swapped in 3800sc. starts right up, then quits like the gas is shut off. (Non reprogrammed ECM) Fuel pump still pumping, so there is Pressure. does the computer stop sending "signals" to the injectors to stop the flow if the VATS have not been deleted ? is that HOW the VATS works ? starts but quits almost immediately ? Thanks
Yup. That's the VATS. You've got to get in there and De-select VATS.....i think. It's that simple on the earlier code masks, but I don't know about that one.
OK, Who is the most knowledgable and most "Reasonable" to reprogram a 1998 box ? a Bone Stock 3800SC (1999), 4t65e, Retaining the EGR , Retaining stock "shift points". So, what exactly needs to be "Changed" ??? is all that's being done is "Deleting VATS" ? do they "CHECK" everything Else in the box to make sure the rest is good to go ?? thanks.
VATS bypass module. I've seen them for a car that came with Vats and you want to by pass it, but HOW is it wired for the harness of a 3800 in a fiero ?
"These can be bought (any remote start dealer should have one) - or you can build your own." **** My 4.9l wiring thread has the drawing for a DIY module.****
Your 4.9 wiring thread ?? where might I find that ?
VATS bypass module. I've seen them for a car that came with Vats and you want to by pass it, but HOW is it wired for the harness of a 3800 in a fiero ?
"These can be bought (any remote start dealer should have one) - or you can build your own." **** My 4.9l wiring thread has the drawing for a DIY module.****
Your 4.9 wiring thread ?? where might I find that ?
Never done a 3800 - but I would assume that the bypass module gets wired to the VATS input on the ECM
What's the PCM? A Buick Regal? I had to flash my pcm to a 98 GTP for it to start.
Even if we turned Everything we could in the DHP file for Vats it still wouldn't start.
I do have a spare PCM from my swap I could send you. It's geared for 3.29 in the trans though. I'd change it out for you but I can't flash anything in the Fiero at the moment as I yanked the harness out.
Buck531 I have" NO IDEA HOW" the boxes are" reprogrammed / flashed". (wish I did) Does it take "special equipment" ? I always figured it was the box hooked up to a laptop and things were added/deleted, but then you'd have to Know "WHAT to Change" and" How". (that lets me out) LOL I wouldn't care what it's geared for as long as it will let it RUN.
Buck531 I have" NO IDEA HOW" the boxes are" reprogrammed / flashed". (wish I did) Does it take "special equipment" ? I always figured it was the box hooked up to a laptop and things were added/deleted, but then you'd have to Know "WHAT to Change" and" How". (that lets me out) LOL I wouldn't care what it's geared for as long as it will let it RUN.
Do you know what the computer came from? Was it with the drive train that's in the fiero now?
Yeah it does take special equipment. You can either get HP Tuners or be cheaper (but effective) and pick up a used DHP box for $200-$250. You'll need a laptop to connect to the OBD2 port and then the software is free. But then again if you don't know what you're doing it could be very overwhelming.
If I were you I'd run down to a junk yard and pick up a 98 GTP PCM (I think later years had vats? ). I know the Regal does.
These are What I've got out there now, Tried Both. #12209624, and #09361735. Both will "run" the Engine, but only on "quick start "Ether. Fuel pump runs, but seems the injectors don't get "signal" to allow fuel. (have not yet hooked up NOIDS to check for signal). If VATS is the case, and either of these boxes will work, WHO does the best job at the Most Reasonable Price ? This is for a "Bone Stock"/ automatic 1999SC. Is the "Only thing" needing to be Done , "Deleting" VATS ??? if not, what else ??? Also, for future reference: Is there a certain Year/ Model that I can pull in the boneyard, that Does Not Have Vats that is just Plug n Play for 3800SC ? the boxes are only $10 in the u pull. Thanks
IF,( Like in the cars these Computers came out of), there are a few wires that go up to the ign Key switch , that CAN Have a "Bypass chip" put "in line" to eliminate the VATS". ( I know there are 15 different value chips) * But seems here's a "Million Dollar Idea". * If someone "Marketed" an "Inline Chip" that can be wired into the 3800SC Wire Harness (when it's being made) that will "Bypass" the VATS ! I am Very Sure everyone "Building a Harness" Would Buy One, rather than paying over $120 ONLY to bypass VATS in the Computer. All you Computer "Wiz's" out there and No one has made one ?????! I can see paying $125 for a "Fully Reprogrammed" Computer, BUT , $125 just to Bt Pass VATS !!! Surely Someone has solved this. Am I wrong, can it NOT be done? Anyone ??
Like was said above, 98 gtp pcms have VATS disabled from the factory. There are other codes that usually need deleting for the Fiero to get rid of the service light that make the reprogram more worth it.
Even with a GTS PCM, you will have a solid on (aka worthless) check engine light. Since almost all want at least a functioning check engine light, that means you might as well bite the bullet and get the PCM reprogrammed. Get everything else you want programmed in at the same time. Make sure the programmer adjusts for the tire size you will end up running so the speedo is accurate.
IF,( Like in the cars these Computers came out of), there are a few wires that go up to the ign Key switch , that CAN Have a "Bypass chip" put "in line" to eliminate the VATS". ( I know there are 15 different value chips) * But seems here's a "Million Dollar Idea". * If someone "Marketed" an "Inline Chip" that can be wired into the 3800SC Wire Harness (when it's being made) that will "Bypass" the VATS ! I am Very Sure everyone "Building a Harness" Would Buy One, rather than paying over $120 ONLY to bypass VATS in the Computer. All you Computer "Wiz's" out there and No one has made one ?????! I can see paying $125 for a "Fully Reprogrammed" Computer, BUT , $125 just to Bt Pass VATS !!! Surely Someone has solved this. Am I wrong, can it NOT be done? Anyone ??
Maybe I missed something reading the thread (I have the 4.9, not the 3800). What you are talking about sounds just like the normal VATS bypass circuit which is available on eBay for $15 (a lot less than $125 you are mentioning). It is certainly better to have it programmed out of the ECM so that you don't have to worry about the little circuit failing one day. I started with the bypass circuit and eventually had VATS programmed out of my ECM while it was being reprogrammed by Stickpony. I left the circuit in place, but it isn't needed now. One wire connects to the VATS wire on the ECM, then you have power and ground wires, and lastly a fourth wire that is either grounded or left blank depending which frequency you need. Simple to hook up, and cheap.
those work fine when you can just reach under the dash and plug it in (I have one in my 93 Formula Firebird. But using 1998 grand prix PCM in a Fiero, there IS Nowhere To" hook it to" ! that's the whole point, I was asking if something like that COULD be "spliced into" the " New Swap Harness" to override VATS.
those work fine when you can just reach under the dash and plug it in (I have one in my 93 Formula Firebird. But using 1998 grand prix PCM in a Fiero, there IS Nowhere To" hook it to" ! that's the whole point, I was asking if something like that COULD be "spliced into" the " New Swap Harness" to override VATS.
Where is your ECM? The output of the VATs bypass connects to the VATs input of the ECM. You connect power and ground to the bypass module and the output connects to the ECM input (no "under the dash" wire needed).
my PCM is in the usual Fiero Placement. is there a "Diagram" anywhere that shows what Wires on the "By-Pass" connect to what "PINOUT" on the PCM ??? AND do the 15 "variables" of the bypass "chip" come into play here ???
my PCM is in the usual Fiero Placement. is there a "Diagram" anywhere that shows what Wires on the "By-Pass" connect to what "PINOUT" on the PCM ??? AND do the 15 "variables" of the bypass "chip" come into play here ???
I believe that normally the BCM controls the VATS system (the 15 variables you talk about), but then the output is a single wire that goes to the ECM. The VATS bypass ignores everything to do with the key and the BCM and simply sends the required 30hz or 50hz signal to the single VATS input wire on the ECM. The ECM is just looking for that signal...it assumes that the BCM has done the hard work to confirm the correct key is being used. Obviously, you don't have the BCM....hence the need for the VATS bypass module or the ECM being reprogrammed.
Someone else will have to tell you which wire it is on your ECM. As I mentioned before, it's a single wire that connects to the ECM from the VATS bypass. The other wires are simply the power and ground, plus a fourth wire that is either grounded or left unconnected depending whether you need 30hz or 50hz. (If you get the frequency wrong, the car simply doesn't start. No issues. You just then switch to the other frequency and you should be good to go).
