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2001 5.7L EFI Flooding at Idle

I've installed a new IAC sensor, and the TPS is working, I think it's the fuel regulator, and until the test adapter for the fuel pump/regulator arrives I want be able to eliminate those.
 
mastertec Tech Mercury said:
I take it this motor is TPI, if so by looking at spray you can't till what's going on with your eyes....
Here is Tech Tip use a timing light, this will show you if flooding with larger droplets, or you will see nice even spray...
Some one say a EFI can't flood, well yes it can.... EFI with VST like old 502 flood # 8 when needle got stuck...guys in Marine trade know all all about this.....


Steve
Click to expand...

Um, Steve it's a TBI engine. It was me who said EFI can't flood and it can't, not in the sense that a carburetor floods.
Ou, you should have 15 psi at the TBI inlet. That's the optimal fuel pressure. It'll work OK with as little as 12, but not over 15. Too much is too much. Marine-performance-parts.com has a TBI inlet adapter that allows you to put a fuel pressure gauge on it. It may be your pressure is the issue. Could be your pressure regulator needs to be replaced. However, on a TBI unit the regulator is built in to the throttle body, so for them to say they need to pull out the engine to replace the fuel pressure regulator make zero sense.
I think I have one of those adapters sitting around gathering dust from one of my earlier TBI based projects that went nowhere. Yours for shipping.
 
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o2batsea,

The fuel pump and regulator is below the front motor support on this puppy (Ser # M043680), i wish it was at the throttle body.......
Thank you for the offer of TBI fuel gauge adapter, I have one on order from CFM-tech that should be here next Tuesday, it should have been here Thursday......If it's not here by Tuesday I'll take you up on your offer.
Thank you for your input, it's really appreciated.
Fred

Steve, I haven't gotten the vacuum at Idle but will tomorrow, you asked about compression test. Below is that info. Test was performed dry with all plugs out, engine cold, and at WOT. BTW I retested the # 1 cylinder again and 165 psi is what it tested.

1-165 psi, 3-195 psi, 5-200 psi, 7-200 psi, 2-200 psi 4-195 psi, 6-200 psi, 8-209 psi

Thank you also for your assistance, I'm finally getting a handle on how TBI works, with you guy's help I'll get this problem solved.
Fred
 
I had to go to a Marina this week with same problem you are having....
I did all my test then, some.... This on had Bravo 3 diver, when put into gear I seen IAC count to high...
I took off ECM and got it re-flash, put on engine runs great.... Take to a dealer and get them to send it to Mercury, with a note what is happening.
Engineers will change some things in ECM

Steve:rolleyes::rolleyes::rolleyes::rolleyes:
 
Steve,

I should recieved the fuel pump/regulator test adapter from CFM-tech tomorrow, if test is normal I'll focus on the ECM.....what you saying makes sense.
Thanks
Fred
 
On this engine there is no VST, however there is a Fuel Damper/regulator part of the TPI body with a fuel vent to the throat of the throttle body. There is no leakage through the damper.

I did take it apart and it looked good. I think the damper is there to dump high fuel pressure in the event the fuel pump and regulator that is in the cool box over pressures the system. In any event the only fuel that is entering the throttle body is comming from the injectors (2).

Thank you for your comment, I'm looking for any reccommendation, I contacted my dealer today regarding getting the ECM re-flashed as suggested above, he indicated he would let me know but wanted to sale me a new one................
 
OK. I recieved the TBI fuel pump test adapter, installed it and got the following pressures.

A. 36 PSI, only with switch turned on and fuel pump ran up and stopped, pressure bleeb back to 26 PSI after 15 mins. each time.

B. 34 to 36 PSI, Engine running at Idle (600 RPM).

C. I think I found the problem with the flooding at Idle, Just to reconfirm a note from 02batsea above, Fuel pressure to be at 12 to 15 PSI, no more then 15 PSI.......If this is correct I will start try to replace the regulator in the cool box.
As mentioned above, its mounted below the front engine support and the wall of the sub floor, it may be a bear to get out without removing the engine.

D. Is it possible to leave the regulator as it is and then add an adjustable regulater mounted above the engine.....????

Thank You guy's
 
Went ahead and pulled the cool box, regulator, and fuel pump while the boat is in my work shop tonight, wasn't fun and a little tight but got out and on the work bench.

Not much to it, regulator was corroded and rusty on the out side, inside the discharge side you could see what looked like fuel varnish with black spec. The filter below the regulator was clean.

The regulator is made in Japan with the following markings, NR-1 and below that what looks like MEI*HIN, if anyone knows were I can buy one please let me know. (Pressure between 12 and 15 psi max)



Thank You Fred
 
I just reviewed my repair manual again and it indecates 30 PSI as a pressure at the Throttle Body, I measured 34 to 36 PSI is that enough difference to cause the rough idle?
I'm confused............

While it's out I ordered a new regulator from iboats today, it's made by Mallory, Mercuriser (dealer) did not have one.
 
30 PSI is correct for TBI (REGULATOR WITH PINK MARK). In post number 24, I gather that you're saying the vacuum tube was connected to the flame arrestor. Are you sure? Pretty sure it goes to the intake manifold.
 
Yes, the vacuum tube is connected to a connection under the flame arrested that I assumed would allow fuel to vent/dump into the throttle body in the event the regulator diaphragm failed.

When I first saw the vacuum hose routed to the regulator I question in my mine at the time if that was correct. I did remove it from below the flame arrestor and installed it on the only vacuum port that is on top of the motor, which is behind the throttle body on the lower flange/plate. There is a rubber plug that in normally on the port, when I removed the plug from the vacuum port the engine was at idle, and you could hear and feel the vacuum. I attached the hose to the port for four or five mins. and there was no change so I switched it back to the way it was. This is crazy, you think I didn't let it run long enough.......I think I would have seen something, if nothing else a change in the rate of the fuel coming out of the injectors.

Fuel Pressure, I had read that 30 psi was what it should be, but also read it should be 12 to 15 psi, if it is the 30 psi which I tend to agree with you, would the 4 to 6 additional psi make that much of a difference?
As mention somewhere above I got a 34 to 36 psi test at idle.
Thank you guy's for hanging in there with me.........hopefully the new fuel regulator will do the trick.
fred
 
WoodieMan,

Just to confirm the hose route from the fuel regulator in the cool box, it does connect to the bottom of the flame arrestor, the feature prevents fuel from running into the bilge in the event of a rupture in the fuel regulator diaphragm.

Fred
 
What colour mark is on the regulator? If it is yellow and orange, it's for MEFI MPIs which run at 36 PSI. You should have the Pink paint mark (if OEM). So let me get this right; you have a gen II cool fuel under the port side of the engine with an electric fuel pump attached and a regulator mounted on top. There is a fuel line on one end of the regulator and a vacuum tube on the other. If this is the case, you have a regulator that requires a direct intake manifold connection for an accurate vacuum to control fuel pressure. The diaphragm is manipulated by vacuum to either send fuel to the rail or to the return. This is how it maintains a given pressure based on vacuum/load. If the diaphram ruptures, there will be no regulation, and fuel will have nowhere to go but to the rail, return, or into the intake manifold. Vacuum tube going to the flame arrestor is not sitting right with me. Perhaps someone has a service manual that will confirm either way.....anyone?
 
Vacuum Tube, This is what I found in the 2001-06 SELOC Mercuriser repair manual page 7-39 (Fuel Injection Section) a Vacuum Diagram which shows the vent hose from the regulator in the Cool Box on the port side routed to the flame arrestor.
On the bottom of the diagram in the book it says V6 & V8 engines with TBI..........There is other diagrams but they are Multi Ported engines. I have a TBI engine.

Fuel Regulator, it should be the pink one for the Throttle Body injected motor, but there is no pink color or any color on it so i have to assume it was installed at the factory that way. Anyway I ordered the pink one from iboats.com (9-33205 Mallory Fuel Pressure Reg.) my Mercuriser dealer didn't have one.

I should recieve the regulator in the US mail tomorrow, so maybe I will have good news by Monday. I have to move sand bays tomorrow but maybe my wife will let me get back to the boat Sunday.
Thank you for the help.
Fred
 
WoodieMan, More to post # 48, I do have the gen 11 cool box with the fuel regulator mounted on the fuel cooler, electric fuel pump, and the vent hose. All this is now cleaned up a laying on my work bench waiting on the new reg.......except the little fuel filter below the regulator, I lost it.

Also I meant to say sand bags not sand bays, we got lucky this time.
 
WoodieMan,

More to post #48, I checked the regulator again and this time I had my glasses on, I found a small spot of pink paint at the base.............my fuel pressure was 34 to 36 psi at idle, my understanding is the pink reg. is rated at 30 psi maybe that's the fix.
Thank You
 
WoodieMan said:
What colour mark is on the regulator? If it is yellow and orange, it's for MEFI MPIs which run at 36 PSI. You should have the Pink paint mark (if OEM). So let me get this right; you have a gen II cool fuel under the port side of the engine with an electric fuel pump attached and a regulator mounted on top. There is a fuel line on one end of the regulator and a vacuum tube on the other. If this is the case, you have a regulator that requires a direct intake manifold connection for an accurate vacuum to control fuel pressure. The diaphragm is manipulated by vacuum to either send fuel to the rail or to the return. This is how it maintains a given pressure based on vacuum/load. If the diaphram ruptures, there will be no regulation, and fuel will have nowhere to go but to the rail, return, or into the intake manifold. Vacuum tube going to the flame arrestor is not sitting right with me. Perhaps someone has a service manual that will confirm either way.....anyone?
Click to expand...
Yes on the "throttle bodies" the vacuum hose goes to the flame arrestor. Below is a copy and paste of the wording only minus the routing diagram.

Throttle Body EFI

a -
Plenum​

b - ​


Cool Fuel Assembly​

c - ​


Diaphragm Rupture Hose - Fuel Pressure Regulator on Cool Fuel Assembly To​

Side of Flame Arrestor​

d - ​




Vent Hose - PCV Valve to Throttle Body Adapter​

e - ​


PCV Valve​

f - ​


Vent Hose - Valve Cover Fitting To Flame Arrestor​

g - ​


Valve Cover Fitting
h - Flame Arrestor​

For a similar hose routing "diagram" for the "throttle body system" have a look at page Page 5C-6 and/or Page 5C-19.
http://www.maxumownersclub.com/forum/site_files/manuals/mercruiser/24.pdf​

Also the fuel Fuel Pressure should be 30 psi (207 kPa) @ 1800 rpm). See page 1B-8​
 
boat_tech
Thank you for the information, It's been a great help.

Ok, I got a little set back with the new fuel pressure (Pink) 30 psi regulator, it came without the fitting to the fuel line so while taking the fitting off the old regulator it twisted off at the base, so I'm stuck until I find a replacement fitting............Dam fustrating when it happing.

Question; What is the torque on the fitting and do I use loc-Tite?
And does anybody know where I can purchase the fitting? [email protected]
Thank You
Fred
 
ou05648 said:
Question; What is the torque on the fitting and do I use loc-Tite?
And does anybody know where I can purchase the fitting?
Thank You
Fred
Click to expand...
Merc part number 22-808002A1, You should be able to find and buy the part here at marineengine.com.

Here's a direct link with a photo to your fuel system to make sure I found you the right part, See #19 in both links.
http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=809500%2099&ivar=images/COMMON/14152.png&inbr=4856&bnbr=90&bdesc=Fuel+Pump+And+Fuel+Cooler

http://www.marineengine.com/parts/m...ntId=3079&component=FUEL+PUMP+AND+FUEL+COOLER

Also here is all of your parts for this engine.
http://www.marineengine.com/parts/m...V-8+1999&serialId=3264&serial=0L340000+AND+UP
Or to see some good photos of the parts look here,
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=809500+99

I believe the fitting will come coated with the right Loctite Pipe Sealant already applied if memory serves me correctly. I believe that's part of the kit, But could be wrong.

Torque Specifications​
Fastener Location lb. ft. N·m​
Fuel Lines, 18lb. ft 24 N·m​
Fuel Fittings, See Note
Fuel Supply Connections
WARNING
Avoid gasoline fire or explosion. Improper installation of brass fittings or plugs into
fuel pump or fuel filter base can crack casting and/or cause a fuel leak.​

•
Apply #592 Loctite Pipe Sealant with Teflon to threads of brass fitting or plug.
DO NOT USE TEFLON TAPE. ​

#592 Loctite Pipe Sealant with Teflon ,Obtain Locally.
• ​

​

Thread brass fitting or plug into fuel pump or fuel filter base until finger tight.
• ​

​

Tighten fitting or plug an additional 1-3/4 to 2-1/4 turns using a wrench. DO NOT
OVER-TIGHTEN.
• ​

​

Install fuel line. To prevent over-tightening, hold brass fitting with suitable
wrench and tighten fuel line connectors securely.​
• Check for fuel leaks.

​
 
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Purchased a Cool Box regulator fuel line fitting from Mercruiser dealer in New Orleans this afternoon and got everything put back together and back in the boat tonight.

Did a test on the new regulator, it tested at 32.5 psi, compared to the old (OEM) regulator which tested at 34 to 36 psi.
Ran engine at an idle on a hose for 30 mins and fuel pressure (32.5 psi) was steady as a rock, the engine ran better then it ever has, it has always Idle rough, now it purs at idle.

I'm surprised that 3 1/2 psi made that much of a difference but it does.

Will run it tomorrow under load for a couple hours, that should prove up the fix.

I still have on order at boatfix a new fuel regulator fitting and a set of orings, the dealer here originally told me he hasn't had the regulator or fitting in stock in four years, he call me today and said he found a fitting. My dealer makes you want to curse........

Again thanks to all for the help.
Fred
 
Wanted to let you guy's know that I was able to test run the boat yesterday and the flooding problem at idle is fixed.............I ran it on a 12 gal. test tank, at idle and WOT (4850 rpm) it ran great.

I was never able to move from reverse to forward and back without the engine stalling at lease once from the boat being new, it now runs absolutely perfect.......Why wasn't the Mercruiser dealer not able to find the problem!!!!!! (I think it came from the factory with the wrong fuel regulator)

Now to replace the tanks and clean all the dirt dobbers out of the boat.

Again thanks to all that gave me a hand.

BTW, I plan to go with Moeller cross-linked poloyethylene plastic tanks, if any concern please let me know.

Fred
 
School's still out on plastic tanks as far as I'm concerned. When they can last for 30 years without permeation, maybe I'll reconsider my thoughts. And considering that there may be future changes in fuel chemistry that may affect certain plastics, rubber etc., I would not take the risk.
 
I know, I though the same thing about the plastic being used for gas, it's not the gas as much as the additives added during the refining process.
I spoke to a chemist at work and he was the one that indicated the cross-linked poloy..... was what our company uses to transport acid and other chemicals offshore or to land drilling operations. The difference are the tanks are designed with a heavy steel mess around them and can be as large as 2000 gals. and an inch thick.
Anyway if they last ten years I'll be happy, after that I will be to old to care.

Fred
 
I'm sure they'll last a while, I wasn't reffering to the possibility bursting (re steel mesh), and for transport out in the open is OK. My concern is the smell of fuel once it permeates the plastic in an enclosed environment (a boat). Seen it in a deisel application; had to be replaced after five years. Some boat manufacturers that once used plastic have done a 180 and gone back to metal due to recalls. I know plastics have changed recently but I think I'll let someone else be the guinie pig!
 
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