GT40 Low Pressure Fuel Pump Not Being Triggered
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=26811
Printed Date: November-24-2024 at 8:56am
Topic: GT40 Low Pressure Fuel Pump Not Being Triggered
Posted By: tachyon
Subject: GT40 Low Pressure Fuel Pump Not Being Triggered
Date Posted: July-05-2012 at 4:29am
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2001 Super Air Nautique with GT40 engine (and perfect pass...in case that makes a difference!). I've scoured the forums for help, and have finally narrowed down the failure to terminal 86 on the relay plug for the low pressure pump. Turns out that it is not cycling to +12V when hit start on the keypad - or if I crank the engine with the keypad. I have tested both HP and LP fuel pumps, both relays, and finally got out the multi-meter to see what is happening. Terminal 86 on the low pressure pump relay plug is getting -30mV when I crank the engine and with no relay plugged in. For the high pressure relay plug, I get about 12V at Terminal 86 when cranking. I have hard-wired to the low pressure pump from terminal 30 - and the pump runs perfect. I've also done the obvious relay-swapping, etc... with no luck. I have some specific questions; 1. Do the high pressure and low pressure pumps run simultaneously (i.e. is Terminal 30 essentially 'common' to both of the pumps)? 2. If I need the boat to run Friday...until next Sunday... for our 'big' summer vacation, can I simply wire Terminal 30 from the HP pump to the LP pump so they both will run simultaneously? 3. What conditions need to be met for the low pressure pump to run? Are these conditions the same as the high pressure pump? I should note that the boat was running OK on the last 3 outings. I recently re-carpeted & surely pushed the wiring harness around a bit under the dash, etc... is there a wire down there that I should trace? Please help - thanks in advance!  ------------- Manufacturer of the Super Deluxe Boom Mount! http://www.tachyonmotorsports.com - www.tachyonmotorsports.com |
Replies:
Posted By: lewy2001
Date Posted: July-05-2012 at 9:22am
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Rick both fuel pumps run off the same relay. The second relay(EEC) is the power relay for the ECM (Computer). The relay with the green/yellow on "86" terminal of relay is the fuel pump relay. You should have 12 volts on both terminal 30 and terminal 85 of fuel pump relay. The ground supplied by the computer is what activates the relay. Both pumps should run for a short period when you switch ignition on. This is controlled by the computer for initial start fuel pressure. The pumps will run all the time once the engine is started. You can make the fuel pumps run by grounding the STO connector as shown (with ignition on). The STO connector is under a plastic protective shell marked EEC test above the relays. Also check out http://www.correctcraftfan.com/forum/forum_posts.asp?TID=25775&KW=&title=99-sn-gt40-fuel-supply" rel="nofollow - this thread we went through the relay wiring in detail in this thread. Also check for the large fuse holder in your battery box that is known to cause problems for the GT40 engine electrics.  ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: tachyon
Date Posted: July-05-2012 at 11:35am
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Thanks for the info! This is VERY helpful! So I wonder if the problem could also just be an intermittent failure of the low pressure pump? I'm going to do some tests today & HOPEFULLY get it all squared away. ------------- Manufacturer of the Super Deluxe Boom Mount! http://www.tachyonmotorsports.com - www.tachyonmotorsports.com |
Posted By: tachyon
Date Posted: July-05-2012 at 2:02pm
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I ran out and re-tested the low-pressure pump, appears to be working OK. I am picking up a fuel pressure test gauge today & will see if the high pressure pump has failed. I also read through that thread you mentioned, what a GREAT compilation of info on the GT40 - I took several notes and will see what I come up with. Thanks again!  ------------- Manufacturer of the Super Deluxe Boom Mount! http://www.tachyonmotorsports.com - www.tachyonmotorsports.com |
Posted By: ultrarunner
Date Posted: July-05-2012 at 3:11pm
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Hey Rick, I was having the same issue a couple months ago. Turn key, sometimes pumps would activate, sometimes not. And a couple of times, boat would quit after running. I didn't bother pinning out the connector, but simply swapped the fuel pump relay after posting a message here and looking at that thread. Relay is 12 bucks at Autozone. Ultra |
Posted By: MBO090
Date Posted: July-08-2012 at 12:11pm
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Ultrarunner (and everyone else)! I have exactly the same frustrating problem with my GT40 - 1998...! Did you solve the problem just by replacing the two relays beside of the computerbox?! I have changed my relays but my engine still sometimes refuse to prime the engine when I turn the key (for a sec or two) and the engine runs for a couple of seconds then it dies (no pumps are running). Sometimes it just dies when Im drinving the boat but then I just have to turn the key and then it runs perfectly again and runs ok for a couple of days... Questions: Is the box named Test ECC (?) a relay? Are there any fuses under the dashboard that can cause this problem? Any Ideas anyone...?! /Thanks from Sweden! ------------- Livet går i direktsändning! |
Posted By: lewy2001
Date Posted: July-08-2012 at 10:42pm
No it is just a protective plastic housing over the STO and STI connectors used by a Ford OBD1 code reader. No fuses under the dash that could cause this problem. If you have a large fuse holder in the battery box that is a known source of GT40 problems and a modification was done to remove this fuse totally. Also check safety lanyard connections. Have a look in http://www.correctcraftfan.com/forum/forum_posts.asp?TID=25775&KW=&title=99-sn-gt40-fuel-supply" rel="nofollow - the thread I mentioned above it will show you a code reader attached to those connectors. The engine in this thread had similar problems to yours so read complete thread. ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
MBO090 wrote:Posted By: MBO090
Date Posted: July-09-2012 at 7:55pm
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Thanks Lewy! I have investigated the problem and the pumps are ok, the relays are ok and all the cabels are ok according to my multiinstrument... Now its running again and my only conclusion is that the relay for the fulepumps works 85% of the time - they will be replaces with new ones tomorrow. Does anyone report problems with the EFI computer or is it rocksolid?! Thanks anyway!! ------------- Livet går i direktsändning! |
Posted By: lewy2001
Date Posted: July-10-2012 at 4:41am
The EEC1V computer was used on Ford based automobile engines and they proved quite reliable. The GT40 PCM engine was released in 95. So some of these engines out there are approaching 20 years of age. The ECM in the marine application has also been reliable. There have not been many reported failures on this forum. Which would be the best indication as most owners with problems would find their way here via google. Your problem could be a intermittent relay problem. But do not rule out a wiring/connector problem or fuel pump. Having a spare relay or two will not go astray as they seem to be the weak link in a otherwise great engine package. ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: tachyon
Date Posted: July-15-2012 at 4:51pm
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UPDATE: Ended up finding a fuel pump at the local auto parts store. On my 2001 Super Air Nautique with the GT40 engine, after about 2 hours at the store, I found that a 1993 Mustang uses the same pump. Part number E 2061 or E-2061. Below is a link on Summit Racing's website to the same fuel pump. It is currently installed in my boat, and has about 10 hours on it - works perfectly! I am guessing that some other Mustangs use the same part, etc... the key is to make sure it has the two male spades for hookup, and that the pickup end of the pump is concentric with the outside diameter. Both O'Reilly and Auto Zone had the part, I ended up at Auto Zone for mine. http://www.summitracing.com/parts/ATX-E2061/ Thanks for all of your help guys!  ------------- Manufacturer of the Super Deluxe Boom Mount! http://www.tachyonmotorsports.com - www.tachyonmotorsports.com |
Posted By: modularman
Date Posted: May-17-2024 at 11:56pm
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Hello to lewy2001. You seem quite knowledgeable about the Ford EEC IV diagnostics. I am hoping you can help me with my boat. I am new to boat ownership. Recently picked up a 1995 SN GT40 Pro Boss. The boat is incredibly clean. It was very well maintained prior to my ownership. That having been said, I noticed after getting the boat home it would have an extended crank condition. After about one minute of cranking it would fire up and run well. When trying to restart after running it a both, it would fire right up. Once it cooled back down, it would go back to an extended crank. Without getting any time to diagnose the extended crank, I took it to the lake for a quick shakedown, and once in the water, it cranked and fired immediately (faster than it ever started before cold) but would stall after 1-2 seconds of running. It kept doing this at the lake. So back on the trailer and back home. Played with ignition switch (which looked new) and it fell apart while removing it. Figured that was it. Threw a new switch in it and no change. Noticed at this point, fuel pumps don’t prime but will pump when directly jumped to 12v source (could not get the pumps to activate through the STO diag port). After reading your post, I checked my battery box for a fuse (no fuse present), battery cables clean and tight, lanyard attached and appearing to work. I tested for power at both of the plugs that power the relays next to the ECU and found power only at terminal 30. No power at the other terminals no matter if key was on or off. I’m assuming this is the issue since I’m supposed to have power to terminal 86? Seems odd that the running concern changed after simply towing it to the lake. I’m assuming the vibration on the trailer has caused the running concern to change? Let me know what you think. Thank you in advance for any help you can provide. ------------- ModularMan Bay Area Boat Fanatic |
Posted By: KENO
Date Posted: May-18-2024 at 9:19am
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I can't decide if you have a manual with the appropriate diagrams for the fuel pump circuitry, but if you click on the link below, then I'll know that you have a manual  Pages 6-8 and 6-9 should be a help in figuring out your lack of power. to your pumps along with the troubleshooting steps for the pump circuitry. Whether you think your relays are good or not, I'd get myself 2 new relays right now for troubleshooting purposes, install them and see what happens and if they're not the problem you have a couple of spares that can be real handy.. PCM part number is R130011A but you can find them locally at NAPA or any parts store. At NAPA the part number is Echlin AR-174.or it can get cross referenced to plenty of other numbers. Like Lewy said, you need good relays for both the ECM and Fuel Pumps to make the pumps run, so replace both at the same time PS..... there are numerous discrepancies in the manual. It was originally written for the Vovo Penta/ OMC version of this engine that came out a year earlier and my guess is that PCM in a brilliant cost cutting measure, thought they'd save some money, do a lousy proofreading job, and slap their name on the cover. PS again.... I'd rather have power to the 85 terminal since the 86 goes to ground the way these relays are wired and that's what Lewy says above too......power to the 85 And the only way to get power to the 85 on the FP relay is thru a functioning ECM relay The wiring may seem backwards to you on the 85 and 86 but that's how they did it on these relays. Either one can get power with the other going to ground and Ford used the 85 as power for this application. |