3400 question.

[19Cutlass94]

Ok guys, first you gotta know that my car is an OBD I 3100 ( '94 ). Sooner or later ( hopefully this summer ) Ill be doing a 3400 swap. Now for a 3400 motor, Ive been reading that the Gen III ( more specific the heads ) flow much better and it does make a little more power over the Gen II. Now I will be doing a lot engine work do this and would a Gen III be a better motor for this? And is the OBD I to OBD III even possible? I know of the OBD I to OBD II. Would this work, or am I looking at buying a OBD II 3400. I just wanna get all I can out of it because I only wanna do this once.

[Syn]

Re: 3400 question.

Ok guys, first you gotta know that my car is an OBD I 3100 ( '94 ). Sooner or later ( hopefully this summer ) Ill be doing a 3400 swap. Now for a 3400 motor, Ive been reading that the Gen III ( more specific the heads ) flow much better and it does make a little more power over the Gen II. Now I will be doing a lot engine work do this and would a Gen III be a better motor for this? And is the OBD I to OBD III even possible? I know of the OBD I to OBD II. Would this work, or am I looking at buying a OBD II 3400. I just wanna get all I can out of it because I only wanna do this once.

you cans wap the 3400 in no prob and run it with obd I,

and i believe ur engine is a gen III since its a 3100

you'll see a gain swapping it in

[19Cutlass94]

Awesome, thats what I wanted to hear! I just wasnt sure how all of that OBD stuff with swapping worked out.

Im hoping to see a big gain. List of things include:

P&P upper and lower intakes
Stage 2 heads
Stage 2 cam
Cromoly ( sp? ) pushrods
LS1 or LS6 valve train
Bigger TB
Custom tuned PCM

I duno about boring or raising the c/r yet well have to see. but I hope to see nice gains with all of that.

[JMo60]

3400swap.com

[19Cutlass94]

yeah thats a good site. Ive looked at it several times.

[Syn]

Awesome, thats what I wanted to hear! I just wasnt sure how all of that OBD stuff with swapping worked out.

Im hoping to see a big gain. List of things include:

P&P upper and lower intakes
Stage 2 heads
Stage 2 cam
Cromoly ( sp? ) pushrods
LS1 or LS6 valve train
Bigger TB
Custom tuned PCM

I duno about boring or raising the c/r yet well have to see. but I hope to see nice gains with all of that.

stage 2 cam and heads from who?
ls6 valve train as in springs right ? lol

[Guest]

Aight, it looks like we must clarify a few things.....

OBD, not to be confused with ODB.

OBD = On Board Diagnostics. This is simply how an external computer comunicates with the PCM. Also how much info the PCM must/will display on that external computer/diagnostic equipment.

The engine controlling functions are pretty much the same, and I'm sure if it was broken down enough the programming language would even be the same or similar.

The engine itself does not have any sort of "OBD" designation. since it is a mechanical device. OBD is strictly software, not hardware, the engine is the hardware.

So basically all you need to do is make sure that the PCM can retrieve the information that it needs from the hardware in order to control that hardware. This is done through the use of sensors, for gathering information, and actuators to use that information.

Sensors (gather):
-TPS
-CTS
-C(rank)PS (sometimes mutiple)
-C(am)PS AKA CSS (Cam Sync Sensor)
-KS
-IAT/MAT
-MAP and/or MAF
-O2 (sometimes mutiple)

Actuators (control):
-IAC
-INJ
-Spark
-EGR
-DOD
-VVT

Some engines will have some or all of the above mentioned parts, some will have very few.

What you have to do is use the above available parts to interface your PCM with the engine.

Luckily you are replacing your existing engine with one that is almost identicle, save for a few improvments.

The '94 is actually OBD 1.5, that just about everybody hates. LOL

Basically what you need to do is use sensors/actuators that are the same or similar to what you already have in order to use your existing PCM. Not hard since most of the parts remained the same between the 3100 and 3400.
You may have TB issues though (You'll have to very ify the TB you have), and maybe a few other minor hurdles, but should be pretty straight forward overall.

BTW:

https://www.domesticcrew.com

[19Cutlass94]

yeah that OBD stuff always kinda got me, duno why. But thats why I wanted to go with the 3400, since most of everything would transfer from the 3100. I figure it should be a relatively easy swap. But if I get a custom tuned PCM, maybe from Milzy, would he be able to figure all things out and program that in? I mean Im going to need a new PCM to compensate for the bigger motor so I get the full advantage.

Syn, yeah I meant the springs. Im probably going to have to look for some fulcrom rockers, since I dont think full roller rockers ( from either LS1 or LS6 ) would fit. My dad knows a couple good P&P places from when he rebuilt his engine. I was just planning on send the parts out to have it done, but theres places like here, I know some guys P&P, Milzy ( has both P&P and cams ) And for the love of God, please dont bring up OMG your gonna pay this for that why would you do that etc etc. My motor my money. ( Im not trying to be an asshole, I just hope everyone knows that )

[Guest]

yeah that OBD stuff always kinda got me, duno why. But thats why I wanted to go with the 3400, since most of everything would transfer from the 3100. I figure it should be a relatively easy swap. But if I get a custom tuned PCM, maybe from Milzy, would he be able to figure all things out and program that in? I mean Im going to need a new PCM to compensate for the bigger motor so I get the full advantage.

Some research is needed on your part here......

'94 is a hybrid year when it comes to the PCM, since it has a removable PROM, but uses an interface similar to OBDII. Currently from what I have read there is no one, not even DIY hackers that do anything with these PCMs, due to the interface language being a two year only deal and not enough people want to modify the PCMs of these two years.

You can't just get a PCM, and put it in, it doesn't work that way. AFAIK Milzy only has later PCMs for '98 or so and up. I haven't heard of anyone getting a PCM for anything older than that from Milzy.

Syn, yeah I meant the springs. Im probably going to have to look for some fulcrom rockers, since I dont think full roller rockers ( from either LS1 or LS6 ) would fit. My dad knows a couple good P&P places from when he rebuilt his engine. I was just planning on send the parts out to have it done, but theres places like here, I know some guys P&P, Milzy ( has both P&P and cams ) And for the love of God, please dont bring up OMG your gonna pay this for that why would you do that etc etc. My motor my money. ( Im not trying to be an asshole, I just hope everyone knows that )

I can tell you're new to this engine game from this.....

the 3400 comes with roller fulcrum rockers from the factory.

The LS1/6 uses similar rockers, roller fulcrum rockers, different shape.

None are full roller.

I haven't had any personal dealings with Milzy, but what I have seen is that you can get the same parts, elsewhere, cheaper. I fully support getting someone local porting your heads though, as that is what I will be doing with my heads when it comes time to do that.

[19Cutlass94]

I can tell you're new to this engine game from this.....

Thats why Im here. I know you guys know more about this stuff than I do. I mean I know the basics and stuff and how to fix things and put em together, but other than that, sometimes I need help.

[bszopi]

'94 is a hybrid year when it comes to the PCM, since it has a removable PROM, but uses an interface similar to OBDII.

Depends on the car... In this case, since its a GP, then it doesn't have a removable PROM, but is OBD-1.5. Only the A-bodies got the removable PROM PCM in 94-95. The J-bodies and I believe the Lumina kept the 3.1L MPFI for the 94 model year and thus retained the OBD-1, removable PROM ECM.

Since you are looking at swapping a 3400 in, you COULD find a donor vehicle that came with a 3400 and 4T60E and swap in that wiring harness and PCM and then be OBD-2 and have the all of the tuning options out there for the OBD-2 vehicles. More work and more money, but more potential in the long run.

[Syn]

theres lots of info that covers the lsx spring swap

IMO i'd stay with the stock rockers thats what i did

[Guest]

'94 is a hybrid year when it comes to the PCM, since it has a removable PROM, but uses an interface similar to OBDII.

Depends on the car... In this case, since its a GP, then it doesn't have a removable PROM, but is OBD-1.5. Only the A-bodies got the removable PROM PCM in 94-95. The J-bodies and I believe the Lumina kept the 3.1L MPFI for the 94 model year and thus retained the OBD-1, removable PROM ECM.

Since you are looking at swapping a 3400 in, you COULD find a donor vehicle that came with a 3400 and 4T60E and swap in that wiring harness and PCM and then be OBD-2 and have the all of the tuning options out there for the OBD-2 vehicles. More work and more money, but more potential in the long run.

I thought all OBD 1.5 PCMs had a removable PROM? Oh well, that's cool, makes that system even less desirable when there is that much inconsitancy.

If you do decide to swap in a newer PCM/Harness, I suggest starting with a '96 L-body PCM/Harness, as it does not use the PassLok system.

[19Cutlass94]

bszopi, my dad was wanting me to buy a brand new 3400, and I already have a 4T60-E tranny. But if I did that, Id just have to pull a wiring harness from a newer 3400 equiped car right? Because the way it sounds like to me, is that I cant put a custom PCM in my car right now, only the newer ones that Milzy makes ( '98 and up like stated above ) so would that mean I might be able to get a wiring harness from a '98 or so up Monte Carlo that came with a 3400 ( or a cr with the engine/tranny package ) Then I could put a custom PCM in and itll be OBD II.

( Sorry for all the questions and kinda seeming a little lost on this, but I just want to make sure Im understanding everything )

[bszopi]

In a nutshell, yes.