P0301 with the new stroker: could it be the PCM?

1515art

1515art

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2006 tj rubicon with a stroker and 42rle, the other day driving the Jeep on the freeway after accelerating a little a bit Later I experienced a p0301 check engine light difficult to tell but it might have been running just slightly rougher after the light came on. Drove on home and I reset the computer and everything seemed to be back to normal. Drove several days and on the day before taking it to the transmission shop to have the new tranny installed it developed a p0700 code, I wasn’t concerned about that one as I knew the transmission was having problems, the next day after installing the transmission the code reader At the shop displayed 4 codes related to the transmission but no p0301 at that time, they were all successfully cleared according to the transmission shop as any outstanding code would prevent programming the new transmission. Today, a day after picking it up at the transmission shop after accelerating from 40 to 60 quickly about 3 minutes later I got another p0301 and it was running a bit rough. I should have checked the injector then but reset the computer first, after 30 min. Reconnected the battery and it was running smooth checking the injector with a screwdriver that I slipped a jug with the bottom cut off onto the end of the screwdriver handel I could hear the injector firing normally.

what I have is, new engine, new transmission, new fuel pump, fuel tank pulled and scrubbed with the new engine, new plugs, new injectors, new throttle body, 2 year old coil, new crown opda 2 years ago, new O2 sensors 2 years ago, and a Wrangler fix 11 3/4 month old computer that is most of the new line-up, any idea as everything is pretty much brand new, if it was internal I’d think resetting the computer would have no effect I’m now wondering if it could be the computer?
 
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Tomorrow I’ll pull the plugs switch the injectors and also try a different computer. Tonight I took it for a short drive i accelerated from a stop up to 50 and then coasting towards a red light my check engine light began to flash, oil, temp and alternator were all normal. Soon as the light changed I pulled over to the side of the roadway shut the engine off and checked the cluster for codes... I got a done message with no codes and the engine then started normally with no engine light and was fine the rest of the way home.

the one thing in common is it happens after stomping on the gas and then backing off, this doesn’t really rule anything out except it could be getting temporarily starved for fuel? I requested a mopar fuel pump, but I don’t have any guarantee they didn’t use an aftermarket fuel pump I don’t know if the aftermarket fuel pumps are an issue?
 
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The motor was built by Golen and I bought his whole package complete with oversized injectors throttle body and headers along with the Dyno break-in. Overall it’s not Running bad I can’t really say it is missing and the starting from a stop the acceleration is a big improvement over the stock engine when I was babying it because of the transmission I only had an issue after getting on it The one time, but not every time. After getting a check engine light it seems to run a little worse but it’s hard to tell where it feels lacking on power is flooring the engine at higher speeds and then to me it feels a little flat and it has felt that way to me from day one after picking it up from Vegas 4x4, but then I’m doing a lot of guessing on what the performance increase should be? Also, the first 500 miles I was breaking in the new gears so no check engine lights in the beginning until it was Ok to begin test it out.
 
I switched the pcm for the old one that came with the Jeep the engine runs smooth no codes I drove it 20 miles and onto the freeway going easy on the way out and testing it with full throttle on the way back. It accelerated no problem until it hit about 78 and then lost power for a second regaining power after letting up on the throttle, driving normally it was fine the rest of the drive home. I don’t blame the computer yet the exact same loss of power has happened with both computers and both transmissions. I have not pulled the injector rail yet I suspect a fuel delivery problem but it seems more like the fuel pump pressure related?

I’ve got multiple shops involved on this and unfortunately I need to add another, there is a dyno tuner in town that specializes in problem solving custom builds I’m going to take it in and see if he can get everything set up right.

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I talked to the tuner this morning I’m bringing the Jeep in this afternoon and have him go over everything, according to him there is enough difference between the stock 4.0 and the stroker engine with higher compression and more aggressive cam the timing is slightly different and the symptoms I’d described the PCM likely needs adjustment, a friend of my daughter is a technician for McLaren and he told me the same thing basically, hopefully this solves the misfire issue and the tuner says ill have an improvement in power.
 
Picked my Jeep up from the tuner and the stroker is running much better way more power, no misfire or hesitation and so far I’m not getting any codes. The fuel and timing were way out from where they needed to be with the larger injectors the pcm was sending 2 to 3 times the amount of fuel it needed and I got a long explanation on the computer reacting to the sensor readings and not having the setting match the hardware progressively making things worse aside from the larger injectors, higher compression and aggressive cam there were a number of other adjustments made to the computer settings but basically what I care about is it‘s now running as it should. While the engine is advertised as plug and play that’s appears not to be the case as far as the computer is concerned. I was also told it should not have any issues passing the smog inspection due to the adjustments, so that’s good news.
 
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1515art said:
Picked my Jeep up from the tuner and the stroker is running much better way more power, no misfire or hesitation and so far I’m not getting any codes. The fuel and timing were way out from where they needed to be with the larger injectors the pcm was sending 2 to 3 times the amount of fuel it needed and I got a long explanation on the computer reacting to the sensor readings and not having the setting match the hardware progressively making things worse aside from the larger injectors, higher compression and aggressive cam there were a number of other adjustments made to the computer settings but basically what I care about is it‘s now running as it should. While the engine is advertised as plug and play that’s appears not to be the case as far as the computer is concerned. I was also told it should not have any issues passing the smog inspection due to the adjustments, so that’s good news.
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can I revive this old post? I have same set up, golen stroker and 42RLE. when i've simply re-set the PCM, it runs better but eventually drops off. had the same codes pop up during hard acceration (again same issue of PCM likely too overwhelmed). Who did your PCM work? I thought tuning wasnt possible on that PCM. I'd love to talk to someone who's done this work and had success.
 
Looking back on my engine swap there were so many things affecting how my stroker was running all of my results were deciving. The tune I got did make my engine run better but ultimately the DTC’s returned. My main issue was intake manifold and exhaust manifold leaks, missing ground straps and just about every one of the old sensors needed replacing. masking the issue and triggering the check engine light. Affecting performance and causing vibrations was also a bad transmission and bent axles all combined with the lower gears made too many variables with similar symptoms.

Eventually I bought another untuned PCM from wrangler fix and am now running the stock tune trouble code free except for when my exhaust flange bolts vibrate loose driving rough washboard dirt roads then I get a cylinder 6 misfire or engine running to rich DTC, sliding under the Jeep and giving the exhaust a wiggle reveals the exhaust leak at the O2 sensors tightening the flange bolts keeps the engine light away until the bolts vibrate loose again.

talking with Chad Golen he confirmed the stroker with the larger throttle body and larger injectors runs at the limits of the PCM‘s ability to adjust for the difference in fuel demand and any one of the issues needing replacement/fixing were enough to push the computer over the edge and in combination a long road sorting things out.
 
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1515art said:
Looking back on my engine swap there were so many things affecting how my stroker was running ...
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You mentioned you are now back to a stock tune. I'm curious as to why? I recently put a Golen Stroker in my 97 w/ an AX-15. I have new Mopar O2 sensors, new CPS, Golen provided 24# injectors and 62mm BBK TB w/ a header. (Here is my build thread with more detail: https://wranglertjforum.com/threads/woodrow’s-97-green-tj-moderate-build.51602/page-5#post-978662). It runs well and certainly is stronger the the 4.0. However, dyno numbers are less than I'd like (169 HP/211ft.lbs Stroker vs 136 HP/167ft.lbs stock). I'm thinking of getting some help with the tune. In your experience, is that an improvement? Does it cause other problems? Other thoughts? Thanks.
 
thanks, this is super helpful. I've got the same issue with the flange bolts. I'm gonna fix that.

I'll try and do the same with all the other sensors too, just replace them all.

I can't think of any other major problems like you mentioned, that might contribute to my issues. The jeep had relatively low mileage when I did the conversion, with just 42K miles on it. I only did the conversion for the added performance. It does run stronger, but not nearly what I'd expected to gain. It still seems excessively slow showing a stopwatch 0-60 of 11 seconds.

And gas mileage went from okay-ish to horrible. It cant get more than 12 mpg no matter how much freeway, and easy peddle use. It's almost completely stock, 33" tires and 4.88 gears. I've got some weight from a winch and rocker guards, and that's it. It's got the 42rle, and thats in great shape.

I've just sent a note into chad to ask more about what I'm experiencing.
 
I went back to the stock tune based on wrangler fix not recommending it, the fact the tune was done with bad sensors, manifold leaks and missing ground connections and chad telling me it was setup to run the stock tune and after installing an aftermarket wide band O2 sensor I can see the PCM is keeping the fuel ratio around 14.7 where it needs to be most of the time as long as everything else is good.

My fuel economy was 12-13mpg before the swap and is the same now with the stroker and lower 5.13 gears. Honestly with all the hassle of driveline vibrations I wish I’d just kept the 4.10 gears until after the engine swap, then decided if I needed it for my use.
 
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I completely agree - I too have the driveline issues after the lowering the gears. Tried all the common fixes and no one can figure it out. A steady vibe at 60 all the way up to about 72 mph. What was your culprit?

I wish I wouldve just turned off OD button when needed.
 
I haven’t found the sweet spot yet adjusting the rear driveline, I have installed all savvy double adjustable control arms and warn manual front hubs, all new chrome molly axels, and had Adams balance and install new front and rear driveshafts. My rhythmic woom , whom woom now hits around 59 on the flats and is bad up to 80mph, downhill it just about goes away and accelerating it is very pronounced, keeps moving around as I try different angles last adjustment the pinion was around .8* below the driveshaft unless I’m measuring wrong. I made a steel jig that fits snugly against the output housing of the rear diff assuming it is exactly a right angle to the shaft, my jig is also a right angle installed facing both directions so measuring off the top of the driveshaft should be I think in line with the top of my jig?

I took a drive over to the far south end of Las Vegas Blvd away from the city and did a couple of 0-60 runs, my time was the same as yours running 33x12.5 @ 20psi with a heavy loaded up Jeep, 0-50 was quick with 5.13 gears 6-7 seconds then the shift into 3rd I guess is a a bad point in the power curve and 50-60mph is really slow until it hits the 60 mark, this is where some tuning would help for sure.

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Wow - thats a lot of work done. Me too on the driveline issues, speeds noticed etc. And same for going away downhill (no load). Loaded i get the vibe, unloaded not so much or at all. I've done all same angle adjustments, adams driveshafts, even a new MOPAR trans mount. Everything helped, i've got about 75% of it gone. It's super annoying as it gives less whom whom and more high speed drill now, and still makes rear view mirror distorted unless i hold it.

I;ve kinda given up and drive it a lot less as it makes me crazy.
 
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