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which cantuned pcm can be tuned after install?

S

silistring

New member
02 gtp 125k in pretty good shape.
Mods so far: Updated Pacesetter headers from zzp.....no leaks at y, 1.75 primaries
cat replaced by previous owner, no u bend, zzp resonator, stock back
custom cai/ kinda ram air monstrosity (using 2- 1.5" vacuum cleaner hoses to airbox with cone filter factory air box)
Aeroforce and auto meter boost gauge
Dakota Digital 2 stage adjustable fan temp controller wired into factory relays.........still have to wire in loads have p0480/po481 dtc
have autolite 104, but not in yet
fresh oil, and fuel filter


Computer reading coolant temp, factory coolant temp gauge good
Just had abs looked over, c0035, c0244, c0245 due to bad harness to lf wheel, repaired.

p0420 code thats it.

I'm getting 37* timing idle, about 27* with 1/16 pedal, and 1.5* with 5*kr at wot. Believe the pcm to be a major factor in timing issue, and would like a pcm that is safe to run out of the box, and be tuned later. I already have the 3.2" mps and belt, (not installed yet), and with theese readings, think a 3.2" is too small.

I am not a half witted, ignorant poster. I have done much reading on this car, and help would be much appreciated.
I am not an auto mechanic. I quit wrenching professionally at 18, and have been doing HVAC service work since, 10 years with the big stuff, not that puney resi crap, so I am way out of touch with the abbreviated lingo :)

So the question : Intense? Overkill? DHP?
I would rather not tune it myself, but dyno tweaks.
Thanks a lot guys
 


3.2 is too small of pulley to start with.

At a warmed up idle in Park, ign adv should be around 22 if I recall correctly.

Ign Adv will always jump around with throttle %, so those numbers are moving around.

P0420 is a cat code and being that you're 01+, that screws up alot of numbers and how the computer thinks.
 
http://www.grandprixforums.net/remo...1-newer-pcms-things-you-should-know-7092.html ---->p0420 code?

Idle voltage 0.47 vdc I'm guessing it's getting it's signal from tps. The voltage signal tracks linear positive without any drops with steady accel, or holding at any particular position.

Warmed up in park is 27* 0* kr....... 1/16 throttle in gear crusing 37* 0*kr.... then immediate, back well below 20* anything over 1/2 pedal
starts fine, possible cam gear? chain tensioner?

thanks
 
The best canned tune for you is tough to say as each car is different. Therefore, I'd suggest starting off with any of them and then hit the dyno, because you'll need to be tweaked/tuned. Based on the person doing the tuning, they might ask you for the stock tune to retune in their preferred method.

What I'm suggesting is to not bother with a canned tune until you speak to your dyno tuner and ensure they won't want to start fresh.
 
I appreciate the input. Thankyou. I do have a few questions though.
Are any of the aftermarket pcms new, or are they rebuilt/reprogramed cores?
Can there be some other type of issue that I may be seeing to cause down to 1.5* of timing with 5*kr (cam gear, chain tensioner, low fuel press, too much air, floating valves? torque converter?)
I have only used 93 octane since I have owned it. The gas up here does have ethanol in it.

Again, thank you for the help.
 


Sure..you most likely have other issues. I wouldn't suggest your issue is a pcm without diagnosing it. However you kinda stuck it to FFDP when he suggested it was another issue. So I gave you what you asked for and nothing of any real value beyond the ability to shotgun money at a most likely perfectly good part.

If you'd like more info about diagnosing it, let's chat further. There are a lot of things that can get you down that low in timing/power that we can have you test for to rule out.
 
:) true I did jump right to informative info, but if you guys have to read as much as I do on a daily basis, as well as the amount of reading on this site of which I have done, sometimes "just getting to the facts Jack" gets the reader, and writer into the correct mental state.


The cat inefficiency post I thought was quite informative, and wondering could that have some effect on the p0420 code? Especially tied in with the coolant fans dtcs, could this be putting my computer into some kind of a reduction of power mode?
What do you think? I had my computer updated a while after I had it, long before the headers were put on, seemed to shift better, but didn't seem to last.....like the update didn't take. The upper intake gasket has been done sometime in the motors life, and no coolant leaking aroung intake, no little bubbles in radiator like a bad intake, or head gasket. It just seems like for some reason, sometimes if I'm out of the powerband, it's got no power whatsoever, then i can release the gas pedal, go wot, and all the power is back. Before headers, 28mph max in third gear would shift into 1st, after headers 32-34 mph max downshift, anything after that, it stays in 3rd gear, and boost pressure rapidly fluxuates from 5 to 7 psi.

Highest boost seen, 7-10 psi with factory exhaust/u bend delete, and cai.
Trans shifts fine. Up down, slow, fast, it seems fine.
It has far better throttle response at 1/2 pedal, than wot.
Where do you think is a good place to go from here?
 
For those who were wondering about starting with a 3.2" pulley, I have read multiple posts by you guys, and many were very good. My initial plan, even though I know I would be pushing my luck, would be the 3.2" pulley, and 1.9:1 rockers, without intercooling it, and without valve springs, and have it tuned to that. I do not want to install a new cam, or have valve issues above 6000 rpm to where valve springs are needed. The way it is running right now, anything smaller than 3.4" would be quite harmful. I would like a good, reliable tune, on a reliable pcm, and if I like the way it runs with the current mods I have, I may not even go smaller than stock, and just leave it the way it is.
 
It sounds like you are more than half the problem to be honest. You are pushing too far with mods and likely you have more KR than a motor with a bad lower end. Going on the cut to the chase, we don't care where your shifts happen etc, they should occur where the pcm tells them. If not, tell us about the problem, not how things changed slightly as you modded.

Let's start off simple here.
1. You feel you read alot, get used to it. I'm all about teaching someone about the car and not handing them answers without understanding. You'll fish when I'm done with you.
2. Tell us all your mods. We like brand names and model etc...like which plugs you are running and what they are gapped to, last tune up, etc etc. I don't like to read a ton to solve things either..sometimes it's the details that matter.
3. Pull out the scanner and monitor KR. Likely you'll see a ton when the car acts powerless.
4. Clear the cat code, does it come right back within two or three drive cycles.
5. How do your front bank 1 O2 readings look? Always rich?

To clarify my pushing too far comment. 1.9's w/o springs may be fine when the car has 30K on it as the springs haven't weakened, likely you don't have 30K and your springs are pathetic, add boost and change the valvetrain a bit, hello valve float. Your springs can't gain muscle by working harder etc, they just get worse over time.

3.2 pulley, on rockers alone this is too much pulley envy. Too many people have tested this in the past and learned that there simply isn't a reason to use a 3.2. Your motor can't process that much air, so instead you end up spinning the charger fast which generates more heat and heat causes predetonation in the cylinders. Right..your choice of pulley is costing you power. More pressure building up in teh LIM (where the boost reading is taken) does not mean more power from the engine.
 


3.2 pulley on nothing more than a intake, headers, stock catback, with AL104's and a fan switch thingey?

I swear...does ANY 3800 OWNER ON THE DAMN INTERNET READ THE SAFELY MODDING THREAD AT ALL?

for ****s sake. :th_beatdeadhorse:
 
how can I contact you bill? I have read unsubstantial evedence that you really know what you are talking about. I'll try to get you some decent readings, but, with boredom, I decided to screw with this car. It usually sits. My dd is a maybe 9000 pound work truck :) I would really like to talk to you, and to all of whom I've read so, so much good advice............ask it........question it......smell it even........ :) I have quite a few questions, most will be figured with plain english. I'm sorry to say, I'm like McGiaver"s supplier>>>>>>>>>>>>> why? when? what? how?..........and.you actually sniffed that? :) hahahahahahahahahhahah
 
let me get you guys some pics of of what would they call it............................ software? hardwarre? my car sucks because of normal ware with bad pcm
 


sorry guys, pullin the plug. i tried for the evening.....done. check out Dakota. there is no redially availiable schematicitic to go from. you must ohm everything out,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, fan 1 =run .........no dtc + (fan 2 + relay )= no diagnostic trouble codes. ohms updated
 
:) My bad Bill, and to all reading that if you didn't understand. Had a long day, and was kinda loopy, and buzzed from figuring how to modify this burner
http://www.namfg.com/c-index/c-lit/dual-fuel/6100-1_suppl.pdf
to theese controls
Boiler Upgrades that will Save Fuel and Energy on Industrial and Commercial Boilers from 50 HP and UP! - Industrial Controls
lots of electrical, and pnumatic controls tied together. Have 27-- 10,500,000 btu burners to upgrade to this.

I'm going to be busy this weekend, but hopefully I can get some more good, helpful,additional information up here for you with pictures. I had a hard time uploading pictures yesterday, but I'll figure it out.

Again, thanks for the help, and the information you have already posted has been quite helpful, not just to me, but if, and when I take it to a mechanic.
 
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