I have decided I am going to add in the stock spider injection plug on the back of my manifold so I wont have to cut my truck harness. If anyone knows a good place to get this, let me know. All the junkyards around here that actually have a Vortec 4.3 wont sell just the intake.

 

615-859-9493 Shrum's Auto Salvage in Ridgetop, Tn. They also own a core shop, so they usually can come up with strange parts like that.

 

There is this 30 wire junction box from EFIConnection.
http://www.eficonnection.com/eficonn..._junction.aspx

Sure looks like the Vortec connector.

And no, I havent seen any back to back L31 to marine intake dynos yet. There are guys over 400rwhp and 500rwtq with Whipples on Vortec 350's.

peace
Hog

 

Hey 4.8, does the 4.3 marine intake engine still have that bog/stumble during throttle tip-in?

This could be caused by the difference in injector aim vs. the original poppets. The original poppet valve had a more optimal shot towards the intake runner, whereas the marine intake injectors fire at the cylinder wall.
the poppets are placed towards the inside of the intake port pais and are angled towards the intake valve. The marine intakes dont have near this type of injector placement.

Transient fueling, acceleration enrichment and/or cylinder wetting tables may need to be adjusted. Esp if you are experiencing a lean stunble upon tip in.

My V8 marine intake does this quite bad when cold, but gets better when warmed up.
Both the blown and NA marine intake guys are suffering from a lean tip-in issue.

HPQuck has a V8 marine intake and Whipple, Aloicious has a NA marine intake setup.
http://forum.efilive.com/showthread....nsient+fueling

http://forum.efilive.com/showthread....nsient+fueling

This doesnt explain you constant lean +20 trims. I do know that the marine intake FPR's run about 6-8 psi lower rail pressure at idle(high vacuum) than the stock L35/30/31 FPR's do.

peace
Hog

 

i haven't actually done this yet. it is all stock. but you don't actually cut the sensor out of the maf you just cut the two sensor wires. just like when you move the iat sensor on turbo trucks. i have a syty sensor hooked up to my manifold on my Tahoe and cut the wires from maf and wired them to the sensor.



that's just it it shows lean but the plugs are all black and it smells extremely rich. i believe this is caused by the misfire. its not burning the fuel so therefore not burning the air (O2) and causing the sensor to think its lean. its the only thing i can come up with. but i have to figure out why the misfire. i think i;m going to fire it up with maf off and intake tube off. then stuff the rubber plug it came with over the throttle body and see if anything leaks. if the motor still run i will chase the his and see what happens. if it dies i know there is no leak. we rechecks the wire as per the write ups. i think there may be a leak around the map sensor. her is a log if you have hptuners. there is a racket in the motor as it warms up too. maybe lifters i dunno. i wish i could go back and build the motor by myself and done this myself instead of "hey lets hurry hurry hurry"

 

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.

 

what about high oil pressure. my book mentions it but doesn't say how high. it idles at about 60psi when warm. 70 or so when cold.

 

I think mine idles 50-60 when cold, maybe more, not certain. I know its 50+.

 

what is it when warm?

 

On idle, cold, 50+. On idle plenty warm, 40 I think. I sent you a PM.