Fuel pump not coming on

[SHOdude03]

Finally got my SHO(90 MTX) back together after an engine swap that I started 7 months ago. Now the fuel pump isn't coming on. I put in a new one figuring that was the problem, but it still doesn't even come on. So I found ProjectSHO89's electrical circuit diagnostic . I tried step 1, didnt help. Tried step 3, it read 2.8 Volts(I kept the EEC-IV FP connection grounded, reading was 0 without it grounded). So I figured it has to be the connection in the back, the one that actually goes to the fuel pump. So I drop the tank down far enough that I can get to the clip. Pull the clip off and hook a multimeter up to it, reads 2.8. I reconnect the clip hoping to hear the fuel pump come on, but it doesn't. So I take 2 wires, hook them up to the old fuel pump clips, and then touch them to the battery. the old fuel pump starts whining, sounds strong as ****. So I take the 2 wires that are hooked up to the old fuel pump and touch them to the connections in the clip that goes to the FP. Nothing happens.

Now I'm fairly sure I did something wrong with checking all this, seeing as how my FP SHOULD be working but it isn't. So can anyone tell me what I did wrong? Or if I somehow managed to do this correctly, whats wrong with my car? Any help would be appreciated, I've spent about 20 hours this week getting my car put back together and I really need to feel those secondaries open up.

<small>[ March 07, 2004, 01:36 PM: Message edited by: SHOdude03 ]</small>

 

[MOSHO92]

Maybee the wires on the fuel pump itself are reversed. Try that paper clip thing again but revese the contacts.

EDIT: It is possible that you new fuel pump is defective.

<small>[ March 07, 2004, 02:13 PM: Message edited by: MOSHO92 ]</small>

 

[RStalveyARFF]

This could be several things. One could be the CCRM located on the radiator support. Another could be the crankshaft sensor. Yet another could be the inertia relay.

 

[SHOdude03]

took the IRCM off my friends 89 and put it on mine, still didnt start. Also checked the inertia switch, tripped it, and pushed it back down.

the crankshaft sensor would cause the fuel pump not to come on?

 

[SHOdude03]

Checked the clip that goes to the fuel pump assembly for power again, now its not reading anything at all. Trying to figure out where Fusible Link J is(thats the one for FP right?) but I can't seem to find it.

 

[projectSHO89]

Your test result indicates that there is a fault in the power supply from the IRCM. 2.8 V is way too low, you should be seeing between 8 and 11 volts.

At idle speed, power to the FP is via fuse link J, thru the resistor on the firewall (dead center, top) then the relay inside the IRCM.

Take voltage readings on both sides of that resistor and see what you have. If fuse link J is good, one side will have battery voltage and the other will be lower (how much?, FP activated).

Steve

Steve

 

[projectSHO89]

Your test result indicates that there is a fault in the power supply from the IRCM. 2.8 V is way too low, you should be seeing between 8 and 11 volts.

At idle speed, power to the FP is via fuse link J, thru the resistor on the firewall (dead center, top) then the relay inside the IRCM.

Take voltage readings on both sides of that resistor and see what you have. If fuse link J is good, one side will have battery voltage and the other will be lower (how much?, FP activated). If the link is bad, you will have low voltage on both terminals.

Steve

Steve

 

[SHOdude03]

OK I have some really stupid questions(my knowledge about wiring and stuff is extremely limited).


First stupid question: which one is my resistor? There are 2 things in the middle top of my firewall, one has a rectangular plug in that has 3 wires, the other has a circle plug in(like O2 sensor plugs) with 2 wires. I assume one is something that couldn't possibly be the resistor and I'll seem like a retard but oh well.

another stupid question: how do I test before and after the resistor? Do I need to cut the lines?

Third stupid question is where is Fusible Link J? Wires from both plugs run down to the huge collective of wires in the heat shrunk cover(I think its heat shrunk anyway?) and I don't wanna cut into that unless I know for sure its in there.

<small>[ March 08, 2004, 12:09 AM: Message edited by: SHOdude03 ]</small>

 

[projectSHO89]

SHOdude03:
OK I have some really stupid questions(my knowledge about wiring and stuff is extremely limited).


First stupid question: which one is my resistor? There are 2 things in the middle top of my firewall, one has a rectangular plug in that has 3 wires, the other has a circle plug in(like O2 sensor plugs) with 2 wires. I assume one is something that couldn't possibly be the resistor and I'll seem like a retard but oh well.

another stupid question: how do I test before and after the resistor? Do I need to cut the lines?

Third stupid question is where is Fusible Link J? Wires from both plugs run down to the huge collective of wires in the heat shrunk cover(I think its heat shrunk anyway?) and I don't wanna cut into that unless I know for sure its in there.

The resistor is the sand-colored component mounted to a bracket with two wires. To test the voltages on either side of it, you will need to backprobe the connectors or otherwise make contact with the conductors on either terminal with the FP energized. Do not cut the lines in any circumstance unless advised to do so.

The fuse link is supposed to be hanging off the starter solenoid on the driver's side strut tower.

It is my opinion that you have at least one of the following faults:

1) Dropping resistor too high of resistance. It should be less than 2 ohms.

2) Fuse link J has too much resistance

3) FP is drawing too much current. If so, that resistor is likely getting hot.

4) Relay in IMRC is defective (low probability since it was swapped)

5) There is a connection or conduction in the circuit that has too much resistance.

Measuring the circuit voltages at various places whil it is under load is a standard procedure for determining where the voltage is being lost.

Steve

 

[SHOdude03]

OK my friend informed me that while he was connecting the battery a few days ago there was a large puff of smoke from the area around the starter solenoid(yes I really do have a ******* friend, not just covering for my own screw up). So most likely Fuse link J got fried. There are 4 different 16GA fuse links there, 1 or 2 20GA, and 3 14 GA, which one is fuse link J?

Also, it occured to me that while putting in new battery cables wires could have got put on the wrong post of the starter solenoid. Can anyone tell me which wires are supposed to be on which post?

<small>[ March 08, 2004, 03:27 PM: Message edited by: SHOdude03 ]</small>

 

[SHOdude03]

can anyone help me please?

 

[projectSHO89]

As for the wires on the solenoid all of them except for the one that goes to the starter motor should be on the terminal that connects to the battery.

As for which link is "J", you will probably have to take resistance readings from the dropping resistor to the load side of the links to determine which is which.

"J" also supples full battery voltage to pins 1, 2, & 12 of the IRCM via BK/O wires. Check there first.

Steve