Last year, I purchased a used 1993 travelaire 34' class 'A' MH w/t a chev 454, (TBI i believe) and has the 4 speed A/T. I live in western Canada, and have since made several trips into the rockies. I've never owned a class 'a' before, only an older class 'c'.The biggest issue I seem to be having is lack of power, and that's where I'm looking for some assistance. At first, I thought the issue might have been dirty gas. I replaced the fuel filter located on the frame (It was extremely dirty). I then ran a few cans of Sea-Foam through it, but no change in power - or very little.The MH has 58000 kms on it (about 36K miles).I realize this is a large machine, and GVWR i believe is 16000lbs, so it will not accelerate like a car, but it takes about a full minute to reach highway speeds (65-70 mph).I've changed the cap, rotor, spark plugs, wires, air filter. A point worth noting - the engine runs perfect otherwise (no stumbles, misses, pinging, and starts perfect each time).I have not checked compression.It would almost appear that the engine is starved from fuel from what I perceive to be a lack of power, esp going up hills (at those times it also heats up and borders on going to red).This summer, I would like to be able to tow a trailer behind, but not with this low power.I know that a lot, if not most ppl will call BS, but this also seems relevant, my gas mileage is, in my opinion, absurdly high- 17.5 mpg (imperial gallons) averaged over 6500kms, that includes mountain and prairie driving.My last MH, only 24 ft w/t a 350 chev had a ton more power, but only ran a best of 9 mpg. This is why Im thinking it is a fuel delivery problem.If anyone can offer any suggestions, it would be greatly appreciated.

Check the fuel pressure first.Timing is ok?Read your plugsDoes it have a cat? Early signs of plugging/disintegration?One lesson I learned the hard way and I always consider when I see any over heating condition is core/fin separation. It's very common with older radiators. With age or harsh/salt conditions the fins to cooling tube bond can be lost and the heat transfer from the tube through the fin and out to the air can be reduced. Check your radiator for loose fins that pull off the tubes easily. Be sure all the basics are there and then you probably get into making it breath better. I have never owned a MH with theses issues but it seems like the Banks kits and other tricks were very common back then.Random findsMoreLean if too high of fuel pressure

Yes, it has a Cat, never thought of that, will have a look and see what kind of shape it's in. The timing does seem good as it never backfires or pings under load, and starts and shuts off perfect. I also failed to mention that there is no difference in acceleration beyond 1/4 throttle, at any speed.

mikebrassard wrote:Yes, it has a Cat, never thought of that, will have a look and see what kind of shape it's in. The timing does seem good as it never backfires or pings under load, and starts and shuts off perfect. I also failed to mention that there is no difference in acceleration beyond 1/4 throttle, at any speed.Timing has to be exactly right. 1/4 throttle and up seems like a serious issue not just the normal slug nature of many RV's.TimingFuel pressureOpen catNo collapsed /rusted mufflerTemp control/good coolingFeed back system is functional. Proper timing control.Others will be in here with more ideas.

Does it factory cast iron manifolds? What size is the exhaust? Is it the standard two inch or larger?7.4 TBI is a good engine. Believe your problem could be an exhaust issue.Have the exhaust system pressure tested to see if cat or muffler is clogged.Have you checked for debris between the AC condenser and the radiator? Can take AC condenser loose to blow out debris.

Just came back inside - I checked the plugs, they are on the lean side, but not to a point where I would say that it is bad (they are a very light tan, and I stress light). The exhaust manifold is stock cast iron, as well as the remaining exhaust is >2" in diameter. I checked the radiator for debris last year, that was clean, the clutch fan works well, and the electric fan as well. I haven't located any other filters other than the frame mounted fuel filter, although I have seen other posters indicating that there should be one somewhere near the fuel inlet to the TBI.

1993 Travelaire 454 chev p30 low power | Good Sam Community

Gale_Hawkins
Explorer
Jan 28, 2015
Do you have access to premium ethanol free gas. Ours will make more power on premium? Are you making sure the RPM's are in the 3500-4000 range when climbing? Has the radiator been recored? Does the water pump fan sound like a jet engine for the first few minutes after you first start it?

We have the 1992 454 TBI and one shop said it was the most powerful one he had seen in a MH. We have since added new plug/plug wires.
Gjac
Explorer III
Jan 28, 2015
I would do several things to narrow down this problem. The first thing I would find a flat stretch of Highway and do a 40-60 mpg test and post the time,if your wt is about 15,000 lbs with no mods 20 secs would be about normal and your MH would be normal, you only have 230 HP stock. The second thing is to check your computer and see if you have any stored codes,it should be an OBD1 and the service light will flash what codes are stored. If you search this forum it will give you the details on how to do this with a paper clip. Third, look at the spray pattern of the two jets in the TBI, it should be a nice cone shape with no drips, a flash light helps to see better into the throttle body. I would then check the timing should 4 degrees before TDC. Some have advanced their timing up to 12 degrees before TDC. I advanced mine to 9 and it took 2 secs off my 40- 60 mph time. When you increase the idle speed the timing marks will should advance, mine will advance if I remember correctly to about 22 degrees if it doesn't you found the problem. My distributor is electronic, your 93 may be mechanical and others have already commented on that and the cat. Good luck and let us know what you find.
mikebrassard
Explorer
Jan 28, 2015
Gale Hawkins wrote:
Do you have access to premium ethanol free gas. Ours will make more power on premium? Are you making sure the RPM's are in the 3500-4000 range when climbing? Has the radiator been recored? Does the water pump fan sound like a jet engine for the first few minutes after you first start it?

We have the 1992 454 TBI and one shop said it was the most powerful one he had seen in a MH. We have since added new plug/plug wires.

As for the premium ethanol free gas, yes. As a matter of fact, i only use that in the MH. I don't have a tach on it, but it downshifts good, and I would guess from the sound of the engine that is in the area of 4000 rpm when climbing steep ascents.
Rad has never been recored, i spoke with the previous owner, and he says never had that done, but he did have yearly flushes. (The service receipts confirm this)
As for the water pump - no, i can't say it sounds anything like a jet engine or anything close to it.
riggsp
Explorer
Jan 28, 2015
I would be checking for a restricted exhaust...that will cause low power and overheating.
mikebrassard
Explorer
Jan 28, 2015
Gjac wrote:
I would do several things to narrow down this problem. The first thing I would find a flat stretch of Highway and do a 40-60 mpg test and post the time,if your wt is about 15,000 lbs with no mods 20 secs would be about normal and your MH would be normal, you only have 230 HP stock. The second thing is to check your computer and see if you have any stored codes,it should be an OBD1 and the service light will flash what codes are stored. If you search this forum it will give you the details on how to do this with a paper clip. Third, look at the spray pattern of the two jets in the TBI, it should be a nice cone shape with no drips, a flash light helps to see better into the throttle body. I would then check the timing should 4 degrees before TDC. Some have advanced their timing up to 12 degrees before TDC. I advanced mine to 9 and it took 2 secs off my 40- 60 mph time. When you increase the idle speed the timing marks will should advance, mine will advance if I remember correctly to about 22 degrees if it doesn't you found the problem. My distributor is electronic, your 93 may be mechanical and others have already commented on that and the cat. Good luck and let us know what you find.

Unfortunately, the weather has turned sour today, and is expected to saty this way for next few days, so I won't be able to test drive it, but I can say with certainty that 40-60 mph is closer to the 40 second range, perhaps a little bit longer. 0-30 mph is where the MH seems to work best, then after that it will fall flat on it's face until I reach about 65 mph. At that point it shifts into high gear, and assuming i have no inclines, will haply stay there all day. Any incline at all will have it shift down into 3rd, and no matter the throttle position, will only make 'noise' (engine revs are higher), but no additional power/acceleration. beyond 1/4 throttle, makes no difference in power.
Since I first wrote this post, I've noticed that the service engine light has come on, and the code is 44 ( Oxygen sensor error (lean condition indicated)), so I will have to look into the cause of that before I can rule that out.
The timing was difficult to read, but it appears to be at 4 BTDC( Access is difficult at best), in park with the engine warmed up and at idle.
I will have a look at the distributor and injector spray patter as you and others have mentioned in the next few days as well.
I did have a leak at the passenger side exhaust manifold (rear bolt broke off, and I've since repaired that) not certain if that was the cause of the code 44, but will reset the computer to see for certain.
I certainly would have expected the gas consumption to have decreased with O2 sensor indicating lean, however that is not the case.
Gjac
Explorer III
Jan 28, 2015
I am thinking that this being your first class A motorhome and it being much heavier than your class C motorhome,it may be just normal performance that you are experiencing. The 40 to 60 mph test will tell the story. I timed mine from underneath the motorhome with the tan wire removed from the distributor. I think if you time it from the top you use spark plug number one and if you time it from the bottom you use spark plug number five someone who has done it more recently can correct me if I am wrong.
hawkeye-08
Explorer III
Jan 28, 2015
Some have used a "test pipe" to check the catalytic convertor. They install a pipe in place of the catalytic convertor to test to see if it is plugged.
Gale_Hawkins
Explorer
Jan 29, 2015
mikebrassard wrote:
Gale Hawkins wrote:
Do you have access to premium ethanol free gas. Ours will make more power on premium? Are you making sure the RPM's are in the 3500-4000 range when climbing? Has the radiator been recored? Does the water pump fan sound like a jet engine for the first few minutes after you first start it?

We have the 1992 454 TBI and one shop said it was the most powerful one he had seen in a MH. We have since added new plug/plug wires.

As for the premium ethanol free gas, yes. As a matter of fact, i only use that in the MH. I don't have a tach on it, but it downshifts good, and I would guess from the sound of the engine that is in the area of 4000 rpm when climbing steep ascents.
Rad has never been recored, i spoke with the previous owner, and he says never had that done, but he did have yearly flushes. (The service receipts confirm this)
As for the water pump - no, i can't say it sounds anything like a jet engine or anything close to it.

The fan mounted to the water pump is mounted on a fan clutch. The first few minutes after I start ours the clutch will be locked up and the fan noise is LOUD until it releases. We will hear the same sound setting at a long stop light sometimes when it engages.

If this clutch is not locking up ever then the engine can run hot. There are ways to test it but it can be dangerous when working through the doghouse with a running engine.
DSDP_Don
Explorer
Jan 29, 2015
I too would guess that it has a plugged catalytic converter. Next time you drive it, try a hill climb. As soon as it starts losing power, pull over and look at the cat. They will often get red hot when plugged.
hawkeye-08
Explorer III
Jan 30, 2015
Let us know what you find out... good luck

Forum Discussion

1993 Travelaire 454 chev p30 low power

About RV Newbies

Related Content

1993 Cobra alternator problems

1993 Ford E350 Tioga Class C

1993 Dodge Cummins potential purchase

1993 Allegro Bay

Battery location: 1993 Jamboree Searcher