MclarenF1

So yesterday I bought a '93 touring auto. It felt like it was boosting low, so today I bought a gauge and did some boost testing. At WOT in L, there is no boost until about 3000rpm, where it starts at 5-6 psi, and then builds to 7.5-8.5 psi up until about 4500rpm, when the secondary turbo is supposed to come online. At that rpm, the boost drops a few psi, and then only builds up to 5psi up until redline. The motor runs perfectly fine, although it only pulls 13 Hg of vacuum when stationary in drive.



And sometimes under WOT from 4500 to redline, a large amount of blue smoke come out of the exhaust. This also happens when I rev it to around 6000rpms in neutral 2 or 3 revs in a row.



According to the previous owner, the car still has both cats (working on getting a downpipe as we speak, hesitant on getting rid of the main cause I don't want to cause overboost), and a catback exhaust (motoria?) that is really quiet, even though I can fit my fist in the muffler.



So my guess is that there is an oil seal on the secondary turbo that is broken, causing oil to get into the engine, creating smoke at high rpms, and that the turbos might need to be replaced.



So my plan of action is to:

- quit driving it

- replace all the vacuum hoses with silicon ones

- install a downpipe

- check all the solenoids and control valves

- replace turbos (if needed)





Am I on the right track here in properly diagnosing these issues, or does anyone have any suggestions?

Speeder

Think you`re on the right track. How many miles does the car have on it?

MclarenF1

Just over 76000 miles. Apparently a rebuild was done at about 58000, and I have the receipt for it. I also have a receipt for a turbo rebuild too, but all it says is, "reuild turbo" and the cost.

Speeder

If your turbo has been rebuilt, check the vacuum hoses down by the turbocharger for the restrictor pills. One should be in the wastegate control actuator line & another should be in the turbo precontrol actuator line. My turbocharger was rebuilt also & low & behold, no pills in either line when I bought my car. I hear it is a common thing for rebuilders to replace the hoses during turbo rebuilds & inadvertently leave out the pills. I knew my boost was low & was confirmed after I bought a boost gage. I was getting about a 5-3-5 pattern. Might be one of your low boost issue problems to look into. If you`re looking at the actuators from the front of the car, both of the lines to look at would be on the LEFT side of each actuator. I have heard that the newer year cars have the restrictor built into the F nozzle of the compressor housing but mine wasn`t so I know that my pills were never put back in after the rebuild. Might be worth a look see.

Signal 2

I'm not familiar with autos...at what rpm does the car idle when stopped in DRIVE? What rpm does it idle at when in neutral and what is your vac reading then?



The smoke is likely the turbos. From what I've read and from some friends who have had it done, rebuilding these turbos is a crap-shoot. Some have gotten several more thousand miles of HARD boosting at 12 psi, and others end up with smoking turbos worse than what they sent in.



As for the boost issue, what Speeder mentioned was the first thing that came to my mind. If the motor was rebuilt recently, they should have checked the solenoids and replaced hoses too. If you've got slicone vac lines instead of OEM rubber at least you'll know those were changed.

What speeder described does happen. In other cases is the owner removes all the aftermarket stuff to sell seperately and returns the car to (as close to) stock as he can. Problem is, when they put a Boost Controller in the car they replaced those lines that had the pills and didn't save them. A simple solution is to buy or make a set of manual boost controllers.

Signal 2

Edit above...just remembered you said you had a pre-cat. The PO probably didn't have a BC then, so what Speeder said was most likely. I don't see a reason to stop driving it, but get that DP on ASAP.

MclarenF1

Did some inspecting under the hood and came across this. Time to upgrade the Y-pipe and crossover?

AwakenNoMore

You need to do some major cleaning in there.

Also, go non-sequential, its way better . . . your car will feel like a rocket, and turbo problems disappear.

1Revvin7

Sounds like you're secondary turbo is shot..