Multiple problems. Please help!

[JRSTANGE]

Well, I've been working on restoring my 90 gsx for nearly a year now and can't seem to get it going right! It seems i fix one thing for another thing to pop up and create a problem. By this time Nearly everything is new on the car.

First thing is I found my fuel pump voltage was getting lower in to the 9's once i got into boost. Were out of the boost I was seeing proper voltage. So I decided to do a fuel pump rewire from an Ebay kit. The install went well and was very easy. All wires are correct and has a good solid ground after wire brushing off the paint and the bolt attaching it. However, The car starts and runs but, if I shut the car down it wont restart and the battery has been drained and needs to be recharge or jump started. Curious if there is something else that went wrong here? Like say the stock relay for the pump is bad or something. I didnt have this propblem before the fuel pump rewire was done. Perhaps the relay is the kit is bad. I have no idea and am hoping someone else does. I also couldnt find any issues searching like this.

The other issue is after the fuel pump rewire, well at least tonight I started getting idle surge. Hadnt had this happen before. The ecm is good as it's a fresh ecm with a socket recently installed running off the stock chip while i wait for the extra chip to be burned. Obviously this is a 91 ecm but, I swapped the two pins around being 6 and 14 as well installed the tach adapter from dsmchips. All seems to work well with it from what I can tell.

Next thing is I found when data logging now after the two above changes I dont show any fuel pump voltage. The fuel pump voltage stays at .3 and never moves now. I then reinstalled my origional non eprom ecm after swapping the pins back etc... and found with the origional ecm I see 9.3v with no change throttle or boost etc...

I'm seriously confused and frustrated and just want to drive the car. I've seriously only driven it for about 2.5k miles in a years time now. Each time a new issue showed it's face.

in my profile I have mods but, will list what I can recall at the moment.

255lph pump
550cc injectors,
2g maf
20g turbo
3" turbo back no cat
front mount intercooler and hard piping

Trying to thing of any additional that may effect the issues.

I also have new throttle body shaft seals and so on. Literaly nearly everything is like brand new. I had a new knock sensor to put in as well. It's one of the few origional parts on the car. I still need to do the coolant by pass on the throttle body to help with warm up.

Please help and ask away as I'm all ears ans want to get it going. Thanks!

oh as well prior to these changes all boost leaks were addressed via blt tester and water bottle and soap.

 

[Sustaplex 325]

i recommend never buying stuff off ebay..ive always had bad luck.. i use STM | STREET TUNED MOTORSPORTS | DSM | EVO | SUBARU | PERFORMANCE & DYNO TUNING for alot of my parts.. they have good stuff also EXTREME PSI : Your #1 Source for In Stock Performance Parts is another good one. on some of your issues do you tune your own car?? your gunna need a good tune with that 20g turbo. i recommend bigger injectors as well. you should need that fuel pump rewire kit.. i would start there and go back to the way it was and go from there.. the rewire isnt necessary unless u wanna use the 255pump to full potential from what i can remember. have u looked at your power tr unit on the air intake mani to make sure its good as well as all the wires and plug.. it can cause alot of problems as well.. thats all i got for now hope it helps. def sounds like u got some wiring issues tho

 

[JRSTANGE]

Thanks! I plan on getting a different relay and seeing how that goes.

Before I stopped seeing the fuel pump voltage I would run lean under boost and during acceleration. I noticed the fuel pump voltage would drop when accelerating and worse when under boost. Thus the need fot the fuel pump rewire. Seems the 255 needed some help.

For the fuel pump voltage. I saw voltage before i put in the 91 ecm. This is also before the fuel pump rewire. At that time I swapped the pins and installed the tach adapter and saw .3v on the logger. So I reversed everything and put the stock ecm back in and saw a steady 9.3v to the pump but, it never changed with load or boost. It was stuck. So I went ahead and put the 91 ecm back in and at that time the fuel pump rewire kit came in so I installed it. But, I still dont see fuel pump voltage on the logger. Obviously I'm getting fuel since the engine runs etc... Seems my wideband took a poop also so I cant confirm a/f at this moment to know how well it's all working. Since before with the voltage drop my a/f dropped as well.

I plan on getting a new lc-1 with sensor, relay for the rewire mod and anything else reccomended. I also have a new knock sensor to put in once I receive the other parts.

I also didnt have a battery draining issue before the fuel pump rewire. So after driving for a bit on the rewire I'll either get home or stop for gas as it's happened an the car wont start due to a dead battery which it new also. I'm thinking this must be a bad relay or the grounding circuit in the relay.

Just looking for ideas or confirmations on what to do or fix. Thanks!

In thinking could it also be related the to the MPI/MFI stock relay being bad or going bad. Wondering what if anything I could have done to it when swapping pins etc... since it sits next to the ecm harness.

Thanks again.

 

[Sustaplex 325]

who tunes your car cause it def. sounds like you need a good tune.. that 20g is too big for the injectors as well not sure tho.. but i kno anything over a 16g def needs a tune. i run a big 16g and at the time 450 cc injectors and 255 walbro fuel pump.. i got major fuel cut.. ran like garbage.. also my power tr unit plug was all jack and also threw my voltage off like yours.. as far as running lean and rich. mine did that as well until i change to 880cc injectors and my friend will tuned it.. now it runs like a charm.. hope this is some help.. im not the best but im throwing out ideas from problems i had and fixed.. a good tune will go a long way on a dsm thats modded..

 

[1gboost]

Hey sustaplex could you throw up a log or 2? I just got a 2g with a 20g that I'm trying to tune I'm really curious what your run would look like.

 

[JRSTANGE]

Thanks. I'm not positive it's a tune thing since I'm only running on 10psi right now. As for tuning, I basically take logs and send them and my chip off to a guy 2 hours away who tunes it and sends it back. Right now I'm on the stock chip waiting to get the new one back.

I will take a look at the wiring and the power tr unit plug for sure to see if it brings the fuel pump voltage back to my logs.

But, even with the 20g and 550's I'm tuning not for boost or horse power but the safest duty cycle of the injectors. Of course knock etc... Not going for a power house just something fun to drive.

 

[Sustaplex 325]

Hey sustaplex could you throw up a log or 2? I just got a 2g with a 20g that I'm trying to tune I'm really curious what your run would look like.

i dont tune myself.. my best friend is amazing at it.. i took it to a couple of places before like carz and mac. i didnt get much out of it.. then i let my friend will and now its a beast.. he ran mid 10's in his stock evo 8. im like most and dont take it to a track.. just want a beast for the road to smash out on those who dont know about the 4g63 power.. alot of us dont really know how much a good tune will help until you actually get one.. taking logs from someone else isnt the best way to get what your looking for. every car is different. chipped, mods, built lower end, to end built, turbo size, and so on. 1gboost i see what i can find to show you though okay. my friend has a 20g on his 1g. he might have his data saved.. ill send that to u. mine will be different with my big 16g. JRSTANGE dsm's seem like they always have wiring issues. especially if a 6 or 7 bolt swap was done.. with the way the voltage was.. i would say u have wiring issues somewhere. u might check both fuse boxes to. i wish i was there to help.. good look. i hope im some kind of help to you all.