What Should I Rev Too?

[srtthis]

correct....

and i think i know where your going with that... yes it injects its own fuel. BUT it also needs that fuel from the injector to keep the air fuel where its at and not melt things down.

 

[Noobz347]

correct....

and i think i know where your going with that... yes it injects its own fuel. BUT it also needs that fuel from the injector to keep the air fuel where its at and not melt things down.

No... not what you're thinking. I think we had part of this conversation elsewhere already. Wet nitrous + EEC fuel shutoff limiter = BOOM (insert favorite mushroom cloud picture here).

I like the fuel cutoff that the EEC provides but I run boost and not nitrous. You'd think though, that the model specific nitrous kits would have a way to cut fuel and nitrous when the EEC does. No boom, and no backfire like what can happen by retarding timing.

I totally get it though about how fuel cutoff is undesireable in a wet system.

 

[srtthis]

there is a way, everyone should be running a window switch... but not everyone does. most people with autos i know dont. and even they need it for things like tire spin or blowing though the clutches. (been there done that in my 95 when i first sprayed it.

 

[vpap1]

ok check the gap on the autolitw 3924's they were set at .042 i brought them down to .035"

cleaned and clocked the maf and applied come dielectric grease to all ignition contact points

car feels great and still pulls all the way to hard to 5300 , so really no change for that

hard to say if it gained power with out hitting the dyno though

next i will try and diagnose the tfi pip and coil and see where i stand after that

 

[5.0Droptop]

If you are NA You need to open the gap to.052-.054. If NA Why would you run a tight gap? The wider gap gives a longer spark to burn the fuel.

 

[5.0Droptop]

Btw. I ran a msd box and dizzy on my 347 i ran .052 gap. No issues

 

[Noobz347]

If you are NA You need to open the gap to.052-.054. If NA Why would you run a tight gap? The wider gap gives a longer spark to burn the fuel.

I think he said earlier that he runs nitrous and is planning to run an even larger shot.

 

[5.0Droptop]

I think he said earlier that he runs nitrous and is planning to run an even larger shot.

Oh ok i missed that sorry.

 

[vpap1]

Oh ok i missed that sorry.

i'm aborting that thought for now till i figure this high rpm break up issues first, im gonna set them to .045" and continue looking at the ignition system

 

[5.0Droptop]

Any updates

 

[vpap1]

Any updates

ok tested resistance on the dyna mod TFI (came with car)

here are my findings=

A to C = 22.3 kohm
B to C = 1.093 kohm
B to 4 = 84.6 ohm
A to 6 = .3 ohm
C to 1 = 99.7 ohm

coil is getting full 12 volts with car on engine off

once installed I revved the engine by had while watching the Fuel pressure gauge, pressure dropped from 40 to 35 when it revved to about 4100 rpm

is this right?

I also have a small vaccum leak that sounds like its coming from the tps. i might just pack the top with black RTV

idk where to next?????

V

 

[5.0Droptop]

Fp should not drop. Rev it a few times see it it keeps dropping. I had a bad fuel pump on my 91 with 347. I rev it a few times and it would keep dropping.

 

[vpap1]

Fp should not drop. Rev it a few times see it it keeps dropping. I had a bad fuel pump on my 91 with 347. I rev it a few times and it would keep dropping.

the fuel pressure goes back to 40 once off throttle, would the manifold vaccum take that much fuel away at higher rpm?

 

[5.0Droptop]

Fp should rise as you rev and lower at idle. Stronger vacuum at idle makes it lower. You have a weak pump or restriction

 

[5.0Droptop]

Or bad regulator

 

[88LX5.Oh]

ok tested resistance on the dyna mod TFI (came with car)

here are my findings=

A to C = 22.3 kohm
B to C = 1.093 kohm
B to 4 = 84.6 ohm
A to 6 = .3 ohm
C to 1 = 99.7 ohm

coil is getting full 12 volts with car on engine off

once installed I revved the engine by had while watching the Fuel pressure gauge, pressure dropped from 40 to 35 when it revved to about 4100 rpm

is this right?

I also have a small vaccum leak that sounds like its coming from the tps. i might just pack the top with black RTV

idk where to next?????

V

Try changing the fuel filter.

Silicone isn't always the best answer.

 

[vpap1]

Try changing the fuel filter.

Silicone isn't always the best answer.

i will try changing the filter, last changed about 3ooo miles but its cheap i'll give it a go

also regulator is new and pump is at 3000 miles as well, i understand they can still fail though, best way to check if its fuel pump while pump is still in tank?

here is the dyno sheet ...

shop said it was breaking up at high rpm

possible detonation in one of the rear cylinders

decarbonized the system and it helped they said, recommended a griffin radiator to help as well

..........

V

 

[5.0Droptop]

Id be looking at the fuel system. Detonation is not a good thing.

 

[vpap1]

ok i'll start checking fuel. best way to test the fuel pump at high rpms with out a dyno? Then how to diagnose a regulator?

thanks

 

[vpap1]

update:

just returned plugs to .045" , no change from .035"

did a compression check and

here are my findings :

Cylinder#
1 185
2 205
3 198
4 201
5 180
6 182
7 189
8 182

plug # 1 seems a little light in color while #2 was very dark and oily, maybe vavle stem seal leak???

also

check fuel pressure at idle with vaccum line connected= 40 psi, when revved drops 5-6 psi then returns when off throttle in park
fuel pressure at idle with vaccum line disconected= 43, when revved barely drops 1 psi in park

I know i need to run in under wot on the road to really test it however does this rule out fuel pump and fuel pressure regulator issues?

what are signs i may need to lash my vavles? they are a little noisy on cold start but are fine when warm, i lashed them when motor was assembled but not again. Just passed 1400 mi since new build


so far everything seems the check out, what am i missing?