Pump Voltage Reads 9.3V with ignition on the "ON" position.

Breakdown: Using mmcd. The voltage on the pump (4th tab) reads 9.3V with ignition on the "ON" position.
Any ideas? Would someone please check and see if theirs reads the same.

The problem im having is this. The car is hard to start. You can smell alot of fuel being pumped. I believe that the engine is being flooded.

as my previous thread states:

UPDATE: 9-23-09

Found out the compression was horrible...about 70-80 per cylinder.
Replaced the rings and timed the motor -Dead on. Compression is right on.

Car still will not start right off! /ubbthreads/images/graemlins/banghead.gif

Connected my palm up, using mmcd, checked for anything abnormal, get to the 4th tab... (PUMP) the voltage with key on the ON position reads is at 9.3V

Reconnected the palm up to my GST, get to the 4th tab... (PUMP) and the voltage with key on the ON position reads 0.3V

/ubbthreads/images/graemlins/bawling.gif

 

[jepherz]

The pump should only be getting voltage in the "start" position and while cranking (CAS getting signal).

 

Quoting jepherz:
The pump should only be getting voltage in the "start" position and while cranking (CAS getting signal).



I might have confused you, the key is on the start position and i also get the same reading while cranking.

Pulled the MPI Relay, as per manual, i energized it. via pin 8 and pin 10.
Checked the voltage on 4 and i get 9.3V...the same as what the mmcd says. i reconnect it to the harness.

I pull c-10 and check pin 107, i get nothing. however, i check pin 106 and i get the 9.3V.

Swapped out fuel pumps, no change. Swapped out MPI Relays, no change.

I should get back my GVR ECU back today. I have been using a 92 GSX ECU.

 

I am not aware of any usable "FUEL" item that can be logged by MMcD. Are you sure that you aren't just chasing a non-issue here? What version of MMcD?

 

Quoting Keydiver:
I am not aware of any usable "FUEL" item that can be logged by MMcD. Are you sure that you aren't just chasing a non-issue here? What version of MMcD?



Jeff,
I wish it was a non-issue. Using the latest version of MMcD...ill recheck and verify.
If you go to the number 4 at the upper right. 1 2 3 4 H

You will see PUMP (sorry, that i labeled it FUEL)

It is constantly stuck at 9.3 ...which leaves me to believe that its pushing so much fuel out that its flooding the engine making it hard to start.

 

[Hertz]

The amount of fuel, properly regulated, from the pump shouldn't matter unless it is too low. The injectors control the amount of fuel going into the cylinders.

Are you sure you have spark?

Did you put the CAS on 180 deg out of phase?

 

Quoting Hertz:
The amount of fuel, properly regulated, from the pump shouldn't matter unless it is too low. The injectors control the amount of fuel going into the cylinders.

Are you sure you have spark?

Did you put the CAS on 180 deg out of phase?



Spark - I sure do, i replaced the plugs, wires. Checked the PTU and coilpack. I indeed have spark.
The CAS -its possible, however i have flipped it around and the position its in is the only way i can remotely get it started.

 

As I said, I am not aware of any item that can be logged by the ECU that would tell you what the fuelpump is doing. There is a feedback pin from the fuelpump to the ECU, pin #13, but I *think* it is a strictly ON/OFF thing that will throw a CEL if there isn't any voltage. The signal is just connected to the base of a transistor, if I recall, but I am not aware of any possibility of logging that voltage.
The thing you have to be cautious about with MMcD is that many features on some versions were developed BY 3000GT/Stealth guys FOR 3000GT/Stealth guys, so they are either wrong or meaningless on our cars,

 

Quoting Keydiver:

As I said, I am not aware of any item that can be logged by the ECU that would tell you what the fuelpump is doing. There is a feedback pin from the fuelpump to the ECU, pin #13, but I *think* it is a strictly ON/OFF thing that will throw a CEL if there isn't any voltage. The signal is just connected to the base of a transistor, if I recall, but I am not aware of any possibility of logging that voltage.
The thing you have to be cautious about with MMcD is that many features on some versions were developed BY 3000GT/Stealth guys FOR 3000GT/Stealth guys, so they are either wrong or meaningless on our cars.



Jeff,
Ok, i didnt mean to sound argumentive! The car isnt throwing a CEL. This is what is causing me to /ubbthreads/images/graemlins/banghead.gif
Im running out of ideas.

I really appreciate your help!

 

[cspetros]

You're probably using V. 1.8 of MMCd (the best imho), which has a "Fuel" item for logging. As keydiver said, it's meaningless on our cars. Disregard it /ubbthreads/images/graemlins/smile.gif.

 

[stevep]

There are many items in the 1.8g version of MMCd that were added to support special hardware that was going to be sold by the author. That includes MAP, WBO2, OILP, OILT, Fuel, PLEN, VSPD, and PUMP.

So what your looking at happens be be what ever value is at location 00E1 or 00E7 converted to look like a voltage depending on which item (PUMP or FUEL) your looking at. It isn't however anything really useful.

 

[Hertz]

Do you have a rewired fuel pump? Is it a Wally 255 or something big like that? I wonder if you're just overrunning the stock fuel pressure regulator.

Is it always rough/too rich starting, or is it only on warm starts?

 

Quoting Hertz:
Do you have a rewired fuel pump? Is it a Wally 255 or something big like that? I wonder if you're just overrunning the stock fuel pressure regulator.
Is it always rough/too rich starting, or is it only on warm starts?



Hertz,

The fuel pumps wires are stock. No rewire has been done.
The fuel pump is also stock. Im wondering the same as far as the FPR, you can smell it dumping alot of fuel while its cranking. Once the car is running, u can still smell it.

After all the help that everyone has given me, It does make sense that it has to be something mechanical/not connected to a sensor.
I was starting to think it was the FPR..but dont have another one to test with.

May have to buy new...

Thanks again guys.

 

[Hertz]

I did have one go bad on me, which I replaced with an adjustable. When I pulled the vac reference line, it was weeping fuel.

 

[thecman02]

If you can smell fuel... it must be leaking somewhere in the pressurized system.

 

[gvr4ever]

Quoting Hertz:
The amount of fuel, properly regulated, from the pump shouldn't matter unless it is too low. The injectors control the amount of fuel going into the cylinders.

Are you sure you have spark?

Did you put the CAS on 180 deg out of phase?



That's what I was thinking. As far as the injectors go anyway. Fuel pump only controls fuel going to the fuel rail. Injectors control how much fuel is going in to the cylinders. Also, FPR would control how much goes to the fuel rail, not the pump.

It is possible for fuel rail pressure to be too high for the injectors to compensate, but that would be a FPR problem, not a pump problem.

 

Quoting Hertz:
I did have one go bad on me, which I replaced with an adjustable. When I pulled the vac reference line, it was weeping fuel.



Quoting gvr4ever:
That's what I was thinking. As far as the injectors go anyway. Fuel pump only controls fuel going to the fuel rail. Injectors control how much fuel is going in to the cylinders. Also, FPR would control how much goes to the fuel rail, not the pump.

It is possible for fuel rail pressure to be too high for the injectors to compensate, but that would be a FPR problem, not a pump problem.



Well guys, i pulled the vacuum reference line (one thats connected to the intake Mani and FPR) and its dry as a bone. Even cranked it over a few times to see if it would let out some fuel. nope /ubbthreads/images/graemlins/frown.gif

I swapped out injectors as well, thinking that it could be the problem as well. It didnt change a thing. I have the GVR4 ECU back today and connected that as well. Nothing seems to be working.

Side note: I almost have to pump the gas pedal for a while to get it to start... wondering if there is something going on in the Throttle body... hmm

 

[Hertz]

I'm wondering, if you want to give this a try, report back if the starting symptoms are the same with the MAS plugged in, vs. unplugged.

 

Quoting Hertz:
I'm wondering, if you want to give this a try, report back if the starting symptoms are the same with the MAS plugged in, vs. unplugged.



No change Ryan. Also swapped in a new evo8 255hp. Swapped CAS (difference in NA and Turbo?)

 

[Hertz]

So if there is no change between plugged in and unplugged I would think that there is something wrong with your airflow sensor?