i just helped a friend hook up his hahn stage 2 kit yesterday and today we hooked up his DynoJet wide band kit. no matter if we turn the fmu up or down, it always reads 14.5 under boost. the fuel pressure is more than what it should be so i dont understand. and we are talking about going all the way up to 100 psi to see if it made a difference. the inline pump is working fine and the injectors are spraying fine. we let the new o2 sensor warm up for a bit thinking this might cure it but got nothing. the kit and car seems to running exactly as mine did when i first got it going but i had mine dyno tuned.

we have the new 02 sensor hooked to the wideband and the factory 02 sensor is just dangling around but plugged in, but i dont think this will cause it. any suggestions?

Had and have same problem with my kit.
Good luck. I never really found a good solid answer
other than people saying get a safc II

i had the same problem....then it amazing went down to 12:1. sometimes it goes back to 14:1. for some reason the eco doesnt kick into openloop at WOT like most cars. its weird.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

Sounds like you're running out of fuel pressure.


- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

sounds like its not calibrated

I have the innovate and it works wonders



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justinsecotec wrote:

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the fuel pressure is more than what it should be so i dont understand. and we are talking about going all the way up to 100 psi to see if it made a difference.

Skilz10179 wrote:

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Sounds like you're running out of fuel pressure.

100psi of fuel pressure and running out.

well, i got it to work. we went down the interstate and if you get into it gradually or slowly, it will stay at 14.5. now if your rolling and you give it some gas and let the clutch out fast, it will work. so im thinking that maybe a diaphram or something may be stuck in the fmu. im not sure how its setup inside. i'll check the fuel pressure again later and see if the fuel pressure rises gradually if it should. if it does then maybe hipsy is right about the selective openloop the ecotecs have

If you're working on an Eco, there have been other posts about this same problem. Seems as though GM's got the tuning down to where they can keep it at 14.7:1 and still make good power.

1st, is your wideband installed before the cat? Probably a dumb question, but the WB needs to be between engine and cat to make sure you're not reading the AFR of "cleaned up" exhaust.

2nd, the ecm can't command 14.7:1 if it can't see 14.7:1. Disconnect the vehicle O2 sensor and see if the AFR comes around where you want it. If this works then the easiest way to force open loop is to electrically disconnect the O2 sensor every time you want 12:1 under boost. A pressure switch that opens around 2 or 3 psi could be installed on the O2 wire to make it almost automatic.

hth

-->Slow

My eco does the same thing when spraying nitrous no matter what fuel jet i use. I just gave up and dont spray. Modifying these cars is never going anywhere untill someone comes out with a package for engine management. MY CAR HAS 4,000 miles on it and dont want to blow it up. I was going to try an early eco PCM but dont have a good# for salvage part(2002-2003). I was hoping that the calibration was a little diff than 04???

Let me rephrase myself. If you are hitting 100psi on one setting with the FMU and then you adjust it to richen the mix and you're still only hitting 100psi that means you fuel pump is not up to task and you're running out of fuel pressure.


- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

well, the fuel pressure is going from 80 to 105 depending on where i set it. the car doesnt have a cat converter. does the first (bank 1) sensor have anything to do with this? i guess the injectors may be shutting down. im not sure if not having the second 02 sensor would hooked up would make a difference either.

The second O2 sensor shouldn't make a difference, it's only to monitor catalytic converter efficiency. The Bank 1 sensor monitors AFR for engine control. The closed loop idea has been proven on at least one other J Eco.

-->Slow

Quote:

Disconnect the vehicle O2 sensor and see if the AFR comes around where you want it. If this works then the easiest way to force open loop is to electrically disconnect the O2 sensor every time you want 12:1 under boost.

so is there a particular wire, or just all of them on bank 1 02 sensor



TURBO KIT...$4,000
RUNNING 20 PSI...ANOTHER $2,000
SMOKING THE TIRES ON A 3RD GEAR ROLL...PRICELESS

The signal wire to the ecm is the one to interrupt. Does your car have a heated O2 sensor? If so, 3 wires or 4? What are the wire colors in the vehicle harness side of the connector? GM has used purple for the O2 signal wire since the mid 80's, so I'd expect to see a purple wire in there. If not, I'll try to dig up some info when I get to work. Nothing I have at home goes past 2k.

-->Slow

well, i unhooked the upper 02 sensor and im getting great readings on the wideband now. its running between 11.7 to 12.5. at idle it flexes from 13.2-14



TURBO KIT...$4,000
RUNNING 20 PSI...ANOTHER $2,000
SMOKING THE TIRES ON A 3RD GEAR ROLL...PRICELESS

fstcavZ24 has a 03 with hahns kits , and he has the AEM wideband

and from the time we installed it he was showing readings of being richer than the gauge would read , once we got the fuel pressure right and the boost up closer to 10 the afr runs in the 11-high 12 range under boost


his has never read in the mid 14's , even at idle with the 320cc injectors , it bounces around from high 13 low 14 to high 14 to mid 15's , from what i remember

^^^ Crazy stuff. I wonder if there's two very different calibrations floating around for the Eco.

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well, i unhooked the upper 02 sensor and im getting great readings on the wideband now.

Sounds like your car is trying to stay in closed loop, then. The hobbs switch might be a good idea. #78632 looks like the one I'd order. You could try an oil pressure sending unit from a vehicle with an idiot light instead of a gauge. You'd want one with 2 terminals, and it would be listed as something like "NC" or "opens at X psi." Put this inline with the O2 wire so whenever there's boost, the O2 sensor signal isn't available to the pcm.

No guarantees, but this type of switch is what I'd try if my car were acting up.

-->Slow

Sounds like the exact same problem I'm having. I have 440 injectors, fpr, FMU and with the fuel at 60psi and 5lbs of boost my car still adapts out to 14.0-14.5 under boost. I have DEFIANTELY narrowed it down to the car not entering open loop mode. I have the autotap and you can actually watch the stock ECU pull back on the injector Pulse Width until the wideband reads close to 14.7.

I was thinking about trying a primary O2 bypass when in boost, but wouldn't that cause the ECU to get really pissed and pull a bunch of timeing on you??? I know when I disconnected my primary I was able to maintain solid 11:1's at only 40PSI fuel so it's defiantely a problem with the ECU and not seeing whatever it needs to run open loop.

This one has had me stumped for over 4 months now and I have pretty much decided that I'm going to wait for the ecotec SC reflash to become available and then hore myself out to get it.


<img src=http://home.comcast.net/~richnj221/smiley.gif>

The computer has to be pulling the reading off of the TPS sensor until say about 70% throttle. At idle my wb says 14.1-15.7. Under boost if I go gradual into it I can keep it around mid 14's. It seems like if i just push the gas a tad farther down it'll go into the 11.2-12.1 range. It seems like I can ease into boost but once I get the throttle position over a certain % the AFR drop.

MORE PROBLEMS. the wide band wasnt going below 13.5 UNLESS i had the ac running
but sometimes, it will drop when i ease into it and sometimes it will drop only if i mash the gas down hard.



TURBO KIT...$4,000
RUNNING 20 PSI...ANOTHER $2,000
SMOKING THE TIRES ON A 3RD GEAR ROLL...PRICELESS

hey Slowolej, does that hobbs switch have a place for a vacuum line? i didnt see one in the picture.

Quote:

This one has had me stumped for over 4 months now and I have pretty much decided that I'm going to wait for the ecotec SC reflash to become available and then hore myself out to get it.

is this reflash going to help out the turbo ecotecs in any way?



TURBO KIT...$4,000
RUNNING 20 PSI...ANOTHER $2,000
SMOKING THE TIRES ON A 3RD GEAR ROLL...PRICELESS

that hobbs switch seems to me that when it makes pressure, the two terminals would make contact. am i looking at it in a different way? and now i see, you would have to put the vacuum line on the threads where the small hole is.

Yep, you can connect it with a vacuum hose for testing. You'd probably drill and tap the manifold then screw the switch right in for a more permanent installation.

You're right, the picture is for a switch that turns on under pressure. The switch # I gave is for a normally closed switch. It's "on" when there's no pressure at the switch. It's preset to turn off when pressure reaches 1 psi. The switching pressure is adjustable between 1/2 psi and 24 psi so you can set it where you want. Let us know when you need a switch that works at more than 24 psi.

-->Slow

man, this whole thing got me wondering about my car. lmao. i took some stuff off mine and started testing my a/f and its doing the same thing. my buddy tim is on the back burner now. lol. i'll try this switch definately. thanks for the help. i'll never see 24 psi unless i screw up big time.

Has anyone tried this on am Ecotec? Seems that the PCM would think that the o2 senser whent bad and throw a code?????? There are many cars now that never go into open loop at full throttle. I would like to try an early Eco PCM(2002-2003) to see if it fixes this but need the # off an actual unit so i can match up at the yard(not the part# in book) ANYBODY????????