power loss please read

[eb66]

Hello,
First of all, I do not have a dsm (please don't stop reading this post now!) I have an evo, but you all seem to have more experience with troubleshooting. I haven't had any luck on evom with this problem yet.

My car has been down on power, I'd say about 20%. I had the car dynoed to prove it. I took it to a professional well known tuner shop to be boost leak tested. I also did a boost leak test myself. It seemed to loose boost pressure quickly, but I could not hear any leaks. Is there any way that a boost or vacuum leak might be missed on a boost leak test? Where? a/f seems to be almost 10% off. (leak?) STFT is between 5-20% - usually 10-15ish, and ltft is 10-15% usually. (leak?) I had a couple misfires, and I have some knock - high only once in a while.

Shop did not know what the source of the problem was.

I have boost leak tested - ok.
Taken out turbo- ok.
compression - ok.
a/f - not rich or lean enough to be an issue, but seems to be 10% richer than the MAP. I don't think there is a fueling problem. This is with a wideband.
coils/wires/plugs - replaced.
no codes
logs look fine except for a high boost error - sometimes max, and high stft and ltft, and occasional high counts of knock
no exhaust leaks

If you know anything that could potentially be helpful please let me know!

 

[Zdrummer15]

You said you could not hear any leaks, but did you spray potential leaking areas with soapy water or just listen for leaks. I would think a shop would know to do this, but just in case you didn't, spray soapy water and look for bubbles.

 

[GSXSixteenG]

Was the boost leak done on just the intercooler system and not the intake manifold/throttle body as well?

 

[eb66]

You said you could not hear any leaks, but did you spray potential leaking areas with soapy water or just listen for leaks. I would think a shop would know to do this, but just in case you didn't, spray soapy water and look for bubbles.

No I did not. I figured the shop had done so many boost leak tests that they would have known how to find them. I will try that.

Was the boost leak done on just the intercooler system and not the intake manifold/throttle body as well?

The time I did it, it was done at the turbo. I am not sure about the shop.

Another thing, I tried spraying carb cleaner over spots that could be leaking to find vacuum leaks, but nothing.


I read somewhere on here that if boost pressure doesn't hold for very long during a boost leak test, that indicates it is leaking somewhere. What is the typical amount of time it should hold for? More than a few seconds?

 

[GSXSixteenG]

You should separate the system and test it in sections, then this will make it easier to consolidate where the leak is. Make a plug for the intercooler piping then pressurize each section accordingly. It very well could be a leaky intercooler.

It should not take less than 30 seconds to bleed down to zero...

 

[DSMDavid85]

they should have done a leak down test,along with a boost leak test to check and see if the valves or rings are leaking, also do you know if they used a smoke test machine?

do a leak down test
use a smoke machine to put smoke in the system to help find leaks while doing a boost leak test

 

[KKneipper]

I had a loss of power a few months back. No misfire or knock though. It turned out to be my alternator. Take it to AutoZone and have it checked?

 

[eb66]

they should have done a leak down test,along with a boost leak test to check and see if the valves or rings are leaking, also do you know if they used a smoke test machine?

do a leak down test
use a smoke machine to put smoke in the system to help find leaks while doing a boost leak test

They did not advise a leak down test because the compression test was ok. Do you think a leak down could show something even though the compression test was ok?

I just briefly googled smoke machine, and holy sh** they are expensive. Maybe they didn't use one. I don't think I will be getting one unless there is a cheaper alternative I am missing.

Thank you everyone for your input!

 

[black_gst]

when you and they did a boost leak test was it always done on the turbo inlet? does you car burn oil at all?

if yes how much between oil changes?

 

[eb66]

when you and they did a boost leak test was it always done on the turbo inlet? does you car burn oil at all?

if yes how much between oil changes?

Nope it doesn't burn oil. I am not sure if they did the boost leak test at the turbo inlet, but that is what I did. I am planning on taking GSXSixteenG's advice and retesting different areas.

 

[KKneipper]

Yeah, retest every place there is a coupler on your intake route. Get a spray bottle and fill it with soapy water. When you do the leak test, spray all the areas that are being charged and you might see some bubbles forming. Remember where the bubbles are, then put the car back together. Check to be sure all of your fittings are tight, and start the car. While its running, spray some carb cleaner at the same spot where the soap bubbles were and listen for the engine to rev a little bit.

 

[350war]

Have you checked/replaced the PCV valve?

 

[eb66]

Have you checked/replaced the PCV valve?

According to the carfax, it was replaced before I got the car. I was also thinking it could be the egr valve. I'm trying to find the info on testing it. I might just get an egr block off plate.

 

[KKneipper]

There is a thread on here and VFAQ that will show you how to make a EGR block off plate out of a beer can. It will work for a short time, but will probably need to be replaced every oil change (give or take a few miles). That would be the cheap way to do it, but if you want to spend the money you can pick one up that will last.

 

[eb66]

There is a thread on here and VFAQ that will show you how to make a EGR block off plate out of a beer can. It will work for a short time, but will probably need to be replaced every oil change (give or take a few miles). That would be the cheap way to do it, but if you want to spend the money you can pick one up that will last.

Ya, I think I'll try that. It doesn't need to last I just need to see if that is the issue.

 

[eb66]

Well, finally gt my hands on a compressor and did the boost leak test today. My injector seals are leaking pretty bad. Not sure how the shop missed it, it was pretty obvious even before the soapy water. Do you guys know of any good aftermarket injector seals?

 

[1990AWD]

Well, finally gt my hands on a compressor and did the boost leak test today. My injector seals are leaking pretty bad. Not sure how the shop missed it, it was pretty obvious even before the soapy water. Do you guys know of any good aftermarket injector seals?

OEM seals should work fine, don't think aftermarket is necessary


Sent from my iPod touch using Tapatalk