the next thing that makes this vintage do this is lack of fuel volume. You should only have an electric fuel pump in the fuel tank pumping all the way to the carburator. The 460 is capable of burning 26 gal/hr and even if it has 5-7 lbs of fuel pressure when checking at idle it may not have enough volume. It needs to be able to pump between 2 and 3 quarts a minute to keep up. To make matters worse, the system uses a fuel bypass just in front of the carburator that returns a portion of fuel pumped back to the tank to lessen vapor lock. This fuel bypass is available with 3 different return orfice sizes and I always put the smallest on. I'm sure you will find that the fuel pump is failing and not pumping enough gas. The reason the backfiring seems worse with the bigger pipes could be because the engine is breathing better and needs more fuel at a throttle setting than it did, or the pump is just slowly getting worse. Spark plug wires and spark plugs need to be in best shape also. The module on the distributor will not cause the condition you describe. when they fail they will shut it off dead. Yours may have the module mounted on the body firewall out of the terrible heats way.
I have a 96 Winnabgo Vectra with a 460efi engine
changed fule pump,fule filter,check back pruser ok.After it starts to
get warm it back fires and has no power at all,it will barley pull it self, the
RV Dealer macanic are stump ?
I have a 1987 460 with carburator. I am having problems with it losing power under acceleration and on hills. It sputters and backfires. If I run it easy, it will hold its speed. I recently had the exhaust redone - installed 2-1/2" into 3" with hi flow muffler - old system blew apart from the manifold - flared pipe slipped out of flange. This seems to have made the problem worse. Previously, it would backfire under compression - coasting down hills but I had occasional power loss on acceleration/hill climbing. I have replaced the plugs, wires, air filter, fuel filter, distributer cap, rotor button and pcv valve. I have not had it properly tuned. I have found an airleak under the carb but have not had time to search any further into it (plenum between carb and intake manifold?) A friend suggested the plug wires are shorting out but the local auto shop guy disagreed. Any suggestions of what to try would be appreciated.
Thanks for the feedback on this problem. Replacing the carburator gaskets has made a huge difference in performance. The motor home is a 35' Fleetwood Limited. I live in BC and I drive from Vancouver (sealevel) to a ski hill 2 hours east that is at 5000'. On the drive up I never experienced any problems after changing the gaskets - it was a nice feeling to think I've finally solved it. The drive home proved I still have something else going on too. What I found going home was a loss in power climbing hills. I feel it is a fuel problem. If I accelerate hard on level ground - it was ok, but on some hills I feel power surges and loss of power and it backfired a few times. Oh yeah - on way up I had a full tank - on trip home I was down to 3/4 tank.
This week I plan to replace the fuel filter. I haven't found the return line to the tank yet - the fuel line comes up to something on the drivers side back end of the engine, but there is only 1 line coming out of it. This RV does have only the electric fuel pump - I am thinnking to change it. I haven't checked which ignition module this unit has yet. I don't believe the timing chain has jumped - the unit has 55,000 miles on it.
The joys of owning a motor home. The fun never ends!
Again thanks for all the feedback and useful tips - I will post the outcome as I try each.
I have a 1987 460 with carburator. I am having problems with it losing power under acceleration and on hills. It sputters and backfires. If I run it easy, it will hold its speed. I recently had the exhaust redone - installed 2-1/2" into 3" with hi flow muffler - old system blew apart from the manifold - flared pipe slipped out of flange. This seems to have made the problem worse. Previously, it would backfire under compression - coasting down hills but I had occasional power loss on acceleration/hill climbing. I have replaced the plugs, wires, air filter, fuel filter, distributer cap, rotor button and pcv valve. I have not had it properly tuned. I have found an airleak under the carb but have not had time to search any further into it (plenum between carb and intake manifold?) A friend suggested the plug wires are shorting out but the local auto shop guy disagreed. Any suggestions of what to try would be appreciated.
Thanks for the feedback on this problem. Replacing the carburator gaskets has made a huge difference in performance. The motor home is a 35' Fleetwood Limited. I live in BC and I drive from Vancouver (sealevel) to a ski hill 2 hours east that is at 5000'. On the drive up I never experienced any problems after changing the gaskets - it was a nice feeling to think I've finally solved it. The drive home proved I still have something else going on too. What I found going home was a loss in power climbing hills. I feel it is a fuel problem. If I accelerate hard on level ground - it was ok, but on some hills I feel power surges and loss of power and it backfired a few times. Oh yeah - on way up I had a full tank - on trip home I was down to 3/4 tank.
This week I plan to replace the fuel filter. I haven't found the return line to the tank yet - the fuel line comes up to something on the drivers side back end of the engine, but there is only 1 line coming out of it. This RV does have only the electric fuel pump - I am thinnking to change it. I haven't checked which ignition module this unit has yet. I don't believe the timing chain has jumped - the unit has 55,000 miles on it.
The joys of owning a motor home. The fun never ends!
Again thanks for all the feedback and useful tips - I will post the outcome as I try each.
Sheldon
Sheldon,
One thing I forgot to mention and it sounds like your problem. Since you rebuilt the carburetor the promary float setting is too low so the engine starves at hard throttle on hills. Almost acts like vapor locking doesn't it? I had the same problem once and all I had to do was loosen the primary (front) float setting lock screw and turn the float nut ccw about a 1/8 -1/4 turn. That will solve your problem.
I'm sorry I don't have details, but Ford has a recall regarding a lot of cars and trucks for ignition module problems. There is a class action suit that requires them to fix it no matter how many miles are on the engine. I believe you might qualify. I don't know if a dealer would tell you the details. I'm sorry to just give you what I read about, but it might explain the problem?? good luck
It's not really a recall, only a reimbursement award IF you've experienced an ignition module failure.
This class action suit has been settled with a huge amount going to the lawyers, (natch, that's why these lawsuits are started), and the Ford owners getting a trifle each. The lawsuit applied to the EEC-IV TF, (thick film), ignition module that is mounted in the side of the distributor. The '87 Ford 460 would have the Dura-Spark II ignition module that is remotely mounted, these are not prone to heat-induced failures.
In response to your 460 engine, I might offer you the following suggestions. Check the crimped fitting inside the rubber fitting that allows the stator wires inside to the magnetic engine pickup. I have seen the crimped fittings completely become disconnected while enclosed in this rubber grommet fitting. This will cause your problem of running for 15 minutes and then the backfire, once the connection cool, the wires join back together and then it runs for another 15 minutes or so until the pickup wires disconnect and then its backfire again. Sometimes the crimped wires get hot while inside the rubber grommet and show no evidence of separation but they do and open the connection either to the magnetic pickup or the side to ground. If that does not correct the problem, check the coil connections around the crimped connectors in the coil harnness and delete the coil harness altogether by using stacon connectors to the positive and negative connectors on the coil, If this fails try checking the wiring harness behind the key switch assembly for hardness as the insulation on the key ignition wires will crack and separate with age., If this fails you might try replacing the key switch assembly, I've seen these go bad as well. Just as a sidenote, I've rebuilt 4 F460 engines and 3 C-6 transmissions in my diamond conversion motor home. Each engine lasted 200 thousand plus+ and each C-6 overhaul went 130 thousand plus. If you need any other information its NaFilm1@aol.com Good luck, Eddie Reasoner Nashville
Sorry, I guess I failed to identify the location of the crimped connectors in the precending reply. They are located at the conncection between the ford plastic connector and the inside of the distributor. The rubber grommet fits in a groove located on the distributor underneath the rotor cap and on the side of the distributor. There are at least two wires in this grommet, one goes to the stator magnetic pickup and the other to ground.
I have had a lot of fords with electronic ignition, both Duraspark and TFI. Both have been troublesome with intermittent cutouts. That is why the orange and purple wires off my distributor go into a DELCO HEI LX-301 module(amplifier) and then to the coil's terminals. The coil is supported by a 30 amp relay triggered by the ignition key(red/blu.stripe). Flawless service here. The LX301 is mounted to a strip of aluminum on the firewall and wrapped in tape and silicone. 5 wires come out(red+,green(-coil),org(dist),ppl(dist)blk(dist.hsg)..Simple as that. It,at times, throws a spark 2-1/2" to the valvecover when I yank the coil wire.------The other truck with EFI, I ALWAYS carry a spare moduleTFI with its 3 spade-pins tied to #1,3,6 of another TFI plug, so I can intercept the plug on the existing distributor. The #'s 1,3,6 wires are "pass-through" of +,-,anf PIP signal. The TFI let go a few times, once in front of a local Ford police car, which locked my rear wheels on a backfire, almosyt having him rearend me. He laughed and said he knew right away as he drove a ford. He gave me a ride to the parts store. The old duraspark, with its multiple supply wires used to cut out periodically. Embarrassing incident was passing a girl I liked and waving to her,as my truck backfired, and shot a large flame,out the 3"tailpipe into her driver's window. She shook her finger at me next time I saw her, but remained friends.
I have a 1987 Ford E-350. I am in a unique situation, as my business is mobile and I have all of my paint equipment and paint and compressor on my van. A couple of weeks ago, it started to "bog" when I accellerated. I guess you would call that a loss of power. I replaced the plugs, cap and rotor and put in some fuel additive. It got worse. I cleaned the fuel filter but no help. I have two tanks and assume that they each have their own fuel pump inside them. Switching tanks seems to have no effect either...so I have ruled out the fuel pumps. I installed a rebuilt holley carburetor and it got a little better in that I did not have to pump the gas pedal just to get down the road, but now after a week, it still sputters and pops when I try to accelerate. I am stumped. All of the emission stuff has been removed and several vacuum lines have been plugged. It has 135K miles on it and doubt if the timing chain has ever been changed. I am pretty sure according to my book that it has the duraspark II ignition. Oh yeah, I know a good parts guy and he let me take a new ignition module out for a couple of hours....no help, so I took it back. HELP!!!!!!!!!, I can't afford to have my van not running and am scared to death that it is going to completely die one of these days. I am going to try the timing later, (when it cools down).
email Sheldon Marche
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