engine problem diagnosis w/ codes

[super97gst]

I have a 97 GS-T. my mods are in my profile. about a month ago i was sitting in my car with it just idling and all of a sudden it just started idling really low. low enough it doesnt show on the tach. the engine also shakes really bad because it is idling so low. anyways, the first thing i did was a boost leak check. i found no boost leaks whatsoever. i then did a simple tune up, ngk bpr6es, new ngk plug wires and a fuel filter. nothing different again.

i then borrowed a diagnostic machine from a friend and ran a check. i came up with 2 codes. the first was a po300b, which is a random/multiple cylinder misfire. the other code was a p1104, which on the diagnostic maching said manufacturer controlled fuel/air metering malfunction. but when i looked that same code up it said it was a turbocharger wastegate solenoid malfunction.

as for the first code, it said ignition pieces were most likely the guilty culprit. so i put a new oem ignition coil pack on it today. that did nothing to help me as well. also i have an msd dis 2 ignition on my gst. i ran through the checks on it as well, according to how msd says to check the ignition and tach/fuel adapter. all of that is good, i have also checked all the wiring from the msd ignition and adapter to the coil and there is no problems. i have run out of options here, and dont know what to do next.

the car just wont run right at all, it will idle and drive, but its like its only running on 3 cyl. whatever the problem is it was intermittent at first. it happened one day then i went out and cranked it the next day and it was fine. for a couple days it ran fine then just driving down the road it went back to nothing. driving down the road i could stomp it and it wouldnt get over 1500 or so rpm's. and the boost wouldnt build much over 5-10 psi.

any help would be much appreciated on this. like i said i've been trying to figure this out for like a month or more. thanks a lot for any help.

[PieEyedPiper]

Thanks for the link.
Definitely do something about that title though.

Go ahead and recap your progress so far, cause I know you've been tinkering since this post.
We'll start crossing things off the list and get a better idea of whats going on.

It seems like your issue is more parallel to bboyalan's than I thought. Your issue is at idle and affects driveability throughout the entire RPM range and is NOT triggered by a certain event such as steady throttle at 3krpm on the highway, correct?

So yeah include all testing to date and the parts you have swapped out, like your CAS.

BTW, I'm liking this alternator idea. It seems to fit the story a little better, hopefully we can get a chance to try that idea out.

[super97gst]

how do i change the title on this thing??

and no its not triggered by any certain rpm, engine load, nothing. it just happened and hasn't gone away since.

ok things i have done so far:
1. changed spark plugs- new NGK BPR6ES
2. changed spark plug wires- new NGK 7mm wires
3. changed ignition coil pack- new oem mitsubishi piece
4. changed coolant temp. sensor- new oem mitsubishi piece
5. changed CAS- new oem mitsubishi piece
6. tested ignition power transister- good
7. tested TPS- good
8. have bought new CPS and knock sensor, haven't replaced yet
9. checked for broken timing belt teeth- good shape
10. did boost leak check- all good, no leaks at all
11. have spent hours on top of, underneath, in front of and any other place you could possibly get and look for broken wires or damaged connector terminals.

so anyways, theres what i've done so far. dont know what else to do. maybe this alternator idea that we've gotten on will pan out. i'll try my best to get it swapped out or at the least checked sunday.

[bboyalan]

Wow, big time similarity there - 1500 rpm, ~5 psi, and it feels like 2-3 cylinders. I know it's tiring playing/working on your car like a jungle gym in elementary school, but we're all doing it together! Seeing as we've tested and replaced similar parts, I think that if you tackled the alternator swap while Tom [Artago] and I did the ECU swap, we can almost narrow our problem down to something similar between one or the other. Either that, or maybe we just have a bad short/ground like voodoogsx's thread.

Let's cross our fingers for the weekend results! Good luck!

[PieEyedPiper]

I think to change the title you have to edit the original post and you must enter in a reason why you're changing, it or else it won't take.

[super97gst]

Originally Posted by bboyalan

Wow, big time similarity there - 1500 rpm, ~5 psi, and it feels like 2-3 cylinders. I know it's tiring playing/working on your car like a jungle gym in elementary school, but we're all doing it together! Seeing as we've tested and replaced similar parts, I think that if you tackled the alternator swap while Tom [Artago] and I did the ECU swap, we can almost narrow our problem down to something similar between one or the other. Either that, or maybe we just have a bad short/ground like voodoogsx's thread.

Let's cross our fingers for the weekend results! Good luck!

well, lets hope we can finish narrowing it down. and about the short, of course its possible i have a short or a broken wire or any number of wiring problems. we both might, but i cant find ONE SINGLE problem with the wiring, anywhere. oh well, we'll figure it out sooner or later.

also, pieeyedpiper, the title doesnt change. it just changed the title right above my 1st post. it wont change it on the problem diagnosis page.

[SpyderDSM]

hey just wondering if you guys have gotten any further on this...

im having similar problems, not exact, thru the whole RPM range the engine shakes and i keep getting cylinder misfire codes. the idle seems to be around 750.. this came after i put in a Greddy UICP and Type RS BOV, currently i have the stock parts back in, and have since reset the ecu

[bboyalan]

Hey! The OP has started another thread here: click
And if you have the time, you can read our combined efforts in my loooong thread here: click2

good luck and have fun! hopefully it's nothing too out of hand

~AL

Originally Posted by SpyderDSM

hey just wondering if you guys have gotten any further on this...

im having similar problems, not exact, thru the whole RPM range the engine shakes and i keep getting cylinder misfire codes. the idle seems to be around 750.. this came after i put in a Greddy UICP and Type RS BOV, currently i have the stock parts back in, and have since reset the ecu

[SpyderDSM]

thanks, just wondering - ive had the same code 4 times now, its the po301. its saying specifically cylinder 1 is misfiring, could i have messed this up when i had to move the fuse box for the uicp? this seems like its a little different than the others i guess.

also - when driving the shaking starts when i push a little on the gas, accelerating very slowly and not spooling the turbo seems to keep the engine from running strangely, however it still shakes on idle.

[bboyalan]

So I'm assuming everything was fine prior to the uicp/type-rs right? If that's the case, you should check for any leaks. Our cars are very sensitive, yet retarded, when it comes to leaks. I'm willing to bet that's the problem if you haven't touched anything else

[SpyderDSM]

will do, thanks. hopefully its just a cracked hose, that would make everything a lot easier (assuming i can find it )

[super97gst]

I've pretty much halted this thread man. Jump over onto the other one that Alan stated above. Post your question on it and we can discuss it there. But I will go ahead and agree that it's most likely a boost leak situation. You might as well go ahead and run a full boost leak check on the car. Do the normal check from the turbo then one at the throttle body. That'll give you an idea of where to start. If that for some reason is not your problem run through the plugs and wires. 90% of the time that's where most of your misfires will come from. If you want, read up a little on my other thread and Alan's old thread. It might come in handy if you have more problems down the road.

[SpyderDSM]

ok will do.. sry about that. ill jump back over after i do the tests if its still misfiring, cant really do anything for another week and a half, im up at school and had to drive a different car, done the 23rd so ill repost then.