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Old 08-25-2008, 01:03 PM   #1
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Default Sanity check...why so lean

I recently installed a 99 engine into my 96 using the 96 electronics/FPR (CAS, tan top injectors). The car ran fine on the stock ECU after the swap but was quite lean up top which I thought was unusual (AEM WBO2). I drove it for a few hundred miles (avoiding WOT) while sorting out some EGR issues till I could get my emissions inspection sticker then installed a MSPNP9796.

The car starts/runs but is very lean (see attached datalogs)...the car can barely get out of its own way which I assume is the lean condition?

My MS setup is the stock 9697 map with my trigger angle set per instructions and adjusted to use my AEM WB02...other than that no settings have been changed except for disabling launch control (for some reason the MS thinks my clutch is in when it is not...pins 10-11 connected on middle connector).

Question 1: Does anyone see anything out of the normal that would warrant a different plan of attack than just cranking up the fuel?

Question 2: What sort of AFRs should I be shooting for with no load (in neutral)? I am assuming even in netrual they should not be lean like mine.

Question 3: The 96 engine has a vac solenoid that plugs between the vac source and the FPR. I did reinstall this with the FPR when moving it to the 99 engine. When is this supposed to actuate and can someone confirm I still need it? If it is not actuating as expected then my FPR is not getting the word to up the fuel pressure.


The smaller datalog is with the car on jack stands...thus all in neutral.

The larger datalog is a whirl around the block.

I did the TPS calibration towards the end of the larger datalog...forgot to do it initially <slaps self>

Fuel filter was changed when the engine was swapped.

Fuel pump is stock.

Fuel pressure is unknown.
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Old 08-25-2008, 03:13 PM   #2
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96 head flows like crap compared to the 99 head. the ecu is still tuned for a stock '96 motor and will run leaner, especially up top. Add more fuel, that's why you have a megasquirt.
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