DriftDreamzSS

iTrader: (4)

I have a brand new gm map sensor from rx7store and the harness from banzai racing and it wont work. Both Rotary Power and Neptune Speed have tried and the car just dies, They both confirmed the correct input for the pfc. I tested continuity in the harness and its good. I noticed that the center wire on the sensor side becomes an outside wire on the connector to the stock harness, but when looking at banzais website their picture shows the same change in wire positions. Are these sensors known to go bad right out of the box?

Jason

iTrader: (5)

We have never had an issue with them right out of the box. What are you Power FC settings?

Jason

cewrx7r1

iTrader: (2)

Here are some scale/offsets used for the old beige box FD3S DL.

Un calibrated GM 3 bar setting by different people
41800 offset 0 tworx7
43500 offset 320 ccarlisi
43860 offset 0 lups
44000 offset 357 pluto

The DL UNIVERSAL "black box" version shows PIM Scale differently than the FD3S "beige box" version.
FD3S value divided by 6.66 equals the UNIVERSAL version.

DriftDreamzSS

iTrader: (4)

it was 41800 offset 0

DriftDreamzSS

iTrader: (4)

It would idle but die immediately when you blip the throttle. It runs perfect on stock map sensor and pulls 14in of vacuum at idle so I dont think there are any leaks.

cewrx7r1

iTrader: (2)

Since the stock and this map sensor were not calibrated to run true/correctly with the PFC, changing from one to another can cause the PFC to run in different cells thus hosing your previous good tune.

It is almost a requirement to retune all after such a change.

Easy test: look at which cells it idles in with the original and new map sensors.

DriftDreamzSS

iTrader: (4)

The car was never tuned with the 3-bar because it wouldnt work. It was installed and then removed when it failed to work on 2 separate occasions by professional shops. All tuning has been done on the stock sensor.

arghx

iTrader: (3)

I don't know what shop you took it to, and I don't know what their diagnostic procedure was. Maybe it didn't work immediately so they just assumed bad sensor when it is a tuning problem all along. Here's some troubleshooting of your own that you can try if you have a datalogit. When I first started my car with a GM 3 bar (also did a full fuel system at the same time) the car wouldn't idle or run right. AFR's turned out to be too lean. I had to do a bunch of datalogging to figure out which cells to modify.

If you don't have a known good GM sensor I would do a back-to-back test/datalog between the two MAP sensors. So on the working stock MAP sensor, start the car, let idle, rev it up to a certain RPM for a certain time period. Datalog your AFR's (get that wideband hooked in there). Also datalog your PIM. Recreate the same test pattern (as best you can) on the GM sensor.



That's a screenshot of me working on my idle tuning (yeah I know it's not perfect). Get your FC-chart open. I find 4 separate graphs with separate scales to be easier to read. Then you get your INJ or basemap open in another window on top and it will trace through whichever cells you are going through as you move the tracer line across the map (I don't like using map watch for this type of tuning, personal preference). You just have to play with those cells. As you can see in the pic, I like to have rpm, wideband, PIM, and TPS voltage for figuring out this type of problem. So you can see if, say, TPS voltage goes up and AFR's get leaner for example. Or replace one of those graphs with a water temp graph and see what's happening as the car warms up.

In my case, I figured out that as RPM's got under about 1000 the map was just too lean (I did not start from the Apex'i basemap in my case), and thus basemap/INJ map changes were necessary. In other situations I noticed tip-in problems and I used a similar chart setup to determine that there were lean cells in my basemap.

In your situation check for a big difference in PIM and a big difference in AFR's (and the cells the car is running in) between the two MAP sensors. If the GM sensor doesn't seem to be changing PIM based on throttle position, load, etc, then there's a decent chance it's bad or needs a different calibration.

cewrx7r1

iTrader: (2)

^ We would assume that these PROFESSIONAL shops would do the obvious and check AFRs and if the load point cells drasticaly changed.

DriftDreamzSS

iTrader: (4)

Sorry guys, I don have a DL, a friend is going to test the pim for me, couldnt re-create the afr testing on the 3bar because the car just dies as soon as you touch the throttle. Thanks for the info, hopefully ill have a better idea whats up after the sensor gets tested.

arghx

iTrader: (3)

^^ dude I don't trust much of anyone anymore, at least local tuners... I was just recently giving tuning advice to the biggest local tuner shop in my city, the capital of NC. they have an FD there that they are building with a GT35R and PFC and they don't even have a datalogit. Another local rotary shop in NC 'tuned' my friend's FD a couple years ago and it ran like complete crap--WOT AFR's were ok but driving around town it would cut off and hesitate... since I have recently gotten into PFC tuning I pretty much followed a lot of your recommendations in your tuning notes and got his injectors set up properly, accel enrichment, and cruising basemap--really basic stuff that this "professional" shop didn't do. And obviously I'm hardly an expert or a professional at all.

I'm not saying that these two shops don't know what they're doing... but wasn't it Ronald Reagan who said "Trust, but verify" ? I mean the process of checking AFR's and going through multiple datalogs could potentially take a few hours to figure out, hours that they would most likely not be fully compensated for. So there isn't necessarily an incentive for them to spend 3 hours diagnosing this when they could only charge 1 hour of diagnosis without pissing off the customer.

I guess his only option is to swap in a known good sensor then and see what happens.