So I've finally gotten around to getting the EVO in shape for use as my DD again. After putting the battery in and cleaning the air filter I went to take the car for a drive, really bad hesitation after it warms up esp. and eventually it will throw a P0304 cylinder 4 misfire. I checked the coil packs and they appear to be sending spark, cleaned the MAF which was a bit dirty, and drained and replaced the gas to no avail. The hesistantion (and some surging) worried me enough that I didnt even want to drive it up the street and back. Any thought's on what the problem could be?

The car has been sitting for most of the last year, and the mods are in my sig. As I mentioned in a thread a while back I had been geting some intermitant (what I believe to be phantom) knock but it was rarely above a 2 count and never above a 4. There was no rhyme or reason to it though, and I think that may have been from a rattlely tie bar/DP. Before it sat though I have never had any issues with drivabiity let alone something like this. We are going to pull the plugs tomm to check those, but and thoughts would be much appreciated.

 

Most likely, you need to check/change plugs.

 

Update:
Plugs are fine, thought they are a bit sooty, perhaps running a bit rich? Ecu testing shows that all actuators appear to be working (fan, injectors, ect). OBDII is still readable through Evoscan, but it will ocassionally lose link. Here is were it really gets screwy, the Flash is not readable through either evoscan or ecu flash. It simply wont allow me to pull the flash.

Some more light driving around the block after swaping the lugs around showed that the car ran ok at low TPS/Load, but any significant acceleration will cause the stumbling to reoccur. After the plug swap no CEL after I cleard the P0037 i have been getting from no cat and the P0304 misfire code. However I didnt drive it far or at all hard (no more that 10% or so TPS, less than 3k rpms). I'm leaning towards a ****ed up ECU, a corrupted flash, or a burnt out flash chip. It's a really weird problem though, anyone else have any thoughts?

 

How are the plugs "fine"? What model are they? How many miles? Whats the gap??

90% of the time, misfires are spark related. Most likely the spark plugs are not "fine". And what your describing, is most likely a spark plug issue.

The chances of a messed up ECU, corrupt flash or burnt chip are very very slim. The chances of wrong plug or plug gap is much much more likely.

 

I didn't check the gap, but the plugs had no damage. Electrodes were all there and appears uniform across all cylinders. No cracking, no blown off tips, nothing of that sort. They are IKH24's as indicated in my sig. They were installed about a year and a half ago and have less than 3k miles on them. We put them in shortly before the car sat on and off for much of the last year. I suppose I could pick up a set of stock plugs and throw them in to see what happens.

 

Haven't had time to pick up/install another set of plugs yet, but I did review the datalogs from last weekend. Really weird. I know we did more than 10 seconds of logging but that's all that shows up. The logs show the RPMS and may be other values up and down, pretty much all oer the place. It almost looks like the timescale on the log is wrong or the ecu is seeing RPMs incorrectly. Couple one counts of knock, but at this point I'm not even sure if that is legit. Just thought I'd keep this updated.

Could a bad set of plugs really cause such screwy behavior by the ecu?

 

sounds like you are dead set into not changing those plugs, but another thing... it could be you have bad fuel. if its been sitting this long it sounds like you might have bad/contaminated fuel.

 

just out of curiosity, did the battery need to be charged? I had my evo in storage for about 2 years, and I was having all kinds of problems starting the car.

Turns out the battery (new before I put it into storage) just didn't have a decent charge. I put the Evo on a battery tender and now when I start the evo, the engine starts within 1/2 turns of the starter on a cold engine, just as it did when it was my daily driver.

So you might check the charge on the battery, that might be part of the problem when pulling the ROM. The ROM chips really need to have the correct voltage applied to the proper pins in order for the chip to enter the correct mode for you to download the ROM image

 

Hmm interesting thought. Yes the battery did die. I then pulled it, took it to the store, and they tested it. They said it was good to go, so I brought it home and threw it on the tender until I was ready to install it. All my gauges are showing 12-13v. I'm gonna try a few more things if I have time this weekend, but I'll may try hooking up another battery to see what happens.


The datalogs were what had be worried as well. Really all over the place on some of the values, and I KNOW that we logged for more than 10 sec total. Only 2 logs were in the folder though, one 4sec and one 6 (with I think 2 one counts of knock).

 

if the battery died, then put it on a nice long deep cycle trickle charge.

For the weird logging values, check your ROM definitions against the latest stuff and make sure nothing has changed. The ecuflash developments move pretty quickly and I could easily see bad logs due to incorrect or obsolete logging settings. (been there done that)

 

This run a trickle charger and change the plugs bro it takes 5 minutes. Or swap plug 4 with plug 2 and see if the CEL follows.

 

Sorry if I wasn't clear, but we did swap the plugs around (same plugs different cylinders) when we checked them. The CEL didn't return, though I didnt run the car for more than 5-10min. It did however continue to run like crap. The only thing that I can compare it to sound wise, is the time I forgot to hook up a coil pack after doing a plug change and two of the cylinders werent firing. It's not quite that rough, but there is definitely something inhibiting proper combustion in one of the cylinders. Whether that be a fuel issue, a spark issue, or one of the two subesquent to an ecu problem I have no idea.

One more interesting thing from when we did the plug swap, the problem changed a bit. It was initially running ok when I first started the car after doing the battery/airfilter, then began to run rough when I drove it. From then it idled poorly (though the warm up sounded ok) and drove worse. After swaping the plugs around between the cylinders it kinda started to idle ok again, and drove iffy at very low load, but any real throttle imput and it stumbled. Now we only drove it around the block, but while it was running crappy still the P0304 code didnt pop up. Whether that is because we didnt drive far enough or because the misfiring changed cylinders I'm not sure.

 

The battery had been on the charger for most of a month before I put it on. I put it in the car, and then cleaned the airfilter and put it back in within a couple days. So I dont think the problem could be solved by more time on the charger. However since the battery died when it sat, perhaps it wont take a good charge (though I was asured it would when I took it to the store to have it tested, but that may just be so they wouldnt have to warranty it). Like I said though the gages in the car read approx 12.5 volts.


I just did a clean install on this computer and reinstalled evoscan and ecuflash from scratch so I dont think the software is the problem. But who know's. I'm gonna install it on my toughbook and see if I can get a good read with that.

The thing that really concerned me about the ECUflash/Evoscan issue is that I couldn't even read the rom off the ECU. So if it is damaged or corrupted, or if the ECU is going toe up then I'm screwed as company that did the tuning is now out of business (DTM, and I think the tuner is persona non grata here and has probly made himself difficult to find given the questionable business practices he was accused of engaging in) and the only other copy of the ROM was lost when wiped my laptop.




As an aside, as most people reading this can probly tell I'm a bit of a malingerer and a slacker when it comes to working on my cars. I like driving them, working on them... .... not so much. So I'm a bit slow in doing stuff. But this problem/set of problems really has to get sqaured away and I'm really stumped on whats going on given my limited expirience. So thanks for the help, I really appreciate it. I just hope I can get this figured out.

 

Sounds kinda like a coil pack going out still. I'd start cheap and throw fresh plugs in it though. Good time to go COP otherwise.

 

have u given the tps a look at>? forgive me if u have posted that in here i just skimmed through it real quick