Hello all. I'm a fairly new owner hoping for any insight.

My car (details below) seems to be in limp mode and I'm having issues diagnosing. I can accelerate through the rev range and boosts to nearly full boost (8-9psi, full ~10) as long as I'm under ~50% throttle, anything more, the injectors are cut off and I can't get on the throttle until I come off and get back on under ~50%

I've tried putting the car into diagnosis mode to no avail. I'm not getting any CEL light under normal circumstances, much less the codes. ie. without TEN and ground shorted, I'm not getting a CEL with the ignition in the ON position. Bulb itself, as wells the cluster, is confirmed to work if powered manually, took the cluster apart to confirm this before I realised... Also, I can get the CEL to come on and stay on if I ground TEN and FEN (found this out while attempting to read any codes with a multimeter/LED)
- Grounding TEN, no CEL
- Ground TEN and FEN, CEL constant (6v via multimeter).
- Tried connecting LED from FEN to Ground to see if the codes will display like in RoW vehicles that don't have CEL, LED does not flash but CEL comes on (this is how I found out the CEL comes on when shorting FEN/Ground)
- Have tried variations using both grounds in the diagnostics box

Other things.
- TPS via PFC seems to be in the proper range for VTA1 and VTA2
- replaced plugs very recently
- reset ECU, still in limp mode.

93 LHD
Street Ported Single Turbo, GT35R (rebuilt by RP within the last 1000 miles though 6+years ago)
PFC
Greddy Profec Type S boost controller (although neither low or high settings led are on and I don't recall if one was when the car was running fine)
mileage: 75k-80k (TMU due to cluster replacement)

I'd really rather avoid just throwing money at it blindly and hoping something will stick but that would also be my back up plan if I have to. Any help/insight would be greatly appreciated

 

There is no CEL.

You need to test codes at the diagnostic terminal using an LED light.

Opps, that works with the stock ECU. And on RHD. Sorry I did not read your post correctly.

I thought "Limp" mode typically refers to RHD cars.

If you have PFC, does not it have its own diagsnostic readouts?


You need one of these and a short jumper cable. Hook then up right and count away.

 

I've tried using a LED (and a multimeter as alternative) but have not been successful unfortunately.

As far as the PFC, I'm not sure? I have checked the sensor/sw check and nothin is highlighted (signifying malfunction). The overheat exhaust light is not lit up with the ignition on.

 

Open up the ecu and see if it is corroded inside. Mind not to bend pins.

 

my cars does this sometimes I figured out that disconnecting negative terminal and putting on the positive side for around 30 seconds then hooking it back up, will fix this .. works for me

 

There is a group that provides (sells?) a diagnostic program for the PFC. You can hook up to a laptop and it will analyze your set-up and may even reset your set-up to run best. I think it is a subcription service.

I think the group is called: FCTweak on facebook.

https://www.facebook.com/FCTweak/
My friend has used it and is very pleased.

 

I'll go have a look when I get a chance.

Can you elaborate? Do you mean you disconnect both cables and put the negative cable on the positive terminal? Or do you only disconnect the negative cable and put it on the positive terminal with the positive cable still attached? Seems like the latter could be potential for damage.

Thanks, I'll check them out. I have a FC Datalogit in the box and may resort to installing and figuring out how to use

 

yea just disconnect negative side and hold it on the positive terminal for about 30 seconds