First gen lope?
 

So i just put 75 hp DDP injectors in my 89. And now if i let off the throttle it hits idle and starts to lope... I asked my bud in town what it was doing and he said that when the fuel entering the cylinder exceeds 16psi it starts to lope. Is this true and is it a bad thing or a bad a** thing? There are no leaks in or on the injectors or the injector lines so its not air in the fuel. I will try and get a video of it this afternoon.

It sounds like he knows what he's talkin about but I can't say for sure cuz I'm not really familiar with the first gens. With new injectors and stock lift pump you could be pushing it to the limit with bigger injectors so it's probably having a tough time keepin them fueled. I'm guessin so don't take my word for it.

So if i got a bigger lift pump it would help me to get the full power of the injectors? :w2:

Not necessarily "bigger", but a better lift pump. Such as an AirDog or FASS system that can move fuel from your tank to your injection pump more effectively. Now, I don't know if FASS makes a compatible system for the first gens but I do know that an ADII can be used for them. I believe using onr for a 2nd gen 12valve will work just some grinding/modifying is needed so it can fit the VE. I know there are some lift pumps that you can mount to the engine and run off the belt but I'm not educated enough on them to tell you much more.

As for getting full power, I'm pretty sure you're injectors are doing their job perfectly. Just know that if you're constantly hot-rodding around your lift pump will fail and in time so will your injection pump. I would higly recomend getting a fuel pressure gauge to see what you're running at idle and WOT to be safe, then take it from there. Good luck man :c:

O do post the vid, I'm a huge fan of the first gens :tu:

whats your idle at? did your tamper with injection pump at all?

I got a Denny T stage 2 pin and turned the star wheel 2 turns but no smoke screw and no idle

Ill try and do a vid in a bit

my truck has been doing the same thing but mine i was told by the local diesel shop is caused because with new injectors you usually have to adjust the idle a bit. and he also told me to bump the timing 1/8 of an inch and that will help too

We at FASS have systems for the First Gen's up to 150 GPH.

Gov spring, put a 3200 rpm in it and it'll probably stop. Mine would hit idle hard, can't recall it loping but it was all after I turned the pump up.


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Cow pies.

yeah...

when i installed my 5x14's i raised the idle and turned down my fuel screw (too hot) (but turning down the fuel alone will cause you to raise the idle) I think you just need to adjust your pump. do a lot of reading before you start so you are sure you know what your changing, especially when you get to that fuel screw. your not getting the full potential of those injectors yet.....then you will need to address the fuel supply. :choochoo::choochoo:

the lope your getting is probably because your new injectors pop pressure is set for a p-pump i bet!

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bc where you from?? b.c. ??

"We at FASS have systems for the First Gen's up to 150 GPH"

what is the advanteges to this? and does a fass system just suppy fuel to the pump with more pressure then the stock primer pump? and what do you do with the primer pump when you install a fass system?

You can either feed the stock primer pump or you can bypass it. We suggest bypassing the stock primer pump and feeding directly into the VE pump.

Installing larger injectors coupled with turning up the fuel (IP) can result is the IP demanding more fuel than the lift-pump is capable of supplying.

Increasing the fuel pressure available to the IP will not correct a starving IP. Increasing the volume of fuel available to the IP is what is needed.

While fuel pumps like the FASS are very capable of meeting the demands of larger injectors / turned up IP, the less expensive low pressure piston lift-pump if not the 12v 2nd gen high pressure piston lift-pump (with a pressure regulator) will satisfy the demands of the typically bombed VE fueled 1st gen just fine. :pca1:

I went with the walbro fuel pump, with a regulator and i have it set at 14psi. at wot the gauge needle doesn't even wiggle now. :choochoo::choochoo:

Very good advice.

I ran the same set up on my 89, that walbro 392 pump is awesome!

Same here. I'm running the Walbro 392 with a bypass type regulator set at 12psig, 3/8" supply and 1/2" return lines. At full song, the 6x0.016" injectors are putting just shy of 500hp to the ground while pulling the IP inlet pressure down to only 10 ~ 11psig. ;)

where does your 1/2in return line go to on the tank? cuz i know on my tank the old return fitting on top of the sending unit isnt 1/2in.

I've modified the crap out of my OEM fuel module putting it mildly. :s:

- The stock/OEM fuel pick-up plumbing has been enlarged to 3/8" ID using the original float and valving in the bottom of the module's reservoir. That way I retain the ability to run the tank all the way down to near empty without sucking air like the basic fuel "Draw-Straws" do.
- Using the spare bung in the top of the module, I installed a 1/2" bulkhead fitting so as to have the return play into the module's reservoir as it should to keep it full.
- The work includes things like installing a lid on the reservoir so as to keep the fuel from climbing up the back wall and spilling out during a hard launch.
- And other stuff. :w2:

oh wow nice. so do u think i basicly shot myself in the foot going with a draw straw? cuz now im not sure what to do for the return.

From what I've read online most who do the typical draw-straw type pick-up don't run below a 1/4 tank of fuel. Do they suck air as the fuel moves to one end of the tank.

Talking about putting a return in there, this is typical of what I did.

The top has one spare bung . . .

Attachment 39660


Pull it out and hollow it so as to fit the new bulkhead fitting . . . .

Attachment 39661



The actual fitting may be too big to pass through the hole in the top of the module, so put what's left of the hollowed bung-plug in, then slip in the bulkhead fitting . ..

Attachment 39662


Attachment 39663


Now connect as needed inside ... .

Attachment 39664



You might consider using a 90* fitting to screw directly into the assembly so as to have room once installed. I use AN connections in my heap. . . .

Attachment 39665

wow that looks nice. i think they changed that setup with the sending unit cuz on my 89' it doesnt look like that. it dont have that extra bung spot on mine.

Gotta big copper coil for the return line that spirals around the basket? Mines just like it lol. I put the draw straw in my basket and one of the returns dump back into the basket through the factory pick up. Can't remember if it's the bypass return from the AD or the IP return. I've ran the truck down to 1/8 tank or lower and never gulped any air. Then again my draw straw sits right on the bottom of my basket and I cut reliefs around the bottom of the straw (looks like the top of the rook chess piece)


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so what size is your return 3/8 or 1/2?

I think I used the factory return for the return from the injector pump (makes sense) and used the quick disconnect that came with the air dog for it's return via the factory pick up


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