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Discussion Starter #1
OK, here's the deal. I know air/fuel gauges are not accurate, blah blah lecture lecture. I get it. However, what I have to work with is an air/fuel gauge, and it's probably the best one out there, so here goes....

My car has been burning up a ton of gas ever since I got it, and I've been trying for ages to straighten it out. I got new plugs, wires, O2 sensor, and it didn't change anything. I also swapped out my KV sensor. We knew I had a problem with my VSV due to the bad heat soak I was getting, so I bypassed that. I put the fuel pump to continuous 12V power, bypassing the resistor, and I replaced my ground to the coil pack. Still no results.

So I installed this RS*R air/fuel gauge that I got from DBSupra last night. It seems to be working right, but I get the craziest results from it. When I'm idling, or when I'm cruising on the freeway, it oscillates constantly from lean to rich, lean to rich. It will sometimes get really nuts, and go clear off the chart lean and then to full rich. Here's the goofiest thing. I'm having a fuel-cut-like hesitation when I give it anything more than 1/3 to 1/2 throttle. When I step on it, the A/F goes rich, and then drops straight off, but comes back up. It gets even better. When I come to a stop, as soon as I push the clutch in, or let off the gas, it goes full rich for a couple of seconds, then goes back to oscillating.

Here's what I'm thinking, but please give me your feedback. I think I have a screwed up injector, or maybe my cold start injector that is sticking, causing a periodic influx of fuel. I don't really know how to account for the stuttering under wot, other than maybe it is just screwed up altogether and it's firing out of order or something. Which brings me to the next point. My motor has been out. Supposedly it has a JDM 7M in it. I was thinking that it could possibly be that when they rewired the injectors, that they mixed two of them up, and now two of them are firing when they shouldn't be. I'm really pretty baffled by the whole thing, and I would like to know if anyone here has had a similar experience.

Also, I had it on the dyno a couple of weeks ago, and the AF mixture was really weird there too... Here's a link to my dyno: http://www.cardomain.com/memberpage/818664/2


If anyone has any input, please let me know!!! I'm going crazy!
 

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Back to boosting!
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Full 12v power to the fuel pump is how toyota raised the fp for boost usage. That's prolly the main reason you are dumpin fuel. The oscillations at idle and cruise are standard, that's called closed loop operation. It's how you keep the cat lit.
 

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Discussion Starter #3
I know it should oscillate in closed loop, but is it supposed to go full spectrum every time? I thought it should oscillate on the middle third of the gauge or so...
 

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animantoric said:
Full 12v power to the fuel pump is how toyota raised the fp for boost usage. That's prolly the main reason you are dumpin fuel. The oscillations at idle and cruise are standard, that's called closed loop operation. It's how you keep the cat lit.
Fuel pressure will still stay the same regardless. That's what the FPR is there for. More fuel, more bypass. The relayed 12v deal is for longer pump life by using lower voltage.
 

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Discussion Starter #5
ok, well, what else could it be? i have thought it could be the following:

coolant temp sensor: no connection keeping it in startup mode... except that it is going into closed loop once it warms up.. i think that eliminates that...

fpr being jacked up... might account for loss of power, but i don't know how it could account for my horrible gas mileage

leaky/sticky injector: this is the one that seems most likely to me... like it's sticking open and dumping fuel sometimes, and sticking shut and causing a false fuel cut other times...

give me your input please!
 

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It's hard to say. Those narrowband gauges are far from accurate. Not to mention they don't have any values, therefore you really have no clue what the afr is. Everything may be perfectly normal. But if something is amiss, I'd look towards the O2 sensor.
 

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Discussion Starter #7
Racefiend said:
It's hard to say. Those narrowband gauges are far from accurate. Not to mention they don't have any values, therefore you really have no clue what the afr is. Everything may be perfectly normal. But if something is amiss, I'd look towards the O2 sensor.
Yeah, I know they're not accurate. However, mine has values on it, and is supposed to be one of the "high resolution narrow band" gauge (it's the RS*R gauge). Also, my O2 sensor is a brand spankin new bosch. I know that everything is not normal, because I am burning up waaaaay too much fuel... you can smell the unburnt fuel while I'm driving... being behind me is not pleasant! I am sure there's something going wrong in my fuel delivery system, but I just can't find a diagnosis that makes everything come together... hoping someone else out there has had a similar experience...
 

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you gotta get rid of that narrowband, geez man, what are you new? lol good luck josh
 

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Discussion Starter #9
Yeah, I'm straight noob. I think I'm gonna get me a Type-R or GTR badge, just to make sure I get the most horsepower out of my ride! it's gonna be so tiiiite!
 

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wiredjosh said:
Yeah, I'm straight noob. I think I'm gonna get me a Type-R or GTR badge, just to make sure I get the most horsepower out of my ride! it's gonna be so tiiiite!
well, you bought a NB o2 gauge, and fell for 'high resolution'
 

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BTW, your A/F's on the dyno look about right for a stock ECU. But the A/F's and your power output are not very consistent. Looks like the ECU may be doing too much leaning/enriching beyond the maps. I'd look towards a faulty sensor then. TPS, coolant, maybe afm. Your assumption that since the ecu goes closed loop the coolant sensor must be good is wrong. The ECU still uses it for fuel. Check it's resistance values. Also, check for a leaky CSI, and a working CSI time switch.
 

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Discussion Starter #12
ok. now that's the kind of stuff i was hoping for! Got any links/hints on how to test all that? I know how to test the tps and coolant sensor, and I assume I can get resistance/voltage values out of the tsrm... I just replaced the afm with a known good kv sensor. as for the rest, is it all in the tsrm?

Thanks!!!
 

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RoastBeefCurtain Commando
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again . its not the gauge thats bad, Its the sensor not reading the correct voltages to give you an accurat reading.
You can argue all you want and say its top line and accurate. But its not a wideband , so its not accurate

For the reccord I had an A/F gauge read rich under high load. I then got on the dyno and realized I was 17:1 a/f under load. guess what i was lucky not to blow an expensive motor. We are all young once and make mistakes.

Moral of the story is, ditch that gauge
 

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Discussion Starter #15 (Edited)
OK OK OK, I get it. The gauge sucks. See the top of the page? I said I know they're not accurate. I just thought I'd put in all the information I have. Crap. Forget I ever mentioned the gauge. I'm not a noob, I'm not stupid, and I'm not making "young" mistakes. I'm just trying to get all the info I can. I don't have the cash flow for a wideband right now, so I put in what was available to me. Also, it just so happens that I was on the dyno just a couple of weeks ago, and it also just so happens that my A/F gauge reads pretty consistent with what the dyno said. Just because I don't have a bajillion posts doesn't mean I'm a moron.

What I'm trying to get at is this: my car is guzzling gas. Like 12-15mpg. It's annoying. I put in a new O2 sensor, plugs, wires, and KV sensor, and no change in mileage. Not only that, but since I changed the KV, I am having an annoying fuel-cut-like loss of power around 3K rpms. my mileage still sucks. What should I look at to cause my car to be dumping gas? That is the question. The question was not "Is this a good gauge", nor was it "do you guys think my gauge is accurate". The question was, what could be causing my car to dump gas. Simple question. Thank you to Racefiend for some valid input! Everyone else, I got it. You don't have to keep posting how bad my gauge sucks. In fact, I don't even have an A/F gauge. What's an A/F gauge? I've never even heard of that.
 

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Discussion Starter #16
mullenc525 said:
well, you bought a NB o2 gauge, and fell for 'high resolution'
Oh, and no, I didn't. I replaced the O2 sensor, and a friend had this gauge laying around, so I put it in. I didn't "fall" for anything. Still missing the issue. Still not addressing the question at hand. Still just finding something to trash on someone about.
 

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RoastBeefCurtain Commando
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i Missed the dyno part. I thought you were going soley from the gauge.

Looking at your dyno you are not making power becuase you are sooo damn rich. I bet there is another 30whp or so n there just from getting the fuel where it should be. That is also obviously the reason for the gas mileage.

As far as why its soo rich?
-Well they came rich from the factory.
-Could be stuck open injectors. .but i doubt it. Take the injectors out and clean them or matter of fact test the injectors to see the spray patterns with cups or something. Just a thought.

Usually when you have fuel probs there is more of an issue with not enuff fuel because something giving up.

I could be totally off, but if you really think its the injectors replace them with well known working ones or test them and see.

I honestly think its just lack of tuning.
 

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Discussion Starter #18
OK, so get this... I put back in my old KV sensor, since I was just borrowing one... the old one of mine was giving me afm codes, so we thought we could swap out the kv and see a difference. Well, now, with the old one back in, the car drives 100% better, and just runs really rich. (at least according to my crappy, non-working, inaccurate NB a/f gauge, which is definitely wrong)

At the very least, I can smell the fuel like crazy when it's running, so I have a fair idea that it's still running uber rich.

I'm still thinking jacked up injectors, or maybe my csi... any ideas?
 

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I can only hope you've fixed this by now, but I had very similar troubles. My problem was a bad ground--in my case, the ground bolted to the #5 runner on the intake manifold. The bolt was loose on my car, and caused so many problems; the air/fuel problems were the worst, but also, my temp gauge liked to bounce around in physically impossible ways.

Good luck!
 

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Moo
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Check for cracked/leaking intake hoses. Ditch the gauge (narrowband sensors are only accurate at 14.7:1 no matter what gauge you put on it) and NEVER tune by the NB sensor.
If the FP vsv works put it back. Put the fuel pump resistor back. These "mods" are only
hurting you unless you have some sort of EMS.

That ground to the manifold is E1, the motor ground for nearly all sensors and electronics on the motor.
 
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