[HighanDry88]

Getting -6, -4 etc on cyl 1-4 on WoT. Did an oil change and new plugs gapped at .026. Same issue persists, you can audibly hear the dings going off on WOT, gets real bad at 5kRPM in 3rd gear and up. 1 and 2nd aren't too bad.

I did move to philly in the past couple months, maybe the gas is just crappier around here compared to the suburbs?

I'm thinking off reaching out to my tuner to write me up a new tune for the new gas, but other than that anything you guys think it could be?

 

[STallion18]

Any codes?

 

[HighanDry88]

Any codes?

Yea, misfire detected on startup, cyl 2 misfire and random misfire
300, 316, 302

they havent really come back since the plug changes, I thought it was just due to that.

The car runs fine if I drive it like an upstanding citizen

 

[rob99rt]

Has your learned octane ratio changed? If so, what is it now?
Who are you tuned by?
What was the elevation at your previous location vs Philadelphia?
What octane was it tuned for vs what you have available now?
You said new plugs, but which plug are you running now? (Brand/part number)
Have you done a compression check yet?

 

[HighanDry88]

Has your learned octane ratio changed? If so, what is it now?
it goes back to 1.00 every time I reset, which I think is normal
Who are you tuned by?
jst
What was the elevation at your previous location vs Philadelphia?
I think its the same, I lived in bucks county about a hour away north
What octane was it tuned for vs what you have available now?
tuned for 93, I'm getting 93 from sunoco
You said new plugs, but which plug are you running now? (Brand/part number)
I switch to rutheniums - NGK 90495 LTR6BHX Ruthenium
Have you done a compression check yet?
nope

 

[rob99rt]

You said new plugs, but which plug are you running now? (Brand/part number)
I switch to rutheniums - NGK 90495 LTR6BHX Ruthenium
Have you done a compression check yet?
nope

There's your problem. Those are the stock heat range. You need ngk 95605/ltr7bhx for the 1 step colder plugs. Swap those out before you kill the motor.

ETA:. You may want to borescope and/or compression check the motor to see if you damaged anything running too hot a plug.

 

[HighanDry88]

There's your problem. Those are the stock heat range. You need ngk 95605/ltr7bhx for the 1 step colder plugs. Swap those out before you kill the motor.

ETA:. You may want to borescope and/or compression check the motor to see if you damaged anything running too hot a plug.

I only drove home 45 min with them from the mechanic today, so hopefully nothing crazy. Should I just pop my old spark plugs back in for now

 

[rob99rt]

I only drove home 45 min with them from the mechanic today, so hopefully nothing crazy. Should I just pop my old spark plugs back in for now

If they were the correct heat range, I definitely would.

And just because you only drove 45 minutes on them, that doesn't really matter... Based on what you said above, you had some massive negative corrections and audible pinging, which to me screams bad things were going on in that motor any time you got into boost, which you must have at least once.

We've had folks install a Cobb ots tune without the supporting mods, do a few minutes of aggressive driving, and crack ringlands. It happens fast.

I'd pull the plugs and at least do a compression test (rent the tool from AutoZone or another parts store). If it comes back good (all within 10% of each other), then go buy a lottery ticket as your second purchase... The correct heat range plugs should be the first purchase.

 

[HighanDry88]

If they were the correct heat range, I definitely would.

And just because you only drove 45 minutes on them, that doesn't really matter... Based on what you said above, you had some massive negative corrections and audible pinging, which to me screams bad things were going on in that motor any time you got into boost, which you must have at least once.

We've had folks install a Cobb ots tune without the supporting mods, do a few minutes of aggressive driving, and crack ringlands. It happens fast.

I'd pull the plugs and at least do a compression test (rent the tool from AutoZone or another parts store). If it comes back good (all within 10% of each other), then go buy a lottery ticket as your second purchase... The correct heat range plugs should be the first purchase.

Gotcha. Well hopefully nothing is wrong, I put the old plugs back in and drove it around the block. went into boost into 1st gear (cant do much more since its the city) and no neg corrections. Hit 22 psi boost according to the accessport. I'll test drive it some more when I take my wife to work.

I didn't have a compression tester laying around, I'm going to order some new spark plugs and do it then. I may just buy a compression test kit if you have any recommendations.

thanks for all the help

 

[rob99rt]

You could buy a compression tester, but you can rent them for free...

From what I've heard the harbor freight one typically reads low, but at least it's consistent.

Getting into boost in 1st gear won't tell you much since the load is so low on the motor, but until you get a new set of correct heat-range plugs, just drive it easily and stay out of boost.

 

[HighanDry88]

You could buy a compression tester, but you can rent them for free...

From what I've heard the harbor freight one typically reads low, but at least it's consistent.

Getting into boost in 1st gear won't tell you much since the load is so low on the motor, but until you get a new set of correct heat-range plugs, just drive it easily and stay out of boost.

The old plugs I had are 1 step colder, they were fine for the 10k miles I had them in. Anyway I put them back in gapped at 25 and the car was running ok for the most part until 5 min in the drive while taking my wife to work it starts feeling like its going to die at every stop light... and all the CEL codes came on at once, misfire at startup, misfire in cyl 1, 3, Random misfire detected...

At this point, what would be the cheapest scenario I would be dealing with? I'm at a cross roads where I think I'll have to decide whether or not to scrap the car.

I had just gotten a cracked cylinder head fixed 3 months ago too. I don't smell or see any coolant coming out of the exhaust right now so I don't think thats the problem

 

[rob99rt]

First thing to do is check compression. Get a tester from Autozone/Advance Auto/NAPA/O'Reilly, pull all 4 plugs, and do the flood procedure (clutch and gas pedal on the floor and then hit the starter) to check compression in each hole. Until you do that, you don't even know what condition the cylinders are in... If they all come back fine, then you can (likely) rule out any ringland damage from running the stock heat-range plugs.

How many miles are on this motor, btw? It's possible we're dealing with some really bad carbon buildup on the back of the valves as that can cause misfire issues.

One thing to also consider is hold old the purge valve is. It's a known failure point on these (and other) motors and can cause misfires when it goes bad (some guys have had them go bad in less than 20K miles). It's a relatively easy repair and doesn't cost that much for the whole assembly (less than $80 from O'Reilly, most likely). Since you mentioned that it's trying to stall out at every stop light, I'd look into that if the compression test comes back good.

 

[HighanDry88]

First thing to do is check compression. Get a tester from Autozone/Advance Auto/NAPA/O'Reilly, pull all 4 plugs, and do the flood procedure (clutch and gas pedal on the floor and then hit the starter) to check compression in each hole. Until you do that, you don't even know what condition the cylinders are in... If they all come back fine, then you can (likely) rule out any ringland damage from running the stock heat-range plugs.

How many miles are on this motor, btw? It's possible we're dealing with some really bad carbon buildup on the back of the valves as that can cause misfire issues.

One thing to also consider is hold old the purge valve is. It's a known failure point on these (and other) motors and can cause misfires when it goes bad (some guys have had them go bad in less than 20K miles). It's a relatively easy repair and doesn't cost that much for the whole assembly (less than $80 from O'Reilly, most likely). Since you mentioned that it's trying to stall out at every stop light, I'd look into that if the compression test comes back good.

The guy that worked on my work mentioned it could be the coil packs, since its cylinder 1 and 3 shooting error codes every time, or at worse the fuel injectors. Suggested I should switch the coil packs to see if the issue follows

 

[rob99rt]

The guy that worked on my work mentioned it could be the coil packs, since its cylinder 1 and 3 shooting error codes every time, or at worse the fuel injectors. Suggested I should switch the coil packs to see if the issue follows

You can, but it's very seldom the coil packs on these cars that cause misfire problems.

How many miles on the motor?

 

[HighanDry88]

You can, but it's very seldom the coil packs on these cars that cause misfire problems.

How many miles on the motor?

48000, its a rebuilt motor though has this now Mountune High Performance 2.0L Short Block (6063-Sb-930) but with the original internals. Then the cyl head cracked after he rebuilt the motor about a year later. otherwise its been great

he said it could be coil pack or injectors, do you think the injectors could be the cause?

 

[rob99rt]

48000, its a rebuilt motor though has this now Mountune High Performance 2.0L Short Block (6063-Sb-930) but with the original internals. Then the cyl head cracked after he rebuilt the motor about a year later. otherwise its been great

he said it could be coil pack or injectors, do you think the injectors could be the cause?

It's possible to have an injector failure, but at 48K miles, I wouldn't expect it. Heck, we've got a guy on here with over 1/2 million miles on his ST, and he's still on the stock injectors. Most of the time when somebody swaps injectors on our platform it's because they needed to upgrade to a HPFP and higher flowing injectors due to a turbo upgrade. I've not heard of one being changed out due to failure.

If the purge valve has 48K on it, then I'd be suspicious of that being an issue causing the misfires/stalling.

 

[HighanDry88]

It's possible to have an injector failure, but at 48K miles, I wouldn't expect it. Heck, we've got a guy on here with over 1/2 million miles on his ST, and he's still on the stock injectors. Most of the time when somebody swaps injectors on our platform it's because they needed to upgrade to a HPFP and higher flowing injectors due to a turbo upgrade. I've not heard of one being changed out due to failure.

If the purge valve has 48K on it, then I'd be suspicious of that being an issue causing the misfires/stalling.

Maybe I can just replace that myself then? do you have a link where I can buy and a guide on how to install, thanks

 

[rob99rt]

Maybe I can just replace that myself then? do you have a link where I can buy and a guide on how to install, thanks

Standard Ignition 2 Terminal Canister Purge Solenoid CP940 | O'Reilly (oreillyauto.com)

There are videos on youtube of how to swap it out, but it's not bad... maybe 30 minutes.

ETA: you still should do a compression test, though...

 

[TurboGT]

Do a compression test as rob said. You may have created another issue separate from the original now.


Have you tried any other gas stations or tanks of fuel since this issue popped up?

Regardless, I recommend adding 1 gallon of e85 to a full tank of 93 from another station to see if it was bad or misadvertised gasoline.

 

[SSgtjrobertson]

I recommend if you're not big turbo reflashing back to stage 0 and performing the compression test as suggested.

"it goes back to 1.00 every time I reset, which I think is normal"

And do you mean -1 or 1? ThereThere's a world of difference between the two.