light throttle hesistations with lean symptoms
03-08-10, 10:43 PM
#51
Symptoms to date 
AFR's with boost sensor connected..
View My Video
AFR's 30 mins later disconnecting the boost sensor...
View My Video
Now, I picked up the pill from the local Mazda dealership, haven't had a chance to install the little thing but do you actually think that tiny orifice is causing that drastic change in my fuel delivery or does the problem lie elsewhere because I did try a 'known' working boost sensor prior to this discovery and the problem was still there.
Thanks for the help guys,
~Ant
AFR's with boost sensor connected..
View My Video
AFR's 30 mins later disconnecting the boost sensor...
View My Video
Now, I picked up the pill from the local Mazda dealership, haven't had a chance to install the little thing but do you actually think that tiny orifice is causing that drastic change in my fuel delivery or does the problem lie elsewhere because I did try a 'known' working boost sensor prior to this discovery and the problem was still there.
Thanks for the help guys,
~Ant
03-10-10, 10:22 PM
#52
pp
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Mine did the same thing after I installed my lc-1 although not as bad. I ditched the stock O2 and tried using the nb sim...which made the car run like ****. Once I unplugged that the car ran fine.
03-11-10, 08:33 AM
#53
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No. The orifice or lack of would cause bucking when the pedal is stomped on. Not what I see in the crusing at seventy video. That shows a lean reading. Running too lean for unknown reasons imho. Even when you barely let off the pedal at seventy.....the afr reads lower (normal thing when barely letting up on the pedal), but even that reading is too lean (was in the fourteens???). Should be reading richer than that when letting up barely. Should read in the 13's or so doing that.
Guage problem? Wideband problem? Got me.
Guage problem? Wideband problem? Got me.
03-11-10, 09:05 AM
#54
I have noticed my car will do this in 4th. It seems to occur at lower RPM plus strong enough vacuum, which is why it rarely shows up for me cruising the highway because I'm pulling 8-12in Hg at ~3000RPM. I'm going to see if I can't get my simulated narrowband output to work and if I can see if this problem still shows up.
03-11-10, 11:29 AM
#55
It can't be that complicated...hopefully not. I'll keep trying different things and keep you guys updated, sounds like more people than just me are having this problem so it would be nice to find a solution. With that being said, if someone gets theirs running right before me please let me know 
~Ant
~Ant
03-11-10, 09:37 PM
#56
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I am having a similar problem with my T2, but haven't got time to work on it since i came back to Toronto for a family issue. Would like to know if OP has come up with any solution yet.
03-12-10, 10:56 AM
#57
03-17-10, 01:04 AM
#58
so worse case scenario I don't figure out what's causing the boost sensor to make the car run lean...when I upgrade to the rtek 2.1, will I be able to tune the car without the boost sensor being connected or does the ecu need that to know where to add fuel on the maps?
03-23-10, 10:39 PM
#60
update:
I installed a friend of mine's 318 boost sensor that never showed any problems on the previous rx7 it was on and I installed the 'pill'. I let the car warm up and as soon as I plugged the sensor back in the car ran went lean, misfired, and did everything you saw in the previous videos.
I'm driving fine without the boost sensor but have to be weary of boosting too much because I don't think the ECU is compensating fast enough for the extra air w/o the boost sensor, at least that is what my AFR gauge is showing.
BUT...i'm out of ideas....any more ideas guys?
I installed a friend of mine's 318 boost sensor that never showed any problems on the previous rx7 it was on and I installed the 'pill'. I let the car warm up and as soon as I plugged the sensor back in the car ran went lean, misfired, and did everything you saw in the previous videos.
I'm driving fine without the boost sensor but have to be weary of boosting too much because I don't think the ECU is compensating fast enough for the extra air w/o the boost sensor, at least that is what my AFR gauge is showing.
BUT...i'm out of ideas....any more ideas guys?
03-28-10, 11:27 AM
#61
I might just go standalone.... the time and and money it will take me to figure out this problem will probably be about the same as just upgrading to a standalone with new(ish) sensors. With that said, if anyone that has followed this thread wants to let theirs go, shoot me a pm and we could possibly work out a deal, I've got some parts for trade too.
Thanks for the help guys,
~Ant
Thanks for the help guys,
~Ant
04-05-10, 04:12 PM
#64
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You go to the ECU and backprobe the boost sensors input wire and write down the voltage and post it. Post it at just key ON, engine OFF and at idle with a fully hot engine.
04-08-10, 05:27 AM
#67
I have been saving for the rtek 2.1 upgrade but this dilemma has set me back some. I know the rtek 2.1 allows you to monitor the engine sensors while the car is on/driving etc. Would this be beneficial to troubleshooting this problem or would you suggest I try and figure out my problem before upgrading?
04-08-10, 04:02 PM
#68
we have 3 guys in another thead with this problem, myself included..
if you have a fuel pressure tester, can you hook it directly to the tank output line with no return, and set the intial set connector(or just [try to]start the car).. this is the only thing i could find wrong with my car.. i have 55 psi which should be 71-92 psi, it also doesnt hold the pressure for more then 20 mins, after that it's dropped down to like ~5psi.
my pump is 12v wired, and 2k miles fuel filter.
if you have a fuel pressure tester, can you hook it directly to the tank output line with no return, and set the intial set connector(or just [try to]start the car).. this is the only thing i could find wrong with my car.. i have 55 psi which should be 71-92 psi, it also doesnt hold the pressure for more then 20 mins, after that it's dropped down to like ~5psi.
my pump is 12v wired, and 2k miles fuel filter.
04-09-10, 04:44 PM
#69
we have 3 guys in another thead with this problem, myself included..
if you have a fuel pressure tester, can you hook it directly to the tank output line with no return, and set the intial set connector(or just [try to]start the car).. this is the only thing i could find wrong with my car.. i have 55 psi which should be 71-92 psi, it also doesnt hold the pressure for more then 20 mins, after that it's dropped down to like ~5psi.
my pump is 12v wired, and 2k miles fuel filter.
if you have a fuel pressure tester, can you hook it directly to the tank output line with no return, and set the intial set connector(or just [try to]start the car).. this is the only thing i could find wrong with my car.. i have 55 psi which should be 71-92 psi, it also doesnt hold the pressure for more then 20 mins, after that it's dropped down to like ~5psi.
my pump is 12v wired, and 2k miles fuel filter.
04-14-10, 05:10 PM
#71
04-14-10, 10:22 PM
#72
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So why dont we find out whats what and what simularities are set ups are because same problems are for me now too.
Boosts great
bucks low speed like 1st or second mainly when slowly climbing rpms. bucks more higher rpm 1/4 throttle the worst
Mine
s4 T2 large streeport
no emmissions(egr/acv/csa/rats nest/twin scroll)
still have bac
problems occured after I installed fmic(no vac leaks everything works great)
ontop of running very low on gas(my light still works)
I have Bov to the 3rd nipple down on uim
top nipple blocked
2nd nipple ran directly to my wastegate metal tube
pressure sensor and boost gauge teed on the stock side uim vac nipple with orfice installed
question is the Idle air bypass valve??? that used to be ontop of the uim that the bac ran a vac hose too was tossed and im thinking that was my only real change
So sorry to be elaborate but seems alot of people are having the same problems so we need more elaborate posts
Boosts great
bucks low speed like 1st or second mainly when slowly climbing rpms. bucks more higher rpm 1/4 throttle the worst
Mine
s4 T2 large streeport
no emmissions(egr/acv/csa/rats nest/twin scroll)
still have bac
problems occured after I installed fmic(no vac leaks everything works great)
ontop of running very low on gas(my light still works
) I have Bov to the 3rd nipple down on uim
top nipple blocked
2nd nipple ran directly to my wastegate metal tube
pressure sensor and boost gauge teed on the stock side uim vac nipple with orfice installed
question is the Idle air bypass valve??? that used to be ontop of the uim that the bac ran a vac hose too was tossed and im thinking that was my only real change
So sorry to be elaborate but seems alot of people are having the same problems so we need more elaborate posts
06-05-10, 03:55 PM
#73
Got around to doing some data logging with my lc-1 wideband on my laptop today. I did some testing on the effects of my meth injection as well as observe the difference of having my boost sensor plugged and unplugged...the results where staggering to me.
Anybody know how to post data files in a forum?
Anybody know how to post data files in a forum?
06-06-10, 09:51 AM
#74
Ok, figured it out.
So here's what you're looking at. At 30 seconds I give the car light throttle like I would to accelerate from a light then at 40 seconds I give it more throttle, enough where I would have gone into boost if the car was under load and not free revving. These were with the boost sensor disconnected, you can see it richen at 40 seconds to compensate me increasing the throttle input like it should...
At around 1:20-1:25 seconds I reconnected the boost sensor and did the exact same test. You can see how erratic the AFR's get and it leans out hard when I give it more throttle? Any ideas guys?
So here's what you're looking at. At 30 seconds I give the car light throttle like I would to accelerate from a light then at 40 seconds I give it more throttle, enough where I would have gone into boost if the car was under load and not free revving. These were with the boost sensor disconnected, you can see it richen at 40 seconds to compensate me increasing the throttle input like it should...
At around 1:20-1:25 seconds I reconnected the boost sensor and did the exact same test. You can see how erratic the AFR's get and it leans out hard when I give it more throttle? Any ideas guys?
07-14-10, 01:10 AM
#75
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Paper Filters are trash
If you PREMIX your fuel you must eliminate your stock fuel filter or replace it with one suited for premix. i Fought the same problem for Three Weeks.