[SOLVED] No power, enters limp mode on acceleration

[chris' speed 3]

Pizza in the intake.

I looked over the whole intake system, it must be something on the exhaust side

 

[L337TurboZ]

Shit that's a good point lol, what else would cause the engine to choke?

An easy test for a clogged exhaust is to remove the oxygen sensor before the catalytic converter and drive it. If it accelerates better than you need to look at the exhaust being clogged. You said you put a new downpipe on that doesn't have a catalytic converter right? Unless the cat broke down enough that it shot crap into the muffler assembly or resonator and it hasn't exited then I don't know what would be clogged.

 

[chris' speed 3]

An easy test for a clogged exhaust is to remove the oxygen sensor before the catalytic converter and drive it. If it accelerates better than you need to look at the exhaust being clogged. You said you put a new downpipe on that doesn't have a catalytic converter right? Unless the cat broke down enough that it shot crap into the muffler assembly or resonator and it hasn't exited then I don't know what would be clogged.

I have a CPE downpipe thats catted, which was installed in an attempt to fix this problem when it first started. Ill remove the 2 extra bungs that are in the downpipe and see if anything improves. No resonators just a muffler
Im starting to think exhaust is unlikely I really need to smoke test the intake I feel like there might be an issue with turbo control systems, waste gate or ebcs or smt

 

[StreetSpeed6]

I have a CPE downpipe thats catted, which was installed in an attempt to fix this problem when it first started. Ill remove the 2 extra bungs that are in the downpipe and see if anything improves. No resonators just a muffler
Im starting to think exhaust is unlikely I really need to smoke test the intake I feel like there might be an issue with turbo control systems, waste gate or ebcs or smt

Did you not report before replacing the DP that you pulled the o2 sensor and it ran way better?

Did you drive it with the new dp on but unconnected?

 

[chris' speed 3]

Did you not report before replacing the DP that you pulled the o2 sensor and it ran way better?

Did you drive it with the new dp on but unconnected?

So im trying to figure it out today, i pulled out the 2 extra bungs in the CPE downpipe and it seems to be a little bit better like it starts to choke up at a slightly higher load.
I was also messing around w the MAF and the VTCS and it ended up giving me a p0304 but I didnt do anything specifically to cylinder 4 so i'm thinking that is the problem cylinder like the last shop suggested.
Its pouring rain rn so i don't feel like going on the floor to disconnect the DP but I'm going out to do my leak down test soon. most likely disconnect the DP tmr

 

[StreetSpeed6]

So im trying to figure it out today, i pulled out the 2 extra bungs in the CPE downpipe and it seems to be a little bit better like it starts to choke up at a slightly higher load.
I was also messing around w the MAF and the VTCS and it ended up giving me a p0304 but I didnt do anything specifically to cylinder 4 so i'm thinking that is the problem cylinder like the last shop suggested.
Its pouring rain rn so i don't feel like going on the floor to disconnect the DP but I'm going out to do my leak down test soon. most likely disconnect the DP tmr

Yeah don't blame you there but make sure to try the dp disconnected as that will immediately tell you if the muffler has stuff plugging it up.

 

[chris' speed 3]

So did the leak down test and I have good news, ranges between 14-18% so my engine isn’t the problem here which is a big relief
As for spark plugs, I don’t understand what’s going in with mine. The first 2 are white/tan and 3,4 are darker, what would cause this? Is this also a clue to solve the issue?
@L337TurboZ @Enki @StreetSpeed6
Here are some pics of spark plugs and leak down results

 

[StreetSpeed6]

So did the leak down test and I have good news, ranges between 14-18% so my engine isn’t the problem here which is a big relief
As for spark plugs, I don’t understand what’s going in with mine. The first 2 are white/tan and 3,4 are darker, what would cause this? Is this also a clue to solve the issue?
@L337TurboZ @Enki @StreetSpeed6 View attachment 23775
Here are some pics of spark plugs and leak down results

Did you check what their gaps are? It indicates a rich condition most likely in those cylinders. If the gap is much bigger it could be having a less powerful spark or something. I would just see about the exhaust and let us know if it helps running an open dp.

 

[Enki]

You do realize that there's no reason to tag us directly every time you respond to this thread right? We see it regardless.

 

[chris' speed 3]

Did you check what their gaps are? It indicates a rich condition most likely in those cylinders. If the gap is much bigger it could be having a less powerful spark or something. I would just see about the exhaust and let us know if it helps running an open dp.

So the white ones are lean and dark ones are rich? Ill disconnect the downpipe this weekend

 

[chris' speed 3]

You do realize that there's no reason to tag us directly every time you respond to this thread right? We see it regardless.

I did not realize that, thanks for letting me know ill stop tagging you guys, sorry about that.

 

[StreetSpeed6]

So the white ones are lean and dark ones are rich? Ill disconnect the downpipe this weekend

The white ones are more lean but look about right in my opinion and yes the black sooty ones are running rich

 

[chris' speed 3]

Im a little concerned with my leak down results, i texted my mechanic and he told me that its not 18% leak down its 82%, Because the second gauge was reading between 14-18 psi but I didnt hear air escaping anywhere. On cylinder 3 I didnt have it at TDC and I heard air hissing out of the intake and the second gauge jumped to 80psi. Is it possible this one is like reversed or something? I doubt i'd have 80%+ leak down on every cylinder.

 

[Enki]

Just had a chance to look at the pics. Did you follow the instructions for doing the leakdown? You really need to make sure that the piston is at TDC with the valves closed (if memory serves) or the air will just leave via the intake manifold or exhaust manifold.

If you pull the crankcase breather hose and check the outlet of that while doing the test it can give you a (very rough / inaccurate) idea on how much blowby you have.

 

[chris' speed 3]

Just had a chance to look at the pics. Did you follow the instructions for doing the leakdown? You really need to make sure that the piston is at TDC with the valves closed (if memory serves) or the air will just leave via the intake manifold or exhaust manifold.

If you pull the crankcase breather hose and check the outlet of that while doing the test it can give you a (very rough / inaccurate) idea on how much blowby you have.

I watched a couple videos of people doing leak down tests with the OTC tester, Im fairly certain I was at TDC, the only time I heard air coming out somewhere was from the intake valve and the psi jumped up to 80 instead of the 14-18psi I was seeing, I wasn't at TDC so i adjusted it and it dropped back down.

 

[Enki]

Sounds like you had it right and then rotated it far enough to no longer be doing it right. The goal is to see how much pressure is leaking past the rings with all the valves closed, so if you only get 18 psi out of that then either you aren't flowing enough into the cylinder through the tester or a fat chunk of the ring is gone or it's not gapped/aligned properly.

 

[chris' speed 3]

Sounds like you had it right and then rotated it far enough to no longer be doing it right. The goal is to see how much pressure is leaking past the rings with all the valves closed, so if you only get 18 psi out of that then either you aren't flowing enough into the cylinder through the tester or a fat chunk of the ring is gone or it's not gapped/aligned properly.

14-18 psi is leaking out, I had 150 psi on my compressor and i was flowing 100psi into the cylinder. i think its good my results were good.
The tester is supposed to be higher tho like say it was actually 18%leakdown it should have been at 82psi not 18 psi but maybe this one is just different. Either way im confident my engine is good or else there would have been a big difference between one of the cylinders

 

[Enki]

Pretty sure that's not how it works. I'd verify via instructions that should have come with the unit or the mfg website.

 

[L337TurboZ]

Do this

Step 1, take off valve cover

Step 2 turn engine to TDC cylinder one compression stroke both valves closed

Step 3 connect leak down tester to cylinder. Set regulator on tester to fully released so it doesn't add air in

Step 4 slowly crank regulator to add pressure. You only need 30-40 psi max.

Step 5 look at leak down reading and listen for sources of leaks

Step 6 repeat for all cylinders

 

[L337TurboZ]

The point of removing the valve cover is so you can easily see when the valves are closed