Fuel pump issues

[Ryan]

OK. where to begin???

I took my car to a local mechanic to have a safety inspection done so i could get it legal here. When i got to the mechanics lot and turned the car off it never started again. It was running a little hesitant on the way up there. So after paying him and a tow truck a lot of money to look at it and move it back to my house the mechanic tells me that the fuel pump and ccrm is bad. I replaced both at a hefty cost. Even got a new ccrm. Still the car does not start.

When the key is turned on b4 start the fuel pump does not engage. If a hot wire is run to the #5 wire on the ccrm the fuel pump runs. What should I be looking at now as the source of why my fuel pump wont run when key hits on position?
I checked all fueses in the fuse box in the car and under the hood. None are blown.

I am really clueless as to where to begin looking now. Any help would be GREAT! This car has about 2 weeks before it goes to get crushed if I can not figure this out.

Thanks everyone!

95 SHO 3.2L ATX

 

[hawkeye18]

Knowing what year and transmission your SHO has would help quite a bit. Offhand, since wire #5 is power to fuel pump in J, D, and M code CCRMs, if the fuel pump ran with 12v applied to it, that rules out the fuel pump and the emergency cutoff switch. That leaves the CCRM (again), the ignition switch, or the wiring between the ignition switch and the CCRM.

With the key to ON, check for +12V at the wires indicated by the charts here: http://www.shoforum.com/showthread.php?t=75065. Look for the big letter on the CCRM itself to figure out which chart you need to look at. It'll say either J, D, or M. Looks like it's wire 12 (yellow) for all three.

Once you let us know what code CCRM you have (and year/trans of your SHO), we can help you out more. This should be a fairly simple problem to fix.

 

[Ryan]

Knowing what year and transmission your SHO has would help quite a bit. Offhand, since wire #5 is power to fuel pump in J, D, and M code CCRMs, if the fuel pump ran with 12v applied to it, that rules out the fuel pump and the emergency cutoff switch. That leaves the CCRM (again), the ignition switch, or the wiring between the ignition switch and the CCRM.

With the key to ON, check for +12V at the wires indicated by the charts here: http://www.shoforum.com/showthread.php?t=75065. Look for the big letter on the CCRM itself to figure out which chart you need to look at. It'll say either J, D, or M. Looks like it's wire 12 (yellow) for all three.

Once you let us know what code CCRM you have (and year/trans of your SHO), we can help you out more. This should be a fairly simple problem to fix.

It is a J model ccrm bought brand new never used. The car is a 95 SHO 3.2L ATX. I realized I forgot that in the original post.

 

[ViPER1313]

Most likely the problem is the small ground wire coming off of the battery - terminal became disconnected or corroded at the battery or small black connector on the end of it, or the fusable link that runs between the battery + and the CCRM is blown and no power is reaching the CCRM. I forget where this fusable link is located in the engine bay, maybe someone else here can chime in (it's separate of the fuse box) Also check again to make sure the ACC FEED fuse is good in the underhood fuse box./

 

[Ryan]

Most likely the problem is the small ground wire coming off of the battery - terminal became disconnected or corroded at the battery or small black connector on the end of it, or the fusable link that runs between the battery + and the CCRM is blown and no power is reaching the CCRM. I forget where this fusable link is located in the engine bay, maybe someone else here can chime in (it's separate of the fuse box) Also check again to make sure the ACC FEED fuse is good in the underhood fuse box./

All fuses are good to go. I have pulled them all. The ground off the battery also looks to be very well connected and intact with no corrosion. I was thinking about fusible links being the problem, but I have no idea where to begin looking for them.

 

[ViPER1313]

This is just from what I found searching around.... Check for the fusable link near where the smaller + wire coming off of the battery goes into the wiring harness.

 

[hawkeye18]

Start checking for +12v at all the places indicated here. If you're missing it somewhere with the key to RUN, there's your problem. If you're not getting it at the fuse, then a fusible link melted on you.

 

[ViPER1313]

CCRM Fuel Pump Control

Pin 15 is ground.
All versions provide output on Pin 5.

Types D and J:
(93-95 ATX, 94-95 MTX) CCRM has a single FP RELAY. B+ power is supplied to the common terminal via pin 12. The FP RELAY is energized by the PCM (or grounding the FP TEST pin on the DLC) by grounding pin 18.

So check to make sure you are getting 12v positive on pin 12, that pin 15 is always grounded, and that when you turn the key to on pin 18 is grounded (at least momentarily when the car tries to prime itself) as well.

 

[Ryan]

Ok. so how do I test for 12V and grounds? This will be my first attempt at an electrical problem on a vehicle. What tools will I need? I am sure I will have to go buy some. Could it be the PCM that went out? another guy is trying to sell me this idea so il buy more parts. When I get home again I will check out some more things and get back with you all. Thanks for all the help!:thankyou:

 

[jonheese]

"The wire looks good" means nothing. A volt/ohm meter will tell the tale.

 

[ViPER1313]

You need to buy an electronic multimeter - they are under $7 on Amazon and under $20 at Walmart / RadioShack. To check grounds you measure resistance between the ground wire and the vehicle chassis (0 ohms / very low resistance means that the wire is grounded properly), and to test voltage you set the multimeter to DCV (reads DC voltage) and put one lead to the wire in question, the other to a vehicle ground.

 

[Ryan]

Awesome. Ill go out and buy one today. I think harbor freight has them real cheap. When I get back down to my house Friday I will get to poking around and see if I can determine anything. I will update this with anymore info at that time. You guys are a great resource. Thanks.

 

[hawkeye18]

FYI: A multimeter is one of those tools that once you learn how to use, you will use all the time. Their uses in troubleshooting and safety (is this house circuit really off?) are incalculable. While a $20 multimeter will probably work just fine, you may want to invest a little more in a quality multimeter with a few more functions (auto-ranging is a good one to have). I have an Innova 3320, available at Sears (and wal-mart sometimes). It costs $30, and IMHO is a great compromise between being cheap and being useful. Comes with a battery tester for small batteries (AA, 9v, etc.) which actually works really well, and is auto-ranging, and has a large display. I've had mine for two years now and I love it. Even comes with a little elastic-ey thingy on the back for strapping it around your wrist as you make measurements.

http://www.walmart.com/ip/Equus-332...0000003142050&ci_src=14110944&ci_sku=14644666

 

[Ryan]

http://www.harborfreight.com/ac-dc-digital-multimeter-37772.html

This is the one I was looking at. I am not sure what auto ranging is?

The one you linked to is rather nice as well and is cheaper than the one I was looking at.

 

[jonheese]

I am not sure what auto ranging is?

Compare the picture of the Harbor Freight meter and the Walmart meter. See all those little choices under Volts on the HF one, and notice how there is just "ACV" and "DC10A" on the Walmart one? That's auto-ranging. It means that it will automatically adjust the voltage range being displayed on the screen based on what it finds.

Example: Say you want to measure some voltage, but you don't know whether it's going to be around 0.01V or 1,000V (extreme example, I know). With the cheaper meter that doesn't auto-range, you have to start at the higher end, 1000V, test the leads, and move down until you see a measurable voltage. With the auto-ranging model, you just put it on "Volts" and it does the scaling/ranging operation itself. Very convenient.

 

[Ryan]

Ok. I kinda thought that was what it was, but always good to know for sure. So, is the auto ranging the thing to have? It seems like a lot of the meters I looked at don't seem to have auto-ranging?

Oh, another good question???
How do you test the wires running into the ccrm with out damaging them? How do you test them while connected to the module? do you poke holes in the wires with the probes on the multi meter to test them?

 

[hawkeye18]

Well, to test input power, you can simply disconnect the connector from the CCRM and probe that wire (red to the wire, black to ground [any piece of bare metal, the lifting eye works well - negative battery post is best]) to see if there is 12v coming into it. With the key in RUN, I would check for 12v at wires 8, 12, and 13.

Checking output voltages is a little harder. The easiest way, if not the least destructive way, is to back-probe the wire; you take a paper clip, unfurl it, and stick it in between the wire and the connector on the back side. Here, here's a picture:

Of course, it'll be different with the huge honkin' CCRM connector, but you get the idea. Once you get the paper clip wedged far enough in there (your multimeter leads are gonna be way too fat), you can then simply touch the probe to the paper clip and measure as normal.

And yes, auto-ranging is a huge time-saver. Obviously, when working on a car, most voltages are going to be either 5 or 12 volts, so the 20VDC range will work fine, but it is a lot easier to just let the multimeter deal with it. And it's a lot less confusing. You get one selection for volts DC, and one for volts AC. Well, and a few more for current, but don't worry about those for now.

Oh, and make sure to note the setting with a little speaker-looking icon on it. It's the continuity checker setting, and when on it, if you touch the tips together, you'll note it makes a continuous beeeeeeeeeeeep. This means that any time the multimeter detects continuity, it'll beep. This means that you can check to make sure wire runs aren't broken, etc. without even having to look at the meter. Very handy.

If you get the Innova 3320, and I recommend you do, definitely read the manual. It is a good primer on how to use a multimeter, and they are very useful devices. It's one of those tools everybody needs to have, IMHO.

 

[Ryan]

Back probe= Great Idea!

Thanks for that one really. I believe that I will take your advice on that tester. I will have to run around and see if I can find one.

 

[hawkeye18]

I can guarantee you Sears will have the 3320. Wal-Mart may have it.

 

[Ryan]

Success!

I finally bought the meter and made it home to do some checking. I checked all 12V spots on the diagram. I got to #13 wire and found the problem.
I unbolted the harness from the ccrm and found that the #13 and #14 wires had been pushed back inside the wire harness and were no longer making contact to the ccrm. Pulled both of them back out and bolted the harness back on the ccrm. Turned the key to success! :woo-hoo::woo-hoo::woo-hoo::woo-hoo::woo-hoo::woo-hoo::woo-hoo::woo-hoo::woo-hoo:

Thank you all so very much for your help with this issue! Now on to more issues in other threads.