SilverR8

my car runs great at normal driving but when doing large hills it goes turtle slow mode! the temp gauge is normal but I think it is running hotter than normal temp. can it be the higher set points of the cooling fans? car has no cat, engine sounds ok, how can I know the flash version? when passed the hill the car cools again and powers up...

zoom44

why do you believe its hotter? what "higher set points of the cooling fans? " higher than what?

how about some basic info about the car and what changes have been made and recent(6 months) maintenance

Snrub

Does the car accelerate properly when on flat surfaces and you use high levels of throttle and high revs for a sustained period? Are you using higher revs on hills?

Rickjames25

And what gear are you in when you go up hills. its normal for anything to go up a hill slower and the rx8 does not have that much torque in low rpms

SilverR8

higher temp set points = higher temp needed to turn on the engine fans...sorry for this I work in the industry and that term is used a lot....I think my car is running hot on hills because the engine response is not the same...hills that the car can do in 4th I need to downshift to 2nd and then after the hill when the car is"cooling down" it powers up again please tel l me you understand

PitchBlaC

Just my guess. Fuel pump problem.

Rickjames25

the temp guage is trash thats for sure but thats on any car there just there to tell you its warm and when your cars overheating thats it you cant see small degree changes like the oil pressure gauge. but i do believe if the engine was heating up enough to cause performance problems then you would see it in the gauge. then again i dont think your problem is a heat issue i dont know what engine overheating does to performance because i never drove any car when it was about to overheat but i dont think its something as kind as performance loss. when a car overheats you can cause major damage to the engine. is there any other symptoms you can tell us??? also if your still stuck on it overheating theres a diy somewhere in here to make your own fan switches where you can turn your fans on any time you want that would help with your set points

zoom44

christ, im not bloody dense or using English as a second language and I do not lack reading comprehension.

do you think that for some reason YOUR RX-8 has higher set points for the fans than other RX-8s? or do you think RX-8s all have higher set points than other cars? or do you think some rx-8s have lower set points than others?

Do you mean that the car, under your ownership, USED to do this same hill in 4th gear and now you have to shift to 2nd?if so, how long has this been going on?

you still have not provided any info on the car(except we now know it has at least 4 forward gears) and its alterations(except cat) and maintenance history.

laythor

need a lot more maintenance history to even make a guess.

SilverR8

zoom44 very rude from you! I was not expecting that from you as an administrator... the maintenance of this car... oil changes every 3k 5w20, it is his 2nd engine, new coils plugs cables air filter 75k miles

RIWWP

iTrader: (2)

Silver, you really aren't being clear enough on why you think it's a heat issue. Can you answer each of these, in line?

1) Is your temperature needle actually moving?
2) Can you feel the heat from somewhere? (center console, dash, floor, etc...)
3) When you get to the hill, and you stay in 4th, with your foot to the floor, do the RPMs drop off?
4) if they drop off, do they drop off smoothly or suddenly or in fits and starts?
5) If the RPMs do not drop off, but your speed does, do you have an automatic?
- If the RPMs do not drop off, but the speed does, and you have an automatic, this may be a torque converter problem.
- If the RPMs do not drop off, but the speed does, and you have a manual, this is probably a clutch slipping problem.
6) Do you have full normal power on flat and level ground?
7) Does it idle steadily at about 850rpm? Any shaking or noticeable vibration?


You have to give us enough to work with to help diagnose the problem. Give us descriptions as detailed as possible on not just what the problem is, as you see it, but when it IS NOT occurring as well. Any 1 symptom with the 8 can usually be traced to multiple things, and we need what is NOT present to narrow the possibilities.

Currently, from your descriptions so far, these are the possibilities that I can see. We need more information to eliminate any of them:

- Compression loss and imminent engine failure
- Fuel filter clogged
- Fuel Pump failure
- Clutch failure
- Torque converter failure
- MAF sensor dirty
- Clogged cat (leaving this in even though you said no cat)
- Front O2 sensor failure
- SSV sticking or failed
- Vacuum leak

zoom44

its exasperation. you didnt answer the question before and you havent done so now. I havent actually been rude yet. on the contrary, it's you have been rude to us by asking for help and then not providing the information requested.

we now know this is someone else's car. we know that he got an air filter at 75k miles and oil changes every 3k. but we have no idea how many miles he has currently. we know its his second engine but we don't know how longs its been in there or why its been changed.

we dont know what changes from stock have been made.

answer the questions.

SilverR8

1 as normal
2 when the car is in temp it feels warm sometimes a little hot from the floor
3 I floor it only when I want to get it to redline in flats otherwise when I am coasting and this power loss happens I can floor the gas and no response
4 they drop smoothly and gradually to some moment the car has no power I need to clutch the car to make the hill sometimes
5 it is a manual and is not slipping
6 full power on flat/level ground after some time from the hill
7 no noticeable vibration on idle on the moment and after

It does that power loss when loaded ie when doing a hill...

SilverR8

please be kind as RIWPP did...im ok hope you are too... don't hate me

RIWWP

iTrader: (2)

From this, it tells me that you are having high load power loss. If it is even and consistent as you suggest, then I lean much more towards air flow restriction.

In order to make power, the engine must flow air. The more air it flows, the more power it makes. Conversely, the less air it can flow, the less power it makes. Restrict the air flow somehow, including low RPM, clog, block, unstable air flow, valve trouble, and you will have power loss.

At this point I would lean towards either a severe block in your intake track (namely air filter ingested something), or a block in the exhaust preventing the evacuation of the exhaust gases, which in turn prevents clean air from entering.

I would also suggest that you DO NOT have full power on flat ground, you just simply are not demanding enough air flow from the engine to realize that you do not.

With an airflow blockage, some amount of air can still pass through normally, and if you are only demanding this amount of air or less, you will have "full power". Demand more, and it is choked off.

If you sit in 3rd on flat ground at 50mph, and then punch the pedal to the floor until redline, you should take roughly 6 seconds to hit redline (~93mph). I'm guessing you take somewhat longer than this.

I do not think that this sounds compression related, as compression loss related power loss is typically a problem across the entire rev range, somewhat more focused to the lower end of the RPM range (we gain compression as the rotors spin faster, you can actually run our engine at redline without apex seals at all...terrible power, but possible)

Fuel pump overheating may be an issue still. Under high demand (high power output), the fuel pump may be overheating, leading to reduced fuel flow, and reduced power. The fuel pump is under an access panel under the driver side rear seat, so you won't be feeling any heat from it. A failing fuel pump is dangerous to your engine, as it is restricting fuel flow, and prompting more of a lean condition, getting worse the worse the pump gets. I know of several engines that blew because of fuel pump failure, including 2 that were reman replacements that blew on the shake-down because they hadn't changed the fuel pump yet.
I do not know the testing procedures for a fuel pump to determine if it's failing. Most failing fuel pumps end up shutting off the engine however, so I suspect that this is not the case with your 8.


You said that you do not have a cat on the 8.

Are you 100% sure that this is the case? That comment that there is no cat on the 8 is the only thing keeping me from diagnosing this as straight up catalytic converter clogging.

1) it generates heat under the center console area, which can radiator through the floor depending on heat shielding missing or not
2) causes high load power loss
3) failures / clogs prior to 80,000 miles are common
4) if the coils/plugs/wires were replaced at 75,000 miles, I would expect it was because one or more failed (standard replacement is at 30k and 60k, so either you had 30 and 60, then it failed early and replaced at 75k, or you ran it too long on the old parts), and more clogged cats are from failed ignition components than any other method. By far. Mine was one.

zoom44

still have not provided answers to these questions. what year the car is or where it is. still have not told us about any modifications. still have not given us timelines. still have not told us much of anything.

zoom44

re-read the thread and some of your other posts. so this is your car- i mis read when you said "his 2nd engine" earlier. You are in PR yes?

SilverR8

Is this used commonly to compare situations? If not, it is a good idea to create a thread regarding time tests like the one you asked me to do and compare them between users to be used in troubleshooting or just to know if the car is running like the others... I will try to take the time with a stopwatch in these conditions:

In 3rd shift on flat ground at 50mph as you said and then punch the pedal to the floor and the stopwatch at the same time until the beep of the tach. I think this is a good idea because you can drive and forget about looking to the speedo and just be alert to the beep to stop the stopwatch... for security reasons you know.

Let me know if this is a good idea and state clearly to the others to just try this in safe conditions...

SilverR8

ok zoom44 my car is a 2004 RX-8, it has aprox 75k miles and I am his 2nd owner, completely stock his entire life only cat stripped about 2k miles ago, plugs, coils, air filter, all genuine done about 3k miles ago, 5w20 for oil, my ambient temps are between 60 to 94 Farenheit, I have a big salad of roads, twisties, long flats, trails, big hills and twisted too!, what can I say, My car just need some traction tires and it can be a AUV " all utility vehicle" in a good way, I do not punish this car in a bad manner, sometimes I do like all of you, scream the %$#@ out of him once every two days to clean the devil spirits off the engine...

RIWWP

iTrader: (2)

Well, im not goung to say 'its a good idea', since redline in 3rd is 93mph, and that is likely an illegal speed to hit. Byt yes, if you are going to do it, be safe about it. A better timer would be hitting record on a video camera or audio recorder (your phone probably has both), the calling out when you start, and the beep lets you know the end, then just go back and look at the time stamps when you are not driving.

Its not really a 'standard' method, but cars putting out equal power at equal weight will have the same time. Slower means something is wrong, as you dont have full power.

zoom44

thank you silver.

have you always had trouble up a hill like this or is it a recent change? if recent how recent in time and miles. for instance- has it changed only since your last tank of gas or did it change soon after you did the plugs etc?

Razz1

Going up hill problems are usually the clogged CAT

zoom44

except he doesnt have acat Razz

SilverR8

well you are right I will downshift then to 2nd and make a timing I will try to videotape, zoom the change of the coils and others are trying to solve the problem but I suspect something... I did oil change some days ago again and when doing the famous hill the power loss is much less hmmmmm....I bought 4 quarts of royal purple 5w20 and was scared about the warranty so I ended in 4 quarts of genuine toyota motor oil 5w20 :/

nycgps

iTrader: (1)

5w20 = failed.

use something else.

sounds like yours is automatic ?