Fuel issues? Please help going crazy
 

Ok well I'm new on here and have been finding good info so figured I would join.

I bought a 1999 baja outlaw with a 454 mag MPI
I've been doing nothing but fixing the previous owners hack job on just about everything!!
The boat had a steady flat spot at about 3,500 or so when I took it out before I began any work. After taking back home I started looking into the ignition parts, one plug wire was rusted full not even touching plug so I replaced the cap, rotor button, plug wires and plugs. I also added sea foam and after I added the sea foam it would nt even rev past 3,000 rpm but maybe one time out of 5 attempts so I'm assuming it knocked something lose in the fuel system?? Did I mess up the electric fuel pump? How do I remedy this problem? I'm supposd to take a trip leaving wed and boat is far from good.

Also on spark plug note someone said run the bpr6efs plug... Is that ok? I noticed the reach is over 1/4" longer than the ac delco MR43T that I pulled out...
I gapped them at .35 like a stock plug says to, is that correct?

Sea foam shouldnt do anything to the fuel pump but a plugged filter can cause problems like that. I would replace the filter, see if there is anything in the old one, if the fuel smells bad change it. wouldnt be a bad idea to check fuel pressure also, not sure but I think it should be in the 36-38 psi range & steady. As far as the plugs go if the tag says mr43t which I think it does I would use them. If the plugs stick too far into the combustion chamber they can hit a piston! Also would be a good time to do a compression test to see where your at. Hope that helps, Randy

Compression is good, I checked that already. Changed fuel filter also and wasn't much of anything. Pulled the plug and no damage from anything like plug being hit by piston. Checking fuel pressure in am.

How do you suggest going about changing 70ish gallons of fuel??

On mine i disconnected the fuel lines from the engine added some line to get it out of the boat and put air in the fuel tank with a compressor not to much,it will come out.

sounds like a clogged injector or 2....common

So how do I "unclog" the injectors

Well I changed plugs to ac delco 10 which is what they said was cross to mr43t.
And I put a gauge on schrader valve to check pressure, it's 34 at idle, fluctuates bad by 6-10 pounds, at any given rpm, when I rev (this is out of water in a bucket in neutral) it gets to about 3,000 rpm an will drop as low as 26-28 then jump up to mid 30s but it stumbles and falls and such. The thing I don't understand is the smell of raw fuel when it does this??
Please help running out of time

Checked it again with fuel reg vac disconnected, fuel pressure was right around 40-42, when you revved it the fuel pressure drops a bit then when you rev to where it's at 3,000 and stumbles bad it flat lines at about 32

I think you found your problem, pressure fluctuating like that wont fly. With your time constaints you might pull the injectors & check for contamination in the fuel rails, ohm out your injectors & replace bad ones unless you have someone local that can clean them. F/P should remain constant throughout the rpm range. An injector that is stuck open will cause f/p to drop out, raw fuel smell, & can wash down cyl walls causing more damage. Does the oil have a fuel smell to it?

The plugs all looked the same, but little wet... Are you leaning more towards it being an injector over the pump?? Also to remove the pump do you have to remove the motor mount or how does that process go? I'm pretty good with cars I build LS stuff all day but these boats are a diff world and a work of art to get parts located

The oil is fresh and deff has a fuel smell so that would most likely be clogged injector or rail correct?

Sounds like you have 1 or more injectors stuck open. The pump & regulator sound ok. You will have to pull the plenum to get at the injectors, you might try to flush the injectors before you pull things apart but thats iffy, Better to find the root cause instead of a bandaid & make sure you change the oil again. You should be able to match injectos with gm units if needed I would still change out fuel if it smells bad. Best of luck to your new project & hope you get things fixed in time to play this 4th let us know what you find. Randy

I pulled the intake, one body was breaking and another body broke on re installation so does anyone have the part number or GM number of the injectors I'll just replace all 8... And a part number for intake gaskets.... So tired of "projects" I have a race car that I get to work on enough as it is! I just want to USE the boat not work on it!!

What can I do to the fuel system if anything to prevent damage to the new injectors sense most likely this issue was most likely due to breaking lose or junk in the system? I don't have time or the place to get them tested so I'm just going to replace all 8 with a rebuilt set or is it a must to buy brand new? Do you think that this is all I have to worry about per the situation I've given you of what the boat is/has been doing?

If you flush the fuel rails, run fresh fuel, & a clean filter theres not much more you can do. Sounds like you have the basics covered hope you get it running in time to enjoy the 4th. Randy

So you think I need to drain all 60-70 gallons of fuel that's in the tank?? Also is the pickup under the large screwed down cover that also has the seats mounted to it??

What do (YOU) think?
 

If your having fuel problems like this & the fuel smells bad to you, what do YOU think? A tank of fuel is a drop in the bucket if it keeps from breaking down on the water with a loaded boat. The fuel sender should be under the big screw down cap if your thinking of taking the sender out & siphoning the fuel out just be careful to clean any spills, shut power off so no sparks or open flames & do it in a well vented area. Randy

Stripping fuel tank
 

If you have a jabsco electric pump you can disconnect your fuel line where it goes into the seperator filter and hook up you pump there and suck out the fuel that way or top off your tank with 93 octane(no ethanol) and a couple of cans of octane booster and it should stabalize your fuel enough to run your engine with out any issues.Did you change the small canister filter that s mounted on the back of your intake that goes directly to the fuel rail/injectors?

I understand what your saying, it doesn't smell bad really at all but it also has a lot of sea foam in it. And that cap just gives me access to the fill line and vent line not the pickup.
I overnight ordered 8 new injectors from my buddies at fuel injector connection they hooked me up at 644 shipped!
I am hoping this solves the issues! After talking to the injector guys it sounds as if this is a seriously common problem

There is no filter or canister at the back of intake or fuel rail. I added sea foam and at about 40 gallons of 93 octane. I have some 116 leaded race fuel I'm going to add 5-10 gallons of that also. That should deff stabilize or equal it out!

I am watching this thread really close as I am having what sounds like the same issues. I too am a drag racer and know performance engines but this is kicking my butt. Check out "Baja 272 454 Mag fuel issues" I have done everything from sending the ECM off to be tuned, replaced the entire fuel delivery system with an aftermarket external pump, had the injectors cleaned and flow tested, changed plugs, wires, cap, etc.etc. Flattens out at 3200 rpm's and sounds like it's laboring or loading up. Only change was when I changed fuel filters and installed the new one empty which I'm assuming created a lean condition. Ran like a champ for the short time until the filter and system filled up. Keep posting your progress, hopfully it will help both of us. I've given up all hope of enjoying the 4th.

Well the guys I got the injectors from said it is very common for these injectors to be bad and rust on inside... They said they sell 2-3 sets a week. I'm praying that's all it is, if it's not only option and in your case could be the same would be a valve, or valve seat issue... I'm hoping that's NOT the case as I'm out of time if the injectors doesn't fix it.
I'll repost tomorrow after I install the new injectors

I don't think mine is going a valve seating issue as the engine was completely rebuilt over the winter with every single internal part new from the valve springs to the crankshaft so I've ruled out any mechanical issues. I guess I may be old school because I'm starting to hate anything with a computer in it. Very close to scraping the EFI and going carb.

Well about this time tomorrow I'll know if it was the injectors or not... Praying like heck it is!! Gonna change the oil in motor again sense it had fuel in it and change the drive oil tonight... If the injectors don't fix it I really don't know what to do... I be leaving it with the mechanic in somerset Ky to fix it!!

Well after overnighting 750$ in parts still same exact issue... Revs to 3200 then like its just on a rev limiter, once in a great rev it'll go on past it.
Wth!?

quick thought, recheck your firing order and recheck that each plug is correct. chevys are in a different order then fords... assuming thats your race car and you fix it alot. i know i do to mine.

i had an issue on my car, i used the regular 302 firing order instead of the HO order..... had me stumped for a few weeks and countless parts.

id also check for loose or broken vaccum lines. have you had it on a scanner ?

Firing order is good, idles great at 600-650.... Hits like 2500-3000 and just falls hard... Every now and again revs to 5,000 like a dang race car! I'm thinking fuel pump but everyone says no??

Fuel pressure gauge would help w that answer ...

Previous posts have my fuel pressure data

Well after new injectors, no fix.... New cool fuel, regulator and fuel log still same issue, put it on the computer and all values are in check, no codes... It beeped twice during the rpm issue which was exactly 2500 if running up slowly. Decided to go pick up from the second mechanic and continue to work on it at the lake, started messing with coil pack and noticed a slight change, well as we went to test it the starter went out!! How convenient!!! Well got a ride back to the dock, picked up a coil and new starter. Put new starter on and new coil. Bam issue solved!!! Maybe.... Took it out and it ran good but then about 20 min just fine and started to cut out again so we played with the coil mount which is in turn the ground for the coil and it ran fine again. So far so good!! A lot of wiring work to do when we return home!! Hope this helps some others after I threw 2,000$ in parts at it just ended up being a coil or coil/distributor ground