eca1987

Greetings,

I want to swap my original carbed LG4 with an 89 5.7 liter TPI engine. The first thing that comes to mind is that I will need to swap out the Fuel Pump and add a Fuel Tank Sending Unit

My questions are:

1. Will my current fuel tank accommodate the fuel pump and fuel tank sending unit?
2. Fuel Sending Units seem to support certain wiring harness codes such as FPH, FES, FPJ, and FPL. How do I determine which FSU to get? What harness code will it need to support.
3. I have also identified the following additional parts needed:
   1. Fuel Pump Strainer
   2. Fuel Pump Gasket

Any other parts I will need/should get/replace?
What about fuel lines? Will they need to be changed?

I appreciate everyone's input.

Thanks,

Ed

Dan Hubbard

I am in the painful process of a similar swap. I pulled the original carbed 305HO from my IROC Z28 (87) and put in a 350 TPI. I was able to find a gas tank complete with fuel pump, sender, etc. It was sort of a pain to replacd the tank, but now thats all done. Have to get a new connector onto the pressure hose from the tank due to higher fuel pump pressure from the TPI pump. I swapped out the engjne harness, and reinstalled the chassis harness. The donor engine and harness came from an unknown f-body, i think. There are 6 wires that dont match and two of them are probably related to the fuel pump circuit. I didnt replace anything in the pump circuit other than some rubber hoses and steel fittings. Haven't tried to prime the fuel rail yet though, so i cant tell you if it worked or not. I'm going to guess not until i get those two wires fjgured out.

Dan Hubbard

Connected the fuel lines to the TPI fuel rail this evening. Decided to take a few pictures of the unknown wires. On the firewall (picture P1011925.jpg) at the relays, there is the orange/white wire, which according to the diagrams I have, should be going to the fuel pump or to the fuel pump switch. Problem is, I don't have any connectors that are missing this wire, and don't understand where I need to splice it in. The other says to the fuel pump prime and is a small all-orange wire. Again, don't know where this one connects.

Picture P1011924.jpg shows a black and pink wire set. I traced this one back on the original harness (the female portion of the connection). The pink is ground, and the black is ECM-IGN, 10A fused, hot in run. The new harness doesn't have anywhere to connect this (went to the ECM on the old harness). Do I just leave this one disconnected?

Picture P1011922.jpg shows an orange wire that was connected to C16 on the carbed motor's ECM. No corresponding connection on the TPI motor. Any ideas?

Pocket

iTrader: (24)

1) Yes, any 3rd gen tank will accept any 3rd gen sender

2) If buying new, specify its for a TPI engine. With EFI senders, the only thing that changed was the pump. If going used from a JY, any EFI sender from an 85+ 3rd gen will do. Put a TPI or newer pump on and its ready to use

3) The sock should be replaced anytime the pump is removed. 100 miles or 100k miles. O-ring gasket is subjective. Its good to have an extra in case the original doesnt come out nicely

Fuel lines will be the biggest challenge. In addition to coming out on the opposite side of the engine, the will also not have the threaded saginaw fitting used in high pressure systems. They use barb fittings like older cars

To properly use these, cut off the barb and slip a threaded fitting on of your choice. Stock saginaw, AN fitting etc. Flare it and use hose/ends rated for fuel injection

If you will have the engine out, itd be easier to simply swap the lines with some from a JY EFI car. V6, TBI, TPI doesnt matter

Other stuff to keep in mind
Wiring

If your car came with the in-tank helper pump it will already have the pump wire in the chassis. This comes out at C207 pin L and will have to be moved to wherever you feed it from the FP relay on the 89 harness

If it didnt come with the helper pump, you will have to run a new 16ga or larger wire to the pump and connect it to the 89 FP relay

Those are on top of the standard TPI into older car wiring changes like the lack of INJ1/2 fuses in your block

You can make these changes easier by finding an 89 dash/chassis harness in a junkyard

diablizzard

iTrader: (8)

to add on to this, I also have an 86 origionally with the LG4. It has the fuel pump wire that goes from fuel sender/pump connector up to the dash connector. easiest way to check is to look at the connector by the tank and see if there are 3 wires on the chassis side. The connector that it goes to is behind the driver's side kick panel and it looks like the C207 really close to C100. What I just did was take an extra pin and inserted it into the other side of the connector, it saves having to run a new wire down to the pump aasembly.

Dan Hubbard

Can you take a picture or two of your setup and post them here?
What is C207 and C100? I'm assuming they are connectors, but what do they connect and where are they? I don't see any reference to them on the wiring diagrams I have.
Any help you can provide would be greatly appreciated!

diablizzard

iTrader: (8)

The C100 passes through the firewall in the driver's side. The C207 is under the dash on the Passenger's side.

The first and third pic are of it's location. In the second pic there is a wink wire that is very blurry and it is seperated from the rest is the one I added. That is in pin P. I just took the hot wire that Pocket described and plugged it into there. How you connect to it is up to you. A new dash harness would probably be the cleanest and easiest to match up to the TPI harness

Dan Hubbard

Caveman posted a scan of the C207 connector, and it shows L as being part of the passkey circuit. Is the '86 C207 connector different than the '89? I'm really struggling to understand how the three fuel pump harness wires make their way from the rear of the car, up to the dash, and to the engine side fuel pump relay. I have black, grey, and purple wires from the tank harness. Black and grey run the pump, and purple is the sender. Somehow, the orange/wht wire from the fuel pump relay needs to connect to this harness, probably under the dash? Diablizzard apparently plugged his in to unused pin P, on one side, and somehow made it to the tank on the other side.

diablizzard

iTrader: (8)

The way I found it was by taking out my interior and tracing the wire all the way up to the dash area.

Street Lethal

iTrader: (16)

Put the LG4's intake, dizzy, carb and mechanical fuel pump on the 89's 5.7...

Dan Hubbard

I was afraid of that.
But, since I have most of the interior out already, maybe it's not so bad.
Thanks for all of the advice. Hopefully I'll get her running soon, and not need to go the Street Lethal route and scrap the TPI setup....