Fast355

iTrader: (2)

Well started looking for a problem that my brother was experiencing with his daily driver 3.1 powered 1989 GMC Jimmy. He bought the truck with mid-length headers, a 4.3 TBI (2.8 injectors), an adjustable fuel pressure regulator, and a 3.1 swapped into it. The truck would run great, until the RPMs passed about 4,000. Once it hit 4,000 rpm, the 3.1 would go pig rich, the tone of the engine would dull out and it would fall on its face. Going uphill @ WOT (which you frequently use going uphill with these trucks) it would not even reach the factory 5,500 rpm WOT 1-2 shift. I searched high and low for a factory 2.8 bin calibration. Finally pulled his prom chip apart and read the factory prom. The factory chip runs on the $4E code "8062" ecm. Here is what I found staring me in the face. Thats right, GM only elected to calibrate the fuel tables up to 3,200 rpm.

JohnBlazeLTZ

Oh wow...that is bizarre. No wonder those engines always ran like junk. I have seen people put after market exhaust on the 4.3 Vortecs and even they run nice up to a certain point and then they fall on their face under throttle too. Man...GM gave us some pretty messed up stuff and we just ate it up.

Fast355

iTrader: (2)

It just got a PCM swap and an electronic speedo cluster put into it. Starts immediately when cold, runs great, idles smoothly, pulls harder than before. In fact, we buzzed the little V6 up to 6,300 rpm and it was still pulling. (Custom ground 276/276 @ .006, 224/224 @ .050, .450/.450, 110 LSA) The engine made enough torque to obliterate the stock 700r4. It is now knocking heavily from deep inside, it is parked and a 4L60E is being built for it. I am using a 1995 Camaro 4L60E from a 3.4 V6 car. It has the 60* bellhousing pattern but is a 2wd model. I have to take both transmissions apart and put the 4x4 700r4s output shaft into the 2wd 60* V6 4L60E. The shafts are completely interchangeable with a 4L60E. The difference is the 700r4 shaft has splines for a governor gear that the 60E does not have. Both of the transmissions are apart now. The case is out at a local transmission shop being cleaned. I get the cases cleaned as well as have the teflon seal rings and lip seals in all the clutch drums installed for $60.00, then build the transmissions myself. It is getting a complete Superior shift kit, corvette 2-4 servo, boost valve, and built to V8 clutch pack specs. It will hold 400 HP when it is said and done, reliably. The V6 is getting a Faegol installed soon, so it will need it.

JohnBlazeLTZ

Cool Fast. Man your really going all out. BTW...what is a Faegol?

Fast355

iTrader: (2)

This isn't my truck, but it has a Faegol.

A Faegol is a Blower that was designed for the GM 60* V6. They came with either a VaraJet 2bbl top, TBI top, or standard holley 4bbl pattern for the top plate. I have one from a local wrecking yard. Only gave $200 for everything. Turns freely and has very clean rotors. Unlike this guy, I am keeping the A/C and am going to have to fab up some brackets to relocate it.

EDIT- I also added a picture of the installed gauge cluster, it is from a Typhoon. Payed $75 on Ebay for it. After some re-pinning and adding a 2 bar MAP for it, it functions well. I will be messing with the $0D code to see if I can run a 2-bar on it. I think it will probably work without too much trouble. Probably just need to make some changes to some constants in the code. Then the tables will read 2x the KPA they currently do. 40KPA-200 KPA. Currently the engine idles with about 55 KPA MAP unloaded so 40 KPA won't present much of a problem.

JohnBlazeLTZ

Oh wow...that is going to be a screamer huh? Dang. Another creative endeavour by my favorite TBI builder!!!!!

Fast...when did you start this project? Is something that your brother WANTS or is this something you would like to do for him (against his wishes) to satisfy your deep inner desire to take the most fuel efficient possible engines and make them the fastest things ever known to man?



LOL...of course...I can't wait to see the results (....and seeing that you always put stuff on video...I do truly mean I can't wait to SEE/HEAR it.)

JB

Fast355

iTrader: (2)

He WANTS it. We were going to drop a 305 or 350 into it, but decided against it given the fresh engine and the pain in the rear V8 4x4 swap. He also like the 24 mpg highway performance of the 3.1/700r4/3.73 gear. The stockish 3.1 was too dogishly slow for him. That is when we cammed it, ported the heads, and did the exhaust. The factory cat was so plugged that the vacuum would drop when the engine was held at 1,500 rpm without a load. Gave us tuning fits when we first started to dial in the 3.1.

I'll make a video of the beast running on the PCM with open exhaust today. The cam and open exhaust sounds sweet, IMO.

EDIT- Added some pictures. GMPP rates the lower end of this engine at 350 HP and 7,500 rpm. My cam and spring combination will do 6,500 rpm. The shift tables on the 4L60E end at 6350 rpm.

JohnBlazeLTZ

Yeah! That's what I am talking about!