GVR-4 Code 42 Fuel Pump Circuit Malfunction

[GsxEcutioner]

So my gvr4 352/1000 has been down for a couple months waiting on a new ecu, during that time, i bought dsmlink lite, and all that, yesterday I installed the ecu and lite. And I also rewired my fuel pump. Well I tried to start the car, it would start for two secs and die,I got the CEL Pump circuit malfunction, so I reconnected the fuel pump to be stock wiring again, and I still get this code. Did I burn the pump? Ive tried two different MPI's Thanks
-Shane

 

[steve]

A 42 fault code means that the ECU tried to turn the fuel pump on but it didn't see 12v on the largely undocumented fuel pump sense pin #13.

Since you have ECMLink now, go to the Misc tab and try turning on your fuel pump. I expect it won't and if it doesn't you either have a bad ECU still, the wire from the ECU pin 56 to the MPI relay is broken, or your MPI relay is bad.

If the pump turns on but you still get a 42 CEL then it's either a bad ECU or the wiring to ECU pin 13 is broken.

 

[GsxEcutioner]

A 42 fault code means that the ECU tried to turn the fuel pump on but it didn't see 12v on the largely undocumented fuel pump sense pin #13.

Since you have ECMLink now, go to the Misc tab and try turning on your fuel pump. I expect it won't and if it doesn't you either have a bad ECU still, the wire from the ECU pin 56 to the MPI relay is broken, or your MPI relay is bad.

If the pump turns on but you still get a 42 CEL then it's either a bad ECU or the wiring to ECU pin 13 is broken.

I activate the fuel pump by link, and the code pops up. I tried two different MPI's same result, the car turns on, revs high then loses all power. So I know the pump turns on and runs.

I read on Gvr4.org that the fuel pump circuit is right in the spot that the ecu caps leak at -__-.
I am going to run a constant 12v from the Fuse tray, Will this be ok?
-Shane

 

[steve]

No, hot wiring the fuel pump is a good way to burn to death and it's not clear that it's even the problem.

When you turn the pump on via link does the fuel pump stay running until you turn it off? I don't care at this point what the engine does.

 

[GsxEcutioner]

No, hot wiring the fuel pump is a good way to burn to death and it's not clear that it's even the problem.

When you turn the pump on via link does the fuel pump stay running until you turn it off? I don't care at this point what the engine does.

No it does not, if i activate the pump via link, it will toss the code and shut down.
I wired the MPI Relay pin to the Fuel pump Relay pin 13, and now the car runs fine 0_o.

I added a 12v source and now it works, so I guess pin 13 wasn't getting power off the ecu?
-Shane

 

[dsmmikej]

this code has haunting me for a while. I have the same problem except that my car stays running and doesnt die. My ecu has leaking caps which were covered with white silicone from the previous owner.

 

[steve]

No it does not, if i activate the pump via link, it will toss the code and shut down. I wired the MPI Relay pin to the Fuel pump Relay pin 13, and now the car runs fine 0_o.
I added a 12v source and now it works, so I guess pin 13 wasnt getting power off the ecu?

Pin 13 is used by the ECU to check if the fuel pump is getting power like it thinks it should be. The only place I found it documented as in the 90 manuals and the 1G DSM technical manual. It runs from the fuel pump output of the MPI relay (pin2) that goes to the fuel pump to the ECU. When the ECU turns on the fuel pump relay using pin 56 it watches pin 13 to see if it goes to 12v confirming that there is power to the pump.

Since you say that you "wired the MPI Relay pin to the Fuel pump Relay pin 13" and you say that you "added a 12v source and now it works" I can't really tell what you did or be sure that was bad but it sounds like you had a wiring problem in the car so that ECU pin 13 wasn't connected to pin 2 of the MPI relay electrically any more.

this code has haunting me for a while. I have the same problem except that my car stays running and doesnt die. My ecu has leaking caps which were covered with white silicone from the previous owner.

I doubt the PO put the RTV silicone on the ECU.

There is a company that's known for drowning the ECUs in RTV silicone after "repairing" them. The problem is that they don't actually clean all the electrolyte off the board so it continues to rot the ECU away until something important gets eaten away and the ECU dies.

To fix the ECU at that point you have to remove all the RTV, clean up the mess it made, the mess that should have been taken care of originally, before you can fix the problem.

 

[dsmmikej]

my ecu did turn out to be faulty, just to let you guys know what the problem was

 

[GsxEcutioner]

yea , same here.....