Code 96 - Secondary fuel pump circuit fail - no pwr pin 19

[90topdown]

Trying fix a problem with code 96 - secondary fuel pump circuit failure. Car starts and runs fine bit it dies intermittently. I have no power at pin 19 at the ECM

So far I have:

-replaced fuel pump relay - no difference- still dies

- jumped out inertia switch - no difference- still dies

- visual check and wiggling of all fuel pump wiring which seemed ok.

- re-did all the grounds and added ground from starter solenoid ground to engine. Re-doing grounds really helped raising system voltage

- have 11.5 volts on both sides of the fuel pump fusible link so I assume that fusible link is ok.

- If I jump out the fuel pump at the self test connector, fuel pump runs and I have power ( 10.5 volts) at pin 19 at the ECM

With just key on (FP not jumped out) I have no power at pin 19 at ECM.

FYI- With key on I have 10.5 volts at pin 58 at the ECM

How do I fix this??

 

[HISSIN50]

When you have no power at Pin 19, does your pump run?

 

[joel5.0]

Trying fix a problem with code 96 - secondary fuel pump circuit failure. Car starts and runs fine bit it dies intermittently. I have no power at pin 19 at the ECM

So far I have:

-replaced fuel pump relay - no difference- still dies

- jumped out inertia switch - no difference- still dies

- visual check and wiggling of all fuel pump wiring which seemed ok.

- re-did all the grounds and added ground from starter solenoid ground to engine. Re-doing grounds really helped raising system voltage

- have 11.5 volts on both sides of the fuel pump fusible link so I assume that fusible link is ok.

- If I jump out the fuel pump at the self test connector, fuel pump runs and I have power ( 10.5 volts) at pin 19 at the ECM

With just key on (FP not jumped out) I have no power at pin 19 at ECM.

FYI- With key on I have 10.5 volts at pin 58 at the ECM

How do I fix this??

FP activation is...... 2-4 seconds when key is cycled to IGN ON and shutoff. It then waits for a PIP pulse to be present (sign engine is turning) to reactivate the FP relay. With the the ignition switch left in IGN ON, the FP will not turn on after the initial priming pulse, and no voltage should be present at pin 19.... (FP is off).

11.5 vdc at the fuse link and 10.5 vdc at pin 19 are way too low of a voltage reading (assuming battery, main ground and block-to-frame grounds are OK). BTW.... pin 58 is injector #1 pulse wire.

10.5 vdc is the threshold voltage value at the FPM pin for the EEC to log a code 96 failure. Based on the voltage readings posted, there is a voltage drop condition that is causing the ECM to overcompensate for a low voltage condition, specially if those same voltage readings are present in pins 57 and 37 (VPWR). LUK

 

[90topdown]

Car will start and run normally.

With key in run position and engine off - there is no power at Pin 19 ECM.

With fuel pump jumped out at self-test connector (pump runs continuous) there is power at pin 19 ECM.

I read an old post of Joels and I am confused:

For pin 19......if you have voltage with the IGN ON engine off constantly.....there is the cause for code 96. You should only have voltage at pin 19 following the fuel pump ON-OFF state. When you turn the IGN ON, the system should only detect voltage at pin 19 following the fuel pump prime sequence = 12-vdc ON for 2-3 seconds, and no voltage until the engine is cranking or running. Do you have the fuel pump relay "hot wired" ?.......LUK

Any ideas??

 

[90topdown]

I just re did all the grounds and added the one for the 3g ALT. So I doubt that is the problem.

I have 12.06 volts at the batt with engine off and 13.95 volts with engine running at idle.

I guess I am loosing voltage somewhere. .5 volts to FP fusible link and 1.5 volts to ECM

How do I find it??

 

[joel5.0]

Engine running..... monitor the voltage at pin 19 using the battery (-) post as the ground reference for the DVOM (an extension wire is OK)........ now, check the voltage at pin 19, engine running, using a frame ground reference point for the DVOM. What is the difference of both readings. LUK

 

[90topdown]

1st try- engine running
+ probe to pink/black wire
- probe to - batt terminal 13.10 volts

+ probe to pink/black wire
- probe to frame ground (ECU ground point) neg 13.10 volts

2nd try- engine running
+ probe to pink/black wire
- probe to - batt terminal 12.90 volts

+ probe to pink/black wire
- probe to frame ground (ECU ground point) 12.90 volts

Yes, 1st try to frame ground showed - neg 13.1 all other readings were pos

 

[90topdown]

TTT

 

[joel5.0]

Check that charging system...... 12.9 - 13.1 engine running is a little too low.

 

[hotcobra03]

Do you have code 87?any engine running codes?

 

[90topdown]

Check that charging system...... 12.9 - 13.1 engine running is a little too low.

Ah hah (light bulb goes off)!!

I think that I know what the problem is. When I put the new motor in, I used an underdrive crank and w/p pulley. I think that the underdrive crank pulley is not spinning the alternator enough, hence the low voltage - voltage drop problem.

I had no problem with a voltage drop that I am aware of with the old motor which had the stock crank pulley.

I will put a stock crank pulley back on and check the voltage.

How many volts should I be seeing at Pin 19 with engine running???

 

[90topdown]

Do you have code 87?any engine running codes?

No code 87

I do have some other codes but they are all part of the smog delete and unrelated.

 

[hotcobra03]

My book says 10.5 volts are a pass. Book says you have short in harness. Did u have a test lite in pin 19 and 37 .disconnect and turn key to on lite should be on than ck wire harness again wiggle tap bend .when lite goes out u found it.what were other codes as im reading all pintest other codes can trigger 96

 

[90topdown]

My book says 10.5 volts are a pass. Book says you have short in harness. Did u have a test lite in pin 19 and 37 .disconnect and turn key to on lite should be on than ck wire harness again wiggle tap bend .when lite goes out u found it.what were other codes as im reading all pintest other codes can trigger 96

I agree, normal voltage should be somwhere in between 10.5 and 14 volts.

What book are you reading?? What is the basis for it saying that I have a short in the harness??

I only checked pin 19

Other codes are 67, 91 41. I know what is causing them and I don't think that they are related.

The harness isnt that great so it is very possible that there is a short in the harness somewhere.

So you are saying that I should unplug the EEC, turn the key to the on postion and put a test light in pin 19 and start wigging wires until the light goes out . If I find nothing there, then do the same with pin 37??

I am curious about this as I beleive in the normal key on, engine off position, there should be no power at pin 19. (secondary FP circuit)

 

[hotcobra03]

If your engine is a 5.0 sefi with mass air code 96 says see j92. Check eec-4 harness for short.i think u put test light in pin 19 and 37just in those pins.your other codes 41 91 low fuel pressure code 67 clutch pedal .when retesting push clutch in and 67 will pass.my book is 1988 ford publication

 

[HISSIN50]

41/91 are air fuel trim codes, not fuel pressure codes. The EEC does not monitor fuel pressure directly.

67 can be generated if the HVAC was turned to AC or the car was not in neutral.

Pin 19 is the Normally Open FP circuit. 37 is VPWR, which excites the FP relay. WIthout 37 (seeing 12 volts), 19 cannot happen.

 

[hotcobra03]

Ok fine print.5.0 sefi code 41 91 go to pin test h11 hego.5.0 sefi with mass air pin test h1 check fuel pressure .hey mike wat u got in that thing?

 

[joel5.0]

Pin 19 = FPM (Fuel Pump Monitor) circuit. The only time you will see voltage at pin 19 = FP is turned on = FP relay activated = initial FP prime pulse or engine cranking/running = PIP pulse present.

Code 96 = an open condition (no voltage present), low voltage (<10.5 vdc engine running or <8 vdc engine cranking) when the FP relay is turned on by the ECM and no code 87 (Primary Fuel Pump Circuit Failure) is present.

Possible Causes:
Open in FPM wire from PCM to relay.
Short of FPM wire to ground.
Defective FP relay.
Defective ECM.
Low voltage condition in FPM circuit.

 

[hotcobra03]

Pin test j30 service code 96 check for vbatt to fuel pump relay.note sc96 indicates that when the fuel pump is being activated,power is not being supplied to the pump.pin test j91 check fpm circuit,steps are key off dis connect 60 pin con leave off connect testlite to pin 19 and 37 turn key on testlite should lite.while watching lite wiggle kick shake and tap on harness until you get to fp relay if lite goes out u found the short

 

[joel5.0]

Pin test j30 service code 96 check for vbatt to fuel pump relay.note sc96 indicates that when the fuel pump is being activated,power is not being supplied to the pump.pin test j91 check fpm circuit,steps are key off dis connect 60 pin con leave off connect testlite to pin 19 and 37 turn key on testlite should lite.while watching lite wiggle kick shake and tap on harness until you get to fp relay if lite goes out u found the short

Nope.... pin 37 is VPWR from the EEC relay, pin 19 is the wire connected to the the relay power out terminal and the fuel pump. The test light will stay on due to the ground circuit from the FP...... if the light goes out, there will be an intermittent open condition, triggered by the harness wiggle manipulation.