Heres my setup:
C4 Corvette, LT1 Intake Conversion, 7730 ECM Running 8D XDF/Bin / TunerProRT

The map is a mix and match from both LT1, AUJP and Super8D bins...

The problem I've got is that the wideband and the normal lambda just disagree! I've done my tuning in OPEN loop, I get it pretty close on the VE tables even though some are pretty high into the 99 range. It drives well and feels strong.

I re-enable closed loop (min temperature) and start the car. It sits around 13.5 untill closed loop at which point the BLM's drop 128,124,120,118....108, and I can see the mixture going out to 17-18-19:1 afr - Int doesn't go as low. I tried to drive the car and it stubles and goes to stall - so I would have to belive the Wideband over the narrow band.

In tuner Pro I can see the lambda swing back and forth on the voltage, ive also tried a brand new lambda and still get the same issues.

Can I have somehow set the parameters on the narrowband so that 14.7 isn't 128 or the voltage is different or something? I'm really stuck for ideas?

The only way I can drive the car is in open loop

Any suggestions???

Dan

 

what cam are you running?

are your wideband and narrowband sensors both being installed in the same location in the exhaust?

Make sure your o2 parameters in the bin are not messed up, maybe try a completely stock bin just to see what it does.

what range of output is the NBo2 swinging between- got 100 lines or so of datalog to post as an example?

 

Cam is a very tame SUMMIT 204/214@.50

Both in the same side, Narrowband is on the downpipe from the header, and the Wideband is in the "Gutted" CAT just after that.

I've not got a datalog on this PC but I'll try and get something up soon.
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Another thought I had is that I was using the LC-1 as a simulated Narrowband when the LC-1's digital outputs fried (common fault I found when looking on there website).

I wonder if it spiked the ECU??

 

I've not had chance to do any more logging but I wondered if anyone had some other ideas/things for me to try??

Dan

 

You said you already changed the O2 sensor with a new one, right? Is it a three-wire heated one or a standard one-wire? What brand? I only use AC Delco O2 sensors because a lot of people have gotten bad Boschs right out of the box.

 

well actually - i used a 3 wire one, but only the one wire connected. I'm wondering if this it a problem now?? I just assumed that it would heat up fine as a normal one did in the same place....

 

Ok i played with this a bit more tonight....

When I enable closed loop and run a standard AUJP bin I see BLM's of around 124-128 but AFR of 16:1 on WBO2
(Narrow band shows good voltage crosses - even with a multi-meter)

When I enable closed loop and run a modified richer bin I see BLM's of 104 but AFR of 16.5-17:1 on WBO2
(Narrow band switches between 850-900mv ie high)

When I dissable closed loop and run a standard AUJP bin I see AFR of 16.5-17:1 on WBO2
(I forgot to see what the voltage was doing on the narrowband here)

When I dissable closed loop and run a modified richer bin I see AFR of 14.5:1 on WBO2
(Narrow band switches between 850-900mv ie high)

 

tune the NB to the WB, maybe. see what 14.7 (according to WB) gives you on the NB's mv readings. then set mean, lean,and rich INT O2 stuff around that. I had to do that to my truck, had the same issue.

 

I am not even 50% sure how much that will affect it, but I know the hotter the O2 sensor gets, the better it works. Hook up your NBO2 sensor to ignition and ground and then try it. It should be that way anyway for proper operation. I dont know if not having the heater hooked up will make it read wrong, but from your observation, it sounds that way.

 

Sorry can you explain how I would do that??

 

Gutted cat or a collector flange is probably leaking (can even be after the sensor) and skewing your WB lean.
Otherwise, maybe with the NB on one bank, and the WB on both banks (assuming a single gutted cat), then maybe one or two cylinders on the opposite bank are leaking.
One sorta quick check would be to swap the NB down to the Cat, and the WB up to the header collector. If results are opposite, it's not the sensor's problem.

 

I guess I can try that - I know that the exhaust isn't leaking as i've had it up on the ramp though.

The car runs fine when the WB shows a good lambda, and runs like a dog when in closed loop and WB shows lean. I just don't get it...

 

If it's running bad when it shows lean, then it's likely actually lean.

Maybe your exhaust isn't grounded well??? Just a guess. Maybe you toasted the input on the ECU?

 

I think i'm going to have to try and track down another ECU I don't seem to be getting anywhere as it is... I've also spoken to a friend and he has similar symptoms (but hasn't checked the ECU readings) that his car starts fine and then gets leaner and leaner - he also had an LC-1 wired to run the narrowband that went bad.

Anyone got a spare 7730 ECM??

 

n.m.

 

I am having the same problem with my Camaro that has a 7730 ECM. The engine runs good in open loop but the narrow band starts to pull fuel in closed loop to the point of the engine running poorly and stumbling.

I was wondering if you ever found a solution to the issue?

Thanks in advance.

 

A silicone poisoned O2 sensor reports rich. Drives the INT & BLM down to the point of cutting-out.

RBob.

 

Thanks for the reply. That never crossed my mind since it was a new sensor with the engine build. I will swap it out and see what happens.

 

Same problem here, tune WOT withe zeitronics wb get everything in the 12.8:1 afr, runs strong but when i lift the trottle afr goes in no time to 19:1

Check complete exhaust for leaks, everything ok.

Now i am a dutch, so i dont know exactly what a silikone poisoned o2 sensor is, and how do you get a sensor like that where comes the silikone com from.

btw, datamaster tells me car is pig rich and plugs read coffee brown?

Thanks, Sjaak

 

This may be normal.. Enlean occurs do to max vac. Also in my car in deacceleration enleanment(fuel cut off ) occurs and it goes on WB to 22/1. I I disable fuel cut off still goes to 17-18/1 due to engine pumping more air than the VE table can provide gas.

 

It's not quite the engine pumping more air than the VE can provide, but usually it's the injector PWs are so small that they are either dribbling fuel (especially with batch fire injectors) or doing nothing at all at the extreme low loads of deceleration that causes the 17-18:1 readings with DFCO disabled.

When DFCO is enabled, yes, it should read AIR or 20.9% O2, or at the lean limit of the AFR. It's perfectly normal, and doesn't hurt a thing. When fuel returns, though, it's a big challenge even for me doing OEM work to keep it dead smooth. Some OEM cars don't have DFCO enabled for this reason, and that it also presents a challenge for emissions (filling the cat with air requires draining it after DFCO post haste, but sometimes the temperature gets high as well due to some lean misfires, and then air, and then lots of CO).

 

As Ronny mentions there is DFCO, where the fuel is completely turned off (PW == 0).

As far as poisoning the O2 sensor, silicone is from many areas. Silicone jacketed spark plug wires, silicone (dielectric grease) for brake systems and plug wires.

Many gasket sealers contain silicone. At times the fuel also will.

RBob.

 

I only have DFCO enabled for 2 days now !! I do not see and drivability issues currently. DFCO RPM upper 2400 lower 2200
MPH 50 40 (set so as to not stall)
MAP 40 25
PWexit 2.9
However I just changed rpm-mph-map to new numbers to allow increased effect. Maybe now i will see some issues.

 

I disabled DFCO on the stick shift car. Way to abrupt when the fuel came back on. Others here have had the same issue.

Note that the fuel pulse when exiting DFCO only occurs when the ECM exits for reasons of anti-stall. Such as the RPM dropping to quickly.

No fuel pulse occurs when the driver hits the go-pedal.

RBob.

 

I have different set-up. Its a modified tpi, with 165 ecm. This might help. When my w/b showed lean and tunerpro blm's were lower than 128. I discovered useing blm's to get a/f ratio worked. Try lowering maf tables to get blm's closer to 128 and in my case doing this w/b showed richer a/f ratio.