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6G Celicas Forums > 6th Generation Celica > Engine/Transmission/Maintenance
jgreening
Well, ten days into ownership of the 3sgte and I can safely confirm what everyone else has said over and over....these engines run very rich. I have read many posts about this and about the fact that Toyota made it this way to avoid lean conditions. However, I would imagine that running an overly rich condition cannot be good for the engine over time either. I am wondering whether for engine longevity and reliability purposes, us 3sgte owners should take action either through an S-AFC or stand alone to lean out the A/F ratio. Obviously, we can see some horsepower gains from doing so but I am particularly interested in responses dealing with engine life.
Jdog1385
you should try to lean it out a bit. nothing crazy b/c you'll definitely run into problems. you don't want to start replacing parts.
lagos
my theory is that the swap runs richer then a normal alltrac. it may have somethign to do with the fact that we are running supra fuel pumps with no fpr. the fuel pump resistor pack isint pluged in either (what the hell is it for anyway).

i was driving behind DG and saw nothing but constant black smoke. i doubt an alltrac would do that with just a 3in exhaust
jgreening
Lagos, I am still running the 5sfe pump. Jayson claims it will be fine up to 18 p.s.i. Even with the 5s pump, the mixture is way rich. Anyway, the pump only supplies what is demanded from the ECU so, in general, the pump shouldn't act to cause rich conditions even if it is way overkill.

Also, there is a very interesting thread over on mr2oc.com that suggests you should never upgrade to a supra pump unless you upgrade the fuel rail. It was started by Wolfkatz (sp?) and has a lot of testing to back up his claims - although I must admit, I couldn't follow much of the fluids engineering hyper talk. Also, its quite possible that the conclusions only refer to conditions above the horsepower levels we find ourselves at - so far.
Supersprynt
Keep in mind they have 3sgte fuel pumps that are rated into the 300whp range and we're stuck with the 100whp pumps, thats why he says that. I go the Walbro to put in so that the 5s pump would not fail because its being asked to constantly pump more fuel than it ever did before, this IMO will cause wear faster. Its not meant for these conditions.

Running very rich may cause some cat problems, but if u dont have any then dont worry about that. Its better to be rich than lean, but I think a good tune will do the car well.
jgreening
QUOTE
Keep in mind they have 3sgte fuel pumps that are rated into the 300whp range and we're stuck with the 100whp pumps


Good point. I wonder why people do not use the MR2T or alltrac pump for swaps?
Supersprynt
I figure because they are a different generation. The 5th Gen Celica and MKII's MAY have a different pump setup, its worth looking into. I did some reseach and found the Supra pump would fit with not much fuss so I just got that one, gives me room to breath when I put in the 550cc's and upgraded TC.
jgreening
Whats a TC? Also, are you going to do any engine management when you upgrade Super?
Supersprynt
tc - turbocharger, my bad I start shortening things. Well I am strongly considering the ATS "CT27" upgrade, I'm looking for around 300hp at the crank and this seems like a good option over a used CT20b, which still is something i'm considering. ATS offers a package deal which includes thermostat and fuel pressure regulator and also a ROM tune. Where you send them ur ecu and they tweak it a little bit. If I do that, I'll have them tune the ecu for 93 octane and 550cc injectors. I figure that with a new fuel rail, water injection, (maybe a FMIC dont kno yet. The W/I will help with detonation so the FMIC may not be necessary), a downpipe (2.5 or 3 havent decided), and midpipe it should get me there. That should be good for low 13's if not 12's along with the CM S4 & LSD.
97sccelica
it fouls o2 sensors sooner(only if very very very rich)

but other than that, dont worry about it, unless its so rich that it bogs nearly to the point where the engine stalls

the JDM swaps probably run richer due to the fact that they are programmed for much higher octane, on the 91-93 octane we have here, the ecu sees some knock and probably dumps in more fuel.
Supersprynt
ECU's dont dump more fuel they retard timing. And the 93 octane here is like 97 in Japan. On top of that, Japan uses RON (highest) gas ratings. Europe uses MON (lowest), we use PON (the avg of the 2). So in actuality, its the same gas, just different numbers. Quality controls differ however, depending on the country.
shid
I think the issue about fuel pumps might be something akin to the issue behind hard drives.

You can always buy a bigger hard drive; but the bigger the hard drive you buy, the larger the "smallest" file becomes. IE, on a 60 MB hard drive, u could have files that were sized at only 200 bytes; but if you're hard drive is 60 GB, your smallest file size is now 800k (I forget what the exact numbers are, but the principal should be aptly demonstrated).

This is because hard drives, no matter how large, have a set number of sectors. So, 60 MB divided by 500,000,000 sectors; or 60 GB divided by 500,000,000 sectors.. The one with the 60 GB will have larger sectors; and since a file cannot take up less than one sector, it has to take up a full 800k.

Maybe fuel pumps are the same thing; and can only be divided into so many increments based on the delivery system.

Like, the stock 5fse fuel pump is small, and so 50% of that pump is delivering for 50whp; (or something, I might just be acting crazy), and 49% is 49 whp. But with a Supra fuel pump rated at 500 whp; 50 percent is 250whp, while 49 percent is 245 whp.

Then, instead of risking running lean, the ECU rounds up, and has the pump deliver more fuel in the next incriment it can go.

What do you guys think? Talking out of my ass? No sense?
Supersprynt
No, that doesnt make any sense at all, LOL sorry I tried but I cant make a darn thing outta that.

Your pump doesnt divide anything up, its a pump. Its function is to pump fuel, thats it. Your ecu, using sensor like the AFM, O2 sensor, boost sensor etc..determines the a/f ratio. The pump only knows pump, pump more, pump less.

The reason for upgrading a pump is because at some point the pump becomes a bottleneck. Whereas, it physically cant pump the amount of fuel the engine demands, thats when your in danger of burning your cylinders and detonation.
Kwanza26
Running a bit rich doesn't hurt the engine. It'll eat away at your cat (if you have one) and your O2... but it's a LOT safer than running a bit lean. Running rich has little to do with the fuel pump, although running lean does. It's more than likely the ECU, AFM, TPS, O2, or something between those sensors.
shid
QUOTE (Supersprynt @ Sep 29, 2004 - 7:17 PM)
No, that doesnt make any sense at all, LOL sorry I tried but I cant make a darn thing outta that.

Your pump doesnt divide anything up, its a pump. Its function is to pump fuel, thats it. Your ecu, using sensor like the AFM, O2 sensor, boost sensor etc..determines the a/f ratio. The pump only knows pump, pump more, pump less.

The reason for upgrading a pump is because at some point the pump becomes a bottleneck. Whereas, it physically cant pump the amount of fuel the engine demands, thats when your in danger of burning your cylinders and detonation.

ECU tells fuel pump to pump at 50%
ECU tells fuel pump to pump at 49%.

On the 5sfe 100whp pump, thats not a big difference, but on the Supra pump, it's a difference.


I'm asking if thats a possible issue, as every pump will only be able to discern "pumping more" and "pumping less" to a signifigant figure; 1 decimal place of accuracy, 2.. etc etc
Doge
QUOTE (jgreening @ Sep 29, 2004 - 9:12 AM)
Lagos, I am still running the 5sfe pump. Jayson claims it will be fine up to 18 p.s.i. Even with the 5s pump, the mixture is way rich. Anyway, the pump only supplies what is demanded from the ECU so, in general, the pump shouldn't act to cause rich conditions even if it is way overkill.

Also, there is a very interesting thread over on mr2oc.com that suggests you should never upgrade to a supra pump unless you upgrade the fuel rail. It was started by Wolfkatz (sp?) and has a lot of testing to back up his claims - although I must admit, I couldn't follow much of the fluids engineering hyper talk. Also, its quite possible that the conclusions only refer to conditions above the horsepower levels we find ourselves at - so far.

Running the N/A pump is dangerous. You're seriously just playing with fire... our pumps can pump enough fuel for the 3s.. but its RIGHT on the line. Any more power and its going to cause alot of problems. And if your pump is however many years old... its going to decrease in efficiency. I wouldn't risk it JGreening, you should get a pump asap. Here's the proof. Read the whole thing... you'll be glad you did!

N/A Fuel Pump BAD!
Turbo Fuel Pump GOOD!

The walbro fuel pump is $80 and is a piece of cake to install.. its just worth it knowing your engine will get all the fuel it needs.

And that test about the fuel pump that you talked about on mr2oc... that was a test on 550 injectors on the stock fuel rail. Having a upgraded fuel pump will do no harm to our engines... we are pretty much putting in a fuel pump that is pretty close to the alltrac ones that the engine was meant to run with.


also on the fuel pump resistor... all it does is, at idle it kicks downt the amps that is allowed to the pump... making it work less (basically turning it down) at anything above idle it kicks it back up to full power. Fuel pumps are either on full blast or off... there is no in between, unless you have a resistor... which isnt necessary
Doge
QUOTE (lagos @ Sep 29, 2004 - 9:07 AM)
my theory is that the swap runs richer then a normal alltrac. it may have somethign to do with the fact that we are running supra fuel pumps with no fpr. the fuel pump resistor pack isint pluged in either (what the hell is it for anyway).

i was driving behind DG and saw nothing but constant black smoke. i doubt an alltrac would do that with just a 3in exhaust

is there any way to get a close up picture of DG's engine bay? I think I might know why his car is doing that.
jgreening
Thanks for the post Doge. It looks like up to 12psi and 200 whp I would be ok but beyond that, you are correct - its playing with fire. I have been running 10psi so far and am probably at about 180 whp. The supra pump is going to be ordered tomorrow.
Supersprynt
QUOTE (jgreening @ Sep 29, 2004 - 10:26 PM)
Thanks for the post Doge.  It looks like up to 12psi and 200 whp I would be ok but beyond that, you are correct - its playing with fire.  I have been running 10psi so far and am probably at about 180 whp.  The supra pump is going to be ordered tomorrow.

How do you figure 180whp at 12psi? The JDM 3s's with JDM ecus are rated a 225hp at 8psi so your close to 190-195 at the wheels right there. With 12psi your kicking almost 210 at the wheels, I would think.
thedevilmaycrie
QUOTE (Doge @ Sep 29, 2004 - 6:07 PM)
QUOTE (jgreening @ Sep 29, 2004 - 9:12 AM)
Lagos, I am still running the 5sfe pump.  Jayson claims it will be fine up to 18 p.s.i.  Even with the 5s pump, the mixture is way rich.  Anyway, the pump only supplies what is demanded from the ECU so, in general, the pump shouldn't act to cause rich conditions even if it is way overkill.

Also, there is a very interesting thread over on mr2oc.com that suggests you should never upgrade to a supra pump unless you upgrade the fuel rail.  It was started by Wolfkatz (sp?) and has a lot of testing to back up his claims - although I must admit, I couldn't follow much of the fluids engineering hyper talk.  Also, its quite possible that the conclusions only refer to conditions above the horsepower levels we find ourselves at - so far.

Running the N/A pump is dangerous. You're seriously just playing with fire... our pumps can pump enough fuel for the 3s.. but its RIGHT on the line. Any more power and its going to cause alot of problems. And if your pump is however many years old... its going to decrease in efficiency. I wouldn't risk it JGreening, you should get a pump asap. Here's the proof. Read the whole thing... you'll be glad you did!

N/A Fuel Pump BAD!
Turbo Fuel Pump GOOD!

The walbro fuel pump is $80 and is a piece of cake to install.. its just worth it knowing your engine will get all the fuel it needs.

And that test about the fuel pump that you talked about on mr2oc... that was a test on 550 injectors on the stock fuel rail. Having a upgraded fuel pump will do no harm to our engines... we are pretty much putting in a fuel pump that is pretty close to the alltrac ones that the engine was meant to run with.


also on the fuel pump resistor... all it does is, at idle it kicks downt the amps that is allowed to the pump... making it work less (basically turning it down) at anything above idle it kicks it back up to full power. Fuel pumps are either on full blast or off... there is no in between, unless you have a resistor... which isnt necessary

doge is right i fried my #4 piston from that.... luckly the cylider just ended up needing a little bit of honing i learned my lesson and you dont wanna use a walbo without the use of a high power regulator..... i say use the mr2 stock fuel pump but thats just my opinion from trail and error
jgreening
QUOTE
How do you figure 180whp at 12psi? The JDM 3s's with JDM ecus are rated a 225hp at 8psi so your close to 190-195 at the wheels right there. With 12psi your kicking almost 210 at the wheels, I would think.


221 stock. 10-20% loss through the drive train is 177-199. Maximum stock boost is 10-11 psi. I am not raising it from that. I said 10psi, not 12psi (although I do have an aftermarket intercooler....).

Bottom line, I am not going to play with fire any more. The pump has been ordered.
Supersprynt
I've never heard 221 stock, only 225. Now, 10%-20% is HUGE difference, and secondly 20% is way high for FWD and RWD cars. I think Eclipse GSXs get 25% loss and they're AWD. I think that FWD in general avg 12% drivetrain loss and RWD about 14%. That said we'll use the avg of ur numbers for argument sake.

221 x 15% = 188whp. This is why I was asking where you got your figures because you said at 10psi ur expecting 180 at the wheels, when it should be roughly 188 at 8psi. *From what I've heard* its about 7hp per pound of pressure you turn the boost up. Lets say 5, just to prevent overestimation.
231 x 15% = 196whp.

Just to see the figures on 12%:
221 x 12% = 194whp.
231 x 12% = 203whp.
256 @15psi x 12% = 225whp.

But bottom line is not good using the stock 5sfe pump.
Doge
QUOTE (thedevilmaycrie @ Sep 30, 2004 - 8:06 AM)
QUOTE (Doge @ Sep 29, 2004 - 6:07 PM)
QUOTE (jgreening @ Sep 29, 2004 - 9:12 AM)
Lagos, I am still running the 5sfe pump.† Jayson claims it will be fine up to 18 p.s.i.† Even with the 5s pump, the mixture is way rich.† Anyway, the pump only supplies what is demanded from the ECU so, in general, the pump shouldn't act to cause rich conditions even if it is way overkill.

Also, there is a very interesting thread over on mr2oc.com that suggests you should never upgrade to a supra pump unless you upgrade the fuel rail.† It was started by Wolfkatz (sp?) and has a lot of testing to back up his claims - although I must admit, I couldn't follow much of the fluids engineering hyper talk.† Also, its quite possible that the conclusions only refer to conditions above the horsepower levels we find ourselves at - so far.

Running the N/A pump is dangerous. You're seriously just playing with fire... our pumps can pump enough fuel for the 3s.. but its RIGHT on the line. Any more power and its going to cause alot of problems. And if your pump is however many years old... its going to decrease in efficiency. I wouldn't risk it JGreening, you should get a pump asap. Here's the proof. Read the whole thing... you'll be glad you did!

N/A Fuel Pump BAD!
Turbo Fuel Pump GOOD!

The walbro fuel pump is $80 and is a piece of cake to install.. its just worth it knowing your engine will get all the fuel it needs.

And that test about the fuel pump that you talked about on mr2oc... that was a test on 550 injectors on the stock fuel rail. Having a upgraded fuel pump will do no harm to our engines... we are pretty much putting in a fuel pump that is pretty close to the alltrac ones that the engine was meant to run with.


also on the fuel pump resistor... all it does is, at idle it kicks downt the amps that is allowed to the pump... making it work less (basically turning it down) at anything above idle it kicks it back up to full power. Fuel pumps are either on full blast or off... there is no in between, unless you have a resistor... which isnt necessary

doge is right i fried my #4 piston from that.... luckly the cylider just ended up needing a little bit of honing i learned my lesson and you dont wanna use a walbo without the use of a high power regulator..... i say use the mr2 stock fuel pump but thats just my opinion from trail and error

you had the stock n/a pump when you fried your piston, devil?
Coomer
QUOTE (Supersprynt @ Sep 30, 2004 - 10:54 AM)
I've never heard 221 stock, only 225.

The JDM ST185 3S-GTE is rated at 225 PS, which is approximately 221.9 horsepower. wink.gif

Anyway, good discussion...I'm learning a lot. smile.gif
Supersprynt
http://www.mr2oc.com/showthread.php?s=&threadid=55214

Walbro a NO NO!

After reading through this <very long> article(s) I dont kno if im putting in this walbro because it seems to mess around with the fuel rail and cause pressure drop. This can lead to running rich in some cylinders, destroying them.

N/A pump results:
http://www.mr2oc.com/showthread.php?s=&thr...hlight=pump+dog
lagos
so.... if fuel pressure is controled by the injectors and the ecu, why do people get FPRs and we dont.
Supersprynt
we do have FPRs, stock FPRs.
jgreening
QUOTE
After reading through this <very long> article(s) I dont kno if im putting in this walbro because it seems to mess around with the fuel rail and cause pressure drop. This can lead to running rich in some cylinders, destroying them.


The way I interpret that thread on mr2oc.com is that the fuel pressure drop across the rail is bad for tuning. If you were to try to tune for a 11.5/1 afr, the afr is an average figure for all 4 cylinders. The fuel pressure drop across the rail means that some of the cylindars are more rich and some are more lean.

The good news is that our engines run exceedingly rich. So, while I probably wouldn't do aggressive (or really any) tuning prior to a rail upgrade, I do not think merely adding the Supra TT pump and retaining the stock 440's is going to cause the problems set forth in that thread.
YellowTwo
QUOTE (97sccelica @ Sep 29, 2004 - 10:17 AM)
but other than that, dont worry about it, unless its so rich that it bogs nearly to the point where the engine stalls

What's the danger in having it so rich that the engine stalls? My car (91 MR2t) has been doing this, but it only stalls sometimes. Usually the RPMs will just jump up and down for a few seconds, then even out at the normal idle state. However, on rare occasions it will stall.

I think I'm beginning to figure out the problems my car has been having. It has 550cc injectors with a Supra fuel pump, but NOT an upgraded fuel rail. I've heard the upgraded fuel rail is vital after upgrading the fuel pump and injectors. I'm trying to find out if this is the missing piece to the problem.

The S-AFC supposedly (i.e. according to the seller) was tuned correctly when I bought the car. But on that setting, the car would not go past 4k RPMs (but idles fine). Then when I set it to the other data file (i.e. the default setting) it ran fine, except for the low/jumping idle. What I'm thinking is: a) The S-AFC is tuned for the 550cc injectors, but having the stock fuel rail is causing it to not go above 4k RPMs, or b) The S-AFC is not tuned correctly.

Any ideas?
Doge
Yeah you have to know what you're doing to get those piggyback systems to run correctly. I suggest either get a fuel rail, learn how to tune it yourself, take it to a tuner, or go back to the factory injectors and pump with the rail you have.
YellowTwo
QUOTE (Doge @ Oct 10, 2004 - 1:30 AM)
Yeah you have to know what you're doing to get those piggyback systems to run correctly. I suggest either get a fuel rail, learn how to tune it yourself, take it to a tuner, or go back to the factory injectors and pump with the rail you have.

The problem is the previous owner didn't give me the stock fuel injectors and pump, or I would totally go back to those because there's no reason for my car to have those uprgades. So, I've already ordered the Wolfkatz fuel rail, and hopefully that will help. After I install the fuel rail, I'll try the original S-AFC setting that was supposedly tuned correctly and see if that works. If not, I'll just have to get it re-tuned.
jgreening
I just thought I would share this answer to my original question about whether it is dangerous to run rich:

QUOTE
Overly rich is arguably safer than overly lean, but both are dangerous and undesirable. Running a super rich air fuel ratio is not healthy and will harm your motor. It is also an indication that your tuner does not know what he/she is doing with boost and/or timing. Healthy combustion requires the right ratio of air to fuel being ignited at the right time for optimum burn. You may not realize this, but fuel is an anti-detonant. If you see a very rich mixture (fuel dumping) it is the hallmark of a tuner trying to cope with inappropriate timing and or boost mapping. Donít think rich is dangerous? Too rich and carbon will begin to build up in the cylinder head causing pre-ignition, sparkplugs will begin fouling and misfiring, your catalytic converter will clog up, and the long term health of your engine will be compromised. Matter of fact, if you go too rich, you can cause fuel preignition, which goes hand in hand with detonation, which triggers the knock sensor, which the ECU sees, and then the ECU retards the timing, and the EGTs go up. And so begins the vicious cycle to medium and long term engine damage. It won't be the sudden and catastrophic failure one might see with a sudden lean condition, but will do great harm in the long run.


This is from tuner Ricky B on mr2oc.com, operator of MR Controls and author of the 3sgte Power Primer. Good source.

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