D2W Reader
Aug. 17, 2017 6:31 p.m.

Son has a 2004 SRT4 that all the sudden is running very poorly and not making any boost pressure. My first thoughts are stuck waste gate or blow off valve. What else should I be looking for.

Stefan MegaDork
Aug. 17, 2017 6:34 p.m.

Vacuum lines?

Blown Turbo?


Plugged cat?

Timing belt?

Any codes? Do you have an OBD-II reader to use to monitor the sensors and ECU?

D2W HalfDork
Aug. 17, 2017 6:36 p.m.

No codes. Is there a way to trouble shoot these items other than visual inspections?

Streetwiseguy UltimaDork
Aug. 17, 2017 6:53 p.m.

Its blown a hose off the pressure side somewhere, is the first and simplest thing to check.

underpowered New Reader
Aug. 17, 2017 6:54 p.m.

Besides not making any boost, does it run ok? Is it misfiring? If it's running fine other than no boost, I'd check the charge pipes for loose connections or being blown off.

D2W HalfDork
Aug. 17, 2017 8:17 p.m.

I haven't driven it yet, just found out. Wanted to check here first to get some ideas of the first things to look for. He said it is running poorly, but that could be because it is not making any boost. I'll start with pressure side hoses and work from there.

D2W HalfDork
Aug. 18, 2017 1:30 a.m.

No loose pipes or connections. It seems to idle fine, as revs build it is a little rough. Boost gauge reads -19 at idle and climbs to about 0, no higher. Blowoff valve opens slightly on letoff so appears to be working correctly. Waste gate doesn't move. Since there is little boost this seems normal to me? So that leaves the turbo or the cat. Anyway to test either without just taking them off?

TheRX7Project New Reader
Aug. 18, 2017 4:43 a.m.

Boost gauge reads -19 and climbs to 0? Either the turbo isn't spinning or there is a massive boost leak. Stock I'm pretty sure these cars boost 7 or 8lb EDIT: Nevermind I see you answered that already. Pop the hose off the outlet (boost) side of the turbo and see if it spins manually.

wae Dork
Aug. 18, 2017 5:44 a.m.

It reads 0 psi when you rev it in the driveway or it reads 0 psi at WOT under load?

If it isn't reading any boost in the driveway, that's behavior I'd expect. If you're not seeing boost under load, disconnect the vacuum line going to the wastegate and trace it back to the solenoid. Connect the other vacuum line on that solenoid to the wastegate and see if you get 4psi under load.

Edit: that's all if you are absolutely positive that there are no boost leaks. If you had a loose vacuum line, for example, you get unexpected air in vacuum and leaked psi under boost.

Byrneon27 New Reader
Aug. 21, 2017 4:59 p.m.

Make any progress? I made a living making those dumb things work for a long time feel free to get in touch.

Donebrokeit SuperDork
Aug. 22, 2017 7:14 a.m.

Sounds like a locked up turbocharger, have you tried to spin the shaft?

D2W HalfDork
Aug. 22, 2017 9:05 a.m.

I decided to take it to my mechanic. Work is crazy, and the kid is leaving for college in a few days, and I decided I just didn't have time to figure it out myself. I'll update the thread when he finds out what's wrong.

D2W HalfDork
Aug. 30, 2017 8:49 a.m.

Update: one bad coil pack and a turbocharger that wasn't dead but dying.

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