Do these numbers look right?

[Bobby Fazio]

I do have it in the collector but I'm running in open loop so there is no correction coming from the o2 sensor. With that said, the air fuel ratio isn't fluctuating at all which seems odd.

[Dave Noll]

Bobby,
I was a driveability mechanic for a number of years & my stocker is pre-computer. That said, I'm not familiar with this software. I don't know if it disregards O2 input in open loop but beside's the 14.35 AFR in both graph's the "O2 FBK" is 0 as well. I don't know how cold PA is right now but to get the coolant to 80, that 02 should read something. What I really don't like is the MAP is reading almost atmospheric @ 1200. 7.5ms pulse width is really fat for idle, it does go to 6ms, still fat, revved up but the MAP still looks low.. Vacuum line problem, dead MAP, ........ do you have spare parts that you can A.B.A. test with ? Can you also backprobe the 02 connector with a DVOM to get an actual reading from it ? Does this use the stock MAP sensor ?

[Ed Wright]

As Chad said, put an extension on the collectors for idle & part throttle. Unless you have had eight wide bands in the primary tubes to verify all eight cylinders are equal (they never are unless it has been put into sequential mode for cylinder-to-cylinder tuning) putting one upstream may or may not be accurate. Ten percent variation between cylinders is not unusual. At WOT, using one upstream, your indicated 13-1 a/f could be 12-1 or 14-1 on most other cylinders. EGT is not an accurate indicator either. Things other that air/fuel effect EGTs. Most agree that the average you see in the collector is best indicator if individual cylinder-to -cylinder tuning has not been done. Don't tie yourself into some magic number, find the air/fuel ratio makes your car run the best MPH numbers. Don't worry about what somebody else's car likes. Cars I have worked with like somewhere between 12.5-1 and 13.25-1 @ WOT. Mine likes about 14-1 idling & on the return road, with extensions on the headers, it's always in open loop.
Me tuning extensions are 3' long, with a 45 deg bend in the middle.
Your results might vary. LOL

[Signman]

When my O2 sensor went bad it made the car run really rich, hey don't like to be knocked around.
Try a new sensor along with the other good advise above.

[Bobby Fazio]

But wouldn't "open loop" behave as though there is no o2 sensor connected? It all comes down to MAP sensor and Intake Temperatures, correct? Is there anyone I could possibly send the DFI box to for checking? I feel there might be something internal going on.

[Ed Wright]

Open loop ignores the O2 sensors. Used only for a tuning reference when logging runs.

[buzzinhalfdozen]

Ok, Bobby how bout this. Where is your MAP located..in the ECU or out, in either case why don't you try this. Disconnect the vacuum hose from the engine that hooks to your MAP sensor install a hand operated vacuum pump and pull a vacuum on sensor to around 40ish PKA see how your Pulse width responds, it should go down. Looks like the MAP is very high in the idle shot you posted, other than that and the fact your P.W. looks extremely high the rest looks normal to me. Another check is to use your vacuum pump and pull a vacuum...read the gage (on the pump) and see if it is close to what your ECU is reading. this should tell you if the MAP is skewed or not. Please try this if you can and let us know the results. Not knowing your set up (engine size, injectors cam, ect.) I'm merely guessing but I'd expect to see maybe 2.9-3.? M.S. of pulse width at idle. Again good luck. Joe, Bobby I also noticed you have nearly 2 volts difference in batt. voltage. Though I don't believe that is causing the issue you have you need to be aware that voltage has a direct effect on the injector "on time" just something to think about. On another note does your ECU have any type of "blending function" to blend between the TPS and the MAP sensor to correct for poor MAP signal @ idle?

[buzzinhalfdozen]

Bobby, if you can please try the test I described using a hand held vacuum pump as I'm quite certain the MAP input you're seeing at idle is the cause of your rich fuel mixture. Please try and see if the gage and your MAP reading on the laptop agree while applying vacuum to it...you can do that with the engine off. If they are off by a wide margin then there you go, if not then please post up the results of bringing the MAP to around 40ish with the engine running and see if your pulse width number decreases. Joe

[Alex Denysenko]

Originally Posted by Bobby Fazio

But wouldn't "open loop" behave as though there is no o2 sensor connected? It all comes down to MAP sensor and Intake Temperatures, correct? Is there anyone I could possibly send the DFI box to for checking? I feel there might be something internal going on.

Bobby e-mail pics of your DFI plugs to Tony and me so we can see if it matches up to ours
our DFI's are much older but if the harness plugs match up we should be able to test it for you on our cars. if all is well the readings should be the sameon our laptop

[Ed Wright]

86 KPA is way wrong.