Anyone have these problems with a revtronix chip before?

[Mattheww044]

Ok guys, I finally got the money together and got the revtronix stage 2 chip (used). I got the td04 installed a few months before and it was running pretty good at ~12 psi, by far the fastest its ever been. Then i got a few CEL's and the car was in the fail-safe mode because of the knock sensor code. So i figured we would tackle the CELs before installing the chip.

I had these 3 CELs: Knock sensor, IAC, and purge control solenoid.
So we figured we would tackle the knock sensor first. Come to find out that the knock sensor wire wasn't doing what it needed to, so we re-wired it. That took away all of the CEL's, and the car seemed to run fine.
The purge control solenoid was clicking indicating its getting power and is working...

So we installed the chip, 440s and JECs.
The IAC was acting kind of funny though... on the revscan software the duty cycle % was at like 16, and it needs to be at around 35% Even by adjusting the top of the IAC, it would still stay at 16%, no matter where we had it rotated. I figured that this might be something to do with the learning process of the chip, so I figured I would give it some time and see what happens. For the next week or 2 for the learning process, the car ran fine. I didn't get into boost or anything, just let it learn its way to where it needed to be.

So once that was up, i was hitting boost and all that fun stuff, but in the higher gears, my gauge would bounce from 15-17psi back and forth, back and forth at WOT. I could feel the car physically doing that as well and hearing it, so it isnt my gauge or lines. The car seemed to run fine other than that though. A few weeks went by, and now the car idles like CRAP. When i start it up, I have to hit the gas or it will die, or idle at about 500RPMs bouncing up and down, almost dying. Also, when I drive the car, it runs like crap, its really hesitant, sputtering, bucking, etc... its NOT a good feeling... And worse, the car is running super lean.... in basically all situations, i think its ok at idle, but just cruising or even starting to hit boost it is way too lean for me to drive it daily.

I tried swapping MAFS to a different JECs, to see if that was it, with no luck. Does anyone have any other ideas of what to try before I pull the chip? Has anyone heard of any problems like this before?

I am just so pissed i just bought the chip for 300$, bought the injectors, had them cleaned and flow tested. ALL that money and time, and I can't even drive the car.... ANyways, any ideas are very much appreciated. Thanks guys
Matt

[gijonas]

I have had a lot of these same problems and it is 90 percent of the time not the chip.Sensors bad,wiring,plugs ect.Everything on your car is now being used at its max threshold,you need everything tip top or it gets finicky.Most of the problems i have had have been vac. lines blowing of from the boost.By the sound of things you really need to hunt for vac. leaks before you do anything drastic...dont worry you will get real good at vac./boost leak hunting lol.

[Mattheww044]

what is your advice for looking for vac leaks? i know there are smoke machines... starting at like $600 haha
i zip tied all of mine and can't seem to find it anywhere, also re-tightened all my TMIC/boost lines

[Legacy777]

Matt,

As we've been discussing.....I wouldn't rule the chip out, but gijonas makes very good points about all the other components/wiring being in top shape.

The best way to test for intake leaks is to try and make a plug or something that hooks up to the intake piping some where so you can hook it up to a regulated air source. You should be able to hear any leaks.

[BSOD2600]

I have had a lot of these same problems and it is 90 percent of the time not the chip.Sensors bad,wiring,plugs ect.Everything on your car is now being used at its max threshold,you need everything tip top or it gets finicky.

Word and ditto.

Also, depending on what chip version you have, there is a possibility it's a known problem. There is no way to check what version you have either.. Mike @ Rev would've had to told the seller. I've documented the versions in the The legacy of Revtronix thread.


What are your long term fuel trims at?
Whats the Manifold Absolute Pressure at while idle? it fluctuate or solid? Easy way to check for some VAC leak.

[Mattheww044]

Hey thanks guys, i check all the vac and boost lines I could think of but everything was fine. Also I forgot to mention I am running no codes on D-Check. Im gonna feel so stupid if its a vac leak but relieved at the same time. My buddy is gonna help me try to find it tonight if thats what it is. And Josh I wasn't doubting your advice, just seeing if anyone else has seen this problem. I don't wanna take the chip out if i dont have to, but if i can't find any leaks i think thats the best route to take.

And BSOD, I dont have a laptop, but might look into getting one tonight just for datalogging so ill get something cheap.

[BSOD2600]

I can't say enough, how much this chip takes things to the limit which can drastically magnify the smallest of issues. Even borrowing a friends laptop so you can run revscan would be helpful. Just datalog for 1 min while idling after the car has warmed up. Post the logs. I'm still borrowing one from work

As an example of my little saga is as follows. Bought the 94 SS with the blown engine. transferred the engine + parts from my 94 TW to the SS body, yet the ECU + rev chip never was happy in this body (it was perfect in the TW). Always was an octane factor (OF) of 0%. rewired the knock sensor, new knock senor, fuel injectors cleaned/tested, cleaning/testing/adjusting the IAC, stable idle/VAC, etc.. nothing helped. moved the knock sensor to the bell housing, no help. one day, I got a CEL for injector 1. measured the resistance it it was 50 ohms which is way out of spec. got another one and installed that. still the OF was getting better, but still below 50%. little later, the idle rpms started to increase... as in it was always 1200 rpm. After a lot of fiddling, I adjusted the throttle position sensor and 'stopper g' screws. Finally the damn thing would idle normally. Weeks later, the OF finally increased back to 100% where it's stayed ever since.

[Mattheww044]

Yea man, yesterday i had a couple buddies who know alot about cars, but nothing about the RT chip help me try to find a vac leak. We looked and looked, didnt see anything suspicious, but for some reason the car seemed to idle better, so i took it out for a test drive... and it ran OK... it wasn't too lean or anything but still hesitant and boggy. Then I pulled up to a stop light and the car died.... got it started after holding the key there for like 5 seconds... and it ran like CRAP. It definately would have died if I didn't have my foot on the throttle constantly, and even when I did, it just ran like absolute crap, but this time it was running really rich, i didn't even think I would be able to get it back to my buddies house... but out of nowhere it just like snapped back into the "normal" driving mode and drove like it did before that happened... got it to my buddies house.... found out I have a screw in my tire...
FML haha

[Legacy777]

Matt,

I know you've probably told me many times....but have you replaced the MAF sensor?

[Mattheww044]

Yea I did. I have a few extra I can try but I did swap it a few days ago with no luck

[Mattheww044]

I will get to a laptop asap and post all of the parameters that revscan gives, just so you guys can see whats going on and hopefully pinpoint the problem area and go from there. Thanks so much for your guys' help!

[Mattheww044]

any other ideas that stand out as of what we know now?

[BSOD2600]

Personally, I'd start going through the FSM Josh posted and checking various sensors per specifications. MAF, injectors, IAC, vacuum, etc.

Then with revscan, it'll give you a much better idea what the ECU is seeing, which you can also then compare against other revscan users and FSM specs.

[Mattheww044]

where do i find the DL link for the FSM again? I had it on my old computer but can't seem to find it now.

[Mattheww044]

another thing im wondering is, will i be able to see whats going on if the car is running "normal" or will i have to check it out when the car is running like crap?

[Legacy777]

Look in the stuff you need to know forum. It's in the stickies.

[Mattheww044]

ok thanks josh, that will come in VERY handy. Ill let you guys know what I find when I find it, whenever that may be

[BSOD2600]

another thing im wondering is, will i be able to see whats going on if the car is running "normal" or will i have to check it out when the car is running like crap?

huh?

If you connect up RevScan and start comparing its numbers to those from the FSM specs for each sensor type, you'll get an idea if components are good/bad. Then can do more manual testing of the various components per the FSM. Also can compare your revscan numbers to other users... since the subaru scan tool possibly has different conversion factors than revscan uses, it's not necessarily an apples to apples comparison.

[Mattheww044]

what i mean is sometimes the car runs "OK" (it's not running right, but its at least driveable), and sometimes, randomly, the car will run like absolute crap, like it basically doesnt even drive....

I get what your saying tho, just see what looks outta whack and go from there... will do
as soon as i can get ahold of the software

[Mattheww044]

Ok, right now I am comparing my revscan readings to a fellow board members and the 2 main differences we noticed were that:
His MAF voltage at idle was 1.1, while mine was nearly 1.4
his O 2 sensor mV was reading 320, and mine was 1390
and his short term fuel trims were 4.7 and mine was -20.

I have wide band at the to bung and stock O2 sensor on the bottom bung, which I am just now thinking could have possibly been damaged when I was in the mud pit at the west coast subaru show.... Which read before installing the chip, the code never came up

[Legacy777]

Yeah the O2 and fuel trims look very different. Either the O2 sensor is tweaked and/or you're running very rich and the ECU's trying to lean things out.

I'd start with replacing the O2 sensor and reseting the ECU to see if those parameters come back in line or if they still stay out of whack.

[Mattheww044]

we re-located my 02 sensor to the top bung, and at one point it was reading like 2900, and at another point it was reading 0, so not sure what the hell is going on there..... When I left his house the car was running nearly perfect... and by the time I got home it started acting up again, running lean.... ill replace my plug wires since they need replaced anyways, the 02 sensor... and ive tried several MAFs so not sure why they are reading differently than his.
Also, the purge canister solenoid CEL comes on and off randomly... i even tried swapping it and it still does that.....
UGH

[kimokalihi]

That's odd. I wonder why mine never came on. My vacuum lines are plugged and the canister is removed.

[Legacy777]

Matt,

I really hate to be sounding like a broken record.....but there's only three separate components in the engine system: The sensors, the wiring, and the ECU. It really sounds like you've tried multiple sensors at various stages of the diagnostic. Unless you haven't found that elusive issue/sensor, I think you've exhausted the sensor problem. Next is the wiring. I'm not sure how much you have checked, but an ohm meter, a couple hours, and some paitence, you can check all the wiring from the ECU directly to the sensors to ensure it's good. I'd highly recommend doing this due to the age of these cars and the fact the wiring can get brittle over the years. The last piece in the equation is the ECU. Since it controls everything, and if nothing else seems to be the issue, that's really what you should try next. Primarily removing the revtronix chip and going back to stock, or trying a different known good ECU.

[Mattheww044]

Well doesn't that datalogging info reveal anything?
IDK wtf is going on with the 02 sensor changing like that, but I would imagine the sensor is bad or wiring like you said....
and i have no idea why the MAF voltage would be different
I have a datlogging sheet i will upload in a bit