Well guys. I finally got my air hose, compressor and all connectors, but now I'm really needing some help!!! No boost leak at all that I can tell. First attempt, I just heard air leaking from the clamp on my plug. Tightened that, then she held pressure and I could not hear a peep of sound (air leaking). I released all the pressure, went up to 20psi again a couple times just to be sure and the big hoses were fairly solid. Definitely holding pressure. I have no clue where to go from here besides making a plug for the intake and look for vac leaks. I really do need guidance now. Not sure what else to try.
History: Started driving and noticed very minimal boost and bad throttle response. She would shutter a bit after that at idle too and she was just running like total crap out of the blue. Got codes for both banks lean. I have put new gas in with a trusted toluene added, replaced all coil packs (3 were cracked) all plugs looked perfect. I put in a new fuel filter. Cleaned the MAF and it tests perfect on durametric and with no. 5 wire meter test as well. I put in new upstream O2 sensors. She runs fantastic right until she starts boosting, then jerk, loss of power, occasional pop sound when trying to boost past .5 and my tune is for 1.3 bar. I cleared my codes after replacing the coil packs and I did put in new plugs Markski recommended on another post. Thought it was having a big boost leak for sure, but she is holding 20psi and I can't find anything that is causing a possible boost leak. With the engine running, I "think" I can hear a strong hiss back around the no. 16 valve (That basic area). I use a plastic low pressure water hose to my ear trying to listen for air leaks, but difficult to be sure of anything with the engine noise. I have not had a CEL come on, but only did one fairly long drive for about 30 min. I did see a quick flash of the PSM light when she tried to boost, but no codes came up. I'm not sure where to go now. Well, vac leak test I guess, but it sure seems directly related to when I start to boost. Can rev all the way and sounds great if I'm not boosting. It doesn't feel like a slipping clutch. Please help direct me from here. Thanks very much for any advice. Super bummed.

 

”All plugs looked good”? Why not replace them. Gap them down. 1.3 bar is considerably higher than stock.

Is your new tune mafless? If you’re bypassing the stock maf the air fuel ratio is depending on readings from the oxygen sensors. One bad sensor and you have terrible stuttering and performance.

You really need to consider the plugs. The ignition system on the 996 platform is weak. If the gap isnt small enough you will get missfire and your life will be miserable.

 

Yeah, you can forget about the boost leak. The performance issue you are describing would need a major loss of pressure to present itself. I'm thinking if it were a plug causing that much trouble, it would be accompanied by a code P030x telling you exactly what plug was causing trouble. If they were all bad, you'd get P0300. At this point, I'm thinking fuel pressure - pump or injectors. I'm pretty sure there is no code for insufficient pressure. A bad injector may also present with a P030x, but I've never had a bad one, so I can't guarantee.

 

Have you blasted out your fuel lines, and replaced the fuel filter, and by this point pulled the injectors and cleaned/tested them? It sounds more like your not able to get enough fuel on demand. Wether by restriction, or inability to pump. Along with everyone else also check your spark gap everyone varies between .24 and .27 depending on pressure, gt3's are at .26, and if your running around 20psi .25 is apparently good place to start.

 

You check fuel psi?

Tim

 

What injectors? some injectors can not handle some additives they swell the o rings and decrease the fuel flow.

Tim

 

As some of you can see as stated above, I did replace the plugs even though they looked good. Used Denso platinum plugs. The Bosch plugs with around 10K on them I replaced looked really good. No gunk on them or anything abnormal, and as I stated above, I have a brand new fuel filter. What is factory PSI on fuel pressure? I don't see it on the Durametric, but I may be missing it? Low fuel pressure makes sense to me. I'm wondering if that U bend off the fuel filter is slightly narrowing the fuel line? Where is the best place to get a gauge on it? It sure doesn't seem like an injector to me, because it all looks fine on the durametric and she runs perfectly until boost. I don't have any gas smell, like a leaking injector may have, and no misfire until boost, but no codes. No leaks that I can see anywhere. Compression is all great. Thx for all your guys tips and suggestions. This one is killing me.

 

I don't know if this is supposed to happen, but I quit pressurizing her after soaking everything in bubble leak spray and I found no air leaks, HOWEVER, when I removed my intercooler plug on the opposite side I was pumping air into, I noticed quite a bit of motor oil on it. That's just going past the valves right? A little was noticed in the air intake rubber connector when I removed the air box yesterday too, but very little. Is that reason for concern? I took her out again after finding no air leaks, and she drives perfectly right up to .2-.4 boost, then she has instant loss of power, jerking, but back to perfect after I stop boosting again. No codes. I'm stumped. My actuators are not stuck as I checked those too.

 

Not unusual to see oil in the intercooler after a boost leak check. It takes awhile for the system to restart diagnostics after a code reset so no codes is not unusual. Obd monitors must run 1st. Fuel pressure should be 55 psi base. An improper spark plug gap will cause a misfire just like a bad plug or coil .I do not have experience with the Durametric ,just industry specific scanners, but once establishing the basics ( air- flow , fuel- pressure, fire- coils plugs ) looking at cylinder misfire and long and short term fuel trims to determine the next diagnostic path . Large positive fuel trim indicates lack of fuel . Large negative values indicate too much fuel due to faulty sensor or misfire. Misfire on one bank will also be an indicator. Also a damaged new spark plug can also be an issue if cracked during install . My Car exhibited the same issues as yours due to bad plugs and coils, which looked fine once removed.

 

Nothing abnormal to having oil in the intercooler piping on a turbo car.

 

Maybe I missed it, is the fuel pump new?

 

Thanks for the input guys. My fuel pump is not new. I'm going to try data logging today or tomorrow (Kids have my laptop for online school). Markski is going to take a look at the log. God bless him! I was very careful with the plugs, and new coil packs. The data logging may show some light on this. I'm thinking fuel pressure. It's all I can come up with now unless one of my new parts are damaged. Where is the best place to get a fuel pressure gauge on her? Also thinking my new fuel filter hose was in a pretty tight U curve that looks like it could narrow the hose a bit. It's funny how these symptoms are linked to quite a few things. Hope I can find it with your guys help. Thanks. Now where is the best place to get a fuel pressure gauge on her? Thanks sweeney for the PSI numbers!

 

Fuel pressure will be your culprit is my bet. If you've never replaced your fuel pump than you may likely have a split in the rubber U hose or your fuel pump may be failing. Check to make sure your fuel filter is not clogged. Fuel pressure is one of the most important values to track. Engine off pressure will be right at 55psi while idle fuel pressure will be right at 50psi.

I highly doubt your plugs are the cause if you have replaced them along with the coils. I've never ever gapped my plugs and have run OEM 996Cup plugs straight out of the box on my 3.6, 3.8, and 4.0L turbo Mezger. Never in 10 years of tracking these cars at 1.3 bar have I had any issues. Never. Good luck getting it sorted.

 

I was able to data log a 3rd gear pathetic WOT "pull" haha. I only got to 4K RPM's. It's running ridiculously lean, so It's probably the one thing I did not replace of course. The fuel pump. No MAF issues. No misfires even though my gap is too wide at .030 on the plugs. I really don't want to go right back in to gap the plugs. Ugg. At least no misfire though. I just ordered a fuel gauge from Amazon, so I will test that next. I just need to say that Markski is probably most kind and wise person I have ever talked to about car issues. He showed me how to data log and he is thinking that it's starving for fuel. When I get back on my feet again financially, he will be the only person I would ever want to order from. He is royalty in my mind. The best advice I could probably ever say is," Ask Markski" I've been trying to figure this out for at least 6 months and I'm pretty sure he figured it out in under 5min. I have a 157 IQ, but feel completely retarded compared to him. I'm not worthy. Thanks again for everyone's input. Great call pwdrhound. I think you called it too. I'll report back after I get the fuel pressure gauge. I'm still testing it before buying a new fuel pump. Any advice on a good, but not made of gold, fuel pump? I could trade an electric guitar for one. haha. I'm so broke. Thanks guys!

 

If you don't want an OE pump, put a Walboro in it. It will support more power and Radium sells a nice drop in solution.