hi guys,
I'm trying to cover all bases when restoring mileage on this 2002 Solara SLE V6 (think of gen4.5 camry V6). formerly car seemed to get great MPG on highways (around 27 with no racing, in September), but it was with car in limp mode (AFR HTR failure) then I discovered electrical problem and started working on car, doing also brakes at same time.
Since that time car is driven in mostly city traffic and in cold weather, also usually short trips (but not always).
possibly the front driver caliper might be dragging (problematic guide pins, very sticky old grease, etc.) and front suspension struts are worn out (will be replacing after Winter).
There is no trouble codes present, all sounds good and even looks good in OBD2 scanner, so the reason of low MPG must be mechanical beyond ECU detection mechanisms.
I can feel front suspension kind of "walking" to sides a little when driving over bumps (bad struts confirmation?).
I have a sort of sticking brake pedal sometimes. e.g. on cold car I press brake pedal then release (rear brake light go out), but pedal is not returned fully upwards, it takes a few seconds and then comes up to proper "free" position with a "clink" sound. (confirmation of sticky guide pins in caliper?)
some maintenance history:
PCV valve is leaking, was never replaced and possibly is not working. will be replacing after Winter.
besides that, spark plugs were changed at dealer 28k miles ago, transmission was flushed back then. they also cleaned the TB.
I drained and refilled (including new strainer) tranny like 2 times also recently, actually might have overfilled it a little (noticed today on HOT fluid was past HOT mark by 1'' or so). can an overfilled transmission cause lower MPG by let's say holding to higher RPM or so?
I replaced the fuel filter like 2 months ago with an OEM one.
did a complete brake job all around and installed new ABS pump (from junkyard) as old one had a shot computer. no errors in ABS now and it works fine. flushed and bled the brake fluid like 3 times.
Car's front end seems to be producing a humming noise when wheels are spinning, possibly bad hub bearings? something about drive axles? or that would be the caliper dragging on rotor?
what are your ideas on things that could be causing such low MPG (may be combination of things)?
would like to know what may require attention. thanks in advance.
Reply 1 : 12 MPG city in Winter, 1mz-fe
Hi
If your car is out of alignment, that could cause lower mileage. Also, if the tires aren't at the correct pressure, and then there is the winter blend gasoline which causes lower mileage regardless of any other problems that may be present.
Reply 2 : 12 MPG city in Winter, 1mz-fe
Well, the 1MZ does get poor mileage when used for short trips and when it's cold. My ES300 is pretty bad in this respect, although I don't drive it much at all in the winter. 12mpg is really bad though, have you had the alignment checked? The dragging brakes, pretty easy to check, all four wheels should turn fairly easily, as in they will spin with only a bit of resistance. I have a dragging caliper on my '93 and it's really obvious, the wheel will turn but it takes some effort and it's impossible to spin the wheel and have it keep going for a second or two, it stops right away.
What is the condition of the rubber? The humming noise could be from the tires. As I've learned from what others have posted here, drive the car for a bit then feel the center of the wheel. If one side is much warmer than the other, you have a dragging brake or a bearing going bad. The over filled tranny won't cause the mileage issue, you didn't have much more than the correct amount at all. In fact, I routinely see transmission shops overfill slightly.
Reply 3 : 12 MPG city in Winter, 1mz-fe
the alignment was done right after I brought the car to NJ, it was almost perfect.
then the rear tires were replaced with new Yokohamas (and rotated to front) and recently I pumped up all of them to 40psi at hot tire after driving and ambient 0C temperature, so it makes probably around 35psi at cold tire at 0C ambient, all around.
only thing that I've got a loose strut mount (one of studs has broken threads) on front passenger side, so that may be responsible for walking experience in front end I feel sometimes. wondering how much it affects the alignment while driving on uneven roads, probably a lot hehe
next time I jack the car up I will check each wheel for free spinning. I'm pretty sure the FD wheel had a free spinning resistance prior to the brake job, but I forgot to re-check afterward. rest seemed good.
Though I have to say that both front wheels were at first hot after driving and I also forgot to re-check that later after tires were replaced, wheels rotated, and brake job done... I guess the worst case scenario, both front wheel bearings are going bad ...
I too thought that old front tires were causing the humming noise, and I was right to some extent as they are both in the rear now and some of the sound/noise moved with them to the rear.
But some humming in front is still there, I can almost feel it when driving slowly, on top of hearing it. wondering if a dragging brake would cause that sort of sound (and a little rubbing vibration)...
also good point about winter blend fuel now in stations, I keep forgetting that. probably it had some MPG impact as well.
Reply 4 : 12 MPG city in Winter, 1mz-fe
Yeah, I haven't calculated my MPG (too scared) but some nights when I'm working as a pizza boy, I LOSE money because of how many times I fill up. Like tonight, spent more on gas than I made. And New Years I did the same. Granted I'm pretty heavily modded, and probably need a lot more maintenance than you, and I'll drive 2-300 miles in city a night on average, but none the less, this engine is THIRSTY.
When I would drive my gen 4, that's how I made money every night. $10 of gas got me through the night with $90-100 in my pocket at the end of the shift. But now that it's rebuilt, for the fourth time, I'd rather not subject it to the harshness of delivery driving...again...
Reply 5 : 12 MPG city in Winter, 1mz-fe
I think as you said before, your thermostat is probably killing mpg. I know when mine wasn't operating correcting, I barely got 300 on a tank.
Reply 6 : 12 MPG city in Winter, 1mz-fe
thanks for further ideas.
I'm a little scared of general V6 fuel consumption - used to own a '92 Buick 3.8L and oh boy that car burned fuel like a tank ... was hoping to get some better numbers on Toyota made V6, but hmmm ... currently am at same exact spot as were I was with '92 GM built LOL
yeah, I've mentioned thermostat in other thread, because this car takes damn long to warm up. something around 15-20 mins in parking lot until dash gauge needle reaches normal operating temperature.
local driving doesn't make this process much faster, maybe 10-15 mins if I drive it cold.
Thermostat is in plans for replacement after Winter, together with a coolant flush. I am also planning to sea foam it and do the rest of things requiring attention.
Currently I usually getting around ~260 miles from a 18.5gal tank. let's say around 70 miles per quarter according to imprecise dash gauge. More precise MPG calculations at the pump revealed numbers around 12 MPG ...
and this number doesn't change when I let the car warm up a bit in a lot for 5 mins before driving or start driving it instantly.it used to be getting around 16-17 MPG when it was warm and mechanically nothing has changed.
here is some fuel log:
For now I stay scared
of my V6 fuel consumption in Winter LOL 
EDIT:
I downgraded fuel type from premium (summer), throughout mid-grade (Fall), down to regular now with last refill. can't afford filling it with premium at the moment LOL
Reply 7 : 12 MPG city in Winter, 1mz-fe
You can turn side to side in a safe parking lot. If it's the bearing when the side that gets more weight will be noisier. If the noise doesn't change pitch then it may be something else.
I'm not sure how much an old CV joint with old grease contributes to the noise. But if you ever change out the bearings rebuild the CV joints too. It's a real hassle and you have to keep things clean (for example, all needle bearings) and do the last step of cleaning with alcohol (petro cleaner can leave a film that may interfere with CV grease). I do that using Redline CV-2 synthetic grease. I think rebuilding a good OEM halfshaft with CV-2 is better than getting a rebuilt (even a dealer one) or a new aftermarket axle. For me the alternative, if really pressed for time, is to get a new aftermarket axle, and rebuild the original one that's in good shape when time allows. (Because you have to turn in the core for a rebuilt, but if it's already rebuilt or clicking that's another matter). This way you should be able to get the car back in service after about 30min each side if no major rust related seizures.
Sticking calipers can give a sound similar to bearings. I'd also think your non-contact thermometer can help. Check the rotor, the caliper/pads (if you can) and the hub hat area. The temperature will measure lower than actual on shiny surfaces however.
The pedal return I think is the function of the brake booster. I don't think it's the MC because the MC-to-booster link is not solidly joined obviously, but the booster rod only pushes on the MC end.
Reply 8 : 12 MPG city in Winter, 1mz-fe
thanks John.
good idea about using a non-contact thermometer!
I will play with that (once I find it) in a few days after some driving. first I need to fix headlights on other car, was waiting for good weather for that ... and I am still waiting for a few bolts from dealer...
I think for now I might be able to use it on reading temps without even removing the wheel (except for the bearing itself). that might give some more clues.
when turning wheels at slowly driving (or even at full stop) side to side in parking lot there is nothing unusual, it's very quiet. I'm pretty sure it means the CV joints are in good shape (they would be clicking if bad, correct?).
I'm thinking maybe if weather holds out nice I will re-grease the front caliper sliding pins again. the grease in FD caliper was terribly sticky even in Summer.
I experienced great trouble (busted my knuckles a few times) when removing the unbolted sliding pins from there.
It didn't get perfectly free sliding after re-greasing with Permatex, maybe I need to do it one more time and maybe try to scoop the old grease out from the bracket??
The other wheels' calipers didn't have this sticky pins problem at all.
and the brake pedal behavior, don't worry about it now?
Reply 9 : 12 MPG city in Winter, 1mz-fe
I've read something recently on ecomodders that opened my eyes about idling in parking lots;
Quote:
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An idling engine gets ZERO miles per gallon. |
Same with parking, I don't pull in a spot and lolligag around. Pull in, and shut the car off. Then search the car for whatever you're looking for.
I used to leave my car running when I would deliver to people's houses/apartments. I've changed this habit because
1) an idling engine DOES get 0 mpg
2) my car could get stolen as I'm often at bad areas.
Just a thought to consider. I keep up with ecomodders fairly often, but find it hard for myself to want to make my car look like a boat to save some fuel...
Some of the easier tasks I definitely try to achieve though!
EDIT: As for the T stat, here's my advice. Sounds stuck open. Granted we are both talking about different engines, but on my 5SFE it's taken a very short time to heat up (<5 minutes) while driving. It usually takes around .5 miles and then I can turn heat on and not have ice come out of the vents. Just another thing to mull around the old noggin. Again, I know we're talking different engines.
My 1MZ takes a relatively short time to warm up as well, about 1.5 or 2 miles, but that has an open t stat that needs to get replaced.
Reply 10 : 12 MPG city in Winter, 1mz-fe
Quote:
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Originally Posted by Chris Crash 
I've read something recently on ecomodders that opened my eyes about idling in parking lots;
So I've taken that to heart a bit, so instead of getting in, starting the car, and getting situated, I now get in, buckle up, get everything how I need it to be, THEN start the car. You might not think it would make a difference, but in the long run I'm positive the few seconds will add up. Same with parking, I don't pull in a spot and lolligag around. Pull in, and shut the car off. Then search the car for whatever you're looking for. I used to leave my car running when I would deliver to people's houses/apartments. I've changed this habit because 1) an idling engine DOES get 0 mpg 2) my car could get stolen as I'm often at bad areas. Just a thought to consider. I keep up with ecomodders fairly often, but find it hard for myself to want to make my car look like a boat to save some fuel... Some of the easier tasks I definitely try to achieve though! EDIT: As for the T stat, here's my advice. Sounds stuck open. Granted we are both talking about different engines, but on my 5SFE it's taken a very short time to heat up (<5 minutes) while driving. It usually takes around .5 miles and then I can turn heat on and not have ice come out of the vents. Just another thing to mull around the old noggin. Again, I know we're talking different engines. My 1MZ takes a relatively short time to warm up as well, about 1.5 or 2 miles, but that has an open t stat that needs to get replaced. |
I agree on idling effect, it's a 0 MPG until you move out from a lot and it burns fuel. so look at my fuel log on ecomodders.com (click banner above):
a) one by last bar shows when I was starting to drive cold (and let it suffer from long warm up phase during driving which I thought was killing the MPG)
b) then I started warming it up (last bar) for 5-10 mins in a lot, so it was reaching full operating temperature after like 5 mins of driving. difference in MPG? 0, it's exactly same
I guess I can be getting screwed (MPG wise) by my thermostat, no win scenario in a short driving pattern, MPG always takes a hit.
and yes, wife's 5s-fe warms up almost instantly, as you said <5mins or 0.5 mile is enough to fully warm it up...
... so I think we've got a confirmation on a somewhat partially or compeltely stuck open thermostat. Funny that gen4 is supposed to throw a code for a thermostat problem ... I guess it would for a stuck closed thermostat ... and doesn't do that for a stuck open one ...
Reply 11 : 12 MPG city in Winter, 1mz-fe
You have one of the sludge monster 1MZ-FE engines in your car, CHANGE YOUR PCV RIGHT AWAY!!!!! Also pull the front valve cover and look for build up.. Other things to consider are clean MAF, replace O2 sensor, replace fuel filter, look for gas leaks..Just some more ideas for you. If you get 1 thing from my post, may it be QUICK PCV replacement..
Reply 12 : 12 MPG city in Winter, 1mz-fe
The ECU enters closed loop pretty quickly after startup, so there's not much you can do to reduce fuel usage during engine warmups. It's based purely on air mass and of course, startup and warmup enrichment (cold start enrichment).
Toyotas idle richly and even moreso when the ambient air is colder. Also, choose a spark plug heat range that's consistent with your driving patterns and local ambient temperatures. For winter, I'm running one step hotter to reduce the rich idle. You can tell the engine idles richly by looking at the base of the spark plug. Usually, it's black with soot. If you do a ton of short trips, use a hotter plug. If you do long range cruising (1-2 hours of constant steady RPM) or sustained high RPM driving, use the stock or colder plug.
20 range (NGK 6) on the left, Denso 16 on the right. As you can see, the plug runs hot as the porcelain is whiter.
I've logged no knock corrections with hotter plugs (2JZGE plugs), but the intake charge temperature is about 40 degrees while moving, so that helps tremendously (for pre-ignition) and it also makes the ECU enrichen the fuel mix as well.
When the coolant temperature drops below 167F while driving, the ECU will throw a thermostat code (MY2001+ only). My MR2 coolant gauge is slow, so I disregard it. During data logging, my 1MZ reaches 176-185F within 5-10 minutes. If I turn the engine off and restart it, my coolant gauge reads below halfway, but the engine temperature is the same. The gauge eventually rises back to half.
My MPG during the summer with 20 heat range plugs was 27 MPG (avg). For the winter, it's dropped to 25 MPG with the 16 heat range plugs. That's with below freezing starts. So, a reduction of 2 MPG is acceptable.
Something is definitely causing increased rolling resistance on your car, as 12 MPG just doesn't seem possible unless you've been ringing the engine out all day or you're doing extremely short trips where the engine doesn't reach normal operating temperature. This assumes you have no air/fuel malfunctions or slow AFR sensors, gas leakage, or other issues.
MPG (on a properly running engine) is affected most by vehicle mass, or conversely, increased engine loading (also caused by dragging brakes or other sources of high friction in the drivetrain). This is also the reason I'll always achieve higher MPG averages than Camry/Solara 1MZs and Highlanders will never hope to achieve our MPG averages.
Reply 13 : 12 MPG city in Winter, 1mz-fe
Quote:
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Originally Posted by tacosteelersman
You have one of the sludge monster 1MZ-FE engines in your car, CHANGE YOUR PCV RIGHT AWAY!!!!! Also pull the front valve cover and look for build up.. Other things to consider are clean MAF, replace O2 sensor, replace fuel filter, look for gas leaks..Just some more ideas for you. If you get 1 thing from my post, may it be QUICK PCV replacement..
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i'm not worried about sludge in this engine at all. it runs cool, especially that for 1-2 years cars was running with jumpered fans all the time and it usual coolant temperature before I fixed wiring was around 190F
no way a sludge can build up at that temperature, because sludge essentially is a cooked old oil. now it seems it has a stuck open thermostat, so again coolant is usually cooler than it's supposed to be.I agree there is some brown varnish, hence why I plan sea foaming it.
Air Fuel Ratio sensors and fuel filter are new. no gas leaks.
only thing from your list is a leaky PCV, i've got the replacement but don't want to do it in Winter, what if I drop the grommet into the valve cover? I have no garage to open the engine up at near 0C and sunset coming at 5pm...
Reply 14 : 12 MPG city in Winter, 1mz-fe
The pcv valve can break it, mine was 5 months old and it still broke in half. It was aftermarket, idk if that makes a difference. Just use a pair of pliers and get a firm grip on it. The grommet will be tough to get out, since there is no room, good idea to wait on replacing it. I wouldn't worry about sludge, before my dad gave me the car it saw 5-7k OCI or even worse. There was barely any varnish when I pulled the covers.
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