Fuel pump doesn't run/ can't get codes SOLVED!!!

[TimboSHO]

Ok, background on the car (90 3.2 MTX) is the engine apparently locked up on the PO. I got it, got the starter hooked back up, but the fuel pump doesn't prime. I try to jump the EEC harness to get codes and nothing happens. I can't find any decent diagnostics on fuel pumps not running. I have a wiring diagram showing me where the pink/black wire goes (power to fuel pump), but get no power even coming out of CCRM to fuel pump (pin 5). I can tap on the CCRM and the cooling fans run, so I replaced the one from my 89. Still no power to pin 5.

Are these 2 issues linked? I would like to solve this issue before I pull the motor (yes, it does appear to be locked up). Thanks!

 

[pjtoledo]

did you ohm out the fuel pump circuit? you should be able to read continuity from the Pink/black wire at pin 5 in the CCRM connector, thru the fuel cutoff relay, thru the fuel pump then on to ground. Somewhere between 8 and 12 ohms if I recall correctly.


Perry

 

[zblackbeast]

Sounds like a bad ccrm and or pcm.. also, check your wiring from the pcm to the ccrm.. ohm that out and see what you get.

If you jumper the connector correctly, and the fans don't even kick on, the ccrm isn't cycling so there is either a bad connection between the pcm and ccrm, or the ccrm or pcm is faulty.

 

[vortex2450]

Check all grounds, and then recheck! Also, have you taken the timing covers off yet?

-josh

 

[SeanMc]

That happened to me as well, and it was the CCRM.

 

[TimboSHO]

did you ohm out the fuel pump circuit? you should be able to read continuity from the Pink/black wire at pin 5 in the CCRM connector, thru the fuel cutoff relay, thru the fuel pump then on to ground. Somewhere between 8 and 12 ohms if I recall correctly.


Perry

I was thinking about this too, but if I have no power to that circuit to begin with, this may not get me anywhere. I have to go to work to get a longer test wire (and tools to pull the motor)....

Sounds like a bad ccrm and or pcm.. also, check your wiring from the pcm to the ccrm.. ohm that out and see what you get.

If you jumper the connector correctly, and the fans don't even kick on, the ccrm isn't cycling so there is either a bad connection between the pcm and ccrm, or the ccrm or pcm is faulty.

Which wire goes from PCM to CCRM? It has to be one of the Black/orange ones?

Check all grounds, and then recheck! Also, have you taken the timing covers off yet?

-josh

The top timing cover is already off and the belt is still on and nothing is jammed in there....

That happened to me as well, and it was the CCRM.

That's what I thought as well, but replacing with one off of my running 89 didn't help (both M codes).

 

[TimboSHO]

Sounds like a bad ccrm and or pcm.. also, check your wiring from the pcm to the ccrm.. ohm that out and see what you get.

If you jumper the connector correctly, and the fans don't even kick on, the ccrm isn't cycling so there is either a bad connection between the pcm and ccrm, or the ccrm or pcm is faulty.

Ok, I guess I missed that the PCM teed off of the same pink/black wire that runs to the back. I ohmed this from the PCM to CCRM and I have an open. So now I get to find a broken wire! Yay!

I also ohmed it from the CCRM to the fuel pump and I get less than an ohm, so that wiring is all good.

Thanks again guys!

 

[TimboSHO]

Update: found and repaired the circuit from PCM to CCRM. Now all circuits are good, but fuel pump still does not run. Unplugged PCM and ran power to pin 19 and fuel pump runs. Plug it back in, and no power coming from pin 19.

When I unplugged the PCM, the bolt that hold the connector down broke off inside the PCM (Someone got in on there VERY tight). Is this a ground, or just to hold the connector snug?

I tried the B9C1 out of my 89, the B9B1 out of the wagon, and a spare ATX computer (H3Z1? I can't remember as I put it back away); but none of these computers have power coming out of pin 19 when the key is on either. What tells pin 19 to supply power?

Thanks in advance!

 

[pjtoledo]

Update: found and repaired the circuit from PCM to CCRM. Now all circuits are good, but fuel pump still does not run. Unplugged PCM and ran power to pin 19 and fuel pump runs. Plug it back in, and no power coming from pin 19.

When I unplugged the PCM, the bolt that hold the connector down broke off inside the PCM (Someone got in on there VERY tight). Is this a ground, or just to hold the connector snug?

I tried the B9C1 out of my 89, the B9B1 out of the wagon, and a spare ATX computer (H3Z1? I can't remember as I put it back away); but none of these computers have power coming out of pin 19 when the key is on either. What tells pin 19 to supply power?Thanks in advance!

pin 19 on the computer does not supply power.


power comes out of CCRM pin 5, goes to splice S152, then splits and goes TO both the fuel pump and the computer on pin 19. 19 is FPM, fuel pump monitor circuit. if the computer doesn't see power going to the fuel pump it kills some of the engine functions.

power starts at key, key sends power to CCRM, relay on CCRM sends power to computer.

I once had my 92 die, it was the splice S142 yellow wire, that corroded and stopped power from reaching both the CCRM and the computer.



Perry

 

[rubydist]

the bolt "just" holds the connector in. I have opened the pcm and repaired the broken bolt / nutsert in the past, so that is a possible option.

the fuel pump will only run for a couple of seconds when the key is turned on - are you able to confirm no voltage exists during that time window?

if so, you should confirm that the key switch is good and actually telling the pcm to "turn on" when the key is turned.

 

[pjtoledo]

engine compartment fuse box, EEC relay, hot at all times feeds power to CCRM pin 8, and computer pin 1. thats the KA pwr,,keep alive power.

CCRM receives power in start or run on pin 13



from a 92 manual.



Perry

 

[TimboSHO]

pin 19 on the computer does not supply power.


power comes out of CCRM pin 5, goes to splice S152, then splits and goes TO both the fuel pump and the computer on pin 19. 19 is FPM, fuel pump monitor circuit. if the computer doesn't see power going to the fuel pump it kills some of the engine functions.

power starts at key, key sends power to CCRM, relay on CCRM sends power to computer.

I once had my 92 die, it was the splice S142 yellow wire, that corroded and stopped power from reaching both the CCRM and the computer.



Perry

I see, I kind of figured I was off on this. I'll do some more testing after church today!

the bolt "just" holds the connector in. I have opened the pcm and repaired the broken bolt / nutsert in the past, so that is a possible option.

the fuel pump will only run for a couple of seconds when the key is turned on - are you able to confirm no voltage exists during that time window?

if so, you should confirm that the key switch is good and actually telling the pcm to "turn on" when the key is turned.

Ok, good to know that the bolt just holds it in. Once I get my fuel problem solved, I'll be replacing that bolt as well.

I have no voltage during the couple of seconds after turning the key on.

engine compartment fuse box, EEC relay, hot at all times feeds power to CCRM pin 8, and computer pin 1. thats the KA pwr,,keep alive power.

CCRM receives power in start or run on pin 13



from a 92 manual.



Perry

Thanks Perry! I'm anxious to get all of this tested today!

 

[TimboSHO]

pin 19 on the computer does not supply power.


power comes out of CCRM pin 5, goes to splice S152, then splits and goes TO both the fuel pump and the computer on pin 19. 19 is FPM, fuel pump monitor circuit. if the computer doesn't see power going to the fuel pump it kills some of the engine functions.

power starts at key, key sends power to CCRM, relay on CCRM sends power to computer.

I once had my 92 die, it was the splice S142 yellow wire, that corroded and stopped power from reaching both the CCRM and the computer.

Perry

Since this is a 90, I think the numbers are a bit different. Splice 403 is the one that goes between pin 19 on the PCM and pin 5 of CCRM and back to fuel pump. So I assume the splice 142 you speak of is splice 275 on this car (it's near C124 right on top of the cooling fan). I am getting KAM power to both CCRM pin 8 and PCM pin 1, so that means the splice is good, and the fuse-able link is good. There are some pretty unorthodox wiring repairs from the deer accident, but I am getting power through!

if so, you should confirm that the key switch is good and actually telling the pcm to "turn on" when the key is turned.

What wire tells the PCM to 'turn on?'

engine compartment fuse box, EEC relay, hot at all times feeds power to CCRM pin 8, and computer pin 1. thats the KA pwr,,keep alive power.

CCRM receives power in start or run on pin 13



from a 92 manual.



Perry

As I said above, I get power to CCRM pin 8 and PCM pin 1. Pin 13 has 1.5V on start. Is this right? I also have 5V to pin 24 on the CCRM when key is on. So from what I'm seeing, it appears wiring is good so far(well, at least the continuity is good, it looks like a rats nest of twisted together wires, electrical tape and wire nuts).

So. Now what? I supplied battery voltage to pin 13 to see if it wasn't getting enough power, but nothing happened. Where do I go from here? It seems like I can find flow charts for no start conditions, but it's only for the starter not working, or no spark.

I'm sorry for all of the questions, but it seems like I get some weird cases. The last 94ATX no start I had took me almost 6 months to solve (including buying a parts car to swap harnesses with).

I'm just looking to understand how the fuel pump is turned on. If I knew exactly what I need to the PCM and CCRM in both key on and start (and what pins, etc), that would be great!

Thanks so much for all the help so far!

 

[pjtoledo]

pin 13 on CCRM should be "hot in start or run". I read that as 12v. from the ignition switch, and thru a fuse.

the power from the ignition switch that feeds pin 13 CCRM also feeds: (via splices)

radiator coolant sensor
cam sensor
crank sensor
DIS module,pin 1
coil
radio noise capacitor


there is a fuse in that line between the ignition switch and the first splice to all that stuff.

if the fuse isn't blowing, then none of those other components are shorted to ground.
my guess is the ignition switch isn't putting out full power.
again, all this info is for a 92, so my fuses, and your fuse links may differ a bit.

 

[pjtoledo]

does you year have the resistor for the low/hi power on the fuel pump?

 

[jimtash]

The dying PCM in my '89 wouldn't work the fuel pump correctly and cut off the fuel causing a lean condition. Eventually it wouldn't even supply any fuel to engine at all causing a no start. Odd thing though is when the key was turned to on, the pump sounded like it primed normally but there was no fuel in the rail.

 

[TimboSHO]

pin 13 on CCRM should be "hot in start or run". I read that as 12v. from the ignition switch, and thru a fuse.

the power from the ignition switch that feeds pin 13 CCRM also feeds: (via splices)

radiator coolant sensor
cam sensor
crank sensor
DIS module,pin 1
coil
radio noise capacitor


there is a fuse in that line between the ignition switch and the first splice to all that stuff.

if the fuse isn't blowing, then none of those other components are shorted to ground.
my guess is the ignition switch isn't putting out full power.
again, all this info is for a 92, so my fuses, and your fuse links may differ a bit.

Well, I think I'll be looking at that circuit then. Maybe I'll have to look at what's coming from the ignition switch as a possible source to the problem....

does you year have the resistor for the low/hi power on the fuel pump?

I don't see it on any of my wiring diagrams from 89, 90 or 91; so that must be a Gen 2 thing...

The dying PCM in my '89 wouldn't work the fuel pump correctly and cut off the fuel causing a lean condition. Eventually it wouldn't even supply any fuel to engine at all causing a no start. Odd thing though is when the key was turned to on, the pump sounded like it primed normally but there was no fuel in the rail.

I've tried 3 different PCMs, and it doesn't prime at all.

 

[pjtoledo]

the resistor for the fuel pump was the early years, by 92 it was gone.
look on the pass side firewall up high.

 

[TimboSHO]

pin 13 on CCRM should be "hot in start or run". I read that as 12v. from the ignition switch, and thru a fuse.

the power from the ignition switch that feeds pin 13 CCRM also feeds: (via splices)

radiator coolant sensor
cam sensor
crank sensor
DIS module,pin 1
coil
radio noise capacitor

Perry. You are the man.

I checked for power at ignition switch, 12V. While taking stuff apart to get to this, I noticed a cobbled up switch on the bottom of the steering column shroud. Turning it on turned a compass mirror on, gave the fan a quick jolt, and made the check engine light brighter. I didn't think too much more of it until I started testing the other things on that circuit and the fuel pump started running when I turned the key on! Problem solved!!!!!

Now, on to getting it running again!

Perry, I owe you fudge, beer, or whatever your heart desires the next time I see you! Thanks again!

 

[boat]

Glad you figured it out.