End-all Be-all plenum thread
Record Breaker
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From: Claremont NC
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Well, I got my truck back from the shop last week. After all was said and done he installed the plenum repair kit, bolt kit, and 185 degree thermostat I had bought from Hughes. He also replaced the rotor, cap, and bypass hose. The spark plug from cylinder #8 was fouled as I told him it would be based on this threads posts, and he replaced it, but he is convinced that it is NOT caused by a clogged cat but rather the other way around. That the fouled cylinder is what clogs the cat, not vice versa. In my case he insists my cat (which was installed new 10 months ago) and O2 sensor are just fine and that if there were a problem it would report it. In fact I have to admit I have no inidication that there is any sort of problem with either the O2 sensor or the cat. Neither on the dashboard nor in vehicle performance. It runs smooth and powerful with no hesitation or lag. I'm thinkin he's on to something there.
At any rate $889.00 in shop charges later (plus the two hundred and some for Hughes components) and it's good as new.......well almost. With the crappy water flow thru the notoriously $hitty heater core of this model truck (yes it's been flushed before) I now get only luke warm heat thanks to the lower temperature thermostat. I may live to regret that decision come January here in Minnesota.
I still plan on running a bottle of Seafoam thru the tank before I put any more miles on it (drove it to work and back, about 70 highway miles total), but I think engine-wise I'm good to go now.
At any rate $889.00 in shop charges later (plus the two hundred and some for Hughes components) and it's good as new.......well almost. With the crappy water flow thru the notoriously $hitty heater core of this model truck (yes it's been flushed before) I now get only luke warm heat thanks to the lower temperature thermostat. I may live to regret that decision come January here in Minnesota.
I still plan on running a bottle of Seafoam thru the tank before I put any more miles on it (drove it to work and back, about 70 highway miles total), but I think engine-wise I'm good to go now.
Retired Moderator - RIP
Joined: May 2008
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From: NH
Well, I got my truck back from the shop last week. After all was said and done he installed the plenum repair kit, bolt kit, and 185 degree thermostat I had bought from Hughes. He also replaced the rotor, cap, and bypass hose. The spark plug from cylinder #8 was fouled as I told him it would be based on this threads posts, and he replaced it, but he is convinced that it is NOT caused by a clogged cat but rather the other way around. That the fouled cylinder is what clogs the cat, not vice versa. In my case he insists my cat (which was installed new 10 months ago) and O2 sensor are just fine and that if there were a problem it would report it. In fact I have to admit I have no inidication that there is any sort of problem with either the O2 sensor or the cat. Neither on the dashboard nor in vehicle performance. It runs smooth and powerful with no hesitation or lag. I'm thinkin he's on to something there.
At any rate $889.00 in shop charges later (plus the two hundred and some for Hughes components) and it's good as new.......well almost. With the crappy water flow thru the notoriously $hitty heater core of this model truck (yes it's been flushed before) I now get only luke warm heat thanks to the lower temperature thermostat. I may live to regret that decision come January here in Minnesota.
I still plan on running a bottle of Seafoam thru the tank before I put any more miles on it (drove it to work and back, about 70 highway miles total), but I think engine-wise I'm good to go now.
At any rate $889.00 in shop charges later (plus the two hundred and some for Hughes components) and it's good as new.......well almost. With the crappy water flow thru the notoriously $hitty heater core of this model truck (yes it's been flushed before) I now get only luke warm heat thanks to the lower temperature thermostat. I may live to regret that decision come January here in Minnesota.
I still plan on running a bottle of Seafoam thru the tank before I put any more miles on it (drove it to work and back, about 70 highway miles total), but I think engine-wise I'm good to go now.
Since you ran the new cat and o2's for 10 months with a blown gasket, I'd replace the o2 and have the cat pressure tested.
And without having an SCT tuner, you should have stuck with a 195 T-stat.
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Joined: Sep 2011
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From: Falling Waters, WV
Who here said the clogged cat causes the fouling problem? Everyone knows the plenum gasket blows first, ruins the plug and carbons up the valve. All the while, the oil from the blown gasket is slowly ruining the o2 and cat. The only thing the clogged cat does is cause #8 to get hot (because it's closest)and can cause a cracked head and or burned valves and ruin the plug after it's clogged.
Since you ran the new cat and o2's for 10 months with a blown gasket, I'd replace the o2 and have the cat pressure tested.
And without having an SCT tuner, you should have stuck with a 195 T-stat.
Since you ran the new cat and o2's for 10 months with a blown gasket, I'd replace the o2 and have the cat pressure tested.
And without having an SCT tuner, you should have stuck with a 195 T-stat.
Consequences
1. Clogged cat
2. Clogged cat will lead to #8 spark plug fouling (rather quickly)
1. Clogged cat
2. Clogged cat will lead to #8 spark plug fouling (rather quickly)
Morning after beer edit: Didnt mean to come accross like an A**hole...
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What he said. I was going to post the very same thing myself but he beat me to it.
Also Hughes Engines didn't indicate anything about not using their recommended 185 degree thermostat without having an SCT Tuner (neither did ANY of the posts on this thread) so I went with it. I don't have any mods on my engine as it's bone stock so I never even considered an SCT tuner in the first place anyway. If for some reason it's not advisable, thats news to me. I was very thorough in reading all the posts here and all of the info available from Hughes Engines. In fact I would be willing to bet it wouldn't even be a problem with a decent heater core. The one they use in these trucks is notorious for restricted flow after a lot of miles and mine is no exception.
Champion
Joined: Sep 2011
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From: NorCal
You shouldn't really just "do things" b/c it was lacking direct basis. I'm not doing a 185 tstat b/c I haven't come across any technical reason why. Yes, I have also not seen anyone explain it. In order to use it, a tuner is needed in order for the PCM to recognize that significant change to the cooling system.
I've never interpreted that Consequences list to also mean in that Order.
I've never interpreted that Consequences list to also mean in that Order.
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From: NH
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You shouldn't really just "do things" b/c it was lacking direct basis. I'm not doing a 185 tstat b/c I haven't come across any technical reason why. Yes, I have also not seen anyone explain it. In order to use it, a tuner is needed in order for the PCM to recognize that significant change to the cooling system.
I've never interpreted that Consequences list to also mean in that Order.
I've never interpreted that Consequences list to also mean in that Order.
How could you NOT interpret that to mean anything but that??? The "consequences" are first of all NUMBERED and second of all Number 2 clearly says: "Clogged cat will lead to #8 spark plug fouling out". That's not a statement thats open to interpretation. It's about as black and white as you can possibly get. Don't see how it can be interpreted to mean anything other than a clogged cat will lead to #8 spark plug fouling out. Hello?
Also, I wasn't just "doing things" because of a lack of "direct basis". Give me at least a little bit of credit here. For one I take my time and research as much as possible before making that sort of investment and two, I don't have that kind of money to just throw around senselessly. I was doing it because IT WAS RECOMMENDED by Hughes Engines and a number of posts on this thread. Sure its possible they (Hughes and other members of this forum) just neglected to elaborate that you would also need the SCT Tuner if you used that stat, but truth is I'm not convinced that they did neglect to elaborate at all. The reason Hughes and no previous post on this thread had claimed you have to have a tuner with that stat may just be because in fact you don't.
I'm not having any problem with the way the engine is running. The truck is running great. It seems to be tuned just fine. My problem has nothing to do with the engines tuning. It's a lack of heat from the heater and last time I checked, a tune isn't going to up the temp of the liquid in my heater core one degree. It's the fact that the flow in the core is so lousy that it requires hotter liquid to generate decent heat. I am willing to bet that with a good core the heat would be just fine. There's nothing wrong with the way the engine is running. It's running like it's brand new. Never better in fact.
SHEESH YOU GUYS! Someone **** in your corn flakes this morning or what???
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From: Clayton MI
How could you NOT interpret that to mean anything but that??? The "consequences" are first of all NUMBERED and second of all Number 2 clearly says: "Clogged cat will lead to #8 spark plug fouling out". That's not a statement thats open to interpretation. It's about as black and white as you can possibly get. Don't see how it can be interpreted to mean anything other than a clogged cat will lead to #8 spark plug fouling out. Hello?
Also, I wasn't just "doing things" because of a lack of "direct basis". Give me at least a little bit of credit here. For one I take my time and research as much as possible before making that sort of investment and two, I don't have that kind of money to just throw around senselessly. I was doing it because IT WAS RECOMMENDED by Hughes Engines and a number of posts on this thread. Its possible they just neglected to elaborate that you would also need the SCT Tuner as well, but in fact I'm not convinced that they did neglect to elaborate at all. The reason Hughes and no previous post on this thread had claimed you have to have a tuner with that stat may just be because in fact you don't. The truck is running great. It seems to be tuned just fine. My problem has nothing to do with the engines tuning. It's a lack of heat from the heater. It's the fact that the flow in the core is so lousy that it requires hotter liquid to generate decent heat. I am willing to bet that with a good core the heat would be just fine. There's nothing wrong with the way the engine is running. It's running like it's brand new. Never better in fact, and tuning it won't do a thing to make the liquid in the heater core one degree warmer.
SHEESH YOU GUYS! Someone **** in your corn flakes this morning or what???
Also, I wasn't just "doing things" because of a lack of "direct basis". Give me at least a little bit of credit here. For one I take my time and research as much as possible before making that sort of investment and two, I don't have that kind of money to just throw around senselessly. I was doing it because IT WAS RECOMMENDED by Hughes Engines and a number of posts on this thread. Its possible they just neglected to elaborate that you would also need the SCT Tuner as well, but in fact I'm not convinced that they did neglect to elaborate at all. The reason Hughes and no previous post on this thread had claimed you have to have a tuner with that stat may just be because in fact you don't. The truck is running great. It seems to be tuned just fine. My problem has nothing to do with the engines tuning. It's a lack of heat from the heater. It's the fact that the flow in the core is so lousy that it requires hotter liquid to generate decent heat. I am willing to bet that with a good core the heat would be just fine. There's nothing wrong with the way the engine is running. It's running like it's brand new. Never better in fact, and tuning it won't do a thing to make the liquid in the heater core one degree warmer.
SHEESH YOU GUYS! Someone **** in your corn flakes this morning or what???
Running the 180 stat makes zero difference on your engine, and can actually hurt fuel economy. PCM EXPECTS the engine to warm to 195, and when it doesn't, it will richen the mixture a bit to help it along. That's the reason folks recommend a tuner to go with it. Then the PCM actually has a clue. This particular topic has been debated to no end here.... LOTS of threads on this particular topic.
But, a tune most certainly will not make your heater hotter.
You could try back flushing it, (that has worked fairly well for some). Or, do a full system chemical flush, and pay some special attention to the heater core. Your problem is more'n likely due to either the core being plugged up to some extent, or, an air bubble trapped in there. (which is unfortunately rather common on these trucks.... silly design really.)
Record Breaker
Joined: Dec 2008
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From: Claremont NC
FWIW, I've been running a 180* stat in my RT for 10 years and have never thrown a code because of it. I can run the heater control temp at no more than half way or it gets so hot inside you have to roll down the windows but I attribute that to preventative maintenance. Every fall since I've owned the truck I've back flushed the heater core and flushed the coolant system every other year.
As far as mpg goes, I get 16-16.5 city/18-18.5 hwy and the engine has always burned a perfect colored plug. These trucks are programed from the factory to run pig rich so tuning with the SCT may help it somewhat but is not necessarily the only way to go.
As far as mpg goes, I get 16-16.5 city/18-18.5 hwy and the engine has always burned a perfect colored plug. These trucks are programed from the factory to run pig rich so tuning with the SCT may help it somewhat but is not necessarily the only way to go.