Too Much Heat In Cab And Around Engine - Exhaust?

[coolcoolrain]

my first post! (and most probably not my last!)..here's my situation: 1993, 21' Conquest, 53,000 miles, third owner - bought from a friend of a friend last fall. Sold off house and all my belongings and hit the road to full time it in January...yep escaped most of those 'polar vortexes' of last winter - and have had some trials and tribulations that would be expected driving a 20 yro vehicle..that is actually in pretty darn good shape... had the truck 'once overed' before i hit the road and replaced all the hoses etc... i am not a mechanic at all, but have a few friends who are real motorheads and for the most part anyone who stuck their head under the hood all said the same thing...what a great little engine (V6), well maintained and all good...(lucky me!!) now for my problem:

while in the san antonio area last march i decided to have the tail pipe and muffler replaced (didn't like the sound the exhaust was making - though it had passed new york states emissions for inspection a couple months earlier)..brought it to ahem, a nationwide chain, and yes they had to do a little extra on the tailpipe - but managed to replace the muffler and tailpipe..i drove away liking the new purring sound of my new exhaust. about 50 miles west of san antonio (heading out to big bend..btw...highly recommend this remote national park!) i notice the floor boards in cab getting hot..i mean HOT..could feel the heat coming through my shoes! pull over and as i am getting out of the vehicle it was like stepping through a sauna of HOT HOT air just outside the drivers door. the hood of the engine? WAY HOT to the touch: btw the temperature gauge showed the internal temp of the engine to be perfectly fine. there was also no noticeable change in the way the rv was driving...just really hot. had a local mechanic take a look see (mostly because i was petrified the whole thing was just going to go up in flames at any given moment) he determined the cat converter was needing replacement, and assured me as long as i pulled over and let the whole thing cool down once in a while i would be able to safely get back to san antonio..aka 'civilization'..which i did: brought the rig back to the AHEM, national chain, to replace the catalytic converter (all pretty costly - but hey...this is my HOME now!). at the time i thought it coincidental that right after they replaced the tail pipe and muffler (and had obviously checked the cat converter which was fine) the cc went on me..but okay..lets move on...next day i find out have to get back to long island pronto...head out on the road in a new york state of mind...this is early may and the weather was warming up. the ride back was brutal...outside the wildflowers were blooming and all was well with the world..but inside the vehicle it was still HOT HOT HOT (again, not only a bit concerned with safety issues...but, me and my two labs were miserable...yeah, i could keep the A/C on directed at the floorboards all the way home from texas...but my mileage which seems to be no where near as good as everyone else's on this forum (i will post that another day) drops even lower with that a/c going...so windows open..nearly naked, and two panting labs ... we got back safely...

have had several different mechanics look at this issue from the local shop of the 'nationwide chain' who told me this had nothing to do with the exhaust (hmmm..even though it all seemed to happen right after the tail pipe and muffler were replaced)..and that my engine was running lean...to a transmission guy (btw...not overweight...had the rig weighed, and though i am just about at GVWR...i am NOT overweight (like my new lifestyle of less is more!! - plus i think driving in this ^%$&* sauna has even made ME lose some pounds!))...transmission guy installed the largest aftermarket cooler he could fit in (umm, yeah at new york hourly rates)...then desperate...i turned to toyota dealership (ny dealership hourly rates...ugh)..they actually were pretty helpful...and determined that yes, engine running 'lean' due to 02 sensor located on downpipe leading from engine right before cat converter...downpipe has small cracks in it (yeah, its old and probably got cracked up when lugheads were working on exhaust down in texas)...heat escaping from cracks, 02 sensor making engine run lean, all heating up...seriously heating up...here's my dilemma: they couldn't find a pipe to replace my cracked up one (the service guy at dealership fell in love with my rig and sincerely trying to help me...way beyond normal dealership service...again, lucky me!)...decided to try to buy me some years of driving by using some sort of special nascar high heat wrap..and basically wrapped up my cracked downpipe to stop the exhaust leaks and prevent the 02 sensor from messing up my fuel ratio...okey dokey:...well maybe it helped, but not really...i am at a loss??? the heat shields are all in place and are in good shape..don't even know if this is an exhaust issue or not (just know that the problem arose right after the initial tailpipe/muffler replacement)...has anyone else had anything like this happen? please help me...i love my new nomadic life in my little ole' toyota (and so do the dogs)...and i am just about finished with my long island stay and am itching to get back out on the road...but not if it means at the worst having my rig on fire on the side of the road (the engine reads around 385 degrees (externally) after driving for about a half hour..) or at best, having to drive with panting dogs and me naked...oh, and the best part: i originally had the tailpipe and muffler replaced because i didn't like the rumble sound from the exhaust...sounded too...i don't know, masculine, but now, because of all of this heat whatever 'insulation' or whatever that is in the exhaust has been 'burned out...my nice purring exhaust sound is back to that offensive rumbly sound....UGH!!!

[linda s]

Front pipe is still available from Toyota. Might find one cheaper somewhere else but here's the part number.

http://www.toyotaonlineparts.com/oe-toyota/1741065041

Linda S

[Donnie]

I read your post again & see no mention of a diagnostic scan of the processor for fault codes...The processor uses information from several sensors to determine the correct engine timing & fuel mixture...I can & will elaborate on these if we need to, but lets wait until some others comment on your problem.

Your O2 sensor needs to see ALL of your exhaust stream to determine what it is seeing & it then will relay this data back to the processor to be combined with input from the other engine control sensor's ------ only then can it issue the correct commands to the fuel system & ign. timing...

O2 sensors get lazy or die completely.....Has it been checked? Or changed? A lazy (read slow) O2 sensor will often NOT show a fault so it is assumed to be OK when it is not..........BUT it is only ONE of several inputs that is needed for the engine to run most efficiently. A GOOD scan tech will be able to see how active this sensor is....

I would suggest a complete scan of processor before throwing parts at this truck....Other opinions may vary or ADD more to what I have said.

I use the word "Processor" when speaking of the engine Computer system, or what ever others may call it......&%$#*&&...:-)........HTH, Donnie

[Derek up North]

Toyota calls it "Computer, Engine Control".

http://www.toyotapartszone.com/parts-list/1992-toyota-truck-pickup-jpp-2-wheel-drive/electronic-fuel-injection-system.html

[Maineah]

The codes will have to be pulled from the computer a scan tool will not read them. You can read on line about how to do that pretty simple but hard to explain in a couple of sentences. Most likely most of your heat is coming from the catalytic converter if the engine is running richer than it should it should throw a check engine light a rich mix will cause the cat to run hotter than it should. You are not the first to complain about hot feet my friend has a 87 Toy home she pulled all the carpet out and insulated the floor with foil back bubble stuff.

[zero]

it had passed new york states emissions for inspection a couple months earlier

You peaked my interest. What part of NY is doing emissions testing on a 1993 vehicle? Not anywhere near where I live (central NY). Can't be a "state requirement." Maybe a New York City thing? I know that the New Jersey suburbs 10 miles from NYC had emissions testing back in the 70s.

Also - are you sure it's not your transmission making the heat? If it's an automatic - and slipping at all - it can make the floors REAL hot. My Ford F250 did it for nearly half a year with the E40D trans until I finally tested it and fixed it. Floor got so hot after awhile it felt like it might melt my sneakers.

[Donnie]

WHOOPS...my bad....I overlooked the YEAR when reading this post.......Maineah is correct, the codes have to be pulled from the processor by jumping pins. This will only point you to a faulty circuit.. You are unable to see the activity of the O2 sensor, i.e. crosscounts using this PRIMITIVE method.

ALA FORD.....until OBD II around '95 or '96........FORD, TOYOTA, & a few others lacked scan tool capability......

Even though my post was incorrect...........my thoughts lean (pun intended) toward a rich condition & a HOT CAT...............Donnie

I knew there was a reason for my bad words for that processor at the end of my prior post..............subliminal ?????????????? I'm out>>>>>>>>>>

[coolcoolrain]

thank you everyone for your replies, but i am still at a loss. the part that the dealership THINKS i need is a specific pipe that is located just before the cat converter (that is where the 02 sensor is) can't be found anywhere (i think they called it a downpipe?)...so that is why they decided to wrap it with that special nascar stuff. i don't think there is much they can do about the 'computer diagnostics' because of the age of the truck. i am not exactly sure what emissions are tested or how they are tested in a ny state inspection for an older vehicle, i just assumed they did it on all inspections...and all i know is that the vehicle passed. also...i was not having any of this HOT HOT problem at all until shortly after i had the muffler and tailpipe replaced while i was down south. i am beginning to think that maybe wrong size or wrong placement (like, could they have actually have installed the muffler backwards or something??)...i don't think the heat is being caused by the cat converter (the first attempt to fix the heat problem was to REPLACE the cat converter..which i am now worried is being destroyed by this crazy heat)

the dealership i took it to really fell in love with this ol' toyota, and i think they sincerely want to help me. so, god knows how much this is going to cost me, but i have decided to bring it back to them and have them look elsewhere for this problem...maybe it was just a coincidence of timing regarding the work done on the exhaust and then the issue occurring?...though maybe they can somehow figure out if all of the replacement parts are correct and placed properly...or maybe there is something going on with the fuel pump (ugh)? or filter?...i do smell gasoline (just straight up gas smell) every so often...sort of randomly, especially when it is very warm outside, having nothing to do with whether i just filled up or not...so maybe they need to look in that direction...i just hate to have a mechanic go on a search and rescue inside my engine...especially, again at new york dealership labor costs..but i just don't know what else to do

i am being told that it is okay safety wise, and yes i guess i could just learn to live with it, or foil- bubble wrap the floors, or again, just drive around nearly naked...but something just doesnt feel right about doing that..i would really really like to have the problem fixed...i love this little rv and want to feel good about driving it, maintaining it properly, living in it...also... i think i need to mention to them (and to all of you) i only seem to be getting around 10mpg...this is less than what it sounds like most of this forum is getting. so far been driving east coast, southern states...relatively flat highways...maintain between 55-60 (again, i like my new life of unhurried travel..though i do stay in the right lane and try to ignore the nasty glares from all of my fellow motorists as they pass me!)..i am not carrying excessive weight..tire pressure fine..so any ideas on why the mpg is so low?? could this all be related somehow (the gas smell..the hot exhaust..)??????

thank you again

[Maineah]

WHOOPS...my bad....I overlooked the YEAR when reading this post.......Maineah is correct, the codes have to be pulled from the processor by jumping pins. This will only point you to a faulty circuit.. You are unable to see the activity of the O2 sensor, i.e. crosscounts using this PRIMITIVE method.

ALA FORD.....until OBD II around '95 or '96........FORD, TOYOTA, & a few others lacked scan tool capability......

Even though my post was incorrect...........my thoughts lean (pun intended) toward a rich condition & a HOT CAT...............Donnie

I knew there was a reason for my bad words for that processor at the end of my prior post..............subliminal ?????????????? I'm out>>>>>>>>>>

Yep OBDII came out in 96 pretty much vehicle wide. There is a method to check the O2 sensor pin Ox in the diagnostic connector goes to the O2 sensor you can read voltage to ground there for the sensor it should be in the 0 to.9 volt range and very active. if it slowly varies or does not move much the O2 sensor is toes up.

[starbrightsteve]

If you are getting only 10 mpg, I think that is an indication of an incomplete combustion process in the engine. The catalytic converter is supposed to complete the combustion process. Under normal conditions the cat gets hot in the process of burning unburned fuel and completing the combustion process, but not as hot as you are experiencing. Your cat is working on maximum overload.

Your solution is related to the oxygen sensors.

[shibs]

Can you pls look under the vehicle and see if you have the heat shield between the exhaust pipe and cab under the vehicle?

I have an 88 rx7 that someone redid the exhaust and took out the heat shields as they usually rust and rattle.

oh boy was it hot in the cab.

check replace your heat shield

also, check your o2 as suggested and there is another cold start sensor that makes the engine run rich, can remember it, someone had posted the check list for running rich in a thread, pls and post for us if you find it.