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I have swapped a 350 TPI to a 355 carbureted. My TPI electric in tank fuel pump was working fine when I had a 650 CFM Edelbrock with a pressure regulator set at 7psi. After switching the carb to a 600CFM Edlebrock, some problems arose. The fuel pump is now only priming for 5-7seconds and then shutting off. Does this have anything to do with the pressure setting at the regulator and no return line to the tank? WHERE IS THE PRESSURE SWITCH? I have located it on the electrical schematics, but not on the car. Should I install a AFPR that has a return port such as the Mallory model sugested in a majority of the engine swap posts?

I don't want to drop the tank unless absolutely necessary. Since it is priming, I am assuming it is still functional. YOUR HELP IS GREATLY APPRECIATED!!!!

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aremy10

iTrader: (3)

you need a regulator with a return, you are probebly overloading the in tank pump. if it turns on for any amount of time , then its probebly still good.


without the return your most likely overloading the pump, this will eventually burn out the pump,

aremy10

iTrader: (3)

the problem is most likely not the carb. you need the right regulator for this to work, the one in the pics is a mallory high pressure reg. good for 4-25 lbs for tb or carb or low pressure fuel inj. ive been waitin for this other guy here to send the money for it, and that was on monday, so i dont know if he is buyin it or not, pretty soon im puttin it up for sale again. 65 bucks shipped

aremy10

iTrader: (3)

the fuse is probebly blown check the inline fuse this i beleive is seperate from the prime conn. so if the pump fuse is blown , it will still prime but not run after that

Adamsapple

Thank you i appreciated it so the Mallory p.n. 4309 should work?

aremy10

iTrader: (3)

i think some people use that one, i have the 4307m its good for alcohol, super charger etc. basicly just has extra ports and such. did you check that fuse?

89FRMLA350

There are 3 wires for the fuel pump. Pink is the fuel level sender, black of course is the ground and the other is the power. All I did was cut into the wire with power and run a switch to my ashtray yo turn it on and off. easy fix if you want to go this route but definitely recommend getting a regulator with a return line.

aremy10

iTrader: (3)

ya you can run a switch if you want,,, i did that once only i didnt cut any wires, i just took the cap off the fuel pump relay , ran two wires from a switch and crimped on some connect/disconnect ends on them . and plugged em right into the relay . then when i needed to i had all the wiring there to put it back. and it then runs through the fuse block too. ( safer ) but in the end i pulled the tank and put steel line in place of my pump with a union fitting. all of these will work

Adamsapple

ya i did check the fuse and its still good

aremy10

iTrader: (3)

the pressure switch is the oil pressure sending unit. that works them both

i never used the oil pressure unit for my pump , i used the switch method. but there are alot of posts here about how to do it.

Adamsapple

Could anyone elaborate or post the link to the 'switching' method for the fuel pump? I have the schematics for the relay. Do you slide a blade connector between the harness of wires and the connector housing? Pulling off the relay cover details...you guys are life savers!!!

aremy10

iTrader: (3)

this is what i did. if you are ever gonna want to use that relay again then dont pull the guts out of the relay cover. find one at a junk yard or somethin you can use and keep the good one



first pic. these are the connectors i used

second pic. this is the relay cap hollowed out with a groove cut in it

third pic. i connected one wire to the orange and one to the grey . and ran the two wires right to a switch

aremy10

iTrader: (3)

this is what it looks like with the cap on, now you can put the relay back where it was . this works well , and the wires are vertually unnoticeable. doin it this way keeps the fuse functional in the fuse block

aremy10

iTrader: (3)

sometimes in the relay end , where you are plugging in your wires, you have to take a very small screwdriver and push the tabs forward a little bit, to make the connectors fit tighter. the cap will aso hold the wires where they need to be too

Adamsapple

So, with the switch method, we are switching the battery hot (fused... in my case it is orange) to the pump hot (in my case tan and white). Cool! Looking at the schematics, the relay is controlled with two inputs. The ECM wire and a wire from the ALDL CONN. Any idea on what the ALDL is? Thanks!

Pocket

iTrader: (24)

You can use run 12v from the switch to the green wire at the relay for it to prime... Just saying

aremy10

iTrader: (3)

ya you could set it up to prime, dont really know if you need to though. cause when you turn the pump on , your pretty much primming it

aremy10

iTrader: (3)

hey pocket,

your pretty good at this stuff, can you check the new posts under the thread, cruise control for tcc and let me know what you think? i dont know if im reading the prints right, they are kind of confusing for this kind of thing, youll see what i mean

aremy10

iTrader: (3)

the aldl is the diognostic connector ,,assembly line diognostic link

i think its for finding error codes etc not 100 percent sure though

Pocket

iTrader: (24)

ALDL is Assy line diagnostic link. You'll also hear it called the DLC: diagnostics link connector

Same thing

Its essentially a collection of terminals to feed back info about the status of the ECM and perform basic tests like fuel pump function etc

Ill post in your wiper thread shortly

aremy10

iTrader: (3)

i thought it was somethin like that.

55ChevyMan

what is an in line fuse on a 86 iroc is there and in line fuse on the tan wire coming from the fuel pump? on my lt1 swap I am using the 86 TPI relay my fuel relay is (A) Tan/white wire goes to fuel pump tan wire( B )black/white is ground (C) green/white Ignition( D) orange to ALCL but now spliced to A7 on PCM red Connector (E)orange hot at all times my fuel pump is not priming at all I used a test light and on (A) tan white there nothing when you turn key on C it lights when you turn key on is this the right way to wire the fuel relay on a lt1 swap? thank for your help I dont know if it maters my fuel regulator is AEROMOTIVE 13101

oguin_studking

iTrader: (1)

I'm currently wiring up a switch for my pump at this moment....gnna be mounting it in my ashtray along w/three other switches. Great info on this thread deff. gnna put this knowledge to use.