Airstream 89 345LE GM454 Issue

[ArStrm345LE]

hello everyone, this'll be my first post here, or related to this subject for that matter; it's a pleasure seeing such an active and collaborative community here, thanks in advance


I have spent the last few hours searching the forums and have found some really helpful content, however, I still hope someone can help me with the following problem I'm experiencing



Summary: Request Confirmation of Engine Timing & Some Troubleshooting help.

Current Symptoms: After light driving (10~20mins) in mild temp (70~80 degs outdoors) the engine temp rises to 220deg and after this period (though maybe even before,) the vehicle cannot climb past 30~40mph, barely manages a mild grade incline, petal fully depressed gets you 30mph.) Starts backfiring (though this subsided a bit after plugs/wires replaced, timing somewhat adjusted.)

A shop which should know better timed the machine to: 4deg before top dead center using the timing marks on the lower part of the engine using the 8th cylinder. I do not think they did anything with the vacuum advance.

What I have read and have been told (same engine but with a different year and model vehicle) is that you time to 8deg before TDC using the 8th(?) cylinder, and confirm the timing advances to 12deg with vacuum advance.

Could anyone please confirm or share with me the correct timing settings? (If possible, a source would be just icing on the cake too!)

Some background, I have just purchased my first Airstream 345LE GM454 Gillig Chassis, (some additional info: Carburator, Banks Headers)

This is what I have done with it so far:

·Oil Change
·Radiator Flush
·Transmission Flush
·Rear Differential Fluid replace.
·Replaced 3 Fuel filters along fuel line (as many as I could find)
·New Mechanical Fuel Pump (along engine) (Note: In addition there's an electric fuel pump right next to the back fuel filter outside of the fuel tank, that seems to run all the time, maybe related to us not finding a related switch for it on the dash.) The Mechanic checked the flow of the fuel line and said that there doesn't seem to be anything wrong with this setup at this stage.
·New Plugs, wires, distributor cap and rotor.
·Prior owner indicated that he put a new Carb (3years back) on it without adjusting from factory settings.
·Belts and hoses look good.

When I purchased the motorhome, it seemed to drive fine, the condition seemed good. During the sale the owner looked as if he was starting it up for the first time this year round. So he seemed confident to demo the vehicle without a trial run. He mentioned that he winterized every year and took fair care of the motorhome. The only indication of mis behaviour was while test driving, the vehicle stalled several times but we thought that it might have to do with a low/near-empty gas tank with moisture/debris etc. We later filled a quarter tank, and some of that 'heat' type fuel additive that's supposed to help with the above mentioned. This allowed us to test the generator (works fine) and stuff downstream. It also allowed us to drive it for 30mins without issue except for a few stalls along the way. Another little bit of testing and I then proceeded to fill the fuel tank to capacity with highest octane from Chevron/shell.

After the fillup, the vehicle started to backfire and run rough, stall more and loss of power. It was at this time that I started systematically performing the work listed above "..what I have done with it so far.." on the vehicle.

Additional items that we suspect need to be addressed:

·Radiator may need a new core, replace Fan clutch.
·Vacuum Advance (vacuum leak or not funtioning.)
·Incorrect timing
·Was told that the butterfly valve shaft was loose on the carb and that the carb is due to be rebuilt or replaced, but I do not think this would be the direct cause of the issues I'm experiencing, rather, improve performance no?

Can anyone offer any advice, or have experienced similar and would share their experiences?

[guy99]

First I suggest you validate the temp reading you are getting from your dash gauge. Many of us have had problems with the gauge or the sender or both. These folks helped me with a new gauge (OEM) and sending unit.
Home Page

Did your mechanic check fuel supply under load? At one point in its life my rig had loose crude in the fuel tanks which produced fuel starvation under a load.

I had backfires and stumbling acceleration which was cured by a new coil. Also have you replaced the ignition module? A failing module can cause a wide variety of symptoms.

[ArStrm345LE]

Thanks for such a swift reply.

Originally Posted by guy99

First I suggest you validate the temp reading you are getting from your dash gauge. Many of us have had problems with the gauge or the sender or both. These folks helped me with a new gauge (OEM) and sending unit.
Home Page

Thanks, I'll check them out

Originally Posted by guy99

Did your mechanic check fuel supply under load? At one point in its life my rig had loose crude in the fuel tanks which produced fuel starvation under a load.

I do not think so. The extent of the fuel supply check was, after replacing teh 3 filters and mechanical pump, loosening one of the filters and confirming flow rate(?) I don't recollect the exact procedure but the mechanic said that nothing seemed of concern there. Out of curiosity, how would one go about checking the fuel supply under load?

Originally Posted by guy99

I had backfires and stumbling acceleration which was cured by a new coil. Also have you replaced the ignition module? A failing module can cause a wide variety of symptoms.

Which coil are you speaking of? (sorry, rather new to the whole moho diy scene)

I didn't check the ignition module because people (and mechanics) kept telling me, it either works or it doesn't. Should I just replace it?

[ScrapIrony-2]

We have a 1989 345 LE-owned it for 1 1/2 years-and have experienced the same problems. I have replaced the rear fuel filter(near the in-line fuel pump) with an improvement in the sputter/stalling issue, but still have a problem with acceleration, especially going up steep(6-8+%) grades...the unit slows down to about 15 mph, with manual alteration of transmission(1st to 2nd gears)...however, I am towing a '95 GEO Tracker, and do have a load on board. Basically, I'm content to move forward, while mileage maintains at about 6 mpg. It is frustrating to me and the folks behind me to lose power on uphill grades, but with 125,000 miles on the odometer, I have opted for getting there as opposed to NOT. I have horror stories from bad care from the Freightliner Dealer in San Antonio and Camper Clinic II in Buda, TX. I have saving grace stories from the Freightliner Dealer in Farmington, NM and Sweetland's, also in Farmington, NM. I have a 345 that is still moving down the road, at speeds that are probably a good thing, given the majority's inclinations. I also have a Gear Vendors Overdrive, and have very little idea as to what that does or means...it came with the unit as is. I will continue to be frustrated at the mechanical aspects of motorhoming, but am not willing to give it up. I can tell you how to repair a step bent awry by a poorly-placed treestump, how to replace a belt, how to replace a fuel pump, and I'm about to be able to tell you how to R&R a gray/black water 3" line with gate valves then patch the ensuing leaks...
I have loved and hated vehicles in the past, but NOTHING approaches the relationship I have wirh the 345, 'cept maybe my wife...? She's been around longer, and treats me better...
mike

[cooperhawk]

I also wouldn't rule out fuel vapor lock if the fuel line runs near anything hot. In fact, thats what it sounds like to me.

[guy99]

Originally Posted by ArStrm345LE

Thanks for such a swift reply.

Thanks, I'll check them out


I do not think so. The extent of the fuel supply check was, after replacing teh 3 filters and mechanical pump, loosening one of the filters and confirming flow rate(?) I don't recollect the exact procedure but the mechanic said that nothing seemed of concern there. Out of curiosity, how would one go about checking the fuel supply under load?

Which coil are you speaking of? (sorry, rather new to the whole moho diy scene)

I didn't check the ignition module because people (and mechanics) kept telling me, it either works or it doesn't. Should I just replace it?

In my experience it is not true that an ignition module either works or it doesn't. In my neck of the woods NAPA stores have the equipment to bench test these. But if I were you I would buy a new one of the best quality you can get and swap it in. If it makes no difference, you have the one you removed as a spare (which you should carry anyway).

I was referring to the ignition coil which on my rig is actually in the distributor cap. Since yours in newer maybe yours is different.

Regarding the fuel flow test, I read of a 'backyard mechanic' test procedure on this site, hopefully some can repeat it or give you a pointer to it. I would expect that a good shop is going to have some way of testing it.

Cooperhawk is right about vapor lock being a problem with these units.

[guy99]

Originally Posted by ScrapIrony-2

We have a 1989 345 LE-owned it for 1 1/2 years-and have experienced the same problems. I have replaced the rear fuel filter(near the in-line fuel pump) with an improvement in the sputter/stalling issue, but still have a problem with acceleration, especially going up steep(6-8+%) grades...the unit slows down to about 15 mph, with manual alteration of transmission(1st to 2nd gears)......

mike

This sounds exactly like what happened when my rig had junk in the gas tank.

[cooperhawk]

Originally Posted by guy99

Regarding the fuel flow test, I read of a 'backyard mechanic' test procedure on this site, hopefully some can repeat it or give you a pointer to it. I would expect that a good shop is going to have some way of testing it.

The problem with vapor lock is that it is difficult to re-create in a shop. The unit needs to be out in the heat and working hard to build up the heat to boil gasoline and cause it. I had this problem a few years back, actually a lot of years back, with a semi tractor that did this same thing. We cured it by installing a second electric fuel pump. I had that one on a switch and when the problem would start, I would turn it on and it would clear right up.

[ArStrm345LE]

Originally Posted by ScrapIrony-2

I can tell you how to repair a step bent awry by a poorly-placed treestump

nice post. I actually would be interested to hear your techique.

Originally Posted by cooperhawk

I also wouldn't rule out fuel vapor lock if the fuel line runs near anything hot. In fact, thats what it sounds like to me.

@ cooperhawk, I thought this might be the case, esp. with the Banks headers but the mechanic that traced the fuel line said they were installed properly and that although the symptoms seemed attributable to vapor lock, he said it didn't seem likely in this scenario.

Oh, and as my 1st post mentioned, this moho has both an electric and mechanical fuel pump, I replaced the mechanical one but the electric was tested as good. But we could not find teh switch anywhere on the dash (didn't look hard though cause there's a lot of buttons up there and some rewiring has kept me from wanting to open that can of worms just yet. I was told during testing of the fuel lines that the electric fuel pump remains on once the engine has been started.

@guy99, thanks for the ignition coil clarification

[3 Dog Nite]

I've had a problem with loss of power which made the engine work too hard. I just replaced both fuel pumps. Did you know there were 2 ? I learned this by following the fuel line. there's one inline near the filter just ahead of the fuel tank. The 2nd is located on the engine block where you expect to find it on a car. BTW - I've got 454cu in a 1989 345LE

[ArStrm345LE]

Update to stuff done on the airstream (Also updated the 1st post with this):

~ Placed in line a beefier fuel filter and added some marine/RV heavyduty fuel tank cleaner stuff.
~ Replaced the coil in the distributor cap.
~ Purchased a new distributor (with ignition module and vacuum advance included) and will install shortly.
~ Confirmed timing to 8deg before TDC using 8th cylinder and advancing to 16deg before TDC with Vacuum advance engaged.

All, thank you so much for all your feedback and advice. I have been without access to the internet til now but as I've now been able to log on, wished to give a status update thus far.

Over the weekend, i took the vehicle to a local automotive & moho shop. They seem very friendly and with integrity from the conversations I've had with the mechanic. I have given them info on what has been done so far and a list of possible issues to address in order to resolve my performance and reliability issues. They can re-core the radiator if necessary and said they will give an inspection and assessment before proceeding in the next few days. I'll post again an update to my issues once I learn more.

P.S. I've also printed out some really informative threads and posts from this forum and the classicmotorhomesonline forum, and given them to the mechanic for inspiration in the troubleshooting process.

Again,
thanks All, and I'll let you know how this turns out. I'm still in a time crunch to get this machine road worthy for my road trip to the Burningman Deserts so if I end up posting the update after that, my story might even include the successes and failures of the trip as well

EDIT: I guess I cannot update the first post as I can't seem to find the 'edit' button for it.

[guy99]

Sorry to be repetitive but be sure you validate your temp reading before you put a lot of money/effort into an overheating problem.

Unless, of course, you want to refresh the cooling system for future reliability.

[ArStrm345LE]

Hi guy99, I've asked the guys at the shop (hopefully, they are decent folk,) to confirm for the the accuracy of my temp gage, in addition, give me an assessment of the condition of the radiator and system employing a temp gun, before resorting to a cooling system overhaul, but I do eventually want to pay (no pun intended, nor exactly wished :P) attention to the cooling system for future reliability and as I'm going into the desert for a few weeks, I'd seriously consider any potential problems with overheating, in anticipation for this trip.

[ArStrm345LE]

2007.08.22 UPDATE: I just got off the phone with the Mechanic and he said they had just re-timed the engine to 4 degrees before TDC. I respectfully mentioned to him that it was my understanding that the proper timing for this motor/moho was 8deg before TDC. He said they knew what they were doing as they have the proper documentation and they are an RV/auto repair shop. Are they correct? Can anyone possibly give me an intelligent response if the timing is indeed 8 before using the timing marks on the bottom of the engine using the 8th cylinder?

P.S. I couldn't seem to find the edit button for my above post to append this one. I apologise in advance for the double posting.

[ScrapIrony-2]

[QUOTE=ArStrm345LE] nice post. I actually would be interested to hear your techique.

Initially, it was really basic...first, I explored new combinations of old epithets. Then, I pulled forward over the stump I had backed over(though not reccomended, this is an effective way to remove old stumps...Kinda like removing a bad tooth when you were a kid). Then, I got out and went to the hot tub. about a week later, I drilled out all the rivet bolts, hammered the braces flat(sorta), took a long bar to the braces coming out of the motor housing, installed bolts, prayed to the Great Aluminum One, and flipped the switch. Nothing happened...till I remembered to turn the chassis battery switch back on. The step is about 3/4 inch out of kilter(gives it that 'homey' look), and checking the bolts is now part of my ever-expanding maintenance routine. I opted for regular bolts, as there are more stumps and other things out there, and I'm almost on a first-name basis with Murphy.
The unit has started to sputter more, so i will be replacing the rear fuel filter, again...someday, I suppose I will have to flush the tank, but for now, replacing the fuel filter is so much easier. I replaced the fuel pump with the spare that came with the unit, then found out it wasn't the pump...anyone with this problem should learn from me that testing the existing fuel pump is an obvious diagnostic tool that doesn't require removal...
mike

[garry]

I may be all wet here but "I think" if you have a Rochester carb. you could have a small fuel filter at the carb where the fuel line attaches. it depends on the carb. and since it has been replaced ???

I would also suspect a vapor lock that would show up in hot weather and a hot engine. I have solved that with a second fuel pump it is difficult to troubleshoot a vapor lock. I had moved the fuel lines around but the problem would come back so on a gut feel a second fule pump fixed it.

I don't remember on the timing but I "think" if you use the bottom mark you need to use the #5 plug.

Another thing is loss of firing to the plugs can give the same symptoms and be caused by the coil, loose wires, electrical module in the dist ect.

Garry

[M Hohnstein]

No way is timing the issue. There is a small filter in the fuel inlet nut that may well be plugged. A 1" tappet wrench and a 5/8" flare fitting wrench are the most logical tools to use to access the filter. This little rascal is frequently overlooked, but is a standard part in the Quadrajet carburator.
If this filter is proved not to be an issue, go after the HEI distributor, don't fool around, get a reman unit from NAPA for the national warrentee.
After 30 years of life on the road with P-30s, Chevy pickups etc. I never leave home with out a spare HEI and plug wire set.

[zamboni]

Are you guys sure you aren't driving my MOHO by mistake? I haven't been to the storage lot lately. LOL. Let's see here...vapor lock probs on my 1979...still vapor lock problems on the 1989 models...Got to like that engineering! )
I've heard of the double fuel pump fixin' it. A friend w/SOB told me he had heard of people putting clothes pins on the fuel line to dissipate the heat. Makes sense, only if you could use metal clothes pins. I finally got tired of the sputtering, and dying "on the way to somewhere" and insulated my fuel lines w/ foil bubble wrap, added heat sheild, added air duct from front of cowl, replaced fuel filter on carb, replaced fuel filter at rear electric fuel pump, replace Distributor cap...Not sure which one fixed it, but hasn;t done it for 5,000 miles.

[klattu]

Originally Posted by M Hohnstein

No way is timing the issue. There is a small filter in the fuel inlet nut that may well be plugged. A 1" tappet wrench and a 5/8" flare fitting wrench are the most logical tools to use to access the filter. This little rascal is frequently overlooked, but is a standard part in the Quadrajet carburator.

Exactly...
Always change this filter same time as rear one.
So cheap <$2
Yes, you need to add a 1" open end wrench to tool box.

Woke mine up big time.

[TomW]

Originally Posted by M Hohnstein

... There is a small filter in the fuel inlet nut that may well be plugged. ...

If performance improves after replacing that particular filter, then part of the problem is weak fuel supply pressure.

That particular filter setup is designed to bypass when clogged. In other words, when the filter gets full of junk, your carb is supplied unfiltered gas.

If it is not bypassing, the last fuel pump in the system should be checked for delivery pressure.

Tom