marine intake injector size

[4.8t]

well it wasn't the plug. so he took off the injectors and sure enough he said number 6 was black and oily looking and just nasty. but he said the spark plug was black too. i wonder if that one is maybe getting stuck open. only way i can see oil getting to anything would be valve seals but they were just installed when the guy did the heads. and still it wouldn't get on the injector. so i think its a nasty injector and sticking open. he pulled it, cleaned it, and swapped it with number 4. he got it back together and it wouldn't start lol. it was getting dark and its in the 20's here so he will start again tomorrow.

[4.8t]

so we played with it some today. i did some logging. o2's show way lean as in it has positive 24 or so trims. but it smells really rich and the spark plugs are black as coal. what gives? and there is a bit of a tick on the passenger side. its not there really when cold but as the oil temp rises it gets louder. is it a lifter failing? maybe they are all failing or something. as it warms up there seems to more racket. its running a bit better but has no power.

[LowestForm]

An oxygen sensor detects oxygen content, so a misfire will actually read lean as the oxygen isn't being used for combustion.

[UR50SLO]

Man you've got some strange symptoms. Are you sure this thing was 100% good before the Marine intake? Somthing's changed and causing you some real headaches and I don't think it's the Intake or the program.
Send me a log if you rememberd to save it.
Somthing's a-miss here.
~Scott
My Phone is in the vendors section if you need to give me a call.

[4.8t]

i saved a log yesterday. and i agree about missfire showing lean. i guess i could log and take control of fuel trims and turn them off. at higher rpm the mil flashes like crazy so i know its missfire. but is it too much fuel causing it or the actual spark. we built the motor prior to this.

[4.8t]

i will post the log on hptuners in the same thread as before.

[4.8t]

well we made some progress kinda. first a question. when you put on a fuel pressure gauge and you hit the key fuel pressure should rise and stay up a bit right? his goes up and then it falls right back down. i tried to pull the injectors up and check them out but it was hard to see anything leaking.

but we did a compression check. before i give numbers remember this thing has like 8.8:1 compression with a 224/224 525/525 110lsa cam. with that being said number 6 had 145 number 2 and 4 had 160. didn't get to do the driver side yet that's coming tomorrow. along with gutting of the cats. I'm afraid all the fuel may have clogged them up. then he is gonna change the plugs out to make sure they are not fowled.

another question/comment. the map is reading really high. as in 20% throttle and map reads like 80-85kpa. it barely take 1/2 to make 100kpa map. is this right? he is going to check the map sensor again tomorrow.

[ffmeltdown]

Yes, fuel pressure should hold. I think 3 things will cause it to drop, defective fuel pressure regulator, stuck injector, and fuel pump check valve stuck.

On the compression check (I'm sure you already know) that if an injector is bleeding down, that cylinder may have the walls washed with raw fuel, decreasing the compression reading for that cylinder. Again basic stuff but thats all i have to offer.

I have no idea on the map reading.

Respectfully,
Tom

[4.8t]

what are "normal" compression readings? i guess i could look in my book. i data logged last night and the computer is actually pulling fuel now instead of adding. every time we drove it it got a little bit better running. i think it needs sea foamed already lol. i can only imagine what the cats look like.

[4.8t]

looked in the book. i think the reading are good. now what about oil pressure. in the diagnostic portion for misfire it says high oil pressure. but it doesn't say how high is high. his oil pressure is about 60psi at idle when warm and about 70psi when cold what causes high pressure? i thought it was just tight clearances, which they were all right within the book. maybe the oil pump just pumps too much i dunno.

[ffmeltdown]

Old post but did you get it all straightened out?

[midnightbluS10]

yea...any updates?

[4.8t]

yeah how about a vid for a update. http://videos.streetfire.net/video/a...43L_700455.htm

sorry guys been bust working on it.

[4.8t]

well guys i was looking through this thread and figured you guys diserve a better update. after we installed the 60lbhr injectors and correct pigtails for them and he listened to me and fixed the damn map sensor leak, we did a 0411 computer swap. we went 3bar with it using hptuners. he also took out those $$$ plugs and put in some ngk's with some 8.5mm wires and heat shields. we got the turbo installed and all hooked up. then it was tune time. all the stumbles are gone, oh we also switched to some 3.90 gears. at 14psi boost the siemen 60's are maxed out and this is with a new 255lph walbro fuel pump. its makeing some great power. it blew the stock clutch apart so he had to upgrade that and the stock nv3500 whines in 1st and second.


he is its first run at the track. it popped out of first on take off. he put it back in first and hit the gas. it had a bad time but a hell of a mph for such a big truck and little motor.
http://videos.streetfire.net/video/4...ado_705885.htm

[UR50SLO]

we also switched to some 3.90 gears. at 14psi boost the siemen 60's are maxed out and this is with a new 255lph walbro fuel pump

What gears were in it before? Mid 3's is what you'd be needing. The higher the gear the less it will load the turbo/engine. It will actually slow you down in MPH and ET.

Don't worry about the ET... That'll come with getting the launch and fuel right there. Most of the time MPH is all I look at to judge weather the changes made a difference.

Your no where near maxing 60lb/hr injectors... at 102mph. I'll bet there at 50% DC. Sy/Ty's or GN's won't max out 60's in the high 10's so there's no way your doing it at 102mph Don't bother changing them out. What was the AFR down the pass? Happen to record it on a data log?

Good progress Keep it up!
~Scott