1997 Malibu 3.1 Upgrade options...

[Baldeagle242]

The only sensor you will "lose" is the oil level sensor in the pan, unless you want to swap over oil pans... this may be a good idea since some have been having trouble getting 04 and 05 pans to work on the older a/c compressors.

Thanks for the info here. I checked the bolt hole for the A/C comp. and as you can see in the pictures it is lower on the 3400. I don't think I would have caught this before I had this in the car.
Thanks again

[IsaacHayes]

Hate to tell you this now but if you don't plan on getting a tuner to edit the computer, you will want to run the 3100 injectors. The 3400 injectors have a higher flow rate, and will run too rich. The computer has no way of knowing that you changed the injectors to higher flowing ones, so it pulses them for the same duration as the old 3100 ones thus squirting too much fuel.

Running the 3100 injectors the computer can adjust (to a certain extent) for the added flow of the motor, and since it's calibrated to the 3100 injector flow, it can do so accurately.

I bet you will have drive ability issues with those 3400 injectors.

Swapping the injectors is a no brainer. Un-bolt the 3100 fuel rail from the lower intake, put on new injector orings, bolt it down to the 3400 lower intake. Simple really.

[Baldeagle242]

Hate to tell you this now but if you don't plan on getting a tuner to edit the computer, you will want to run the 3100 injectors. The 3400 injectors have a higher flow rate, and will run too rich. The computer has no way of knowing that you changed the injectors to higher flowing ones, so it pulses them for the same duration as the old 3100 ones thus squirting too much fuel.

Running the 3100 injectors the computer can adjust (to a certain extent) for the added flow of the motor, and since it's calibrated to the 3100 injector flow, it can do so accurately.

I bet you will have drive ability issues with those 3400 injectors.

Swapping the injectors is a no brainer. Un-bolt the 3100 fuel rail from the lower intake, put on new injector orings, bolt it down to the 3400 lower intake. Simple really.

Wow...I realy don't want to change the harness back to the way it was.

[IsaacHayes]

You can try driving it like it is, but I bet you'd have more power and better mileage and drive ability with the old injectors. Sorry I didn't see this sooner.

Anyone else have a comment?

[bszopi]

I know on my 3400 swap, I just kept the 3100 injectors and bumped up the fuel pressure some. Its run just fine for 3.5 years now.

I know I mentioned the swapping of the connectors, but I guess I should have mentioned the need for tuning. I did mention keeping the 3100 injectors though.

[Baldeagle242]

At this point I am going to go ahead and put it back in the way it is. It is not that big of a deal to change the injectors and the harness once I get it in the car if it proves to be a problem. Does anyone have another harness like the original one for the 3100 injectors?(see picture above) I would like to avoid reworking the harness that I made to use the 3400 injectors.
Is there no one in the Cincinnati Ohio area that could tune this car with these injectors?

[IsaacHayes]

Yeah if you find someone that has a DHP they could update the ECM with the flow rate and you'd be good to go. They could even put the 3400 spark and fuel tables in too so you'd get a little more pep if they wanted to take the time.

[Baldeagle242]

Okay, I got the motor back in the engine bay and bolted everything in. I left the UIM off so I can ponder the injector dilemma a little more.
A few other minor snags I ran into.
1. The throttle cable connecton is a little different. I was able to find a way to get this to work but the cruise control cable will not hook up.
2. One of the heater hose connection from the 3100 will not connect to the 3400 and the 3400 pipe comes out in a different area than where I need it. The 3100 connection is threaded and the 3400 has a pressed in O-ring. I will solve this problem by replacing the preformed heater hose with bulk cut to length heater hose. The only other thing I could do is thread the 3400 intake but I do not have a tap that big.

[Baldeagle242]

Oh...and one other problem.
I found a motor mount(actually a front trans mount) that is bad.
<snip>

[bszopi]

As far as the throttle linkage goes, you should be able to disassemble the 2 TBs and swap the linkage/shafts between the 2 TBs. You might have to enlarge the shaft cutout for the larger throttle plate (3100 TB is 52mm and 3400 TB is 56mm), but that is pretty easy.

Yeah, I guess no one ever mentioned the coolant connection in this thread. If you have both pipes that go into the manifold, it should be relatively easy to just adpat rubber hose between the hard line at the manifold and the connection at the firewall.

[IsaacHayes]

Yeah just swap the linkages over. I did not have to widen the shaft slot when I did mine. A nice write up is here.

For the heater hose, I'd leave the stock metal on in the 3400, and cut it after the bracket that holds it in, then splice rubber hose there to your stock line. Or something like that wherever looks the most secure and reliable.

[Baldeagle242]

Yeah just swap the linkages over. I did not have to widen the shaft slot when I did mine. A nice write up is here.

Thanks for the info. I had thought about this but had not looked into what it would take to swap the two.

[3400-95-Modified]

Very simple to swap the two linkages... just make sure you have the spring right so it has tension on it to close the throttle.

[Baldeagle242]

Again, thanks for the info guys.

Bada Boom


Bada Bing


Bada Bang!


Very simple, Its not that difficult to put the washer back on if you want to. Just lay the linkage on its side and use a 7/16" deep well socket to tap it back on.

[Baldeagle242]

THE BEAST IS ALIVE!
I was able to get the motor to fire and run for a few seconds today. I realized after It started that I had a bad gas leak at the fuel line connection at the fuel rail. I think I may have damaged the O-ring when I put it back in. I'm to tired to screw with it anymore tonight