Fuel Pressure Issue (Wiring? ECU?)

[390Express]

I have a 1996 Crusader XL, 454, 350hp motor that has been out of service for a year and half. The boat had ethanol separation, and the ethanol reacted with the rubber gas line, turning it into a jello like substance. I replaced the gas line, and cleaned out as much of the fuel system as possible. There is no "hard" gas left in any of the lines, and it has all new fuel.

When I first put in the batteries, turned on the main breaker, and turned the "ignition" switch on the panel to "on," I thought I heard the fuel pump kick on. I thought that I have heard the fuel pump kick on during subsequent flicks of the same switch of the ignition breaker, but at this point, I'm not convinced.

Yesterday I completed the install of the new fuel lines, primed the main line that goes to the Oberg fuel filter, turned the ignition switch on, and attempted to check for fuel pressure. The system had some residual pressure (3-5psi), as the shrader valve shot a bit of air out of it and small spirts of fuel initially, then nothing. I don't know if it's possible that this pressure could have been in the system for 1.5 years, or if it was newer pressure built up from prior putting power to the ignition/pump. While I did prime the feed side of the Oberg fuel filter, I did not prime the output side, which feeds the fuel pump. That was the last bit of rubber line that could have been clogged, but yesterday I removed the pump and checked that line, and it's fine. When I started investigating the issue yesterday, I thought that either 1) the fuel line feeding the pump was clogged, or 2) the pump was bad. Neither of those issues turned out to be the case. The feed line did have a small amount of fuel in it, it's now in my bilge. Also, the fuel pump had a decent amount of gas in it, at least 1/2 a pint, maybe more. After I removed the pump and hooked it to a battery, it all shot out. The pump seems fine.

There is a red wire with a black stripe and a black wire that goes to the pump. On top of the motor, there is a red wire with a black stripe and a black wire that goes to a connector, and that connector is connected to nothing. I don't see anywhere that it is possible to plug it in. (pic attached) Could the pump have no power? Does the ECU control the fuel pump in any way? (wondering if the ECU is bad) I will bring a multimeter with me today to check continuity of the open connector to see if it's the same line. Both lines run through that plastic material, and it's taped up to a "T" that later feeds the TBI and more.

If it matters, the ECU is the MEFI 1/2 style, but Crusader brand. I believe they're both "Delphi" computers. I'll check for spark today (another indication that the ECU is good, or bad), and run a continuity check on the fuel pump wiring. Any other tips or tricks?

Thanks in advance for any advice!

[bud37]

Is there anything missing from that engine, ....large gage red wire....whats in the black boot ?......I have come across some crusader pleasure craft engine wiring, Mefi explanations ,there were wiring diagrams as well....try a search for that, could be very beneficial for figuring out all the relationships.

[390Express]

Source of the post Is there anything missing from that engine, ....large gage red wire....whats in the black boot ?......I have come across some crusader pleasure craft engine wiring, Mefi explanations ,there were wiring diagrams as well....try a search for that, could be very beneficial for figuring out all the relationships.

Where would the large gage red wire be? And which black boot are you referring to? Everything else seems in order. There is a fuel pressure relay that I have found could be an issue, and apparently the oil pressure sending unit may have a pig-tail to the pump wiring as well, as a safety measure that can shut off of an otherwise healthy pump.

Do you happen to know if the ECU has any control over the fuel pump? My primary concern is whether or not the ECU is bad. If the ECU is bad, I'm likely junking the TBI setup. I'm not going to pay $900 for a new ECU, only to chase my ass throughout the rest of the fuel system and potential TBI issues.

[bud37]

The one in your pic laying on the engine, sorry thought that is what you were asking about.....in MEFI 1 and 2 no I don't know for sure, I just searched for the crusader pleasure craft info that had all that explained with wiring diagrams and can't seem to find it again.....if I do I will post the link.

[390Express]

Source of the post The one in your pic laying on the engine, sorry thought that is what you were asking about.....in MEFI 1 and 2 no I don't know for sure, I just searched for the crusader pleasure craft info that had all that explained with wiring diagrams and can't seem to find it again.....if I do I will post the link.

Apologies, the pic isn't the best. I was approaching the problem with the idea that it was a bad pump or clogged gas line, and figured out that both diagnosis were wrong at about 10pm. The pic is more to show the red wire with the black stripe, and the wire that looks similar with an open connection on it at the other end. I'll get a better look this evening, and I will be able to run a continuity test on the wire, to see if it's the same wire. I think the open connector is more of a test/bypass deal than something that should be plugged in somewhere.

Does anyone know if the MEFI 1s and 2s can be "checked" by looking at the back side? It may be a good idea for me to get mine checked out regardless. I don't want to spend a ton of money chasing a TBI problem, if I'm gutting the TBI. I will check for spark later today, that should give me some indication as to whether or not the ECU is bad.

[390Express]

Quick phone call to the local marine mechanic has me checking the inline fuse, but he says the more likely problem is the fuel pump relay. Could be the ECU, but unlikely in his opinion. We'll see... I'll post progress and updates when appropriate. Any additional advice is still appreciated.

Cursory internet research says that I can sort of lie to the system and push the throttle forward to bypass some of the sensors and shutoffs while cranking it over.

Marine mechanic told me to make sure the relay is opening and closing, how can I tell? The good news is, according to him, these are all cheap automotive parts (relay, and fuse).

[bud37]

As I promised....you up for a good read..

http://marinepowerusa.com/2014/wp-conte ... Manual.pdf

[390Express]

Source of the post As I promised....you up for a good read..

http://marinepowerusa.com/2014/wp-conte ... Manual.pdf

Thanks, I think!...

[Viper]

Is there any wiring hooked up to your alternator? That usually has a boot on it but the boot is usually on the positive/red/charge lead.

Depending on your set up, the other set of wires with the water proof plug could be to put the ECM in service mode for setting up base timing. It also looks like the harness that plugs into the base of the distributor if that's the type you have; Delco HEI type with two plugs.

The ECM controls the fuel pump by triggering the pump relay. Just disconnect the wiring at your pump and with a meter hooked up to the wiring, turn ignition to the ON position and you should get 12 volts to power the pump. Typically it should power up for just a few seconds if you don't crank over the engine.

The ECM is the last thing you should suspect. Not saying they never fail but it's not very common, it's more likely something else that has failed. Remove the relay from the other engine and try it on the one you can't get the fuel pump to work.

[390Express]

Source of the post Is there any wiring hooked up to your alternator? That usually has a boot on it but the boot is usually on the positive/red/charge lead.

Depending on your set up, the other set of wires with the water proof plug could be to put the ECM in service mode for setting up base timing. It also looks like the harness that plugs into the base of the distributor if that's the type you have; Delco HEI type with two plugs.

The ECM controls the fuel pump by triggering the pump relay. Just disconnect the wiring at your pump and with a meter hooked up to the wiring, turn ignition to the ON position and you should get 12 volts to power the pump. Typically it should power up for just a few seconds if you don't crank over the engine.

The ECM is the last thing you should suspect. Not saying they never fail but it's not very common, it's more likely something else that has failed. Remove the relay from the other engine and try it on the one you can't get the fuel pump to work.

Thanks Viper,

The alternators are not currently hooked up. I had them disconnected because I did not want the circ. pump for the motor (the water pump mounted on the motor) circulating dry. If it's any consequence, the alternators are just hooked up with two wires with eye connectors over the posts, there's no connector or pigtails. I believe there is a rubber boot over the positive wire, but it doesn’t have anything else in it.

I knew about oil pressure sending unit possibly going to the fuel pump and causing an issue, I never heard anything about the alternator doing the same. I would like to jump out the portion of wires that may send a shutoff signal from the oil pressure sending unit to the fuel pump, but I'm not entirely sure how. The marine mechanic said to look for a purple wire. Do you know how to jump that connection? I don't think the oil pressure sending unit is bad, the motor fires with ether (starting fluid), and rpms up fine. While cranking for an extended period of time (15-20 seconds) the motor builds oil pressure on the gauge to 20 psi, after it fires it shoots right up to 40 psi.

The fuel pump kicks on when I turn the ignition switch on the panel in the cabin to the "on" position (for about a second and a half), but it does not stay on while the motor is cranking. It does kick on temporarily when I stop cranking, but after at least 50-100 cycles, (and starting the motor with ether at least 5+ times) it's still not building pressure. It is moving fluid, but not building pressure, at least not yet. When I started this project I drained the fuel/water separators. I have the hard type with the screw on the bottom, not the screw on oil-can filter type. Now, when I open the vent to the fuel water separator, a small amount of gas splurts out when I crank the motor, but when I plug that hole, it doesn't build pressure. Not sure why. The fuel water separator is after the Oberg filter (which is before the pump) and after the fuel pump itself. Gas is getting to and through the pump. The system is tight, I don't see any way of air getting in. I checked all of the connections and don't see any air bubbles or anything leaking. There is a separate fuel filter on the top of the intake, and just before the shrader valve that I am trying to use to gauge the pressure. Could that fuel filter (first pic below, you can also see the coil wiring to the far bottom of that pic), hard mounted on the stainless gas line, be clogged or otherwise rusted shut? I haven't messed with it yet, because it's a PITA to get off, but it seems like it could be the next step in trying to fix this issue.

A guy on the Trojan page told me that he had a similar issue, ran a constant hot to the pump temporarily, and within a minute he built pressure. My auto mechanic told me that even though the pump is kicking on for 1-2 seconds, it may not be enough to build pressure, even after 100 cycles. He said that it may take more continuous action from the pump to build pressure.

Because the pump kicks on when it’s supposed to before and after cranking, I don’t think the relay is bad. I have spark, timing and ignition, I don’t think the ecu is bad. I just need the system to pressurize.

Finally, the stbd motor has a plug in the open connection pictured above. Does that plug do anything? I could pull this plug from the stbd motor and insert it into the port motor that I’ve been working on, but I figure I’d ask before I go poking around. Pic below.