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Discussion Starter · #1 ·
I recently just swapped my naturally aspirated 3.8 to a supercharged 3.8 now issue I'm having is wiring I got the supercharged motor out of a 2001 grand prix gtp and computer as well and found the wiring won't work so I bought a 04 impala supercharged car and figured I could use the wiring out of that but issue I'm having is the main plug that runs into the firewall on the impala is way to big for my car and it's only one plug my car has 3 plugs please help any adive would be greatly appreciated thanks
 

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Ouch, the run-on sentence. o_O

You won't need much more than the MAP and injector wiring to change, if you're swapping into an L36 Monte Carlo (the boost bypass valve can be eliminated in the tune, since it's just traction control/torque management).

Here is a friend's 2002 Monte Carlo SS that I converted to supercharged with its original harness back in April '09:
(you can use a smaller MAP sensor from L32 Series 3 supercharged 3800's to keep that same connector... picture link)

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- Dave
 

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You can keep the same computer in the car, but it will need to be tuned with the proper fuel and timing settings for the supercharged setup. The transmission settings for your non-supercharged car are different, too, so that will be preserved by adjusting the settings on it.

If you were told this wasn't a part of the swap, that was wrong. The 2000+ Chevy's are especially particular to having things just right for their computers (even needing the radio fuse pulled for a bit during programming, since they communicate on the same serial circuit & confuse some tuning traffic).
 

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Discussion Starter · #6 ·
Oh OK so I can't use the grandprix one at all than RIGHT? SORRY just want to make 100 percent sure on things before I do any more if I had of known it was going to be so much work I would have just put a regular 3.8 back in lol
 

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It's just a matter of having a computer programmed for the specific changes to run the new setup. You can order exactly what you need from ZZP to have it going for a couple hundred bucks, unless you want to get into tuning it yourself, or have someone experienced in tuning these cars in your region.

https://zzperformance.com/collections/3800/products/zzp-1-0-pcm?variant=31300261478462
These would be the options, from what it sounds like:
11047


- Dave
 

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Dave is correct, easiest is ordering from ZZP to have no issues with programming. You need quite a bit of experience to get it right. Using the Grand Prix computer isn’t as simple as a plug and play, there’s a lot different from the Pontiac to Chevy systems even though they’re essentially the same car.
 

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Discussion Starter · #9 ·
Well I got my pcm from zzp I plugged it in an still have same issue lots of power but no start starter is not engaging at all
 

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You may have to do a security re-learn. I forget the exact process, but it has to do with turning the key on and leaving it, and off. There's guaranteed to be a previous post about it here or another forum, if you search with Google.

First, shoot an email to ZZP customer service, and tell them the issue. I'd bet they see that often and know the cure.
 

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You may have to do a security re-learn. I forget the exact process, but it has to do with turning the key on and leaving it, and off. There's guaranteed to be a previous post about it here or another forum, if you search with Google.

First, shoot an email to ZZP customer service, and tell them the issue. I'd bet they see that often and know the cure.
theres 2 ways off doing this one is easy one isn’t.
1. Turn key on and leave it on for 30mins, after 30 switch off. Let rest for 10s then try and start.
2. Turn key to crank, release to on, leave 10mins. Switch off, turn to crank and release to on, leave 10mins. Repeat one more time and switch off. Crank it over and if it was successful it will crank. DO NOT MISS A STEP, DO NOT DO ANYTHING EARLY, FOLLOW EXACT TIMES AND STEPS.
 

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Again, hit up the vendor. They know what they did to the PCM, and I guarantee there's dozens of cars that have this security issue when installing.

Let us know how it goes, as I'm sure they'd appreciate people knowing the potential fix being less of a customer service issue in the future.
 

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Well I got my pcm from zzp I plugged it in an still have same issue lots of power but no start starter is not engaging at all
The PCM has nothing to do with the starter engaging (turning over). The PCM will determine if the engine will start and run. If the turns over and the PCM won't allow the engine to start and run, the VATS can be overridden in the program. If the starter can't be energized then its the wires to the starter that come both off the battery and the ignition switch. The start signal from the ignition also goes through the transmission shift switch so check that.
 

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Discussion Starter · #16 ·
OK so i got the motor out of a 2001 grand prix gtp and put it in my 2000 monte carlo ss originaly a 3.8 non supercharged are you talking about the box that has 2 plug-ins on it, it sits on top of the transmission where the shift link connects 2 cause I don't have the plug-ins for that so it's not plugged in can I take that off?
 

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That trans can't be ran from your setup as-is, so your car may not even think it is in P/N to start, etc. Your car started as the newer 00+ style with all electronics internal to the trans, while some cars kept the external switch until ~01-02. I'm not sure if even adding the harness pins will help, since there may be different PCM shift logic required as well (there's a bunch of write-ups on this buried somewhere).

As with many swap considerations:
  • Yes, the parts from various S2/3 3800's and 4T65e's will bolt together physically...
  • But there were multiple electronics changes during the years, platforms, and generations.

You just happened to come across that specific line in the sand for transmission swaps.
 

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Discussion Starter · #18 ·
So I'm just better off swapping the whole trans again for the one that has the internal switch than I do have one the whole motor actually out of a 2004 impala
 

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2003+ had another change that requires different PCM controls. You might have an easier time making the current one work.

I think some of the Fiero 3800 swap info pages detail these things, and maybe some good write-ups on here and other forums. I'd have to do some digging to find it, but look up info on the range selector and internal mode switch, I believe. Start by skimming over these:


There's a lot to chew on there, but those guys are typically 99+% correct in the information they listed.
 
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