Overboosting, wastegate failure?

Zklonne

Member
Started to notice some hesitation at WOT a few days ago - finally looked down at the boost gauge to see I am crazy overboosting. ZZP tuned previously 18-20 psi max, As you can see in the pic and video a quick hard 4th gear pull shot up to 30 psi (note my frantic throw down the phone before I blow the motor as I didn’t know previously it was going THAT high...).

Anybody had overboost issues? Is it right to assume wastegate failure off the bat, or anything else to check off first? Motor is an LNF with Stock turbo.
13953
 

TheNuker

Goblin Guru
The one on the pipe is probably for the stock sensor, I think some of the stock MAP sensors had 2 bolts holding the. The upgraded sensor blue label have 1 as far as I know.

Nuker-
 

Zklonne

Member
Thanks Nuker- Looks like on somebody else’s thread showed just another bolt in to block that hole. Found one laying around to plug that.

Now on to the bigger leak source. Looks like the vapor canister purge valve. Step 1) figure out if it is suppose to be connected On a goblin (I’m thinking not). Step 2) figure out if it is broken or needs to be plugged. I’m taking this as my karma for taking the “easy” path and buying a completed goblin vs building one lol
 

JBINTX

Goblin Guru
Is the third pic the Evap valve? If so, you can remove the whole thing and bolt a plate over the hole it was mounted in.
 

OptimizePrime

Well-Known Member
The evap just needs a nipple on it - it's not connected to anything.

The map sensor hole is a 10-32 bolt found at your local big box (3/4" should be fine). I 3D printed a brace for this sensor to close both bolt holes and keep the sensor inserted as I found it would tilt when just using the one mount. Let me know if you'd like the stl.
 

Zklonne

Member
I’d definitely take that st file if you can find and send it! Thanks! As for the evap solenoid, we plugged it now and boost leaks seem to be gone, but our issue persists. The boost gauge shows we stay in range now and not up to 30+psi like before but at WOT it still sputters like crazy above 10-15psi all the way up to 20, regardless of RPM, and seriously lacks power.

Here’s a little more background of what happened and what we tried as of now.
1) ran perfect for about 300 very spirited miles after it arrived here
2) ran fine one morning for a good chunk of miles that one pull higher in the rpm range something popped and it started sputtering like crazy, now continues on every wot pull when under boost (as mentioned earlier it seems to be throttle or boost related, not rpm)
3) per Rich’s suggestion we checked air to water intercooler levels and found even though the tubes looked full, the heat exchanger was basically a big air pocket that ran the pump completely dry when the pump turned on.. then when shut off the pressure would push the fluid back so the tubes looked full again... POTENTIAL ROOT TO A NEW PROBLEM WE CREATED?.. I purged all the air out, tighten all the fittings and verified the pump was still working, but the sputter issue stayed.
4) Checked DTC’s - only code is “Fan 2 control circuit”. Assumed to be something removed and not needed anyway.
5) checked for boost leaks, found some, fixed them, issue still persists.
6) pulled the maf plug to see how it ran - makes no boost (not sure if it should??) - got a few DTC’s below
7) pulled back into the garage and had another beer to call it a night And wonder if/what I might have wrecked running the car out of fluid in the intercooler. Also noticing what connectors might have been broken or lost/disconnected by accident? Kind of shots in the dark with those. More images below.

Any suggestions here are much appreciated. I have a Bluetooth OBDII connector but not sure of a good iPhone app to get any useful data outside of DTC’s - not opposed to getting one of the Aeroforce Interceptors or other logging hardware if needed.
 

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Ross

Goblin Guru
Compression check all 4 cylinders. Maybe a bent valve? Check the plugs while you are there.
 

OptimizePrime

Well-Known Member
Yea, you may have just fouled a plug bc of the boost leaks.

HPTuners and a wideband may help understand what's going on here if the plugs look fine. I'll attach the STL to this post in a bit

edit: attached - use a 1" 10-32 bolt for the sensor mount side.
14428
 

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Zklonne

Member
Plugs are a little dark but don’t look terrible and gap is right at .035”, but I’ll replace with new plugs anyway.

Compression test showed a potentially promising lead. Initial numbers.
Cyl 1 - 160
Cyl 2 - 135
Cyl 3 - 70
Cyl 4 - 160

After a splash of oil into the cylinders.
Cyl 1 - 185
Cyl 2 - 195
Cyl 3 - 170
Cyl 4 - 170

This should point toward ring wear or failure in cylinder 3?
 

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Ross

Goblin Guru
Plugs are a little dark but don’t look terrible and gap is right at .035”, but I’ll replace with new plugs anyway.

Compression test showed a potentially promising lead. Initial numbers.
Cyl 1 - 160
Cyl 2 - 135
Cyl 3 - 70
Cyl 4 - 160

After a splash of oil into the cylinders.
Cyl 1 - 185
Cyl 2 - 195
Cyl 3 - 170
Cyl 4 - 170

This should point toward ring wear or failure in cylinder 3?
Both cylinder 2 and 3 look like they could use rings.
 

Desert Sasqwatch

Goblin Guru
If number 3 was a ring failure it would not hold at 170, but should bleed down pretty quickly after the oil would leak past anything broken. In my experience you probably have some ring wear on number 3 based on your description - nice old school trick with little squirt of oil in the cylinders. But I'm not sure this would be causing the symptoms you're describing with the sputtering.

The plugs from number 1 and 2, assuming they are in cylinder order in photo, look good with only minor carbon and clean insulators. Number 3 has a darker insulator, but the electrode looks okay - maybe a little oil in the cylinder, but can't be bad. Number 4 has more carbon on the electrode - could be a rich indication. This is just my interpretation of your plugs, others may see it differently.
 

Zklonne

Member
I did do the initial test cold and dry so that should be worst case. I wonder if a few min of run time lubricates the cylinder enough to seal up better. I just have an off the shelf compression tester which I think holds max pressure at the gauge so it doesn’t function as a leakdown tester. I think I can modify it to watch the leak down and see how quickly cylinder 3 bleeds off.

Along with new plugs I thought about getting new coil packs just to rule those out (still might), but from past experience coil related misfires seem to be very random and jerky, whereas our issue here seems to still ride smoothly but lacks power (Along with Sputtering sounding like an air powered machine gun).

I will get a few new videos to upload since it is slightly different now that we fixed the boost leak.
 

Zklonne

Member
A little update from working the last 2 days. I couldn’t get my hands on a “real” leakdown tester so we did a semi-diy leakdown test To see how quickly we bled pressure in the cylinder, using just a gauge and ball valve. Cylinders 1,2, and 4 bled from 90psi to 0psi over 10-14 seconds. Cylinder 3 bled from 90psi to 0 in 4 seconds. Definitely seems to show an issue with rings in cylinder 3 but I would agree I can’t imagine this causing the sputter (especially after a short stint of success today- read on).

Also repeated boost leak test to confirm again to 25psi no issue. Replaced plugs, Ignition coils, and installed AEM wideband sensor (in the bung right off the turbo) with AFR gauge (no HpTuners yet but I think I will get it now). After getting whacky numbers and random red dashes and the same sputter and lack of power we about called it a night. Out of some random will we pulled the battery cable for 15 min to see if we could potentially reset something. I then read reviews about how shitty these AEM sensors can be out of the box for that issue and found out the stock O2 sensor is Wideband and can be connected to the gauge.

Fast forward to today - I hook in the old O2 sensor to the Afr gauge, do my little random look around to double check there’s no loose fuses, connections, intake clamps, etc. Take the car out expecting to get a video of the issue to load here, and low and behold we get 2 good 10 minute runs of zero issue, hard pulls through all the gears. AFR ranges (observed on gauge) 12-13 under WOT .

I was Still a little skeptical at this point so I went out with the Harley gang for a 2 hr ride after this sure as ever the sputter came back halfway through. I got one good video of this, not sure anyone can recognize by noise, but for reference this is what is happening at WOT. Hard to see on the camera but I watched the AFR at 13-14.5 now which to my knowledge is lean for a hard pull but I’m not sure if it’s high enough to cause issue.

As always, appreciate all the help from people a lot more knowledgeable than I here!! Would’ve liked to head down for the Midwest meetup but won’t make it this year. Will have to watch out for it in the coming years.
 

ctuinstra

Goblin Guru
Do you have a fuel pressure gauge? I never thought I needed one, but three times in the past year it has pointed us to fuel issues. First time was the pump not priming at start up. Second time on the dyno, it was low on fuel and starving during pulls, and recently showing over-pressure because of a plugged return line filter. Not saying it's the answer to your problems, but I have a new fondness for them now.
 

Zklonne

Member
I don’t, but I’m not opposed to getting one. For the LNF would I want to see both my high and low pressure pump to diagnose? This is my first direct injection motor experience so I have a bit of a learning curve.

I ordered HP tuners last night so I believe I can see both pressures logged on there when I get that rolling.
 

ctuinstra

Goblin Guru
I don’t, but I’m not opposed to getting one. For the LNF would I want to see both my high and low pressure pump to diagnose? This is my first direct injection motor experience so I have a bit of a learning curve.

I ordered HP tuners last night so I believe I can see both pressures logged on there when I get that rolling.
Not sure about the LNF, but with the LSJ, there is no fuel pressure sending unit. HP Tuner scanning won’t help. Mechanic may be the only way???
 

Zklonne

Member
Well I have a lot of learning to do to really make use of even scanning with Hp Tuners, but I didn’t have a ton of time today so I did a few logs to just get started. Only notable thing I am really seeing is Boost (absolute) cuts And stays right at 30.1psi (16psi gauge) while desired boost raises and sits up to 36psi. Not sure this has anything to do with the issue though, maybe the wastegate opening? Although that should be holding until 20psi . Scan did confirm the fuel rail pressure is smooth up to 2100psi and TPS is steady from 0-100% throttle (cobalt forum suggested possible TPS shorting and opening/closing The throttle plate rapidly under load). Wideband is not wired in yet- i will need to figure out how to do this.
 

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