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Belthasar

87 Fleetwood Pace-Arrow Chevy P30 Chassis w/454, Hesitation, Backfiring and stalling oh my.

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UPDATE to the update... 11/13 - Took it on a test drive last night after visiting my mechanic to check on progress and the work to date... issue is resolved, we were able to swap out the relay, and verify power then VROOM! Ludicrous speed!  (55-65+ UPHILL Even!!) Thanks all for the great advice! I have a nice list of things to follow up on to hopefully get ahead of any future issues!

After our short adventure yesterday, and yet another tow after spending almost an hour crawling up slight hills doing 20 with traffic flying up my butt doing 90,  only to get a 5th of the way to the shop, my mechanic and I have been in touch. The owner rectified the poorly installed fuel tank, and in his investigation he found there was zero way that fuel pump ever worked (old or new one) as the fuel pump relay had fallen into the doghouse, and was dangling by its wires and on closer inspection it was totally gummed up and corroded and absolutely failed (Attached). (Id hate to be his tech who said he confirmed operation of said new pump that likely wasn't needed after install.)

Awaiting update that installation of the new relay got the in take fuel pump working,...

On another fun finding note - he sent me pics of this custom wiring job (also attached) that I did not see when I was poking around - a rats nest is more organized... so now onto trying to find wiring diagrams so I can eventually dismantle the spaghetti mess and get things looking n working right. Why oh why do people do this to vehicles, I get it for if your stuck on the road for a quick fix but jeeze!

 

 

Hey All,

First time posting. My mechanic and I are scratching our collective heads on an issue my new-to-me rv is having and I thought I would reach out to the collective wisdom here. I have read a number of posts and suggestions relating to similar sounding issues but wanted to get this (and some history) in front of the group.

I bought this vehicle about 3 months ago, and it has largely been in the shop since for general chassis maintenance and some repairs but things keep popping up. The issue I am currently chasing down is a frustrating one - the vehicle runs fine after initially warming up, accelerates on WOT just fine, gets down the road nicely. After approximately 30 minutes of easy travel, the engine starts hesitating on heavy throttle, then will begin backfiring and near stalling out under load - "load" being going uphill slightly or trying to speed up. If I stop on the side of the road for 20-30 minutes I can make it another 15 minutes or so with very light throttle use. If it sits overnight, all the above can be repeated. When I first drove it home, It did initially overheat but was not operated in that condition so im fairly confident the head / block isn't cracked.

What has been done so far - 

Full Tune up - Plugs, High end solid core wires, coil, dist. cap, rotor, timing checked.

Radiator pulled - one of the cores was shot so the radiator was rebuilt, new water pump, new hoses. (After buying it, my mechanic informed me that it didnt have a fan cowling, so after two months of hunting one down, it now runs nice and cool)

Gas tank pulled, (No signs of trash in the tank) internal fuel pump replaced, fuel filters replaced.

The prior owner did tell me that he had the carburetor replaced, so for me at least I suspect that it may not be setup correctly - (but until some time of steady use, it runs fine? - I would suspect a bad carb setup would always run bad?) Am willing to entertain a replacement with an upgrade if one is available.

I am about to go pick it up from where I dropped it off last night in frustration - but intend to run it tonight with the doghouse off to check for any grounding / sparking issues. 

Are there any other obvious things I should be looking at?

 

Thanks in advance!

 

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Edited by Belthasar
Updated the update

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Just a few questions. Did you have the fuel pressure checked. When you say internal fuel pump was replaced, do you mean there is a pump in the tank or are you taking about the accelerator pump in the carb. If the carb was sitting for a long time and not ran the accel. pump will dry out and cause hesitations. if the accel. pump is not suppling enough fuel into the venturies, it will backfire back thru the carb. Does it backfire in the  exhaust? If I am not mistaken it has an ignition module and pick up coil (stator) in the distributor that can cause this issue if backfire is in the carb. Did your mechanic check to see how many degrees of slop is in the timing chain? Just a a few things to know before trying to help diagnose your problem. If the fuel pump is in the tank you would probably are talking about the throttle body. It kind of looks like a carb., but has two fuel injectors on top. you can PM me and ill give you my phone number and i can walk you thru what you need to check.

Edited by f442485
more info

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I had a 1987 Bart, with a 454 full injection system.  Biggest problem was lugging, back fire and fuel filters, I carried several in the bay! POS since the coach was custom ordered and built.

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I owned a 1987 Southwind many years ago with same problem. I wound up replacing the spark plug wires with a racing grade was the solution for mine. I went through several sets of those solid core sets for a temporary fix, after going with a very expensive set from a major racing supply here in Birmingham, the problem did not come back while I owned it two more years. Also be sure there are no vacuum leaks.

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It can be a lot of things  

One thing to eliminate is induction on plug wires    space them away for each other and if they cross try to have at 90 degs 

worn advance in distributor  failing pickup or module heat induced 

If you know some one with a big block test with a borrowed distributor 

good luck  and let us know what you find 

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Belthasar, welcome to the forum. What year is the engine? It almost sounds like a vacuum leak after it warms up. I would check all the vacuum lines and check for leaks under the "new" carb Make shure all the lines are hooked up to the carb and in good condition.

Bill

Edited by wildebill308

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This engine is known to be rough on plug wires.  They get old and leak and cause all sorts of missing and back firing issues.   While it is dark, remove the engine cover and start the beast and observe the light show from leaking wires.  

Replace the plug wires with the best high temperature wires you can find with ceramic boots.  Be sure to use the silicon on the plug boots.

Ken

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On 11/7/2020 at 10:35 AM, Belthasar said:

Hey All,

First time posting. My mechanic and I are scratching our collective heads on an issue my new-to-me rv is having and I thought I would reach out to the collective wisdom here. I have read a number of posts and suggestions relating to similar sounding issues but wanted to get this (and some history) in front of the group.

I bought this vehicle about 3 months ago, and it has largely been in the shop since for general chassis maintenance and some repairs but things keep popping up. The issue I am currently chasing down is a frustrating one - the vehicle runs fine after initially warming up, accelerates on WOT just fine, gets down the road nicely. After approximately 30 minutes of easy travel, the engine starts hesitating on heavy throttle, then will begin backfiring and near stalling out under load - "load" being going uphill slightly or trying to speed up. If I stop on the side of the road for 20-30 minutes I can make it another 15 minutes or so with very light throttle use. If it sits overnight, all the above can be repeated. When I first drove it home, It did initially overheat but was not operated in that condition so im fairly confident the head / block isn't cracked.

What has been done so far - 

Full Tune up - Plugs, High end solid core wires, coil, dist. cap, rotor, timing checked.

Radiator pulled - one of the cores was shot so the radiator was rebuilt, new water pump, new hoses. (After buying it, my mechanic informed me that it didnt have a fan cowling, so after two months of hunting one down, it now runs nice and cool)

Gas tank pulled, (No signs of trash in the tank) internal fuel pump replaced, fuel filters replaced.

The prior owner did tell me that he had the carburetor replaced, so for me at least I suspect that it may not be setup correctly - (but until some time of steady use, it runs fine? - I would suspect a bad carb setup would always run bad?) Am willing to entertain a replacement with an upgrade if one is available.

I am about to go pick it up from where I dropped it off last night in frustration - but intend to run it tonight with the doghouse off to check for any grounding / sparking issues. 

Are there any other obvious things I should be looking at?

 

Thanks in advance!

 

unnamed.jpg

What year is your coach?

Does it have a throttle body Quadrajet carb or throttle body injector system ?

Have all the engine Vacuum lines been checked or replaced and how long ago where all the lines replaced?

When was the last time the distributor and ignition  circuit been rebuilt?

This old thread might be some help.

Rich.

 

Edited by jleamont

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On 11/7/2020 at 11:46 PM, f442485 said:

Just a few questions. Did you have the fuel pressure checked. When you say internal fuel pump was replaced, do you mean there is a pump in the tank or are you taking about the accelerator pump in the carb. If the carb was sitting for a long time and not ran the accel. pump will dry out and cause hesitations. if the accel. pump is not suppling enough fuel into the venturies, it will backfire back thru the carb. Does it backfire in the  exhaust? If I am not mistaken it has an ignition module and pick up coil (stator) in the distributor that can cause this issue if backfire is in the carb. Did your mechanic check to see how many degrees of slop is in the timing chain? Just a a few things to know before trying to help diagnose your problem. If the fuel pump is in the tank you would probably are talking about the throttle body. It kind of looks like a carb., but has two fuel injectors on top. you can PM me and ill give you my phone number and i can walk you thru what you need to check.

Hey Thanks! 

I went out today to try and swap out the fuel pump relay - but before I get into that ill try to answer your questions...

  • Unknown on the fuel pressure check, I had hoped my mechanic checked it, but it seems he had a Jr tech working on it...  (see below)
  • Yes, it has been backfiring up through the carb.
  • The Fuel pump I referred to that was replaced, was in the tank.
    • My model does not have an external / rear mounted aux pump that I could find.
    • Upon crawling under to check for the fuel relay and just to check the previous work, I discovered multiple pinched wires between the tank and the frame. (Its waiting on a tow to go back to the shop to drop the tank, inspect the wires for damage, replace, then check voltage on the fuel pump and ensure it runs and to check fuel pressure)
  • I will ask about timing check, but after initially starting and getting up to temp - the thing runs like a champ but seems underpowered, only when I get to WOT or after its fully warmed up (and 30+) minutes away from anything will it start hesitating, backfiring and eventually coming to a crawl. (25mph max)

My current thoughts (other than the shop screwup with the wires) are that the "new" fuel pump was not properly checked for operation after install - I am pretty certain after my recent conversation with the shop owner, the Jr tech likely just started it up and called it a day. (I am of the understanding - please correct if wrong - that these can run at idle and little to no load with the mechanical pump on the engine, but under load especially when warmed it will be starved for fuel, which so far matches my experiences to date)

Also of note - I am leaning towards thinking the in-tank pump may not have ever worked while in my possession as per the info I found during my own inspection and investigation today. I could not find any fuel pump relay in any of the obvious locations for the P30 chassis of my year, but I do have a panel in the front engine compartment that has a port for fuel pump, with nothing in it, but appears to be wired.

Fun times, the journey continues (Right now at 20 mph up the slightest incline, or with the help of a tow winch which may be faster still)

Photo below of location of obviously missing fuel pump relay, if there is one in another location I have not yet traced it down. (Not in the upper left doghouse - from inside, not under / on the wheel wells either side, and nothing obvious in front except for the missing one below)

1111201148a.jpg

Edited by Belthasar
Typos

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On 11/8/2020 at 7:15 AM, kaypsmith said:

I owned a 1987 Southwind many years ago with same problem. I wound up replacing the spark plug wires with a racing grade was the solution for mine. I went through several sets of those solid core sets for a temporary fix, after going with a very expensive set from a major racing supply here in Birmingham, the problem did not come back while I owned it two more years. Also be sure there are no vacuum leaks.

Rgr that on the vacuum leaks - im rebuilding my do-it-yerselfer tool kit roster, but do not have a vacuum gauge, compression testor just yet - its on da list.

 

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7 hours ago, dickandlois said:

What year is your coach?

Does it have a throttle body Quadrajet carb or throttle body injector system ?

Have all the engine Vacuum lines been checked or replaced and how long ago where all the lines replaced?

When was the last time the distributor and ignition  circuit been rebuilt?

This old thread might be some help.

Rich.

 

Thanks for the thread reference, this is carbureted (unknown make) but that's my next option up if all pans out with fuel system working. (prior owner did say the carb was replaced, but dont know by who - and hearing how these carbs are hard to setup right - well ill happy consider an alternative / upgrade if one arises.

 

it is pulling a vacuum, but I did not gauge it. (Need to get one). All vacuum lines "look" good from inspection from top down and bottom up, but Ill be getting a roll of vacuum tubing anyways just to start replacing them. The prior owner apparently did not follow through on any chassis work other than oil changes and fluid top offs, and was mostly focused on the RV portions.

Sorry, We had all components replaced with the "full" tune up, but I will triple check with my mechanic as they are now suspect a bit.

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On 11/9/2020 at 6:51 PM, txiceman said:

This engine is known to be rough on plug wires.  They get old and leak and cause all sorts of missing and back firing issues.   While it is dark, remove the engine cover and start the beast and observe the light show from leaking wires.  

Replace the plug wires with the best high temperature wires you can find with ceramic boots.  Be sure to use the silicon on the plug boots.

Ken

It has upgraded wires, with the heat shields, and ceramic boots now 😃. I at least was able to verify that part of my request to my mechanic was done! :)

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On 11/8/2020 at 11:11 AM, bm02tj said:

It can be a lot of things  

One thing to eliminate is induction on plug wires    space them away for each other and if they cross try to have at 90 degs 

worn advance in distributor  failing pickup or module heat induced 

If you know some one with a big block test with a borrowed distributor 

good luck  and let us know what you find 

Good suggestions, I had not considered the routing, they do cross a bit - ill rectify that when i get it back. Will have to check on the advance.

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With all the findings today, and yet another short lived trip and subsequent tow ... I am thinking a bit out of the box (and into my day- off first scotch of the day so....)

 

I cant stop but think it may be a good idea to upgrade the engine a bit with something like a performance ignition system such as MSD, and upgrade the carburetor or heck even convert to fuel injected... Any thoughts? I am definitely NOT made of money, but at this rate my RV is looking more like a boat with the drivability issues, rather than me putting money into making the RV more updated and comfeeze for my usages. Am thinking that doubling down on just being done with chasing the gremlins and update a bunch of stuff may be called for. yeah, probably the scotch talking - but still...

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On 11/8/2020 at 4:28 AM, manholt said:

I had a 1987 Bart, with a 454 full injection system.  Biggest problem was lugging, back fire and fuel filters, I carried several in the bay! POS since the coach was custom ordered and built.

Very sorry to hear, did you ever get something to work with it reliably for your issues? How long did you mess with it / keep it? I must admit, my daughter wants a tiny house, and its tempting to just remodel and park it somewhere with utilities for her 😃 (Its MY RV, but if it cant do a long haul by next summer I will need to reconsider keeping it,  as I plan on moving in a year or so - likely to the upper northeast US, and if it cant drive and put some distance on more than 20-30 minutes at a time with an hour break in-between, I sure as heck aint shipping it.)

 

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backfiring through the carburetor or exhaust?

How many miles on the engine?

Edited by jleamont

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Most of the time a backfire in the intake manifold/carb. is usually a lean condition or the ignition module and stator are shutting off and back on due to heat transfer thru the distributor. Running out of power while under load (climbing) sounds like you do not have enough fuel flow to the carb., in other words the fuel pump cannot supply enough fuel to the carb to keep the float bowl full. Those two areas should be your primary concerns. If your mechanic can't check that correctly, I would be looking for another shop. Just my opinion. I have been in the automotive, marine, RV and race engine business for over 50 years. You can PM me here and i will talk you thru this issue.

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I has similar problem with a 454 carburetor engine in a P30 chassis back in the late 70's.  It ran fine except in warm weather. Found problem to be restriction in fuel line where it came out of the fuel tank.  There was short section of hose that had sharp 180 degree turn, the hose would collapse and restrict the fuel flow.  The problem only occurred when under heavy load.  What complicated trouble shooting was the problem occurred when  running on either of the fuel tanks, found both tanks has the same problem.

Corrected problem by replacing the short section of hose on both tanks and installing a spring in the hoses to prevent them from collapsing..

Jim

 

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19 hours ago, jleamont said:

backfiring through the carburetor or exhaust?

How many miles on the engine?

Its backfiring through the carb... 29k orig on the engine.

 

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With my experience with the older engines with a module in the distributer is that it works fine for a long time and then one day when you shut the engine off it will not restart.

To me it sounds like the engine is starving for fuel. The first thing I would do would be to install an external electric fuel pump and to mount it as close to the tank as possible. Most electric pumps do mush better pushing fuel rather the pulling it for long distances.

Also along the same line, has anyone thought about a slack timing chain? A 33 year old engine may just be worn by years and not miles. 

There have been some very good suggestion may so far. (Lot of ole gas heads out there)

IMO

Herman

Edited by hermanmullins

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3 hours ago, Belthasar said:

Its backfiring through the carb... 29k orig on the engine.

 

You mentioned the timing was checked, its not too far advanced? Usually that's a condition of timing advanced (could be a problem with the distributor), or lack of fuel.

I'd check the advance diaphragm on the distributor (assuming its vacuum) if all ok pull the carb and have it rebuilt or at a minimum opened up and checked, with that low of miles varnish inside wouldn't be a surprise causing it to starve for fuel or the accelerator pump (in the carb) could have a pin hole in it. 

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You mentioned that it is an in tank fuel pump, many years ago in an old Ford Granada, very similar problem as yours, it turned out to be a fuel filter/sock in the tank that had become partially stopped up. And of course an inline fuel filter in the gas line that has become laden with water can do the same thing. This may not be your problem, but well to take note in case other checks do not solve the problem.

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18 hours ago, hermanmullins said:

With my experience with the older engines with a module in the distributer is that it works fine for a long time and then one day when you shut the engine off it will not restart.

To me it sounds like the engine is starving for fuel. The first thing I would do would be to install an external electric fuel pump and to mount it as close to the tank as possible. Most electric pumps do mush better pushing fuel rather the pulling it for long distances.

Also along the same line, has anyone thought about a slack timing chain? A 33 year old engine may just be worn by years and not miles. 

There have been some very good suggestion may so far. (Lot of ole gas heads out there)

IMO

Herman

Much appreciate all the assistance, I was able take "eagle 5" on a test run last night after finding and replacing the fuel pump relay, we were able to hid ludicrous speed (figuratively) and was pulling well up hills and on WOT. Whole different vehicle! Vroom Vroom!

 

 

 

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