No power to fuel pump relay, why?

lfiers889

Registered User
Have 91 SC has been running fine when some bolts holding pulley to harmonic balancer broke and others stripped out threads. Replaced Harmonic balancer and pulley, turns over but won't start. I assumed it had to do with the crank position sensor but when I checked for fire at the plugs I have spark. Noticed didn't hear fuel pump cycle when turning on key. Inertia sensor has continuity. Fuel pump relay hot wired and I have 40lbs of pressure. Spins over but doesn't try to start with 40lbs pressure. Apparently no juice to fuel pump relay and injectors? Checked high current fuses under hood, all have continuity and power to them. Any ideas on what to check next and how to check it would be much appreciated.
 
Have 91 SC has been running fine when some bolts holding pulley to harmonic balancer broke and others stripped out threads. Replaced Harmonic balancer and pulley, turns over but won't start. I assumed it had to do with the crank position sensor but when I checked for fire at the plugs I have spark. Noticed didn't hear fuel pump cycle when turning on key. Inertia sensor has continuity. Fuel pump relay hot wired and I have 40lbs of pressure. Spins over but doesn't try to start with 40lbs pressure. Apparently no juice to fuel pump relay and injectors? Checked high current fuses under hood, all have continuity and power to them. Any ideas on what to check next and how to check it would be much appreciated.

Do you still have a stock balancer or replacement?
 
Is that 40psi fuel at the valve on the rail?

Is the multi-wire ignition switch down on the side of the steering column original?

Did you confirm the balancer is fully plunged?

12+ volts at the battery?

Upshift or check engine light on while cranking?

Vacuum line at the FPR dry?
 
Answers to questions

Is that 40psi fuel at the valve on the rail?

Is the multi-wire ignition switch down on the side of the steering column original?

Did you confirm the balancer is fully plunged?

12+ volts at the battery?

Upshift or check engine light on while cranking?

Vacuum line at the FPR dry?

The fuel line pressure is measured at the schraeder valve on the rail. The ignition switch is original. The balancer is torqued to 120 ft lbs and in line with the other pulleys. The battery is +12 volts. Upshift light and check engine light are not on when cranking. If FPR stands for Fuel Pump Relay there is no vacuum line in the trunk by the relay. Good questions, appreciate the help.
 
FPR= fuel pressure regulator. Located on hen. Back of the fuel rail toward the drivers side of the motor. Kinda under the whiper assembly.
 
The latest...

Checked the timing just by cranking engine with timing light and it is at 10 degrees per spec. So conclude harmonic balancer is installed correctly. Monig on: Fuel pump relay in trunk has 4 wires; power (black/yellow), fuel pump (pink/black), coil power (white), and what I think should be coil ground? So when switch is on I have 12+ volts at power and coil power, nothing at fuel pump, and 10 volts at the coil ground. Obviously the relay coil wont actuate with no ground, but when I turn the switch off I get a short surge of about 10 lbs from the fuel pump. I am assuming this is due to the coil ground no longer having 10 volts and actually working as a ground? My Chilton refers to this coil ground wire as number 22 on the 60 pin and it is called FP for Fuel Pump. It is connected to the self test connector as well. Which speaking of I can't seem to find so I can run the self test and try to get some codes. I have looked by the AC drier near the firewall on the passenger side, near the master brake cylinder reservoir on the river side, and under the dash on both sides. Where the H E double toothpicks did the geniuses at Ford hide it? Other question I have is what would cause voltage to be in ground wire for fuel pump relay?
 
A lot of times the fuel pump harness cracks and breaks from being brittle above the gas tank, had that happen before...Also had the pink 30amp under the hood blown for the EEC and I wasn't getting fuel pump power.
 
Bad computer>

I tried to run the codes but check engine light stays on when I hook up. Book says that indicates short or open circuit. Fuel pump runs when grounding self test connector for pump indicating circuit is good but not receiving signal from computer when switch is turned on, supposed to run a few seconds to build up pressure to start. Based on that info I want to buy a used computer that was working but replaced for performance enhancement reasons. Anybody got one?
 
Bad Computer?

Since fuel pump works when grounding self test terminal for pump and since tried to read codes but check engine light stays on indicating hard fault (open or short circuit) I believe I need a computer. Anybody got a good used one? lonn1950@gmail.com
 
Good evening


I would check the IRCM before replacing the EEC. If you look at the attachment the IRCM has three relays one of which powers the EEC. Check the connector for corrosion/damaged pins. Below is 2 quick test(s) I do.


(1) Have another person turn the Key On Engine Off (KOEO) while I am next to IRCM. Listen carefully for the relay to energize with a "click". Do this few times. If no click suspect the IRCM and or wiring.


(2) Remove the air box for better access to the IRCM. Repeat step (1) KOEO. Tap on the IRCM case with an screwdriver (handle end) or long 3/8 drive extension to "jar" the relay to life. Again if no click is heard suspect the IRCM and or wiring.


Attachment. http://www.sccoa.com/forums/showthread.php?138032-1990-SC-IRCM-pinout-and-schematic-pdf



Good Luck.
 
Looking for used computer

I may be wrong here but I read if I have spark the ICRM EEC relay is working. I have spark. What I don't have is fuel pump pressure at key on, should run a few seconds. I checked the fuel pump circuit by grounding the self test plug and fuel pump runs. Still think computer has problem not grounding pump for a few seconds. Does anyone have a good computer part # F1WF-12A650-AA, that is the one for the manual tranny. My email is lonn1950@gmail.com Thanks so much for the help.
 
SC eats Computer for lunch

Replaced computer, turned key and fuel pump charges fuel lines, hit starter and car starts and runs, problem solved......for about 5 minutes. Car coughs, sputters, and dies. Turned key off, turned key back on, no fuel pump run to charge lines. Has computer burned out again? I can hot wire pump so there is 35 to 40 lbs pressure but car will not start.
What gives?
 
Good afternoon

When you turn the key to on (Key On Engine OFF) does the following intermittent instrument cluster events and or in the trunk package tray defect(s) occur:


(1) Up shift arrow light "flickers" or does not come on.

(2) Relays in the trunk package tray cycles on and off.

(3) Constant fuel pump "wine" sound.

(4) FIRM light on when the switch is cycled to AUTO.


If so then problem might be similar to what IFSTBRD (and latter myself) experienced. With the exception of swapping out the EEC I used this the thread (see attachment) for the base troubleshooting. Finally found the problem with the EVTM to a RIDE CONTROL module connector interrupting EEC power. I greased the connector with die electric compound and put applied a "max" re-torqued. Problem has not returned.


http://www.sccoa.com/forums/showthr...ns-over-but-won-t-start&p=1103387#post1103387
 
Now that's interesting-Getting weird

Borrowed a scanner and while trying to get it to read codes turned on switch and the fuel pump charged the lines, so I hit the starter and it starts and runs fine. Apparently computer did not burn out. But who knows how long it will last. So question I have is when key is on engine off for codes scan I have an alarm buzzing, shift light, check gauges light, check engine light, and battery light are all on. I may be dreaming but I didn't think there was an alarm buzzing and that many lights on before all this went down. anybody else check and see if their car buzzs and what lights stay on?
 
Good evening


Check the passenger side firewall connector to engine harness connector ( the large "square" one). If the connector pin(s) have corrosion, damage and or did not fully connect the buzzing alarm sound and cluster warning lights will come on. I have seen this on a 1989 Thunderbird N/A 3.8 which was converted from MAP to MAF.
 
Thanks

Good evening


Check the passenger side firewall connector to engine harness connector ( the large "square" one). If the connector pin(s) have corrosion, damage and or did not fully connect the buzzing alarm sound and cluster warning lights will come on. I have seen this on a 1989 Thunderbird N/A 3.8 which was converted from MAP to MAF.

Thanks, that fixed the buzzing when I applied dielectric grease to all the terminals. Now it is back to no fuel pump charging the lines. The inconsistency is crazy. Am trying to read codes with scanner but I get a message of 'no communication from module.' Am unfamiliar with this particular 'borrowed' scanner so will probably have to get owner to get me started.
 
Computer OK?

Here is what I think is going on. When I turn the key to on the computer reads 'some things' and if it don't get the right readings it does not ground the fuel pump to charge the system and it does not fire the injectors. Then when I try key on at a later date it reads 'some things' again and this time it gets the right readings and it grounds the fuel pump to charge the lines and it fires the injectors and the car starts. If this is the case what sort of things do I need to look at? When it charges the fuel lines at key on it starts and runs perfect. When it don't charge the fuel line it cranks but it doesn't even try to start. Sounds like gremlins to me.
 
Ignition switch

Have you checked your ignition switch in the steering column yet? It's known to start separating and cause all kinds of strange issues
 
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