fuel pressure on 200efi

[20vector]

faztbullet got quick question. was wondering if i have 36psi when running good and when acting up if it could still be a fuel issue. i opened vst and cleaned final filter but was already pretty clean. i believe i checked all electronics and no smoking gun yet. thanks in advance ted

 

[CharlieB]

Re: fuel pressure on 200efi

Unfortunately you will need to monitor rail pressure to see if there is a drop when the motor is acting up, which will prove either a dying pump or erratic pump driver in the ECU.

Pump driver grouonds the pump completing the circuit for the pump/motor, this can be monitored with a test light.

 

[20vector]

Re: fuel pressure on 200efi

charlieB thanks for all the help.as far as monitoring fuel rail pressure can i put gauge inline after fuel pump in that short hose before induction manifold? also when checking ground circuit it should be steady? if getting pulse on test light then ecu pump driver will be bad right? pressure at schrader valve being 36psi dont mean rail is getting 36psi? thanks so much CHARLIEB you are the man. thanks again so much. ted

 

[20vector]

Re: fuel pressure on 200efi

was also wanting to know if after market pumps ok to use

 

[20vector]

Re: fuel pressure on 200efi

just wanted to know how to test the fuel pump itself? i thought by checking pressure on the schrader valve told me the pump was good. but didnt relize the schrader valve wasnt on the fuel rail like it is on cars. so with that being said can the fuel pump still be going bad? i checked pressure on schrader valve and got 36psi while running good and when acting up still got 36psi at schrader valve. wanted to know a way i can tell for sure its the fuel pump acting up. thanks so much. im just a lil poor southern boy that dont want to buy a pump if i dont have to. thanks again so much for the help. ted

 

[CharlieB]

Re: fuel pressure on 200efi

i checked pressure on schrader valve and got 36psi while running good and when acting up still got 36psi at schrader valve. wanted to know a way i can tell for sure its the fuel pump acting up.

when acting up, is this 'while' in gear, throttle open? Or at idle, either in gear or neutral, as soon as you get get back to the motor to look at it?

A fuel pump beginning to fail can recover pressure almost immediately once engine load and fuel flow demand is reduced.

This is critical. Sufficient rail pressure while the engine is heavily loaded is more indicative of an intermittant ignition problem.

 

[20vector]

Re: fuel pressure on 200efi

when going out other day and it was acting up had my wife man the helm and i screwed fuel gauge on it. had wife put throttle almost full throttle where it should of been doing about 4500rpm but was only doing 2500rpm and i was getting 36psi. few times while doing this boat picked up rpms and started to take off but quickly fell right back off and whole time this was happening i was still getting 36psi. this was in foward gear whole time. wouldnt go over 2500rpm, if i put in neutral and rev it up rpms would rise like normal going over 2500 way over.thanks again charlieB

 

[20vector]

Re: fuel pressure on 200efi

with this being said does it sound like pump may still be good?

 

[CharlieB]

Re: fuel pressure on 200efi

Fuel pump is holding pressure while under load, it is more likely an intermittant ignition problem.

If you haven't already, download and study the Ignition Troubleshooting Guide availoable for FREE from CDIElectronics

You will need a DVA meter or a DVA adaptor to use with any Volt/Ohms meter to begin testing.

When testing the triggers, disconnect the throttle cable and move the throttle from idle to WOT and back while testing, this will help show an intermittant connection if a wire is broken where they flex.

 

[Faztbullet]

Re: fuel pressure on 200efi

Do you see a slight drop in pressure when you open throttles? What is your TPS reading? Have you bypassed the fuel pump?

 

[20vector]

Re: fuel pressure on 200efi

on my fuel pressure gauge it stays steady at 36psi no drops. on tps setting throttle closed get .3 and wide open its 7.5 . how can i bypass the fuel pump? i was hoping it would go out so i can find out what it was. but been doing this intermitting for past 3 years. but end of last year and already every trip this year been doing every time i go out. when first leaving dock does it but clears up quickly like after few minutes. but everytime after spending 3 or 4 hours on the islands with family when going to start going home it would do it from the get go. last week it took 30 minutes for it to hook up and go. the whole 30 minutes i keep working the throttle from neutral to foward wide open and finally it caught and went. it just wouldnt got over 2500rpm. few times while acting up i threw it in reverse and throttled up in reverse and it would go all the way to 4000 rpm and it sounded normal. instanly threw in foward and throttled up and all it would do is 2500rpm to 2100rpm. i kept thinking it was the tps and checked it about 10 times but always checked out good. i got a manual and a DVA meter and been checking everything since last year and no smoking gun on what it is. i checked everything few times and all readings are in range. thanks in advance ted

 

[Faztbullet]

Re: fuel pressure on 200efi

how can i bypass the fuel pump

Remove the ground wire(blk/red) from ECU to fuel pump and install a jumper from pump to ground,this will make pump run at full pressure. From what your describing it sounds like it may be dropping a cylinder/s. Pm me your address and will loan ya a good TPS. Check that electricial real good as it may also be the MAP sensor...

 

[20vector]

Re: fuel pressure on 200efi

fatzbullet tried to PM you but they say your mailbox is full. if map sensor can i send off to get it checked or rebuilt? is there any other test that you think i need to do. if the MAP sensor is going bad what exactly does it do? thanks so much ted

 

[Faztbullet]

Re: fuel pressure on 200efi

Pm me again as I was out of pocket having surgery. You can send ECU off to Brucatosvs.com and have checked(MAP) is inside it.

 

[20vector]

Re: fuel pressure on 200efi

hello all just update on my findings.. i took intake manifold off today and noticed about 2 teaspoons full of oil and fuel mix at the bottom of the cover. tony brucato told me that the oil might be clogging up my MAP sensor. just wanted to ask if this oil mix in the bottom of the cover is normal or if it was a big deal or not. gonna send my ECU off to Brucatos to check it. but i was wondering what causes this? another thing is that right before i took intake cover off i blew out bleed hoses so i don't know if this is what caused the oil in there?thanks in advance. ted

 

[SparkieBoat]

Re: fuel pressure on 200efi

Pm me again as I was out of pocket having surgery. You can send ECU off to Brucatosvs.com and have checked(MAP) is inside it.

WHAT??? what surgery?? I hope everything is ok..maybe it was cosmetic??

 

[jeffersondodson561]

Re: fuel pressure on 200efi

To inspect the map sensor hose you need to remove the ECU from the air box, I think you are looking at the recirculation hose, which is normal to have fuel/oil mix in it. Your fuel pressure should drop a little from the low pressure in the plenum. I have always tested the fuel pressure regulator with a mighty vac to over emphasize the spring pressure. It should work in both directions pressure and vacuum. Before sending your ECU off I would check pressure regulator and ignition. If this is the Merc with the switchboxes the primary ignition voltage for the cylinders is what triggers the fuel injectors.

 

[20vector]

Re: fuel pressure on 200efi

sorry it wasnt the intake manifold i took off the induction manifold and the cover. i didnt take completely off motor just took bolts out and leaned it foward and took quick look at front of injectors and the back of injectors and thats when i noticed the oil. i didnt get to reed valves. i just read where it could be normal for oil to be in there. tony wanted me to check and see if it was getting clogged up going to MAP sensor fitting. didnt see that much oil in there. i dont know how much is too much. i put it right back together.thanks for all the help guys. any more info please help. i post when i get done with other checks. thanks in advance ted

 

[Faztbullet]

Re: fuel pressure on 200efi

i just read where it could be normal for oil to be in there

It will do to this is a wet reed motor, the oil/fuel mist will leak into the manifold after running and engine trimmed up.

tony wanted me to check and see if it was getting clogged up going to MAP sensor fitting.

There will be a little oil on hole where fitting is and he wanted you to see if it was a thicken glob as if oil was puddled up to fitting it would be about 3" deep in intake...

 

[Faztbullet]

Re: fuel pressure on 200efi

WHAT??? what surgery??

This is why I been off board for a few weeks,had intestinal surgery and bllod sugar problems but getting better....