Fuel pump not running, blown fuse

[Zkdk3000]

I have an 02 Launch SS with 270 hours, ran just fine 24 hours ago. Today I went to start the boat and it would only turn over but not fire. Went through the steps, air - fuel - spark. My indmar 320 is the TBI version, so I sprayed some carb cleaner into the throttle body and it fired right up momentarily. Upon further inspection I realized the fuel pump was not priming at all. Looked through the forums all day and came to a post about a fuse blowing near the ECU that hinders the fuel pump from receiving power. Located the fuse and noticed it was blown. Replaced it, blew again. I must have a short but I'm unsure of where to start looking. I've taken a picture of the fuse area so please give any pointers on where to start looking. Thanks in advance.

Zk

http://i66.tinypic.com/2i0q4wx.jpg

[Zkdk3000]

Turns out the fuel pump is bad and that's what was causing the fuse to blow. Instead of making a new post I'm going to post my next issue here.

I've been on the phone with Indmar and Supra all day trying to get some direct answers on which fuel pump I need. I have not gotten a straight answer but only a recommendation.

My first questions is, does anyone know how much turnkey pressure is needed and how much running psi is needed on these motors? I have read in the chevy truck forums that it should be around 12psi running lbs, but that does not take into account the low pressure pump in my stock setup.

Second question is which of these three high pressure pumps that I've researched seem more appropriate?

Carter 61157
-Max running 25psi
-Static psi 40lbs
-20 gal/hr
-$115

Carter 61171
-Max running 43psi
-Static psi 120lbs
-30 gal/hr
-$70

Indmar s495126
-specs unknown (even Indmar said they did not know and that this is the closest thing they carry to the stock pump that is no longer manufactured).
-$270

I have read elsewhere that someone whom replaced their pump with the Indmar pump now has a poor running condition, guessing too much or too little psi. All three pumps resemble my exact stock pump. Any info would be greatly appreciated!

Zk

[Jenvey]

I see in your post your year is an O2 I have an 08 Inbmar and I had a similar problem but it was a blown relay that feeds the fuel pump.
I had the high-pressure pump psi tested once I got the relay fixed and it was at 60 PSI I don't know if there's a big difference between the years, I think you need at least the 43 PSI.
I don't know if this helps you or not I just wanted you to know that the pressures are pretty high in the fuel pump.


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[Jenvey]

Oh I forgot to mention one of those relays that are down by your hand in the picture also provide power to the fuel pump


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[lively]

If the engine is fuel injected or has a throttle body , it will use a electric fuel pump , that pump needs to maintain 32 psi no matter what , that's what all automotive engines use , and that pretty much the same .


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[Zkdk3000]

I see in your post your year is an O2 I have an 08 Inbmar and I had a similar problem but it was a blown relay that feeds the fuel pump.
I had the high-pressure pump psi tested once I got the relay fixed and it was at 60 PSI I don't know if there's a big difference between the years, I think you need at least the 43 PSI.
I don't know if this helps you or not I just wanted you to know that the pressures are pretty high in the fuel pump.


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Thanks for the reply. My manual says fuel pressure must be 30psi minimum at key up. I've read elsewhere that at idle the psi should be around 12psi. A lot of conflicting info, I think the best option is to try the higher rates of the two and see if it burns out. If it does that means too much in line pressure leading to overheating condition.

Also, do you know which of the relays controls the pump? After I disconnected the HP fuel pump and removed it, I replaced the blowing fuse and turned the key. Low pressure pump primed and starting spitting fuel all over. So I would assume the pump was definitely frozen, or the plug went bad. Either way I just about destroyed it removing it - thing was really really really in there. Thanks again for the info and anymore suggestions please chime in.


Zk

[Zkdk3000]

If the engine is fuel injected or has a throttle body , it will use a electric fuel pump , that pump needs to maintain 32 psi no matter what , that's what all automotive engines use , and that pretty much the same .


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That's also what I thought, but a few guys have told me that throttle body injected engines need no more than about 15psi. Very confusing. There are a couple more carter pumps I have found with similar specs, I just hate playing the guessing game - would rather get it right the first time.

Zk

[lively]

That's also what I thought, but a few guys have told me that throttle body injected engines need no more than about 15psi. Very confusing. There are a couple more carter pumps I have found with similar specs, I just hate playing the guessing game - would rather get it right the first time.

Zk

Take the fuel pump off and find a part number


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[Zkdk3000]

Take the fuel pump off and find a part number


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There is a part number on the side but it doesn't cross reference to anything. GM discontinued it in 2010. Indmar doesn't even know the specs on stock pump.

Zk

[lively]

There is a part number on the side but it doesn't cross reference to anything. GM discontinued it in 2010. Indmar doesn't even know the specs on stock pump.

Zk

What's the number that you get off the pump


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[Zkdk3000]

What's the number that you get off the pump


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344 0872A

Zk

[lively]

344 0872A

Zk

I got nothing , but 12-15 psi is correct out of the injectors , 32 psi line pressure to regulator then to TBI . Find the fuel pressure regulator and see if you get a part number and cross reference specs


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[Zkdk3000]

I got nothing , but 12-15 psi is correct out of the injectors , 32 psi line pressure to regulator then to TBI . Find the fuel pressure regulator and see if you get a part number and cross reference specs


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I had yet to think of that - good idea. Should be up next to the throttle body correct? Or maybe even built in?

Zk

[lively]

Yes looks like a little can , it will be in line to TBI . That won't let anything more than it needs .


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[lively]

I was wrong , fuel press regulator is part of the TBI , its in top of the throttle body itself , its sits between the 2 boosters in the back .


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[Zkdk3000]

I was wrong , fuel press regulator is part of the TBI , its in top of the throttle body itself , its sits between the 2 boosters in the back .


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I'm going to look once it warms up a little bit this afternoon. I've been chatting with Larry the Engine Nut and now I think I understand what you're saying. The line after the HP pump leading to regulator has to have 30 pounds of pressure in it, the injectors put out around 12 pounds of pressure. Correct?

[lively]

I'm going to look once it warms up a little bit this afternoon. I've been chatting with Larry the Engine Nut and now I think I understand what you're saying. The line after the HP pump leading to regulator has to have 30 pounds of pressure in it, the injectors put out around 12 pounds of pressure. Correct?

Yes , and if you have a amp meter you can check the load that the pump is putting out during running condition to verify its within range of the fuse rating .


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[Zkdk3000]

Yes , and if you have a amp meter you can check the load that the pump is putting out during running condition to verify its within range of the fuse rating .


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Thanks for sticking with me on this. New development. Got new pump, plugged it in, turned key, fuel pump fuse blew. This was the original issue. For shits and giggles I unplugged the low pressure pump, plugged in the high pressure pump, replaced fuse, turned key. High pressure pump ran and fuse did not blow. Switched the pumps and the same outcome. Only one pump will run at a time without blowing a fuse. I officially have a headache.


Zk

[lively]

Thanks for sticking with me on this. New development. Got new pump, plugged it in, turned key, fuel pump fuse blew. This was the original issue. For shits and giggles I unplugged the low pressure pump, plugged in the high pressure pump, replaced fuse, turned key. High pressure pump ran and fuse did not blow. Switched the pumps and the same outcome. Only one pump will run at a time without blowing a fuse. I officially have a headache.


Zk

Are they supposed to run at the same time ? I'm in aware on how your system operates , but if the fuse is blowing right away , check the wiring first , and then find out the amps that the circuit is pulling during load application . Can you clarify why it has 2 pumps and how it all works so I can better understand ?


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[Zkdk3000]

Are they supposed to run at the same time ? I'm in aware on how your system operates , but if the fuse is blowing right away , check the wiring first , and then find out the amps that the circuit is pulling during load application . Can you clarify why it has 2 pumps and how it all works so I can better understand ?


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Sure. From the tank runs a fuel line to the low pressure pump. From the low pressure pump runs a hard line to high pressure pump. Fuel filter threads on to bottom of fuel pump. High pressure outlet to throttle body. Return line to tank. From what I've read the low pressure pump just puts out enough psi to feed the HP pump. Around 3/4 psi. I believe they do run at the same time. Engine Nut says both pumps run off the same fuse and same relay. As I said before I can only run one pump at a time without blowing that fuse. Ordered the low pressure pump in case that's the prob. Both do run though when separately tested.
Here's a picture for reference.

http://i67.tinypic.com/ke6fr8.jpgehy

Zk

[lively]

Sure. From the tank runs a fuel line to the low pressure pump. From the low pressure pump runs a hard line to high pressure pump. Fuel filter threads on to bottom of fuel pump. High pressure outlet to throttle body. Return line to tank. From what I've read the low pressure pump just puts out enough psi to feed the HP pump. Around 3/4 psi. I believe they do run at the same time. Engine Nut says both pumps run off the same fuse and same relay. As I said before I can only run one pump at a time without blowing that fuse. Ordered the low pressure pump in case that's the prob. Both do run though when separately tested.
Here's a picture for reference.

http://i67.tinypic.com/ke6fr8.jpgehy

Zk

Well if it was me , I would ohm the pump motors out to see what they read and then find why the circuit is feeding so many amps . Let me know because it's almost either there is blockage or the relay is not shutting off when it's satisfied for start up . Idk I see why they use the low press pump it's just a little feeder from the tank . But to blow a fuse while both are on , high Amps or blockage or little of both maybe . With out a meter or some ohms readings idk . Let me know what you find !


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[Zkdk3000]

Well if it was me , I would ohm the pump motors out to see what they read and then find why the circuit is feeding so many amps . Let me know because it's almost either there is blockage or the relay is not shutting off when it's satisfied for start up . Idk I see why they use the low press pump it's just a little feeder from the tank . But to blow a fuse while both are on , high Amps or blockage or little of both maybe . With out a meter or some ohms readings idk . Let me know what you find !


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Okay good news and bad news! Ordered the low pressure pump and installed it. Both pumps run when plugged in without the pump fuse blowing. Bad news is when it fired up after a couple seconds the idle started to shoot up to around 2500rpm as if I was giving it steady throttle. It then suddenly bogged out and died. The pump I installed was the p61171 120psi static and 43psi max running. I think the pump may be too powerful and flooding the system. After the initial start boat would not start but once every 20 or so cranks and only for a second, would fire and bog out immediately. I also picked up the p5001 pump 30-50 static 9-22 running psi which I'll try next after I let the system sit with battery unplugged for several minutes and try firing it with the 61171 installed.

Zk

[lively]

Sounds good , guess the pump was just had to much amps


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[Zkdk3000]

Sounds good , guess the pump was just had to much amps


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Switched the pump to the 5001 and it fired right up. So in conclusion I used the 4389 Carter for low pressure and p5001 Carter for high pressure. Only issue now is a high idle of 1000rpm pre-throttle at start up and 1500 post-throttle. I already changed the TPS sensor. This issue existed before the pump failed. Any ideas what to look for?

Zk

[lively]

Switched the pump to the 5001 and it fired right up. So in conclusion I used the 4389 Carter for low pressure and p5001 Carter for high pressure. Only issue now is a high idle of 1000rpm pre-throttle at start up and 1500 post-throttle. I already changed the TPS sensor. This issue existed before the pump failed. Any ideas what to look for?

Zk

Air leak , take some brake clean or starter fluid and spray around intake and mating surfaces where gaskets seal the two parts , or what is the linkage adjusted too ? Can you adjust it ?


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[Zkdk3000]

Air leak , take some brake clean or starter fluid and spray around intake and mating surfaces where gaskets seal the two parts , or what is the linkage adjusted too ? Can you adjust it ?


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I will start it and check for leaks near the intake. Here's a picture of linkage, and also is that the IAC in the second picture? Could that be the culprit? And I do have perfect pass which seems to be operating normally.

http://i65.tinypic.com/2dlpvs6.jpg

http://i63.tinypic.com/lblsg.jpg

[lively]

If you disconnect the cable from the back where that latch is that hold it . If you remove that and let the cable loose does the idle change or does it stay the same ? IAC does control most of the idle circuit , but just a quick check of things like air leaks and linkage adjustment should firm up the dial and how much have you driven the boat ? Run a couple good laps and just return to neutral and see if rpm drops


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[Zkdk3000]

If you disconnect the cable from the back where that latch is that hold it . If you remove that and let the cable loose does the idle change or does it stay the same ? IAC does control most of the idle circuit , but just a quick check of things like air leaks and linkage adjustment should firm up the dial and how much have you driven the boat ? Run a couple good laps and just return to neutral and see if rpm drops


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You're saying to remove it on the right side there where that latch type mechanism is? Because I can't figure out how to. I was just going to spin the cylinder Nut off on the left. I sprayed carb cleaner around the base of the throttle body with no change in idle. Visual check of all vacuum lines looked good. I've never driven it I've only owned it a couple months. Trying to get it water worthy so I can test everything under load.

Zk

[Zkdk3000]

I unhooked the cable at the Nut and no change in idle. A separate issue I'm now seeing is possible fuel out the exhaust and maybe even in the oil. I've called the local Indmar certified shop and they don't have any room to get me in.

Zk

[lively]

You need to know what your fuel PSI is . That's where you started and that's what has been touched , the pumps may be too much . . As too speak to a tech and get a opinion , but I would want to know fuel pressure and then start there , cause it sounds like there is too much fuel pressure and it's just dumping . Look at the TBI open the air filter and look as it's running . Smother it with a rag and see if the two boosters are still feeding fuel .


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[Zkdk3000]

You need to know what your fuel PSI is . That's where you started and that's what has been touched , the pumps may be too much . . As too speak to a tech and get a opinion , but I would want to know fuel pressure and then start there , cause it sounds like there is too much fuel pressure and it's just dumping . Look at the TBI open the air filter and look as it's running . Smother it with a rag and see if the two boosters are still feeding fuel .


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You said it has to be at least 30psi at the rail right?

Zk

[lively]

You said it has to be at least 30psi at the rail right?

Zk

Yes , but the regulator could be bad as well because of the other pump that you put on it could've blown the bits apart inside , but I would definitely put a gauge on it and if you go to Harbor freight nearby they got a cool little set up for about 20 bucks


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[Zkdk3000]

Yes , but the regulator could be bad as well because of the other pump that you put on it could've blown the bits apart inside , but I would definitely put a gauge on it and if you go to Harbor freight nearby they got a cool little set up for about 20 bucks


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20 bucks?! Shit I'll def be picking that up tomorrow! Found a mastercraft shop that has the software to scan an Indmar (thank god). Dropped it off and they scanned it - diagnosed the high idle from lazy IAC. Other than that there was a code for low voltage from TPS. Said fuel pressure at the rail was within spec so the good news is im using the correct high pressure pump - as for the regulator if I can find a part number cross for a Chevy I'll replace it. Shop guy said he can't get from Indmar they no longer make. Should I be looking for a "rebuild kit"?

Zk

[lively]

20 bucks?! Shit I'll def be picking that up tomorrow! Found a mastercraft shop that has the software to scan an Indmar (thank god). Dropped it off and they scanned it - diagnosed the high idle from lazy IAC. Other than that there was a code for low voltage from TPS. Said fuel pressure at the rail was within spec so the good news is im using the correct high pressure pump - as for the regulator if I can find a part number cross for a Chevy I'll replace it. Shop guy said he can't get from Indmar they no longer make. Should I be looking for a "rebuild kit"?

Zk

Just look up for a 95-99 blazer with a 5.7 L and look for fuel pressure regulator , that TBI was very common on those models .


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[Zkdk3000]

Just look up for a 95-99 blazer with a 5.7 L and look for fuel pressure regulator , that TBI was very common on those models .


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Okay Lively, I am back to 100 percent and running like a top. After mastercraft guys scanned the ECU they found faults for TPS and IAC. Bought the cross reference car parts from oreillys, they installed them and viola. They also changed my plugs. Thanks for sticking with me through this - I couldn't have done it without your knowledge. Much appreciated.

Side note: IAC from Indmar was 385, same part at oreillys was 54. TPS from Indmar is around 120, from oreillys was 35. Voltages at plug are the same.

Zk

[MJHKnox]

Cool thread to follow.


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[lively]

Okay Lively, I am back to 100 percent and running like a top. After mastercraft guys scanned the ECU they found faults for TPS and IAC. Bought the cross reference car parts from oreillys, they installed them and viola. They also changed my plugs. Thanks for sticking with me through this - I couldn't have done it without your knowledge. Much appreciated.

Side note: IAC from Indmar was 385, same part at oreillys was 54. TPS from Indmar is around 120, from oreillys was 35. Voltages at plug are the same.

Zk

No prob man , that's why this forum is here . I love it when i can come to the forum while I'm over brainstorming things , lol kinda keeps me sain at times ! Glad you got things buttoned up and running ! Enjoy !


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