Locin993

I recently acquired a 1996 Turbo, that has a fault with the Boost Gauge on the dash constantly showing 0.8 bar. The car drives well and boosts around 3500 rpm. I previously had a 993 C2, and there is a noticeable difference in performance, but this is my only comparison.

After reading various threads i can see some people have had success in changing replacing the Boost Pressure sensor, part no. 99360610301 when seeing an inconstant Boost reading in the Dash, but i could not see anyone with it stuck on 0.8 Bar.

Any comments are appreciated.

997 tt/rs

Change boost pressure sensor

speednme

Sounds like a bad boost sensor if everything else is running well but I would check the wiring to the boost sensor too.

Locin993

Quick update - boost gauge on the dash has come to life after swapping boost sensor. I get a linear reading from 0.0 upwards under acceleration.

Max boost I was able to generate was 0.5 Bar, in 3rd gear at 4-5k rpm, which I have a suspicion is down to failed actuator.

Also, when removing intercooler I noticed oil in the hoses, which I'm hoping is down to the non-porsche oil filters that are present.

One step forward and two back! Both look like DIY tasks thankfully.

I wouldnt have got this far without this forum, many thanks!

jac911

I had the same issue when I bought my TT. When I'd take the intercooler off I would set it up vertically with the left side down. The left side seemed to be the most contaminated. After about an hour or so I'd get about 1/3 of an ounce of oil drain out. There was no oil smoke on startup. Taking the advice of the group I did the following. I cleaned the intercooler by sloshing a cleaner inside. When changing the oil, I only refill with enough oil to come up to 1/2 way up between the marks on the dipstick. I put in an anti-drainback check valve between the tank and the engine to limit oil draining back and filling the crankcase. The oil collection in the intercooler seems to have stopped.

Also the oil return lines from the turbo to the engine are not stock. The have a 1/2 loop built in with the loop pointed up. I'm suspecting that this was done by a previous owner to prevent drain back from the engine to the turbos,

Enjoy the TT ride.

JC 96 TT

Locin993

thanks for the advice, ill be following this path. much appreciated.

Locin993

Follow on update -

My pre-purchase inspection highlighted lack of Turbo charger heatshields, incorrect size actuator hose fitted and seized actuator.
And during the boost gauge sensor change I noticed oil in the Intercooler pipes.

Car now boosts upto 0.8 under heavy load in 3rd gear. I am guessing the squirt of WD40 un-seized the actuator.

My next steps are to -
1. Drain Oil & swap to correct filters.
2. Fit Turbokrafts oil feed lines with check valves and scavenge lines.
3. Clean oil intercooler, boost pipes, etc.
3. Remove exhaust & CAT, install Turbo Heatshields. (following the pinned post Turbo charger removal guide up to point where I can install heatshields).
4. Replace incorrect Turbo actuator hose.

Couple of areas where I am unclear -
1. Do i need to replace the Turbo charger studs & bolts if i am only adding a heatshield to each?
2. I cannot find the actuator hose part number anywhere for either side.

Thanks in advance for the pointers.

Basal Skull

If you don’t have an external boost gauge, as the stock boost gauge only reads to 0.8 bar, you actually don’t know if your actuators are working. The actuator opens the internal gates to reduce boost, if not working or stuck, you will be overboosting. Won’t know until the ecu cuts the ignition to protect the engine (hopefully). If one side is working and other side isn’t, I’d think you might end up over speeding the stuck side.
You can just disconnect the actuator and move the lever back and forth until it moves freely to make sure it is unstuck, using wd40 or your favorite oil.

You’d want to replace the nuts, the studs can be reused (unless you snap them off… then need to extract using whatever your favorite method and replace - might need to remove turbo to extract the broken stud).
Should replace the sealing ring between the cat/turbo if taking all that off.

ronnie993tt

This solved the oiling problems on mine without the return line...

Locin993

thanks for the detail. very helpful.

Locin993

I am looking forward to fitting them! i went for the return pipes also.
Still a few few weeks away from fitting anything new - removing rusted parts is proving more challenging than expected!

Basal Skull

yup, I’d use copper plated or brass nuts. Even then, can often end up breaking some studs. There is enough clearance to consider bolts/nuts if you see yourself changing things often. After fussing with exhaust studs in general (on various vehicles), just drilling out, tapping and carrying on often is most efficient, and often can be done without disassembly.

TurboIXXI

I've been meaning to replace the wastegate actuators on my car as well. Is FVD the best place to buy these?

FVD $338
Sunset $909
Pelican $1074

tootrn

Forge Motorsports $570 but worth it. Aluminum billet both housing and piston.
And are tuneable- different spring tensions.