Cliff notes: Car runs lean, tried a bunch of thing, now nothing works anymore. For interesting part, get to the bold part
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I need to release the pressure a bit.. maybe some of the guys in this section can help me out on this on...
I think it happen once in every tuners life where you try to fix a problem, but then you are not so sure anymore of what the hell is going on and only after alot of stress and pain you realize that another problem happened right after the first one and this is why you were not able to fix the first one right away...
Enought with the talking, here are the facts.
Back in September 08, I buy a PRP for my SRT. First thing on the list is rescaling the injectors (60 lb -*> 630 cc approx). Car goes fine and pull allright for an 18 psi .48 50 trim with cat.
During the winter, I notice that the car is starting to run slightly leaner (instead of 11.4 is was more in the 11.9,12 AFR range). I think it's because of the colder air, maybe I'm at the limit of my stock fuel system (with walbro 255 pump).
When the hot weather came back, the car kept the same AFR, didn't came back to my prefered 11.4 AFR. I now have to 'cheat' the PEAS table to get richer and richer towards red line.
But as soon as I'm asking for more boost, AFR start to climb fast.
It was time for a return line and bottle neck fix.
First day I got the car running with the setup, I'm not really impressed with the result. I'm running a little bit richer but I still have to cheat the PEAS table.
I then start playing with the boost reference of my FPR. And from then, everything just started being worst and worst...
Plugged, un-plugged, tune with the reference in vacuum only... boost only... both. Each time the car run lean (13+ AFR range). The best configuration yet is to have the FPR upplugged, with the stock 'compensation'.
I then started eliminating the possilities.
Could it be the tune that is wrong ?
- Tried 4-5 different tunes, all of them have been running great for a year on my gf srt, on my friend srt etc...
Same result. AFR goes up with boost. Not enought fuel....
Could it be the fuel pressure going down in the fuel line ?
- Bought a fuel pressure sender to monitor the fuel pressure with my aeroforce gauge. Pressure stays at 58 psi when using static reference. Goes up when using reference under boost, goes down when in vaccum. Everything is like it is suppose to be. Conclusion : Fuel pressure doesn't go down.
Could it be my fuel injectors that are clogged ?
- Switch back my S0 (s1) injectors. And now the party starts... First, I used the same tune and only modify my injectors size (back to stock values). Car runs super rich at idle.10+ AFR.. the engine tries to die I have to make it rev to go back in the 11.x range, and then goes back to 10+ afr.
Changed the tune for a stock S2 tune, maybe I went to far in my last tune(which I have been running without issues for about 3 months, before trying different tune). Same result. Car runs super rich.
Tomorrow I'm going to buy a new O2 sensor... The stock one has 60 000 miles on it (5 years). Hope this is going to solve THIS problem so I can focus on my first problem... (running lean at wot).
- Next thing to try if I can solve this : Fuel pump...
I'm gonna keep you aware of my progress...
If any of you have an idea.. I'm more then ready to listen !
PS. my friend is trying to convince me of switching to an SDS....
I am running a static 58 psi on rc 650cc injectors , stock turbo , & I had a very tough time getting them scaled for a stage2 code . I cant imagine how tough it would be with a variable pressure return line setup !
I had some of the issues you seem to be having , but mine was mostly during spool-up , once boost leveled out , AFRs calmed down . But the more I worked on the Injector rescale tables (based on fuel trims seen on my aeroforce gauge ), the more I could bring the Power Enrich Tables to reality . As I did this the lean hole got smaller and smaller .
I was hoping we would have datalogging , but .........................
Of course one plan of attack is to eliminate suspects in your setup . Could you swap your injectors & their rescales into another SRT4 and see if it reacts the same ?
The scale of the injectors seems more than fine. the LTFT were in the -7 to 3 range.
Having a vacuum/boost reference didn't really affected the results.
I'm running a 3bar map and tip.
And now I'm really focusing on getting the car to atleast idle at the right AFR !!
Honestly, these type of issues were a lot of the reason I no longer have my PRP. It's amazing how much of a difference it makes to have a sufficient datalogger. What took me hours to do with SCT via guess and check I can now do in minutes, literally.
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Note: I am no longer offer tuning services. Please contact another vendor for tuning. I'm no longer going to compete with people who half ass things, make empty promises, and insist on flat out doing things the wrong way. I apologize for any inconvenience this may cause...
Last page, post #33 has my resolution. Took me a long time to find that.
If your "Spark Configuration" table is correct, check your spark plugs.
After I corrected the "Spark Configuration" the problem seemed to go away, the car was running pretty good, but I was getting some really nasty spark blow out around 5000RPMs. I replaced my plugs, and the car ran super lean when I started it back up. My old plugs were so bad, that I had pulled so much fuel in my tune to get the car to run OK. I loaded an old tune file from before I had this problem, and it runs great again.
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One of a kind custom turbocharged 2004 Chrysler Sebring LX Sedan
.:CarDomain:.
13.5 @ 102mph
Honestly, these type of issues were a lot of the reason I no longer have my PRP. It's amazing how much of a difference it makes to have a sufficient datalogger. What took me hours to do with SCT via guess and check I can now do in minutes, literally.
If your "Spark Configuration" table is correct, check your spark plugs.
First thing I checked was the tune. In a first step I put in a tune I knew was working perfectly (2 of my friends are running it for a year or so). Car still 'try' to idle at 10+AFR (I have to make the engine rev in order to stay in the 10-11 afr range or else it dies).
I tried the O2 sensor.... It's weird but I think it helped in a way. The engine still wants to shut down, but I have heard some 'hesitation' or 'miss-fires' while reving the engine (nothing higher than 2 500rpm).
I also saw my pulsewidth to be around 8.0 which I find weird ....
I'll be swapping my coilpack and wires tomorrow, just to make sure it is not involve in the issue.
Next on the list after is the ECU.... why ?
because the injectors I currently have were originaly on my gf srt. Deka 60lb. I gave her my injectors (rc 750) last year when her car was running on three cylinders because somewhere it was have no gaz at all in one cylinder. After having swaped the 60lb for the 750 on her car, we realize that it was the injector driver in the ECU that was not sending any signal. We put back the original S0 in the car (yes we blew an S1). and the car runs perfectly since then. Now that I'm the one with the damm 60lb, could it be the same problem again ? But instead of having the driver breaking 'closed' could it have broken 'open' ? (but then why are all my plugs black ? I don't know but I think I will had change everything fuel related at this point)
If I keep only the facts:
- Fuel pressure still at 58 psi (gauge on FPR and electronic sender confirmed)
- Pulsewidth @ 8.0 from Aeroforce
- Stock injectors swap in the car caused all this problem
- Old O2 sensor changed after multiple tries, new O2 sensor installed yesterday.
- Tried 2 sets of sparkplugs, first one are a week old, second set I have only tried during 30 second, don't want to srap them, but did no difference.
First thing I checked was the tune. In a first step I put in a tune I knew was working perfectly (2 of my friends are running it for a year or so). Car still 'try' to idle at 10+AFR (I have to make the engine rev in order to stay in the 10-11 afr range or else it dies).
Double check it. I did the same thing, used a tune file I thought was good, a file I hadn't touched in over a year, and still had the problem. Somewhere along the line, an update or something, somehow changed a value I had never even looked at before. All of my old "good" files mysteriously had the same error in them. Took a long time of going through every single table line by line for me to find it.
Double check it. I did the same thing, used a tune file I thought was good, a file I hadn't touched in over a year, and still had the problem. Somewhere along the line, an update or something, somehow changed a value I had never even looked at before. All of my old "good" files mysteriously had the same error in them. Took a long time of going through every single table line by line for me to find it.
were the values in blue or red (like when they are changed) or were they in black ?
Add IAT Sensor to that list. People tend to forget about that one, it does impact your fuel.
Also check TPS. Your high PW value at idle might have something to do with a TPS error... Although you would think it'd be trying to run at a higher RPM if that were the case, still probably worth checking.
Quote: Originally Posted by SRT-What?
were the values in blue or red (like when they are changed) or were they in black ?
Value was in blue indicating it was lower than stock value for the file. If it was in black I don't know that I ever would have found it.
Last edited by SebringLX : 07-10-2009 at 08:09 AM.
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About to throw everything out the window...
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