RV Ratings Go to Main Page RV mechanic on duty. Start at the home page.
RV Mechanic RV engine problems? RV mechanic help only a click away!

454 problems

Home > Discussion Forum > Mechanic's Corner - Engines

Email Author email Mike  Reply to Message reply to message  Post New Message post new message      search forums
hidden layer
ATTENTION: All Postings that advertise items for sale will be deleted from the Discussion Forum. You may post sale items for free in the Classifieds section. Sign up now.
All Messages in ThreadAuthorDate
454 problems Mike 4-7-02  
Just bought a 1979 southwind. Engine ran good and had lots of power. Then.. I took the car to the garage to have the right side manifold exhaust leak fixed. On way to garage I filled up the gas tank. After picking up the RV, on way home I noticed a lack of power on hills and bopping. Plenty of power on level roads from 50mph and up. I have started troubleshooting. Can't find in vacuum leaks. Guage shows about 14#. Sparkplug wired looks okay. Cleaned out the distributor, it looks okay.
Re: 454 problems GB Mulloy 8-20-04  
454 firing order, switched it and now it won't start at all.....used 1-8-4-3-6-5-7-2, before it would start but nothing now. Looses power, lugs down backfires. P-30 chasis....90-91 Winnebago MH......any help would be appreciated. Could it be a diff sized engine on that P-30 chasis? If so what? Where can I find firing order for the larger engines that may be applicable? Stumped in WA! Thanks ahead of time!
Re: 454 problems Bill h 4-7-02  
Popping usually indicates a lean mixture or timing problems.
Re: 454 problems Bo 4-9-02  
Just bought a 1979 southwind. Engine ran good and had lots of power. Then.. I took the car to the garage to have the right side manifold exhaust leak fixed. On way to garage I filled up the gas tank. After picking up the RV, on way home I noticed a lack of power on hills and bopping. Plenty of power on level roads from 50mph and up. I have started troubleshooting. Can't find in vacuum leaks. Guage shows about 14#. Sparkplug wired looks okay. Cleaned out the distributor, it looks okay.
Mike, I don't know what they repaired but you migh take a look to see if they put the right gasket on the manifold. If they put a smaller opening gasket on it would restrict the flow and lose lot's of power. The popping could be caused by the exhaust sensor calling for a leaner mixture due to the backpressure caused by the smaller gasket.
Re: 454 problems Kent 4-8-02  
Just bought a 1979 southwind. Engine ran good and had lots of power. Then.. I took the car to the garage to have the right side manifold exhaust leak fixed. On way to garage I filled up the gas tank. After picking up the RV, on way home I noticed a lack of power on hills and bopping. Plenty of power on level roads from 50mph and up. I have started troubleshooting. Can't find in vacuum leaks. Guage shows about 14#. Sparkplug wired looks okay. Cleaned out the distributor, it looks okay.

Every thing else being equal, tow things could be the problem. The plug wire for the two rear cylinders on the right bank---the one they worked on---could be running parallel and right next to each other, a definite no-no, as this can cause induced ignition in #7 when # 5 fires---firing order is 1-8-4-3-6-5-7-2, odd cylinders are the left bank, # 1 nearest the front of engine. Your condition could be that the # 5 & # 7 plug wires are swapped.14" of mercury vacuum at hot idle is pretty low. If you've got a good hot idle, then you don't have a vacuum leak,. I'd put the vacuum gauge on it with enough hose to bring it to where you can see it as you drive. If you get low vacuum at road speed, then you've got, 1. cam timing has jumped a tooth or so---easily checked with a timing light--each tooth= 7 1/2 degrees of ignition timing change. 2. The shop dropped something down into your exhaust system and now it's restricted, or the pipe got pinched somehow.
Re: 454 problems Mike 4-10-02  
Thanks for all the suggestions. I've learned a lot chasing my problems. What seems to have corrected my problems was the spark plug wires. After changing the gas filter and getting no improvement, I pulled off to the side of the road and seperated the #4 and #8 wires, any cross over of the 2 wires was made at about 90 degrees. Then the RV drove like it had a tune up. still a couple of pops during the half hour drive. Tomorrow I'll get a new set of wires and pay close attention to how I arrange them. Again thanks to all and to the suggestions. M Every thing else being equal, tow things could be the problem. The plug wire for the two rear cylinders on the right bank---the one they worked on---could be running parallel and right next to each other, a definite no-no, as this can cause induced ignition in #7 when # 5 fires---firing order is 1-8-4-3-6-5-7-2, odd cylinders are the left bank, # 1 nearest the front of engine. Your condition could be that the # 5 & # 7 plug wires are swapped.14" of mercury vacuum at hot idle is pretty low. If you've got a good hot idle, then you don't have a vacuum leak,. I'd put the vacuum gauge on it with enough hose to bring it to where you can see it as you drive. If you get low vacuum at road speed, then you've got, 1. cam timing has jumped a tooth or so---easily checked with a timing light--each tooth= 7 1/2 degrees of ignition timing change. 2. The shop dropped something down into your exhaust system and now it's restricted, or the pipe got pinched somehow.
Re: 454 problems Eric 5-30-02  
Yes, there are usualy two wires on each side that fire next to each other. As previously stated, I believe it is 8-4 and 5-7. They need to be arranged so they to do touch each other or are to close. Use good wires, not cheap ones. I run Jacobs 8mm. This give a better shielding.
Re: 454 problems Chris 8-6-03  
I have a 1976 Pace Arrow with GMC 454. Could someone tell me what the cylinder #'s are while standing behind it and what the firing order is?

Also what is the location of #1 on the distributor cap?
Required fields in red
For more info about a field, place your mouse over the More Info icon.
Subject:
Your Name:
Your Email:
Message:



Code is case-sensitive. Helps stop SPAM.
       

Google
Web RVMechanic.com



Watch me paint, sculpt and buy my art


Useful Links
Recent RV mechanic and troubleshooting topics
  Changing Heater core on a 99 taurus
  86 toyota dolphin, when tran's temp light comes on o/d shuts off, is this normal and how do I fix it?
  Propane Tanks
  Onan Generator
  1997 Itasca Gear Lockup
  DC power only when connected to shore power
  Camper trailer wire diagram
  P30 Chevy Hydroboost
  Replacing the heads on a 1992 Winnebago Elante 33
  1985 E350 460 meltdown
  1976 Dodge Midas Mini
  Dip Stick Blows Out of Koler Generator
  Heat stips in a Duo Therm Brisk Air AC unit
  GENERATOR BATTERY CUTOFF SWITCH
  1984 chev with carb cough
  VIEW ALL

RV-Coach Online

My RV Guide

All Things RV




Print-friendly page
PRIVACY POLICY  |  TERMS & CONDITIONS  |  © 1996 - 2008 RV-Coach Network - All Rights Reserved  |  Web Site by ITtelligent