Unn_Impala13 Posted November 1, 2011 Report Share Posted November 1, 2011 Motor went out in my 03' Impala recently. The mechanic working on said vehicle has had no luck finding a 3400 in my area to go into it so is gonna try putting a (LG8)3100 in it from a 2003 Buick century. Will this work alright or will I expect to see problems from it? Quote Link to comment Share on other sites More sharing options...
94 olds vert Posted November 1, 2011 Report Share Posted November 1, 2011 Should work. Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted November 2, 2011 Report Share Posted November 2, 2011 I'm not an expert on the Gen III 60º's, but I don't see any reason that wouldn't work. Is finding a 3400 really that hard around there? I trip over them in the yards here.. Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 Yeah. T_T I live in Eastern Kentucky. Junkyards get scavenged fairly often here. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 (edited) Should work nicely. You might need a sensor or mount or two from the original motor, but it should pretty much be plug and play. The PCM will be tuned for the 3.4 though, so it won't run as "nice" unless you get it re-tuned for the 3.1. Differences exist, I've dug around in plenty of Gen III V6 operating systems to know that they will run like crapola if not running the correct parameters for the engine type. What's your budget like for the motor? Miles/price on the used one? Edited November 2, 2011 by ptcfast2 Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 Well, its used and I'm not sure about the mileage. Motor looks nice though. Everything seems to be hooking up good. I don't have a great deal, but the labor for what all is being done is only about $300. The engine was $650 though. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 Well, its used and I'm not sure about the mileage. Motor looks nice though. Everything seems to be hooking up good. I don't have a great deal, but the labor for what all is being done is only about $300. The engine was $650 though. That's not a bad price at all as long as the miles are under 100,000K. I spent $2,150 on my 2003 turn key crate LG8 a few months ago. At least I saved on labor by installing it myself in my driveway! If you don't like the performance of the engine see if you can't find a place to get your PCM tuned correctly based of values from a LG8 PCM from that same year (a Malibu for example). Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 The Chevy dealer near here might be able to do it. Though how much would that probably cost? Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 (edited) The Chevy dealer near here might be able to do it. Though how much would that probably cost? Well, the Impala didn't ship with a 3.1 during that year, so Chevy wouldn't be able to do anything (they only flash complete operating systems - no OS for the 2003 Impala that suits a 3.1 so no flash). You would need software like HPTuners to edit your PCM and utilize values to tune it correctly to the LG8. You might be able to find someone online to work with you that has a bench setup to work with PCMs out of cars or someone who has a spare they can program and send to you. You could also buy the software and do it yourself...just depends if you have the $500. I'd lend a hand if you were close to me since I've got spare HPTuners credits I wouldn't mind utilizing, but I'm in North Carolina Edited November 2, 2011 by ptcfast2 Quote Link to comment Share on other sites More sharing options...
BXX Posted November 2, 2011 Report Share Posted November 2, 2011 Dealer will only flash to your vin. And you'll run rich with a 3400 tune on the 3100. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 Dealer will only flash to your vin. And you'll run rich with a 3400 tune on the 3100. Well they flash VIN and the OS you might need (from what I've dealt with at the dealers around here) if the OS is from the same year. That's all though if I'm not mistaken? That's why HPTuners + Tiny Tuner is great for these types of situations. Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 T_T Guess I could hope that the mechanic will just find a proper 3.4 if it doesn't sound right once it's fully installed. Maybe next year I'll be able to afford more proper repairs. lol Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 How rich would it probably run in comparison? Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 T_T Guess I could hope that the mechanic will just find a proper 3.4 if it doesn't sound right once it's fully installed. Maybe next year I'll be able to afford more proper repairs. lol Go to http://car-part.com/ enter your make/model and zip and select engine when asked for the part you need. Sort by distance and BAM you've got a listing of local junkyards with 3.4's available. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 (edited) Attached file in later post. Edited November 2, 2011 by ptcfast2 Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 ; I'm not quite sure of the comparison style. Would the #/# cells be the similarity. Cause it seems like this might take a bit of adjusting. Though the air fuel ratio says 17 between the two. I haven't really had any experience with some of the more advanced stuff, though I do want to learn more. O_O Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 ; I'm not quite sure of the comparison style. Would the #/# cells be the similarity. Cause it seems like this might take a bit of adjusting. Though the air fuel ratio says 17 between the two. I haven't really had any experience with some of the more advanced stuff, though I do want to learn more. O_O I'm trying to sort that data out...give me one moment...formatting didn't take. Quote Link to comment Share on other sites More sharing options...
tornado_735 Posted November 2, 2011 Report Share Posted November 2, 2011 Someone here ought to be able to hook you up with a retuned PCM for a few bucks. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 Alright, I attached the file instead. The difference marker is the : between values for single values. When something like 119 of 140 cells is referenced, that means 119 of the cells for the section/table are different. Should give you an idea of the amount of differences between the two engines. 2003 Impala vs 2003 Malibu.txt Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 How much would a retuned PCM probably cost? Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 So what'll likely happen when the motor is started without the PCM change? Quote Link to comment Share on other sites More sharing options...
tornado_735 Posted November 2, 2011 Report Share Posted November 2, 2011 Nothing spectacular, really. It just might not run as well as it should. It's entirely possible you might not even be able to tell the difference. When I was considering swapping a 3400 in place of the 3100 in my 1994 Grand Prix, I was told that I could run a 3400 on the 3100 tune, it would just run a little more lean, and I would eventually need to get the PCM swapped. I think you'll be ok for the time being, the PCM might even be able to make up the difference in displacement. Three Tenths of a liter isn't that big of a difference anyway. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 (edited) How much would a retuned PCM probably cost? Depends on if they get it, you ship one to them, etc... gotta work that out with the seller/member. Kentucky isn't that far from NC! Want to take a road trip when you get the car up and running and I'll help ya out? Edited November 2, 2011 by ptcfast2 I keep forgetting things... Quote Link to comment Share on other sites More sharing options...
Unn_Impala13 Posted November 2, 2011 Author Report Share Posted November 2, 2011 I guess when divided by 6 cylinders too. - o - I do hope that's the case though. If it does work, I can atleast say I have one of the few 3100 sfi Impala's in existence. Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted November 2, 2011 Report Share Posted November 2, 2011 (edited) Nothing spectacular, really. It just might not run as well as it should. It's entirely possible you might not even be able to tell the difference. When I was considering swapping a 3400 in place of the 3100 in my 1994 Grand Prix, I was told that I could run a 3400 on the 3100 tune, it would just run a little more lean, and I would eventually need to get the PCM swapped. I think you'll be ok for the time being, the PCM might even be able to make up the difference in displacement. Three Tenths of a liter isn't that big of a difference anyway. Well, the other problem is spark tables and the transmission shift points/pressures are different. He's not just dealing with fuel, he's potentially dealing with power issues as well. The engine will start and it will run, just not as well as it should and might have a few hiccups. Only reason I'm saying this is because I'm looking at the tables for each OS right now. Many seem to be comparing apples to oranges when it comes to values. Edited November 2, 2011 by ptcfast2 APPLES! Quote Link to comment Share on other sites More sharing options...
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