2nd Generation Specific 1986-1992 Discussion

Rewiring A Fc Tii Fuel Pump

Old 12-23-2003, 11:41 AM
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so, someone on AIM i was chatting with suggested i rewire my fuel pump while i was putting in my walbro. so, i checked the voltage at the harness and i only read 7.5 V going to the pump...at least i think that was the right wire. i thecked the other three wires and got one at 13.5 V (not not sure what it goes to, maybe the level sensor), then i got one alternating between 1 and 3 V, and one at zero volts.



anyway, that person on AIM gave me a link for a good DIY for the rewire process. anyone else done this or got a link for me?
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Old 12-23-2003, 11:46 AM
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i found the link, but has anyone else done this?



http://www.1300cc.com/howto/how2/rewire.htm
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Old 12-23-2003, 12:02 PM
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okay, after reading that whole writup, i realize that i did not take my measurements at WOT, so i need to do that to get the proper fuel pump voltage reading.



although, this whole voltage thing could be the reason for my cold start problems...



i'll have to tackle that tomorrow morning too see what happens.
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Old 12-27-2003, 12:30 PM
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okay, i dont thinks it's as bad as i initially thought. i get 7.5 V at idle, 8 V cruising (i think both of those should be around 9 V), and i get 10.5 - 11 V at WOT and full boost past 4K rpm. i think that final value should be more like 12.5 V, but considering my fuel cut switch and the old wiring, i think i'll leave it like it is. with the walbro 255 lph HP pump, i should be fine.



i just need to port my wastegate soon, i'm seeing creep up to 12 psi in 4th gear sometimes...unless someone wants to give me some bigger secondary injectors
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Old 12-27-2003, 05:50 PM
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you want it to be at least 12 v while running. I'd say rewire it anyways i was able to do mine after a little research in an hour or so. More voltage more fuel.
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Old 12-28-2003, 08:00 AM
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Originally Posted by RX7Aggie' date='Dec 27 2003, 01:30 PM
okay, i dont thinks it's as bad as i initially thought. i get 7.5 V at idle, 8 V cruising (i think both of those should be around 9 V), and i get 10.5 - 11 V at WOT and full boost past 4K rpm. i think that final value should be more like 12.5 V, but considering my fuel cut switch and the old wiring, i think i'll leave it like it is. with the walbro 255 lph HP pump, i should be fine.



i just need to port my wastegate soon, i'm seeing creep up to 12 psi in 4th gear sometimes...unless someone wants to give me some bigger secondary injectors
I would tend to agree. I was pretty sure that the pump sees at least two different voltages. I don't think your readings are reason for concern. Of course, it couldn't hurt to re-wire the thing.



Since replacing my fuel pump with the RP one, my T2 has been running filthy rich, even under WOT. The wiring looked fine, and the car is overall very clean, so I didn't re-wire it. I honestly think it was faster with the old pump, but I didn't want to blow the motor by running lean.



Yah, if you have never ported that wastegate, do it! No sense missing out on all that fun!
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Old 12-29-2003, 05:14 PM
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Originally Posted by 1988RedT2' date='Dec 28 2003, 08:00 AM
I would tend to agree. I was pretty sure that the pump sees at least two different voltages. I don't think your readings are reason for concern. Of course, it couldn't hurt to re-wire the thing.



Since replacing my fuel pump with the RP one, my T2 has been running filthy rich, even under WOT. The wiring looked fine, and the car is overall very clean, so I didn't re-wire it. I honestly think it was faster with the old pump, but I didn't want to blow the motor by running lean.



Yah, if you have never ported that wastegate, do it! No sense missing out on all that fun!
how hard is that WG port? how long did it take?



i ordered a ball/spring MBC for $10 off ebay, but i dont want to turn it up if my boost is going to creep past 12 psi.



i'm running the 1/4 mile on friday with some buddies for a bachelor party and i dont wanna blow up. in the 1/8 mile, i ran it 20+ times and creep up to 11 psi in 3rd at the end of the run, and i get worried. with this cold air now, i'm seeing creeps up to 11-12 psi and i really dont want to explode my engine.



i've hit 11-12 psi multiple times without any bad things happening, but i'm worried that with the 1/4 mile i could be pushing 11 psi through the end of 3rd and start of 4th gears, which worries me greatly.



eh, you only live once. we'll see what happens...
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Old 12-29-2003, 07:51 PM
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The wastegate port took me a long time, but I kind of did it in the middle of a bunch of other stuff. Hardest thing for me was getting to the turbo so I could pull it off. Things are much better now that I've eliminated so much of what was in the way.



If the car already has a downpipe (no pre-cat) and no ABS, I suppose I could do the job in a day. Having the right cutting tool is important too. All I had was a dremel with a carbide cutter and some sanding drums. It worked okay, but it took some time.



I have a MBC set at 9 psi, and I'm not seeing any boost creep past that, so I guess the port is doing its job.
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Old 12-31-2003, 07:16 PM
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Mike, porting the wastegate isn't that hard. The worst part is getting the heat shields off if you've never taken off the turbo. Once you get the turbo off, it's just two bolts on the back side of the turbo, and taking off the c-clip that holds the wastegate rod to the swing arm and you're ready to go. I'll gladly give a hand if you have a place you can work on the car in college station.
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Old 01-01-2004, 01:50 PM
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good deal, thanks matt. lately, i've been pushing my car a little harder (holding it WOT at full boost creep) and i haven't gone past 11 psi, so i think i'll be okay. i should be running a little more rich due to the walbro, so that safety factor should be good enough for seguine raceway. i've got about five 5.0 V8 stanges to kill anyway, i dont wanna let up.



the MBC hasn't arrived in the mail yet -- holidays -- and so i wont use it on the 1/4 tomorrow night. that's probably good, i dont want to stay at 11 psi for longer than 2K rpm and explode my engine.



i'm pumped for the 1/4 mile. i'll get the MBC installed before next semester and get my wastegate ported some weeked when i have time off, then i can run the 1/8 mile in navasota and see if i can break below 9.1 sec.
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