I have a 96 talon with a HRC stage 2 kit, sfmu with dark spring and largest disk, running 95psi fp at 7psi boost with stock injectors. My car is still running lean on top end above 4k rpm. I used a scan tool and noticed that my MAP voltage did not get above 3.89. I thought that this might be do to the hrc voltage clamp, so I removed it to see if I would hit fuel cut off going into boost, but it did not change anything. I then replaced the MAP sensor because I thought it might be bad, and installed a homemade voltage clamp (the one with 2 diodes and a pot.), but again, nothing changed. The MAP sensor is getting its full 5 volts and the output signal changes, but will not go higher than 3.89. Sometimes the car feels like it hits fuel cut at random times just driving normally. I can reset the ECU and it clears up but will happen again at random. I have also replace the coolant temp sensor and both o2 sensors. Thanks for any help.

Always console a girlfriend in the death of a cat. Even if secretly you are the one who set it on fire and threw it into the ceiling fan.

That's a weird one.

What's the map output with the car ON, but not running? How about that same situation, with no fuel cut defencer of any kind?

______________________________
If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.

'95 Eclipse TurboGS (garage deco)
'95 TSi AWD (restoring a survivor)
'97 Talon ESi-T (poor impulse control)
'99 Eclipse RS-T (daily beater)
'13 Evo X (mostly stock)
'17 Sienna (Middle Aged Dad Mobile)



Factory Service Manuals: http://nawdu.de/files/

me and pyschdragon(casey) have been trying to diagnose the samething on his car, his is doing the very same thing. i'm starting to think one of his sensors has gone nuts and the ecu is cutting spark above 4k. He noticed on datalogs his o2 voltage gets to 1V right before the cut, you having the same issue? Have you tried swapping out your ecu w/ another 2gnt and seeing maybe if the thing has just fried itself. I don't know what sensor would do this at 4K but his is doing the same thing.

400whp or bust.

back in the day when my HRC FCD went bad, it was clamping my MAP volts too low, causing a lean condition, no matter what my fuel pressure was..At the time, i said screw it, and took it off completly..I NEVER hit fuel cut, until around 4000+ rpm...under that, it ran great..over that, motor bucked like all hell..As Dino said, measure your map voltage with the key on, motor not running, and you should get 4.5 volts, +/- .1 volt. If its any different, then the Map is bad. Also, double check your wiring harnesses..If its still on the motor, that damn EGR tube likes to melt wiring harnesses..could be causing a short in your map wiring possibly? Just throwing out some ideas..

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

I get fuel cut ~4.65vdc.

So after you reset the ecu it will work right for a while? Then eventually drop again? That is weird. Like Matt said try swaping an ecu.

____________________________________________________
four nails four corners four riders and four horses

Fuel cut or serious issues after 4000 RPM's usually means the ECU is not receiving any type of MAP sensor input, or, it is receiving input and decides it's bunk. The cool part about a speed density system is that you don't NEED a MAP sensor for the car to work (i.e. you can get from A to B without one, because the ECU will fall back on a pre-determined fuel map based probably on every other important sensor but the MAP)

A few months ago I had a similar problem. Regardless of what kind of MAP sensor I used, if i had a Missing Link in there or not, if I had my voltage clamp in there or not, the voltage would get stuck around 1.6 volts after a minute of operation.

So how did I fix it? I checked the wiring. It was all screwed up. I went to the junkyard and found a Sebring with the same MAP sensor harness. I cut it about 1' long, and soldered it to the stock wiring on my car. All of my problems vanished, instantly.

2016 WRX STi Limited (current)
2001 A4 1.8tqms (donated)
1991 GVR4 #1933 (sold)
old.dsmregistry.com/detail.php?carid=218 (dismantled)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Megasquirt powered 420A
Custom turbo system

http://www.ms-custom.com