3500 swap questions

[IsaacHayes]

IAC is trying to adjust for the cam. I've seen similar behavior in my car until it learned the idle. It may never fully learn on your cam though without help from a tune.

[Superdave]

It takes a while for the computer to learn the idle with a bigger cam.. if i unhook my battery it takes about a week of driving to get it to idle normal again.

[PCGUY112887]

It actually can learn the idle? Humm...

I guess everytime I flash my PCM, I am working against myself?

[IsaacHayes]

Yeah I would assume it would wipe it's memory on all the learned stuff after a reflash. It takes a while after disconnecting my battery for the car to have all it's normal power as it fine tunes the fuel tables.

[PCGUY112887]

Well this was pointed out to me...

http://www.clubgp.com/newforum/tm.asp?m=3446542&appid=&p=&mpage=1&key=&language=&tmode=&smode=&s=#3446542

Turns out I have the shitty mount that is short, it's basically the same height as a worn one. That also explains why the mount was so hard to get in there.

However my motor doesn't sit crooked or anything like their L67's do...

Should I worry about it?

[Superdave]

I wouldn't.. but it's a good excuse to upgrade to a better one.

[3400-95-Modified]

Wait, you did a case learn with a 97 Venture ECM????!!?!?!!

Maybe I need to do this... I dont have a code though.

[sprucegagt]

Now for a VE tune eh? fun fun. Any tips? Unplugging my MAF and scanning while driving for a bit and sticking my scan into an excel file to calculate changes just doesn't seem like it would work that well When I read the tuner guide, it tells to unplug MAF, change copy good fuel spark tables to bad fuel spark tables, etc. Then right under it, it says "Another way to tune VE" and it says that you don't have to do all of that, and it explains VE, but doesn't tell me anymore about how to go about tuning it!

Any idea as to why it is hard to start? I mean it starts fine, but if I don't touch the gas a bit the moment I start it, it dies. Starts up like normal, then it falls down to about 500rpm's and dies really fast. No codes or anything. If I tap the gas as soon as it starts to run (going to like 1500 RPM's), then it drops back down to idle fine and stays there.

Also KR... I scanned for maybe 15mins while driving around at various throttles, maxing out at probably around 50%, however I have 0 KR, all over, none at all. I mean no KR is good, but it seems like I should see at least some since it's so out of tune? I thought even stock cars get some KR, or is that mainly at WOT?

Sorry for asking so much about the tuning portion, but everything I read goes against the last thing I read... either that or it's meant for a boosted 3800!

If you had asked this in the OBDII section, you would of had an answer. /

As for your VE problems, this is what you need to achieve.

1. Proper Setup: Good fuel spark table must be copied to the bad fuel spark table; set the entire PE enable table to 100 and unplug the MAF. Upload this setup to the PCM and be sure to check the fuel trim reset box. This is exactly like the setup called for in the tuner guide.

2. Startup: Yes your car will have trouble idling until you get a couple GOOD adjustments to the VE table.

3. Datalog: Getting a good log is paramount. The items you need to scan are LTFT, MAP, RPM and FTC. After starting the car take it for a good 25 minute drive in all driving conditions like city, highway, hills, etc. but except full throttle. After you have done this, shut the car down, let it sit for about 30 seconds and restart. Now drive for about 10 minutes, then start datalogging over the same route you just took. Be smooth with the throttle while making this scan. Large jumps in throttle will lead to erratic LTFT values. The purpose of this is to get the PCM to settle down with it's STFT adjustments. These adjustments have a direct effect on the LTFT measurements that you need. If they are not settled down, then you will have erratic LTFT values in your scan causing your adjustments to be wrong. Once the STFT values stay mostly between -3 to +3 then they are usually "learned" and your scan will have a positive result with your VE adjustments.

4. Making Adjustments: If you don't have Eddie's program, please PM me. Excel spreadsheets stopped being used regularly over a year ago.

5. Achievement: Get your LTFT's between -5 and 0 in all cells that you normally hit while in idle or cruise conditions. If you can get between -3 and 0 then that's even better, but not required. Above all DO NOT go full throttle or anything above 99/100 kPa on your MAP. Also you won't be able to hit all the MAP/RPM cells on the VE table. Reason: Your engine can only run within a certain RPM range for each MAP column.


Now your lack of KR while VE tuning is not unusual. Most don't see KR because a speed density system can adjust faster to changing engine load conditions versus a mass air system.

Finally tuning a boosted 3800 for idle and cruise conditions is no different than a 3500, 3400, 3100, 3.1, 2.8, etc. The methods are identical. The only place where things vary greatly is PE. N/A engines need PE to come in around 90 - 93 kPa and with an initial AFR of about 13.2. This can vary so the only way to fine tune this is at a dyno or with multiple track runs on the same day with the same conditions and very consistent driving.

[PCGUY112887]

3400-95 yes I did do a CASE learn successfully on a 97 Venture PCM, same PCM part # as yours. If I was you, I would do one. Mine gave a code for it, maybe due to my external crank trigger. Regardless it's fine now.

I didn't think anyone really bothered with the OBD-II section here so I never bothered to ask here. I have learned a lot since when I posted that, and I got my VE tune done. Well for the most part, it's close probably within 6+- however it has become almost impossible to drive around with my MAF unplugged. I stall out in every turn, making driving extremely dangerous (had people slamming on their brakes and screaming at me to get a tow truck). The only way I could stop is to very slowly come to a stop, if I hit the brakes too hard the engine would die.

I got Eddie's tool, in fact he is now updating it again leaving out the part that got the program removed in the first place. Newest version is 6 released today.

Right now I am working on MAF, I have some posts over on powrtuner.com about what I am doing, latest update on my progress is here http://www.powrtuner.com/index.php?s...ndpost&p=58055

EDIT - Oh yes and lack of KR... I lack KR all of the time, not just during VE. In fact I have never seen any KR since I got this engine running.

[dukeking]

I am trying to a 3.5 lxe swap into a 3.1 95 lumina I have most of it figured out except for the crank and cam sensors they all look the same and even the placement is the same but the sensors are different along with the exciter rings. I AM STUCK

[PCGUY112887]

The sensors are different due to the difference between OBD-I and OBD-II. Someone else will have to chime in to tell you what you need to do...

[IsaacHayes]

Cam sensor will work just fine, don't worry about it. they changed it up over the years but it works fine.

You'll need to install your 24x crank sensor from the 3100 onto the 3500.

For the 7x sensor, they changed the tooth count. leave it in the block but you'll need the WOT external crank sensor to put your 7x one there.

[mickaz]

So the car is working well? it's been 2 years lol

[dukeking]

I am having problems uploading pics. But there is a pic of my eng. in the photo gallery look under 06 pushrod engs. its the lz4 3500.

So the crank sen. from the block of the 3.1 goes in the WOT kit correct? if so what about he sen. behind the balancer? I don't plan on changing the timing cover b/c of the ports for coolant flow on the front of the heads. The 3.1 timing cover won't clear the "water inlet manifold" ( I dond know what else to call it) on the heads.

And It would be something different when I poped the hood.

[RedBird]

I am having problems uploading pics. But there is a pic of my eng. in the photo gallery look under 06 pushrod engs. its the lz4 3500.

So the crank sen. from the block of the 3.1 goes in the WOT kit correct? if so what about he sen. behind the balancer? I don't plan on changing the timing cover b/c of the ports for coolant flow on the front of the heads. The 3.1 timing cover won't clear the "water inlet manifold" ( I dond know what else to call it) on the heads.

And It would be something different when I poped the hood.

i think this is one of those "Uh-oh" moments..... LZ4 is not the 3500 that everyone is swapping. LZ4 is the VVT-3500, and the only person i knwo of running a VVT motor is josephupson, and he's been working on his for at least a year and a half......

The motor we all go for the the LX9..... not the LZ4....