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**IsaacHayes** · 06-07-2009, 03:27 PM

for the ICM, you can use 2.8/3.1/3100/3400 FWD aluminum engines as well.

Use 3100/3400 accessories, and fuel rail so you don't have to mess with returnless. But then the 3500 injectors won't work as they are too short IIRC.

**robertisaar** · 06-07-2009, 05:05 PM

tuning: yes, lots and lots of datalogs... romulator isn't really necessary since it takes 5 seconds to burn a chip, but your choice...

**nfswift** · 06-08-2009, 12:50 AM

I'll grab a DIS V6 ICM from some yard soon then. And keep my eye out of 3100/3400 alternator and brackets? I don't need A/C so I'll try and find the idler and alt and be done with it.

There is a way to use the 3500 fuel delivery is there not? I would really rather just use all the stock stuff if I could than mess around with a pieced together setup that wasn't designed to run the 3500 to begin with. You can put in a fitting of some kind to convert the fuel circuit to a returnless style Sappy or Joeseph showed me something along these lines. And there was also mention of some kind of adapters to allow the injectors to plug into and work with an older style harness connector?

Romulator just sounds nice for tuning on the road, on the fly. Just eliminates the need to tote around a burner with you when you're tuning and seems like it could speed up the process, Iunno...

**IsaacHayes** · 06-08-2009, 12:13 PM

You could change your setup to returnless like Joseph did with his 3900 if you really wanted to. Using a regulator from a truck or corvette or something.

And having a return system on a 3500 is not a pieced together system. the 3500 is not much different than a 3400 other than better flowing heads... If you ask me it's easier to use bolt on factory parts than to try and convert to a return less system.. And for the harnes, you just gotta cut solder and heat shrink....

**nfswift** · 06-09-2009, 01:46 PM

I just assumed the 3400 rail and injectors wouldn't perform quite as efficiently "out of the box" as the stock setup. The main thing I'm concerned about is just getting them the correct signal to fire off and getting them working with my Fiero harness/7730.

Is it honestly more work to "T off" the fuel lines using that fitting than to swap different injectors and a rails on? There are adaptors for the injector plugs I'm sure I've seen something at least similar to what I need, new injector plug to older style harness connector to put it crudely...

Once the I've repinned my harness for the 7730 my harness injector connectors are probably not gonna work I'm assuming?

**IsaacHayes** · 06-09-2009, 06:06 PM

Injector connectors will work with the 7730, it just depends on what version/style/year mutlec1/2 injectors if the connectors fit the injectors. You could always re-pin them if you didn't want to cut and solder. I re-pinned my rear head temp sensor and ran that to a 3 wire so I could still disconnect all the harnesses from the LIM if I wanted to like stock.

**hookdonspeed** · 06-09-2009, 08:16 PM

go return style, i looked into it a good bit, alot easyer to changeover the wiring then it is to try and setup the returnless... and cheaper....ALOT...

returnless syle systems use a PWM pump with several speeds and from what ive been reading up on about them like to just fry if on high, and the regulators like to go out from being subjected to full pressure all the time

**SappySE107** · 06-09-2009, 08:31 PM

I thought it still returned to the tank and acted like a stock setup short of not being able to support as much hp due to starving the last injector when you push the engine more. I don't know the duty cycle/fuel flow % on any of this, but I am looking at a near stock 3500 essentially.

**hookdonspeed** · 06-09-2009, 09:26 PM

Originally posted by SappySE107 View Post

I thought it still returned to the tank and acted like a stock setup short of not being able to support as much hp due to starving the last injector when you push the engine more. I don't know the duty cycle/fuel flow % on any of this, but I am looking at a near stock 3500 essentially.

so did i till i looked at a 3500 pump, then starting asking questions on the vette forums and v8rx7 forums(since they do the ls1 swaps)

it can be done with using a normal pump, and a 00+ ls1 fuel filter/regulator, just will be a constant 58psi, so youll run a little rich at idle w/o tuning, and it will reduce the life of the regulator as it wasnt exectly designed to regulate out the full 100+psi the pumps put out, altho im not sure what pressures the pwm pumps change to.

**ForcedFirebird** · 06-09-2009, 11:08 PM

Originally posted by hookdonspeed View Post

so did i till i looked at a 3500 pump, then starting asking questions on the vette forums and v8rx7 forums(since they do the ls1 swaps)

it can be done with using a normal pump, and a 00+ ls1 fuel filter/regulator, just will be a constant 58psi, so youll run a little rich at idle w/o tuning, and it will reduce the life of the regulator as it wasnt exectly designed to regulate out the full 100+psi the pumps put out, altho im not sure what pressures the pwm pumps change to.

This makes wonderful sense to me since I have disassembled several 3500's and noticed the excessive carbon, even flaking off the heads and such. Wondering why they run so rich, this actually answers the question

I would have to say the even a pump designed for a return-less system will be rich off idle and maybe even cruising.

This is a bonus for boosted engines, but alos wonder if this is why the 3500 had oil squirters?

**SappySE107** · 06-09-2009, 11:14 PM

Stock 3400 grand am is 65psi max so perhaps not using the PWM pump will not create this 100psi to the regulator ordeal?

**Joseph Upson** · 06-10-2009, 07:27 AM

I must not have posted pictures of it here. Going returnless fuel is as simple as a by-pass adjustable pressure regulator which I was not aware of when I used a modified stock regulator. I haven't installed it yet but it has enough ports to connect all of the necessary lines plus a mechanical pressure gauge and has a vacuum port with 1:1 ratio pressure sensitivity. I have a Mallory regulator purchased from Summit for just under $100 that is rebuildable should it fail.

Summit was taking to long to load so I linked to Jeg's. My pump is black and looks like the 4307M listed with 4 ports and it is also labeled 4305M which is very important because the 4307 has a 25 psi max while the 4305 has a 100 psi max pressure;

Just a moment...

http://www.jegs.com/i/Mallory/650/4305M/10002/-1

**Joseph Upson** · 06-10-2009, 07:38 AM

Originally posted by ForcedFirebird View Post

This makes wonderful sense to me since I have disassembled several 3500's and noticed the excessive carbon, even flaking off the heads and such. Wondering why they run so rich, this actually answers the question

I would have to say the even a pump designed for a return-less system will be rich off idle and maybe even cruising.

This is a bonus for boosted engines, but alos wonder if this is why the 3500 had oil squirters?

I'm familiar with the build up you are talking about but are you sure that isn't a side effect of newer fuel additives or ethanol. I recalled a rather shiny glazed looking appearance that I thought was unusual and noted that the engine I had disassembled was a Flex Fuel motor. I'm suggesting this because anything that would favor more pollution would seem unlikely, also the fuel rail is tall and square suggesting a design function to avoid abnormal fuel distribution.

Another issue I've noticed on some brand new cars is oil consumption particularly those running thin 0w15 and 5w15, my friends car with 25k on it was nearly 2 quarts low by the time the oil change was necessary and a different new car with the same engine running the same weight oil experienced the same. It is a common occurence so much so that we actually found a reference to oil consumption in the owners manual suggesting that may be what you are seeing coating the combustion chamber due to very thin oil getting past the rings, the trade off for better fuel economy.

**hookdonspeed** · 06-10-2009, 08:16 AM

Originally posted by Joseph Upson View Post

I must not have posted pictures of it here. Going returnless fuel is as simple as a by-pass adjustable pressure regulator which I was not aware of when I used a modified stock regulator. I haven't installed it yet but it has enough ports to connect all of the necessary lines plus a mechanical pressure gauge and has a vacuum port with 1:1 ratio pressure sensitivity. I have a Mallory regulator purchased from Summit for just under $100 that is rebuildable should it fail.

Summit was taking to long to load so I linked to Jeg's. My pump is black and looks like the 4307M listed with 4 ports and it is also labeled 4305M which is very important because the 4307 has a 25 psi max while the 4305 has a 100 psi max pressure;

http://www.jegs.com/i/Mallory/650/4305M/10002/-1

using a FPR like that i would think would more work like the 3400 rails, just with a return line before rather then after, my post was more aimed twards using the people using doing swaps who use the vette non-vacuum straight-non variable 68psi regulators. altho if they are failing from stock too, i can see why the buildup is there.

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