7.4GI Volvo Penta No Crank

[Ronald A]

Recently, while cranking to start, the starter and fuel pumps suddenly went dead. I attempted to start several more times but neither the low or high pressure pumps nor the starter reacted. I checked the lanyard kill switch and it was intact. Over the last few days I’ve been troubleshooting, and found that the C terminal on the starter relay has no power, even while the key is in both the ‘on’ position and the ‘start’ position. The fuel pumps relay does have power and I am able to jump that relay and get the pumps to power up. The ignition switch has power, and I have tried bypassing both the lanyard kill switch as well as the neutral safety switch, but still no luck. Any idea where to go from here?

 

[alldodge]

The ECM turns ON the fuel pump by applying a ground to pin 86 on the relay from pin J1-23

Place meter probe on pin 86 of the relay Black/Yellow wire. With the key OFF you should see 12V on the Blk/Yel, and when ignition key is turned to ON it should go to zero volts

 

[Ronald A]

Thank you alldodge, I’ll give that a shot tonight. If I do not have 12v at the terminal, what would you suspect at that point? Also, I see in the schematic you posted that there is a 20a in-line fuse within that connection however, I can’t seem to find where that fuse is located... any idea? I highly suspected a fuse or circuit breaker by the way the power cut out and to both the fuel pump and starter relays simultaneously.

 

[alldodge]

I would agree also first suspect is the fuse. The fuse is on top the motor, and may look like a small rectangle. Follow the Red/White wire back to it.

If you don't have 12V on the Blk/Yel and do have it on the Red/Wht then the coil in the relay has burned out.

In most cases if the fuse has blown this means one or both of the fuel pumps is shorting out

 

[Ronald A]

Thank you alldodge, I’ll give that a shot tonight. If I do not have 12v at the terminal, what would you suspect at that point? Also, I see in the schematic you posted that there is a 20a in-line fuse within that connection however, I can’t seem to find where that fuse is located... any idea? I highly suspected a fuse or circuit breaker by the way the power cut out and to both the fuel pump and starter relays simultaneously.

 

[Ronald A]

I have nothing at pin 23 on the wire harness with the key OFF, and 12v with the key in the ON position. I have nothing at the 86 terminal on the starter relay regardless of the key position.

I traced the red/white wire from the relay to a 20 amp circuit breaker, but can find no fuse anywhere on, behind or anywhere else on the motor. There is 12v to both the terminals on the back of the breaker. Is it possible that the 20 amp breaker is bad?

 

[alldodge]

You traced the Red/Wht wire to a 20amp breaker and had 12V on both sides. Good this means you don't have a fuse you have a breaker and its is passing voltage so all goo on the Red/Wht to pin 30 and 85 of the relay. You should have 12V on both terminals 30 and 85 of the fuel pump relay.

I have nothing at the 86 terminal on the starter relay regardless of the key position.

Pin 86 is the other side of pin 85 of the fuel pump relay coil. Since you do not have voltage on 86 this means the coil of the fuel pump relay has burned out or you have a bad connection

Here is the relay diagram. Note 85 and 86, this is a coil of wire



Take the relay to the local auto store and lay on the counter. Try to find the older guy and not a young kid.

 

[Ronald A]

Just so I’m understanding correctly, it’s the fuel pump relay that is bad, not the starter relay? I was focusing on the starter terminals because the fuel pump terminals have power where it’s supposed to but the starter terminal never got power to 86 despite the key position.

 

[alldodge]

OK thought it was a fuel pump issue.

Note the wiring diagram does have a couple issues, mainly with the power feeding the assist relay

The starter assist relay pins 85 and 86 energize the relay. One side goes to ground and the other is feed from the key switch with Yellow/Red wire. When key is turned to "start" 12V travels on Yel/Red thru neutral safety switch, to the assist relay.

The assist relay when energized sends power from pin 30 to pin 87 thru a larger Yel/Red wire which then goes to the starter solenoid.

WIth getting no power the the Yel/Red coming from the Key, check for 12V on the Red/Purple on key

 

[Ronald A]

First, I want to thank you for taking the time to help, it is much appreciated! Ok, allow me to think out loud here for a sec and kind of repeat back what you’re telling me, so as not to misunderstand.

In the wiring schematic, there are 3 relays pictured. The two side by side are the fuel pump (top - marked “1”) and the bottom the starter (marked “14”). The fuel pump relay has power at terminals 86 and 30, but the starter only has power at 30 and never at 86 regardless of the key position.

When I checked the ignition switch the other day, it had power at all 3 terminals. I also bypassed both the safety kill switch and the neutral safety switch just to eliminate them as potential causes.

Also, what is that third relay? I know where it’s at (behind the 3 circuit breakers on the riser) but haven’t checked it at all. Could it play a role?

 

[alldodge]

Also, what is that third relay? I know where it’s at (behind the 3 circuit breakers on the riser) but haven’t checked it at all. Could it play a role?

Yes that's the start assist relay

Relays

1 = Fuel pump
14 = Main power (turns power on the ECM and everything else on motor)
2 = Start assist relay (energizes starter solenoid)

The Main power relay has a wiring missing that is not shown on the drawing. The other side of the relay goes to Pink/White which is above it

 

[Ronald A]

Ok, so from here I should verify power at the ignition switch and then check the starter assist relay for power at the 30 and 87 terminals?

 

[alldodge]

Ok, so from here I should verify power at the ignition switch and then check the starter assist relay for power at the 30 and 87 terminals?

Yes

 

[Ronald A]

I have no power at any other terminal except
30 on the starter assist relay, regardless of the key position

 

[alldodge]

Then there is a break in connection between Yel/Red on the key to Yel/Red on the assist relay. The wire goes thru the neutral safety switch straight to the relay.

 

[Ronald A]

Ok.... a tad pissed off and frustrated, but also relieved. After all that troubleshooting, it turns out the ignition switch appears to be bad. Though it was one of the very first things I checked, turns out that while checking it in the glaring sun with just a test light and not a meter, I thought the indicator light was lighting when in fact it wasn’t.

Just to be sure though, no power on any of the ignition switch terminals regardless of the key position would be the switch itself correct?

 

[Ronald A]

Well, both a tad pissed off but also relieved. After all that troubleshooting, it appears it’s the ignition switch that is bad. I guess while checking it in the halting sun and using just a test light and not a meter, it appeared as though the indicator light was lighting when in fact it was not.

Just to be sure though, no power at any of the terminals on the ignition switch regardless of the key position would be a bad switch, correct?

 

[alldodge]

Well, both a tad pissed off but also relieved. After all that troubleshooting, it appears it’s the ignition switch that is bad. I guess while checking it in the halting sun and using just a test light and not a meter, it appeared as though the indicator light was lighting when in fact it was not.

Just to be sure though, no power at any of the terminals on the ignition switch regardless of the key position would be a bad switch, correct?

Correct, BUT .... ONLY IF (the big if) there is no power (12V) to the Red/Purple wire feeding the switch

If there is 12V to the Red/Purple then its the key swicth

IF

If there is no power to the Red/Purple, then its most likely the 20 amp breaker/Fuse feeding the helm (dash) panel

 

[Ronald A]

No power on any terminals including the red/purple. There IS power to both terminals on the back of t he 20 amp breaker switch. So power is going to the breaker but not getting past it? It’s definitely not tripped.

 

[Ronald A]

Here are pics of the 20 amp breaker and wiring, and the 12.5 amp breaker and wiring on the riser. There is no red/purple to the 20 amp but there is to the 12.5 amp.