Naughty little bettie!

Hi Guys!!!

You may be my last hope. I’m grateful that you may consider taking a crack at my situation. I am at my wit’s end. Please save my relationship with my car!

I have a car, and she’s a problem. She’s beautiful and fast, but she hates me. Much like my ex-wife. No dealer can find the problem. I’ve tried 3 of them. Here is the background…

Car Name: Naughty Little Bettie

Car Type: 2005 PT Cruiser Turbo Convertible H.O. (2.4L Turbo)
Complete with hot rod chrome, pinstriped with flames, chrome mags, and some aftermarket racing parts. (I know you don’t care about any of this but she’s really a looker. It makes my biceps feel bigger to talk about it).

Aftermarket Mods: K&N Cold Air Intake, Hi-Flow Cat Converter in a 2 ¾” pipe custom exhaust set-up, and a “Diablosport” fuel system. (Problem happens whether I run the car with this “tune” or not.

100K miles, but has had this problem off and on her whole life. Nothing seems to make it better or worse.

The Problem: This little car keeps coding out, and acting like it is going to die for no reason. The check engine light will come on, maybe it will run a little rougher and act like it is going to die. Can’t keep it going. Sometimes, the check engine light may come on or come on and blink, but the car will be running fine. Basically, I drive around most of my life wondering whether the car is going to leave me stranded by the side of the road. If it codes, it usually tells you it is a misfire (last time in number 4.) It’s very inadvertent. She may not do it for a few months. There may be times where it’s happening every day until you get to the dealership. (so they can be baffled.)

Common threads: Bettie does not like to be driven limp. This problem almost never happens when she is being run hard. Whether at highway speeds, or coasting, it almost always happens when she is being run at lower rpms. Say 800-2500 on the tach. She does not like to be “bogged”.

Everywhere I drive Bettie, my quarter mile times improve because I feel like every day is a drag race… If I want her to stay running that is.

What I’ve been told: Dealer said it was a bad fuel injector. Replaced one or two. Dealer said it was a bad Camshaft sensor. Have replaced one or two. Dealer said it may be a fuel pump, but why the engine light? Dealer did an expensive tune up and replaced plugs and wires. Probably twice. Basically, they just scratch their heads and replace a camshaft sensor to make me feel better.

My Theory: I am nowhere near good looking enough to be driving this little car, and she knows it. She hates me. We need couples therapy.

What is it guys? I love this little car. I treat her like a queen. Don’t want to sell her.

Any thoughts? I would love to hear your take on this…

Aftermarket Mods: K&N Cold Air Intake

Did that include a oiled air filter?

Could you give us the code or codes that are showing?

CAI makes no sense because the turbo would make up for any intake restriction.
Just pumps up to the boost limit.
After 100k of hard driven miles a compression test might be in order.

Wild guessing here, maybe a MAF sensor fault or an intermittent intake leak (above the throttle plate, not below)
That’s the area I would concentrate on anyway.
Another area that could cause this would be the EGR system and it’s possible to have an intake tract problem or MAF/EGR fault without a code being set.

Next step may be a divorce lawyer and pray that Bettie doesn’t take everything… :slight_smile:

One more random, and wild, thought here. What about oil change intervals on this vehicle?
Maybe the impeller on the turbocharger is intermittently trying to stick due to oil sludging or coking. Just a thought.

I visited the “diablosport” website and was unable to find out exactly what it allegedly did. That always worries me. If it’s lengthening your fuel injector pulsewidths to add more fuel, as I suspect, than your air/fuel ratio is incorrect. You should not be increasing your injector pulsewidths without also addiing more air…and both need to be done in corrdination with each other to maintain the proper ratio. A Cold Air Intake does NOT add more air. It only allegedly increases the density a bit and reduces restrictions inherant in the OEM system…and if it’s taking the air from the same cavity as the OEM snorkle than it isn;t even really bringing in cold air.

Another possibility, a likely one, is that the oil from the K&N filter has contaminated your Mass AirFlow (MAF) sensor. Oiled filters can do that. The MAF sensor measures how much air is flowing in by exposing a heated sensor to the airstream and measuring how much current it takes to keep it hot. An oil coating changes the heat dissipation and affects the accuracy of its reading.

My bet is that the MAF sensor is contaminated. That would make sense, because it smooths out once it gets a chance to get “feedback” from the oxygen sensor and readjust the injector pulsewidths to maintain the proper ratio.

Allow me to respectfully recommend that when considering additional modifications in the future you research how exactly they work and why. You can always post here for advice. It’s easy to mess things up with bolt ons.

Post back with how you make out. We can be difficult, but we do care.

It sounds like you think this is where you can get responses from Tom & Ray. This is just an internet discussion board. To the best of my knowledge, Tom & Ray don’t participate.

Since wild guessing is about all that can be done without more info (e.g. on maintenance history, what kinds of things have been checked & how, actual error codes that have been read…), I’ll throw mine out.

My “favorite” WAGs are up there & there are 2 of them - one is the oiled K&N filter contaminating the MAF. Clean the MAF really well and drop the K&N for a stock filter for a while. The second is the EGR. These can easily malfunction without setting codes. The computers aren’t as “smart” as they’re given credit for. I’d temporarily disable the EGR & see what happens. (I don’t know the system - vacuum controlled ones are easy since you just pull & plug up the vacuum connectors, though a surer way is to remove the valve & install a temporary blocking plate.

I would also second the suggestion to check the compression.

Tom and Ray? I don’t imagine anyone could get through to them. I’m looking for anyone who has ideas or has experienced this. Can’t tell you what the code says exactly. That’s just what the dealers are telling me. Misfire. Thanks for the ideas so far guys… yes, it is an oiled K&N… Maybe stop oiling it?

You can’t “not oil” the K&N, the best thing is to go back to stock for the air filter. Next thing is this high flow cat. Do you still have the sensors in front and behind it? Do you still have the warm up (pre) cat?

I don’t think this vehicle uses a MAF, so I doubt that’s your problem. Most Chrysler vehicles of that era use a MAP sensor, though I could be wrong.

You’ve told us everything but what codes come up when the check engine light comes on, which is the most critical piece of information. You can easily obtain the codes on a Chrysler vehicle by doing the ‘key dance’. Without starting the car, turn the ignition on-off-on-off-on. The codes should be displayed on the odometer or blink out on the check engine light, depending on the year. Google it if you need more detailed information on how to perform this. Of course a scan tool or code reader can be used as well to obtain this information.

If the problem is ‘off and on’, it’s doubtful that it’s a compression problem. Again, the exact code that’s being generated is key here.

I had a PT Cruiser that had some sort of issue that sounds relatively similar.

My dealer could not duplicate the issue and so put a “Copilot” in my car. When the problem occurred I was to press the button on his piece and it would take a snapshot of what was going on with the car at that time so that they could see the issue and fix the problem.

Perhaps that would be a possibility with your dealer? I had this in the car for a couple of weeks before the problem would replicate.

Was the dealer able to fix the problem?

Cars like nice names, first rename it, and make sure all maintenance is up to date, then take all the mods off, and start from scratch. No telling what is what unless you can start at factory specs.

high-flow cats sometimes cause issues with CELs but I don’t think they necessarily cause the other issues OP posted about unless I misunderstood. I’m strictly amateur though, so take my comments with a grain (large) of salt…

Return car to stock.
Its been acting up its entire life because it hates what you have done to it.

Misfires are caused by several different causes:

Spark plug/wire/ignition coil issue.
Fuel Injector issue.
Compression loss issue (open valve, head gasket leak, piston ring leak, etc).

If you can isolate the issue to one cylinder, then you can run tests on those components for that cylinder, and see if you can find the cause. Compression test, leak down test, ignition coil test (both cold AND hot), check the spark plug gap, swap the plug wire with the one from its paired cylinder for that engine, check the valve clearance, pressure test the cooling system.


These are all really good comments. Thanks everybody for your input. I can’t tell you much about the codes… It’s just what I’m hearing from the dealer. They’ll tell me what the “problem” is, but they don’t actually give me a good idea of what’s going on. Last time a guy at Pep boys read it and told me it was a misfire on Number 4. That’s the last time I got a definitive answer. Basically, like I said, whatever the issues are, they seem to keep wanting to replace a fuel injector, or a camshaft sensor. I tried to keep the mods to fairly mellow stuff that should be pretty plug and play, but honestly, I’m not as experienced with this little girl as I should be. I’m more of a V8 guy. So, truthfully, I probably never should have screwed with the stock stuff. Lesson learned. But man, when she’s running, she runs strong. She’s given more than one Subaru WRX a helluva little surprise! I know. I know. That and 50 cents will get you a cup of coffee anywhere, as my dad always says. Sigh.

Swap the #4 plug, coil, wire, injector etc. with another cylinder.
See if the misfire follows.

Just a WAG, but what grade of gasoline do you use? With the turbo, I can guarantee you need premium fuel, 93 octane min. If you’re trying to use mid-grade (89) or regular (87), this is the single source for all your problems.

@circuitsmith, obviously since this is an intermittant thing, that will not fix the problem. Also, this is a coil pack vehicle. obviously knowing how the ignition system on such a vehicle works helps. Switching the sparkplug wire with another cylinder will not benefit the engine. The coil packs in these engines are controlled by the camshaft sensor and the computer. switching them will only serve to create an immediate issue with startability and it’s operation. Although this would have worked possibly with an older engine with a distributor, it will not work with this one. These coil packs are designed to twice in the 4 stroke cycle. And to switch the plug wires will serve no purpose than to cause them to fire at the wrong times.

Any reasonably competent person would know I didn’t intend the OP to change the firing order.