Need mechanic Dallas area

[guy99]

Hello everyone,
We are currently on the homeward leg of our 6000+ mile trip from Northern California to Puerto Peñasco, MX and New Orleans, LA.

We're in Arlington, TX. The 454 in our 84 310 Limited MH is begining to miss at high RPM and has become very difficult to start the first time in the morning. I'd like to have it looked at before we head out.

I'm looking for recommendations for a competent, fair, mechanic who, might be able to squeeze us in on Monday, Jan 21, 2006. Any ideas? I'm not broken down (yet) so I could also take it to someone located west of here.

[shadejo]

Can't help you with a mechanic suggestion (I am up in Canada), but:

Assuming internals of engine are healthy, when were spark plugs, plug wires and ignition components last changed? The 454, in fact most motorhomes, are hard on plug wires (heat cooks them).

If you can't get a mechanic to look at it I'd be tempted to start by putting a new set of wires on it and a new distributor cap and see if that helps. Pulling spark plugs would be next step, but you probably don't want to tackle that in a parking lot......

Other possibility that may be simple to fix is fuel starvation due to a pump(s) problem or plugged fuel filter(s) Do you know when they were last changed? Typically, a fuel starvation problem is going to be more visible under heavy load, not just high rpm's so depending on when your miss is occurring this may or may not be the issue.

Good luck!

John

[guy99]

I had it tuned up just before we left on this trip. Put on super duper lifetime guarentee plug wires. Replaced both fuel filters.

It was missing at about 3000 RPM in second gear as I accelerated onto an interstate.

[thenewkid64]

Just a suggestion;

Pop the cap on the distributor cap and pull the rotor, check and see if the advance weights on the distributor shaft (almond shaped metal with springs) move freely. The Distributor internals get rusty with non use and these will seize. This will cause it to Idle fine, but miss under load, I had to R&R my distributor on the way home from Lansing 2 yrs ago in an Auto-zone parking lot. If you still need a mechanic, I can give you one in south Dallas. PM me.

[noiva]

Originally Posted by guy99

I had it tuned up just before we left on this trip. Put on super duper lifetime guarentee plug wires. Replaced both fuel filters.

It was missing at about 3000 RPM in second gear as I accelerated onto an interstate.

I know this is repetitive, but sure sounds like wires, fuel, or spark plugs. Any chance one of the plug wires or plugs is not secure? Wires, of course, need to be checked at distributor and at plugs. At least that stuff is fairly easy to check. I've had new stuff malfunction before. Best wishes with this.

Tim

[87MH]

Originally Posted by guy99

....Any ideas? I'm not broken down (yet) so I could also take it to someone located west of here.

It certainly could be any of the things mentioned above, but, considering the symptoms you described, I think that fuel starvation is the lead culprit.

Do a search here in the Forums on "fuel pressure", "fuel pump", "gas filter", or the like. Much has been discussed previously.

The long run from the rear mounted gas tank to the thirsty 454 creates fuel delivery difficulties many Classic MoHo owners have encountered.

The good thing is, most of the time you can "limp" to a safe haven - given enough time between stops.

I don't recommend running this way (fuel starving the engine continuously) since this causes the engine to run way too lean, promoting other internal problems.

Please post your solution to the problem -

Luck.

[GlenCoombe]

Not to point fingers at the folks who did your tuneup before you left....but. Often they miss either the internal carb fuel filter, or the chassis fuel filter. Often the boss says, change the fuel filter. Lowest paid grunt on the list changes one, not both.
Keep us informed.

[noiva]

Originally Posted by GlenCoombe

Not to point fingers at the folks who did your tuneup before you left....but. Often they miss either the internal carb fuel filter, or the chassis fuel filter. Often the boss says, change the fuel filter. Lowest paid grunt on the list changes one, not both.
Keep us informed.

In doing my first tuneup last week on my 370, I discovered it didn't even have a filter in the casing on the carb! I had to research the Ford 460 engine on the Internet to determine what went in there. Odd part was the previous "grunt" who had tuned it had taken out the old one, but left the washer and the spring. The washer was sloshing around in there periodically choking the engine off. Go figure... Point is that tune-ups followed by performance problems usually point to improper or just plain not done maintenance. Would really like to hear what the problem turns out to be.

Tim

[thenewkid64]

One other thing I have experienced is that the frame rail fuel filter acts as a primary filter and can get clogged just from running copious amounts of fuel through the system. There can be sediments that settle in the fuel tank and all the pumping of gas will stir it up. I have changed my frame rail filter approx every 3K mikes since I bought the rig.

[swebster]

Guy99,
Certainly check (and replace) the items as mentioned (fuel filters - all of them) are particularly suspicious) but don't ignore your insticts on the wires. Motorhomes are particularly notrious for burning wires. I replaced my wireset with a new NAPA set for the 454 P30 before a short trip and fried the number eight wire (from the exhaust) on our very next trip.

If you're near a WalMart (or similar) you should consider purchasing a cheap timing light to keep on board. Run the engine, pull the doghouse and and keep moving the timing light inductor from wire to wire to determine which one (if any) is missing.

My solution was to follow the advice of others on the forum and install a set of Accell 9000 wires (sold at AutoZone and PepBoys, etc). They have coated boots and high temp wires. It virtually cured my wire burnout woes.

Of course, I also had fuel filter problems that I was convinced were ignition problems. It's really a matter of eliminating each possibility to find the one thing (or combination of things) that is the root cause.

[guy99]

Update

To review, I was having two problems:
1) An intermittent miss under load at high (3000) RPM
2) Very, very, difficult starting in the morning. It would take 10 minutes or so to get it started. It would just turn over as if I had either no spark or no fuel. Eventually, I would flood it and have to hold the throttle open for a minute, after doing this for one to n times, it would finally catch and eventually start. When it started, it would run rough and spit raw gas out the exhaust for a little while, then run as usual.

I took it to a mechanic recommended by a forum member. He found two things, the rotor (which was replaced 3- 4000 miles ago) had carbon marks on the top and bottom of the plastic part which made it seem as if the spark was sometimes shorting from the rotor button to the distributor body. The carbon/burning was not bad enough to indicated that this was happening all the time but could have been responsible for my intermittent miss. He also observed that the air cleaner housing had some oil pooled in the bottom of it.

He said the rotors in the 454 were notorious for problems and replaced the rotor. He clean out the oil and opined that the rings are beginning to fail. He didn't pull any plugs and I have not had any problem with fouled plugs. He checked out the PCV system, which he thought might cause the oil in the air cleaner, but found no problems with it.

So I took off midday Monday hoping that my problems were solved. Drove the rest of the day Monday (250 miles) with no missing. Tuesday morning I had the devil of a time starting the engine. Got it started finally and drove 450 miles without problem.

This morning before trying to startup, I pulled the distributor cap and rotor and again inspected the whole ignition system. Everything looked really good. I though about maybe the module failed, or the coil was gone, but that just didn't seem to jive with the fact that once I get it started, it runs fine all day. Gas mileage is normal, hill climbing is normal, acceleration is normal...

So I reassembled the ignition, pulled the top off of the air cleaner, found no oil. Tried to start it, nothing. Didn't see or smell any gasoline when I pumped the accelerator. So I sprayed some starting fluid into the throat of the carburetor, it fired as soon as I turned it over. Had to spray it one more time before it would stay running. I conclude the after sitting all night, it has no fuel in the carburetor and that it is taking allot of cranking to get fuel to the carburetor.

Why? I don't think it is fuel filters since once it is started there are no symptoms of fuel starvation. Ditto with fuel pump problems. So what is it?

[cooperhawk]

I suspect that your fuel pump is not holding pressure in the lines when the engine is not running and is not delivering enough pressure when it is running. Have a mechanic put a fuel pressure guage on the fuel line and turn the engine over and see how much pressure you have and if it holds when you turn the engine off.
Fuel will evaporate from the bowl on a warm engine, but there should be fuel waiting in the line so that when the float asks for fuel it is there. If it drains back through the fuel pump, it takes a long time to get it back.And if the pump is weak it takes longer.

[noiva]

Originally Posted by cooperhawk

I suspect that your fuel pump is not holding pressure in the lines when the engine is not running and is not delivering enough pressure when it is running. Have a mechanic put a fuel pressure guage on the fuel line and turn the engine over and see how much pressure you have and if it holds when you turn the engine off.
Fuel will evaporate from the bowl on a warm engine, but there should be fuel waiting in the line so that when the float asks for fuel it is there. If it drains back through the fuel pump, it takes a long time to get it back.And if the pump is weak it takes longer.

I'm assuming the carb floats have been checked to be sure they're not sticking in position. That happened to me years ago. Relatively easy to fix, but a little difficult to catch. The lack of fuel getting to the carb (you're not smelling gas) sure sounds like lack of pressure or (less likely) sticking carb floats.

Tim

[guy99]

I have a hard time seeing why a weak fuel pump won't cause other symptoms of fuel starvation.

If the floats are sticking, why do they unstick and why don't they ever stick except when the MH has been parked overnight?

[noiva]

Originally Posted by guy99

I have a hard time seeing why a weak fuel pump won't cause other symptoms of fuel starvation.

If the floats are sticking, why do they unstick and why don't they ever stick except when the MH has been parked overnight?

I wasn't implying at all that the problem was not caused by the fuel pump. It certainly sounds like that's probable. I was simply relaying that there has been a problem with some carbs with the floats getting "saturated" (talking about plastic floats in particular) while they sit, and then causing the fuel shut-off symptoms. When that does happen, the floats typically will work correctly once they get freed up during the running of the engine. I'm not an expert on carbs, just relaying an experience that happened to me, and had similar symptoms to what our friend is having. A weak or erratic fuel pump certainly would be my first suspicion.

[cooperhawk]

A weak fuel pump will cause these problems. It allows the fuel to drain back to the tank when not running and then has a hard time repriming itself. When the engine calls for more power it can't supply the fuel fast enough. I am not sure what type pump your unit has, but if it is a diaphram type, a small pin hole in the diaphram would cause this.

[guy99]

Jim,

Thanks for your posts. I'd really like to figure this out.

I follow how this might cause my morning hard/non start problem. But I am not having any other fuel starvation symptoms. Maybe the defect is small enough that it's not showing up when the engine is running?

Guy

[guy99]

Originally Posted by noiva

I wasn't implying at all that the problem was not caused by the fuel pump. It certainly sounds like that's probable. I was simply relaying that there has been a problem with some carbs with the floats getting "saturated" (talking about plastic floats in particular) while they sit, and then causing the fuel shut-off symptoms. When that does happen, the floats typically will work correctly once they get freed up during the running of the engine. I'm not an expert on carbs, just relaying an experience that happened to me, and had similar symptoms to what our friend is having. A weak or erratic fuel pump certainly would be my first suspicion.

Tim,
Thanks for your posts. I'd really like to figure this out but I'm having trouble following. If the float was "saturated" wouldn't it sink and fail to shut of fuel flow when the float chamber was full? Seems like this should cause flooding, not starvation, if I understand correctly.

[noiva]

Originally Posted by guy99

Tim,
Thanks for your posts. I'd really like to figure this out but I'm having trouble following. If the float was "saturated" wouldn't it sink and fail to shut of fuel flow when the float chamber was full? Seems like this should cause flooding, not starvation, if I understand correctly.

You're correct, of course. In my haste to get a message written that could possibly help you I didn't explain this problem intelligently at all , sorry. There are really 2 conditions I've seen (rarely) that have affected the operation of carbs on my vehicles in the past. The first is "saturated" floats, which you have correctly observed cause the vehicle to flood. Since you're NOT smelling gas, that's definitely not your problem. After going back over your posts more carefully , I should have written about the remote possibility (which I've experienced once) of the floats sticking in the "up" position, which cut off the gas even though there was none in the carb bowl. THAT is the only way this float thing could be affecting you. I really apologize for not reading more carefully, and causing this confusion. I've appreciated and gotten valuable info from your posts, and certainly didn't mean to cause any more problems for you. In the future I'll be more careful to read fully, and not comment unless I can do a better job than I did on the "saturated" float entry. Please let us know what you finally discover. I am concerned, and have good intentions in spite of that very poor post .

Tim

[shadejo]

Guy, I think you are fairly close to solving this, I would definitely follow the trail on the fuel pump(s) now. I have seen symptoms you are describing on two previous automobiles I have owned, both were due to weak valves in the fuel pump allowing the fuel to drain back to the tank. In the case of a motorhome it is a VERY long run back to the tank, so it makes sense it would be very difficult to get the pump to prime.

Not sure of your exact setup, i.e. if you have a pump at the engine and a pump back on the chassis, it is entirely possible that if you have both, one has failed entirely and the other is just managing to provide enough fuel to keep you going. The suggestion to check fuel pressure, and whether it leaks down is absolutely right, although at this point if there are doubts as to the condition of the mechanical pump on the engine I'd be tempted to change it out immediately - one less variable to worry about.

Incidentally, weak fuel pump valves often exhibit this kind of behavior, leak down of the fuel overnight but able to provide enough flow once the engine is actually running. One of the tricks to get mobile if you have the problem is what you already have discovered - cautious use of starting fluid or small amounts of fuel into the carb to get the engine to start, often then it will keep running as the pump will pull enough fuel at the rpm's the engine is turning when running (as opposed to the very low rpm's it turns on the starter) Such an appoach is suitable to get you home
but you'll still need to replace the offending pump.

Good luck, sounds like you are much closer to home now anyway.
John