1973 K-5 Blazer, TBI 350, TH400, 1 ton axles & 38" SSRs'
1975 280Z, TBI 350, 700R4
1953 M-38A1, TBI Buick 231
1951 Ford Panel, 5.3 with 4L80E
Ok, things just changed up.
I have to have the Motorhome up and running in 2 weeks to move it.
Put the Quadrajet on and its just not running right.
Can I do the basic TBI conversion using the '87 stuff in that time frame?
I need a running vehicle, not smog compliant in 2 weeks.
Tomorrow I can go get the box that I stashed the '87 Throttle body/wires/ecu etc.
The '90 harness I have may be more complete, so maybe I should use that as the ECU is the same...
Not worried about smog pump and cats yet, unless they are needed to run the engine.
I will need to pull the LH banks header to install the O2 bung.
Possible????
Last edited by KeyAir; 11-30-2015 at 10:26 AM.
I've done EFI conversions in a weekend, so it's possible, but if you're less experienced in conversions it may not be so easy, or you may need to dedicate more time to it than you actually can spare over the next two weeks.
That being said you don't need any of the emissions control components in place for the engine to run. Going TBI, it makes the swap to be a little more than a carb swap. Swap the carb for the TBI, the dizzy for an EFI one and add a couple more sensors. You will also need to add the fuel pump and the wiring.
If you take a couple hours to lay all the parts out and plan the swap you should be able to come up with a plan to get everything working, even if you will need to go back in later to re-work the harness to pretty it all up.
The man who says something is impossible, is usually interrupted by the man doing it.
I have nearly 15 thousand miles running a 7427 on a 4l80E manufactured in 1990 (1991 model year) without a single issue, and thats on top of 78,000+ miles the trans ran on a 7060. I had to tune the force motor current tables to get the pressure in line with what was commanded but it didn't take much. If I had it to do over I would have thrown the 7060 in the trash from the start.
94 Blazer, Turbo'd 350 TBI - DD
1991 2500 Suburban Adventure truck - 4wd conversion, 4-link F/R, 582ci CNP Big Block with Terminator X EFI backed by a 6L90 and twin stick'd NP205 t-case
2012 Porsche Panamera Turbo - Date night car :)
1979 16' Action Marine/"Johnny Cash" Merc Bridgeport Champ Motor - Metalflake Maniac
Pretty much sums it up .......
Oh , and I have ran late ('96) '80E's with the 7060 and early ('91) '80E's with the 7427 with no problems either way , I am sure there are differences , but I digress to think they are that big of a deal . My trans guy says no , but some say yes , Dunno.......
TOM
Last edited by Nasty-Z; 12-02-2015 at 09:51 PM.
1994 3500 Dually , 502 (509) , 264HR , Edelbrock MPFI , PFI '7427
1992 S-10 434 SBC/Tremec - '7427
1986 Monte Carlo SS
1984 S-10 , SAS, 496/700R4/205 , D44/14BFF -'7427
1980 Z-28 496/700R4
1979 Corvette 496/700R4
1977 Olds 98 Regency 403/700R4
That good 80e info. My main truck is a 94 and a 6395/7427 but have a 93 trans that came with 7060 and it is destined for my 50 pickup with a 7427.
6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF
I can offer all of you advise with the 4L80-E. I did this for a living many years within GM Calibration. My personal old 77 crew cab I converted to a 4L80-E with only off the shelf parts with the 94-02 TCM from the 6.5L diesel stand alone. (Later adding EFI but kept the TCM)
I observed within and outside shops to find what shops are using to "Fix" the units. I read some use a 91-93 Bosch Force Motor unit and control it with the 94 forward PCM. I wouldn't run this high risk combo on my own truck. I don't think even the best trans shop could actually find the root cause of failure without the knowledge. If you start with some basic paired parts you will have better service and prevent future overhauls.
Some kits have you drill holes in the pump to combine two circuits and one has you "open" a bleed for the pressure reg. balance. These will only lead to noise and unstable line pressure. Another fix causes the converter cl to drag worse increasing the wear factor. This leads to TCC Slipping and Trans Component Slipping codes. The thoughts behind these fixes are not well and completely thought out. They were to address failure modes that were not completely understood. I've fixed many. Sadly these shops believe they do correct the problem when they didn't diag it right.
If you can "Tune the Force motor tables" in a short period of time, the personal who do this take over two weeks to get this correct. My offer is proven with knowledge gained from many years. It's your vehicle and your back to pull it out. If someone says these mix of 91-93 4L80-E with a 94 forward PCM is ok, it's only a matter of time before it fails in my opinion.
If one takes a 91-93 Bosch FM unit/Valvebody assem and installs a Holley or Borg-Warner force motor in this VB, I suggest you take the time to investigate this. Get the manuals and lay the hydraulic circuits beside each other. You should see why.
I don't know it all and never will. I can only offer lessons and the knowledge behind this that may provide many miles of trouble free use. From combos to cooling to mixing parts.
Last edited by billygraves; 12-03-2015 at 02:50 AM.
I talked with a friend of mine who is a 4L80E nut, I mean a real 4L80E nut, not just someone who likes them. So far his car (1971 Cutlass), his girlfriend's car (1988 Chevy Caprice) have 4L80Es installed, and his 1992 (I think) Old Custom Cruiser is getting a 4L80E as well, all behind Olds engines. lol
Anyway, after looking up some reference material he has it indicated that some cars had the force motor valve algorithm to keep the valve from getting stuck, however it only does this in park and it sounds like many domestically sold vehicles didn't have this enabled. Later PCMs don't seem to have this and those transmissions seem to be fine. The change in frequency also doesn't seem to be a problem from his experience.
The man who says something is impossible, is usually interrupted by the man doing it.
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