Hey guys, first id like to say that i havent posted here in years and last time i posted i had a 95 GST. Long story short the engine had rod knock and i sold it. I then purchased a 98 GSX (modded) in Jan only to run into the same problem a month later.

The engine has been rebuilt. When i got it back from the shop i drove it from Olympia, WA to Portland, OR, not a problem at all. Two days later i go to drive back home and it was very hard to start and when it did, it had very poor acceleration, bogging, and was backfiring. Fast forward to now and a new shop is telling me that the FPR was pushing 75-90 psi and that the car was running full rich. They checked the mass-air-flow sensor and said it was working. The first shop also said that they shimmed the timing belt because the belt was rubbing.

Mods: Weapon R intake cone w/ custom metal intake to turbo, 20g turbo, dc (i think) turbo manifold, Apexi 3 in full exhaust, Adjustable FPR, custom FMIC w/ metal piping, GReddy bov, Apexi SAFC, boost, a/f and h20 temp gauges.

I'm thinking it may have something to do with the SAFC because that controls the fuel. I however have no idea what it was set at previously or how to tune with it. I'm also afraid that if i tried i would blow my engine up. The other idea i have is that something is wrong with the shimming of the timing belt. I don't know anything about that either.

At this point any idea is a good idea and any help is appreciated. Thanks for your time.

 

I have never heard of "shimming" the timing belt. The first thing you need to do is get a good logger and a wideband if you don't already have one. Reference this post on how to tune the SAFCII accurately using Evoscan
https://mitsubishiforum.com/forum/sh...807#post248807

 

like he said you really need a wideband gauge to tell you what AFR you are running. What boost are you running right now. Also you need to adjust your fuel pressure at idle. Read here about that one
http://www.vfaq.com/mods/FPR.html

once you have these set you can start to play with the SAFC in order to correctly tune it. Here is a site on that one
http://www.roadraceengineering.com/newafc.htm

 

Shimming the timing belt??? Wtf is that, dont ever bring your car back to that shop.

 

Thanks for all the reply's! I will try to read those guides fully when i get home from class tonight.

I'm kinda on a tight budget so i don't think i can afford a data logger (will they work on various platforms or are they vehicle specific). Can i tune without using one (i think i've read "no") by just looking at the wideband a/f meter? I don't have that much more than a general idea on how to use a safc and i fear that i would wreck my engine. How user friendly is the process of tuning with them.

Sorry if this seems rushed but i'm about to head to class.

 

You can get by with just a logger and tuner off timing and knock untill you get $$$ for a wideband.

I bought a pda/logger off ebay for $20.00 and downloaded the mmcd software for free.

 

I guess i forgot to say i have an adjustable FPR and a wideband gauge as well.

While reading the afc link, i remembered that when i first got the car i noticed that a few things (rpm for sure i forget the others) didn't work like when i pressed on the throttle and the rpm didn't increase. Since it wasn't my work and the car still ran i just left it be.

The shop i have my car at now said that the afc was hooked up "un-professionally" and it sounded like the wires are probably crimped together. Maybe the wires need to be checked? Could the afc have reset and now the values are no longer there?

After reading the afc guide it seems like i could tune by myself (w/ friend) without worrying that i will kill my engine. If i look into this when i get my car back and it doesn't work/i don't understand i will probably take it to a shop.