Fuel Pump / Relay Problems

[ST 2 SHO]

94 SHO MTX is the car type and year.
No Fuel At Fuel Rail / Fuel Pump Doesn't Turn On
NEW TEST INFO HAS BEEN ADDED TO THIS TREAD !
OK I'll just start by telling you that I used the forum searches to find a lot of info on testing the relays and the IRCM BUT !!! even with this info from tread to tread there is a lot of things I didn't understand or were not gone over as far as testing and trouble shotting.

So I need some help testing and trouble shotting this problem. This is what I know so far

1) 4.5 volts at the fuel pump plug ( plug that connects to the tank )
2) 3 ohms across leads on the tank to the fuel pump
Notes : when power is put on the tank leads pump does run and gives fuel to the fuel rail. ( this test was done by running jumper wires from the BAT + and - to the tank pins of the fuel pump )
3) 8.23 volts at the hot side on sender plug ( plug that connects to the tank )
4) I think the ohms across leads on tank was 18 or something to the sender

5) IRCM/CCRM does click upon turning the key ( Yes pin 12 does have 12.7 volts on the IRCM )
6) I have 12.8 volts at the EEC test location
7) Jumping pin 5 to the fuel pump lead does not turn on the pump ( EEC test location )but does click the IRCM
8) all the fuses are good both locations ... Under dash and under the hood behind the strut drives side ( yes even the micro 10 amp fuses )
9) Ground testing from the hot side of the bat. to all ground locations that I see, I have 12.8 volts...to 12.6 volts
a) next to the bat.
b) next to the EEC test location
c) drivers side ground at the strut mount
d) Fuse box under hood drivers side fire wall
10) The switch on the left side of truck has been by-passed ( dunno when ) I have 12 volts when grounded to the body at this location.



THESE ARE THE THINGS I DON'T UNDERSTAND... AND NEED EXPLANATIONS ON..

10) Fusible link..????.. The only tread I found here on this was pointing me to the Starter .. I only see solid wires at this location. BUT I don't know what I'm looking for.
11 ) DIS Ground...... this bolts to the intake..... There are treads here pointing to this unit causing problems with the fuel pump as well ( not sure why )
12) Crank Angle Position Sensor and Cam Angle Position Sensor Do they or do they not have anything to do with the fuel pump relay ( CCRM ) I did read a tread that said if these were bad the fuel pump will not work. Is this true???????
13) Is there another relay that I need to look for other then the CCRM that controls the fuel pump ???
14)Is the IRCM and CCRM the same thing ???? are these just terms for the same control unit ???
15) LFP unit ??? what is this ???. There are treads pointing to this unit as well

I know very little about this so keep that in mind as you explain your thoughts on this problem ( KISS = Keep It Simple Stupid) thats what I say when I don't get it.....KISS LOL
thanks for any and all help
Avery

 

[ST 2 SHO]

bump for help

 

[Pro*banshee]

Uh... What's the problem?

I re-read it a couple of times and you named all of the symptoms and took measurements but I'm not sure what the actual problem is?

Is the fuel pump not coming on regularly? ...at all?
Is the car stalling out under load?

 

[ST 2 SHO]

Fuel Pump Doesn't Run ... At first thought I was thinking the pump was bad. But after testing it does work

 

[Phoenix]

Common issues with the fuel pump is faulty CCRM (also named IRCM) , or faulty fuel pump. the CCRM is a 20-40$ item just swap with a good one.

Of course I'm assuming all fuses are good.

#11 = It will cause a no spark , not fuel related.
#12 = It will cause a no spark , not fuel related.
#13 = no

 

[ST 2 SHO]

I thought the CCRM / IRCM was working if Pin 12 and 5 had around 12 volts...
Theres a lot of info in my first post. I really did try to post all that I could about the car and how I did it. So people could tell me if my test was done wrong or I missed testing something.

 

[Phoenix]

I thought the CCRM / IRCM was working if Pin 12 and 5 had around 12 volts...
Theres a lot of info in my first post. I really did try to post all that I could about the car and how I did it. So people could tell me if my test was done wrong or I missed testing something.

To tell the truth , on my part I dont even waste time on testing , Theres many 12V inlets in there - which makes the tested complicated. If this can help : http://www.quebecspeed.com/pics/SHOCCRM.pdf

If you have acess to rotunda tools , theres a kit that tests just that , like a CCRM tester to check all the circuits of the CCRM

 

[Pro*banshee]

You can always just direct wire your fuel pump to a relay that clicks on with the accessory line

 

[ST 2 SHO]

Pro*banshee You can always just direct wire your fuel pump to a relay that clicks on with the accessory line

Didn't really want to do that. I was hoping to fix the problem the right. ( wired as a stock set up ) Changing things just makes finding other problems down the road even harder to find.

Were connecting a another IRCM today to see what happens. If this doesn't work I'll be at a dead end on what to do.

Good new is with the car being up on the lift for almost week I've had time to work on other things that needed some TLC.

Pointers are still welcome , I'll keep ya posted if the IRCM / CCRM does the trick or not
Avery

 

[Marccus]

I had the many of the same fuel pump problems and symptoms you describe and I traced it to the small wire coming off the positive battery cable or the positive battery post. When I played with the wire and moved it around the pump worked some times and other times it didn't. The problem was in the wiring from this wire to the relay module.

The fusible link had broken. I soldered in a new fusible link and everything was fine after that.

But, as someone had suggested, it probably would have been easier and better to install an inline fuse. Check the rating of the fusible link from the wiring diagrams. You can buy fusible links of various ratings from Pep Boys, etc., or go the inline fuse route.

Also check the male and female connectors for this line and also check the inertia switch in the trunk and make sure it is not defective and is reset correctly; or just get rid of it, as I finally did, since it kept cutting fuel flow when my "braking" would set it off.

Good luck.

 

[SHOZ123]

Did you short the fuel pump test pin to ground at the DATA link connector with the key in run? This should turn on the fuel pump relay and prove out the wiring to the CCRM.

 

[ST 2 SHO]

Thanks everyone for all the tips
The IRCM was bad..... I just wish I had a better understanding of why my test of the unit didn't work out. I would still like to know the proper testing of this unit.

But it is fixed now.... but knowing more about what I did wrong in testing the IRCM is aways better.
Thanks again guys
Avery