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Question(s)?????


mitsu3kgt
01-29-2007, 07:30 AM
If your fuel pump stopped working and your car wont start, but turn over, can that be your MFI relay?? I know the pump is good, because I ran a line straight to the battery. Does the MFI relay runs the injectors and fuel pump?
I also would like to know if you can swap a sl engine into a vr4?? I'm trying to build a motor for my vr4, and I have a sl engine in my garage. If I can, where should I get my internals???

Hotshot8792
01-29-2007, 08:15 AM
Answer to question #1, hotwire your fuel pump
http://www.stealth316.com/2-fuelpump-rewire.htm

Answer to question #2, yes you can swap the blocks. If you have a 4 bolt main tt, then you will be swapping to a 2 bolt main, which means you'll need a new front oil return line (if i remember correctly). If your tt already has a 2 bolt, then you'll basically be swapping in the same block, except you won't have the extra oil squirters (which actuallly take away from your oil pressure). As far as actual internals go, unless you can find a deal on everything, i would just use the stock crankshaft, stock rods, and find some new forged pistons (wiseco, ross, arias, etc.). About all the 3/S tuners sell them.

mitsu3kgt
01-29-2007, 08:59 AM
Thank you for answering question #2. For question #1 Im not trying to hot wire the fuel pump, I'm trying to get my friends tt running and the fuel pump was cutting on when you turn the key. It turned over, but wasnt getting any fuel. I wired the fuel pump so it can cut on, but the injectors wasnt firing. I think that it is the MFI relay. I think we have 2 of them but I can only find the one near the radio. Where is the 2nd relay if there is one? Do the MFI relay control the injectors and fuel pump?

Thank YOU

Igovert500
01-29-2007, 12:52 PM
So you're sure the problem is fuel and not spark?
Are you getting a check engine light?
If it's a 91-93, have you checked the ECU for leaking caps?

Most importantly, have you checked all fuses, both under the hood, and by the driver's left knee?

Power runs from the ignition switch, through the MFI relay (by passenger's left knee), next through fuel pump relay 2, through the fuel pump resistor [during idle]

Hotshot recommended doing the hotwire because it bypasses all of this, and has power going directly from the battery to the pump (via your own relay) and eliminates any problems and also bumps up the voltage to prevent potential lean conditions.

Now if I understood you correctly, you did run a wire directly from the battery to hte pump, and it worked, but the injectors still didn't fire? Then if all the fuses checked out, I would lean towards the MFI. Check for power at your injectors.

Pull the middle of the 3 electrical connectors on the passenger side of hte plenum. It controls the rear injectors. It has 6 wires in a 3x2 configuration. 3 are power, 3 are grounds. With the ignition 'on' the grounds wont be internally grounded at the ecu, but the power wires should show 12V constantly when given a chassis ground.

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