I posted this in the Cherokee section, and should have put it here, so sorry for the dup.
I'm looking to change the timing on my '90 and '01 4'0 motors. Does anyone make a scanner or sell software to let your laptop tweek the CPU? I'm looking for better mileage than what I'm getting. I'm sure it would help if I could tweek the CPU a little. I advanced the timing of my '87 Wrangler and get 4-5 more MPG now. That was easy, for it still uses the mechanical distributor setup. Have anyone of you guys done this to the newer motors? Lou
I'm almost positive no one makes such a software or I'd already have it, lol. The only way I know to tune 'em is by a dyno shop. Or, I heard of a company that can rebuild trashed engine computers that can also custom program them. Custom ECU programming would be ideal and I guarentee you could get significantly better mileage but it would probably cost you $1000 or more to get it done.
"Nitrous? So is that like viagra for your Jeep?" -mom
I'm of the opinion, if you can get 3-4 mpg out of your rig by retuning the computer, it would have come like that from the factory.
You have to remember the emissions parameters were set by politicians, not engineers. And that's what keeps the engines from performing at it's best. A given set of emissions standards does NOT mean the engine is running at it's peak efficiency nor power capability. I have many years experience of building and setting up many motors. Todays motors would benifit from ignition timing advance, beyond what the factory software will allow then to go.
I recently optimized the timing on my '87 Wrangler and picked up 4-5 MPG. This is all I did and it has more power, economy, and better response. I know it will NOT pass a emission test, for it will fail for excessive hydrocarbons. With todays gas prices, is it worth it to you? It is to me!
When I drive my '01, it is obvious it is held back.
when advancing the timing, how much do you advance it?
Don't know exactly the # of Degrees I advanced it to. I increased it in small increments before I went to work each morning for about 3 days. When it reached a point where it started to hesitate on acceleration, I backed it off and I was at the optimum setting. It made a big difference. I imagine I increased it 7-10 degrees. It all depends where you are starting from . If you have your Jeep serveced at the dealer, I guarantee you will see an improvement. Some small garage might set it up in this manner to begin with. You can do this yourself if you have an older NON computer controlled motor.
I still am determined to somehow get my '90 set up properly.
If anyone has any ideas, let me know. I was thinking of fooling the flywheel sensor in some way, for this I believe this is part of what controlls the timing.
What do you guys think?
Quadratec has an adjustable crankshaft position sensor. I think it is in their catalog - but I don't see it online right now.
I am currently battling the exact opposite issue with my 05 motor and my 98 AX15 tranny.
Trust me - I don't think i could recommend fooling around with the crankshaft pos. sensor at all. I am trying to mate the 98 AX15 and the 05 6cyl. and having timing issues (or at least that's what I think it is).
I thinnk my timing notches in the flyhweel are different from 98 to 2005 and causing my CPS to fire when the crank is in the wrong position.
Hesco and Advance Adapters both make a CPS relocation kit that includes a harmonic balancer and a cps that bolts to the front of the oil pan.
You should be able to modify timing with one of those kits.
The are approx $250 - $300 for either one.
Jon Evansville, Indiana
87 YJ/TJ Morph
3" (damned old) body lift, 1" Extended shackles, 1.5" Rough Country leaf springs, MP fuel injected 4.0, 3 row radiator, 33x12.5x15 ProComp X-Terrains, Eagle Alloy 8 Holes 15x10, Champion Winch, TJ Dash, 92 Roll Bar, AX15 5 speed, Posi-Lok, 1997 Dash and heater
i was under the impression that moving the sensor would only affect timing temporarily? isn't that why you need to have a CASE learn -or- crank sensor re-learn/calibration done at the dealer everytime you touch that thing or remove it for service, or else its a crap shoot whether or not its even registering the ticks correctly?
also, I would assume that if a dyno shop could tune a jeep, they would be in possession of a software programmer tool, such as LS1EDIT or HPTUNERS? There aren't any dynoshops around my area that have software to edit jeep's pcm..I can jump on the dyno, and make some logs, but can't change anything..
i really wish there was something..i used hptuners on my gto and once i got rid of the torque management settings, bumped timing a bit, and leaned out the mix, man, it was a whole other beast..
the procedure involves the jeep pcm getting connected to the handheld tech computer the dealers use, and the jeep is started, and then the tech has to push throttle WOT and release, and it does something to learn a certain parameter and and changes a table in the pcm..
it is required if any of the following conditions exist
Crankshaft balancer replacement
Crankshaft position sensor replacement
Any engine repair(s) which disturbs the crankshaft/harmonic balancer to crankshaft position sensor relationship.
-and if you're still interested-
The crankshaft position system variation learning feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, the crankshaft balancer interupter rings, and the crankshaft sensor hall effect switches. The calculated error allows the PCM to accurately compensate for reference period variations. The crankshaft position system variation learning feature enhances the ability of the PCM to detect misfire events over a wide range of engine speed and load.
in some cases a check engine lamp can also be set if its off way far
P1336 Crankshaft Position (CKP) System Variation Not Learned
P1345 Crankshaft Position (CKP)-Camshaft Position (CMP) Correlation
on further note, anyone using an Optimizer from Kenne Belle? they claim to reprogram, but you have to ship them your pcm...this may be a good option, because i'm sure they will do custom work if you just ask them..
I replaced the crankshaft sensor in my '01 myself and never did anything to the software and it's fine. It was one of those decisions of, take it to the dealer for an estimated $500-$700, or fix it myself.