NO BOOST!!!! Did I just N/A my Turbo? (Possibly solved)
 

After discussing with my wife about a certain 944 S2 on rennlist I guess old girl(951) is angry. The car ran great yesterday no issues. Full boost when appropriate, and overall ran fine. I did use the A/C yesterday, but that is the only difference in my routine.

This morning I start the car up and idle and vacuum both look fine. I drive a few miles before merging onto the highway, I go WOT nothing happens. The car just slowly creeps along. No boost what so ever. So I let out and just get it enough throttle to get up to speed. I tried to go WOT a few more times in 4th, 5th gear nothing. No boost at all. As I am getting off the highway I thought I would try a lower gear for boost. No boost in any of the gears.

When I got to work I checked the vacuum lines that I can see(mind you my vacuum is around 17-18 on the boost gauge). Nothing appears to be unhooked or changed since yesterday.

Car is stock minus a gutted cat and K&N cone filter. Turbo(K26/6) was rebuilt 3 years ago by Lindsey Racing.

Could this be an AFM or wastegate issue?

Id check the compressor wheel.

I really hope that isn't the issue. If it is I will most likely shiz myself.

Did you check your TPS connector? I tried unplugging mine a while back to track down another problem, and it almost completely eliminated boost. In almost every other way the car was the same.

Would you get any boost at all? My car is making 0 boost. Should I try to hook up that test light to the test port?

0 on an aftermarket gauge?

I couldn't swear that it was zero, I only have the stock gauge to it was hard to say for sure.

A stock WG with no boost control will only run about 4psi, which will certainly FEEL like "0 boost" and I imagine 0psi will barely register on the dash gauge.

Kinda depends on if it really is making, truly, 0psi. An aftermarket gauge will tell that for sure.

If it's truly making 0psi, then I'd pull the J-boot and have a look at the compressor wheel. Otherwise I'd have a look at your boost controller.

I have an external gauge and both that and my stock gauge were reading about 0. Might have been 1 or 2 PSI tops.

My boost control is all stock. Nothing has changed. How much damage will be done if my turbo is seized up?

How does the car behave on the way to 0 psi? Does it come out of the vacuum as it normally would, just not make any boost pressure? Or is it slower to approach 0 psi?

To me it acts normal until you get to the point where you would normally have that turbo spooling up. It doesn't seem any slower approaching 0 psi.

Could be the wastegate too--stuck open, bad diaphragm, burnt out wg valve, etc. Or even a nasty exhaust leak...

The car drove perfectly fine yesterday. Spooled up good and everything.

I'd check the compressor wheel (easy enough, just pull the j-boot and have a look). If that's fine, then look at the WG. Could be stuck open. Easy way to tell... the short pipe that ties the WG into the exhaust will be hot as the car idles because the exhaust will be flowing through it. (Normally at idle the WG is closed...)

If it was fine yesterday and you have nothing today, I wouldn't immediately jump to the conclusion that its your turbo. You are still running the factory cycling valve, correct? I'd start there. After that, I'd clamp the wastegate line and see if you get boost. IF that doesn't do it, then you can start thinking about the turbo.

I am still running the stock cycling valve. It was replaced about 2.5 years ago when I did all my vacuum lines(when the rabbit hole first appeared on this car) The lines are still connected and appear to be fine.

I will check these things tonight when I get home. I appreciate the support guys. TPS, cycling valve, and lastly the wastegate.

Good call to check the cv by clamping the rubber line to the wastegate. If no boost when the line is clamped, however, it could still be a bad wastegate.

I had a similar experience in my car. Pulled the intake boot, the turbo wouldn't turn over. I pushed on the blades to spin it, got a little 'pop' and it spun freely again. Over a year ago, no problems since then.

On that last part, if the the TPS is not obviously unplugged when you look at it, don't waste any time on it - do what Scott said and clamp off the CV to wastegate hose. If you then get boost, that means the CV has been keeping the wastegate open...an unplugged TPS is one way to cause that but there are others such as (obviously) a bad CV.

Well I tore into it tonight. I noticed my line to the CV from the intercooler pipe was pinched. I just replaced that with a new piece of tubing. My turbo spins freely. So that leaves 2 things CV, and the Wastegate.

I did notice recently some fluttering noise in my exhaust. That is no longer there. I am suspecting that my wastegate is shot. The only vacuum line I haven't replaced is the CV to Wastegate line. It appears to be intact just hard as a rock. How do most people pinch their wastegate line?

I did it using a plastic hose clamping pliers...the kind used for closing coolant hoses when you have to disconnect them but don't want to drain the coolant. I would try clamping it with something anyway. If it cracks a little, I doubt that would invalidate the test completely. Tape it up, then clamp it down!

In any case, if it does crack up completely, cut out the cracked piece and then find something to plug both exposed ends. That is obviously the same test as clamping it down. You will of course have to replace the line then but it looks like that's inevitable now anyway. I used 5/16" fuel hose which is perfect for the CV valve end, but slightly bigger than necessary for the wastegate end. You need a really small hose clamp to make it tight.

I forgot to mention that my wastegate part of the exhaust was hot to touch.

Just use a really small c-clamp on the the line. It's only going to be there for a quick pull.

Today I pinched the vacuum line from the CV to the Wastegate. I went out for a drive and went WOT no boost at all. The car seems to have really low power. In the higher gears I have to floor it to to accelerate at all. So where to go from here? There are still 3 possibilities: Wastegate is bad, turbo is shot, or the exhaust tubing has collapsed.

What is the most probable cause? I am leaning towards wastegate since the wastegate part of the exhaust is hot to touch even while the car is just idling, there is no more wastegate noises when the turbo should be spooling up.

Ah wait, if the car is not making power, then it might be something else completely. If the motor is sputtering, etc., then it may not have enough energy to make boost. Is it running poorly or just weak from the lack of boost? If running poorly, then you'll need to sort that first -- and you may find the boost comes back on its own. Low power can be so many different things, though stumbling on heavy load is often a weak ignition -- plugs, cap, rotor and wires. Do you have a wideband O2 sensor? Does it feel fine until you try to accelerate hard? If so, check the ignition. If it feels weak all the time, then you'll need to look deeper -- AFR problems (bad afm, tps, sensors, fpr, leaks, etc.) or bad ignition, or mechanical problem (low compression, timing belt jumped, etc.). If it's just weak from a lack of boost, then I'd either pull off the WG and take a look, or slide a copper sheet in at the flange to block it off temporarily (and test very carefully by letting up as soon as you see it making boost, as you will over-boost like crazy if you keep your foot on the gas). Also, have you ruled out bigger exhaust leaks before the wastegate, and pulled the j-boot to make sure the turbo is spinning freely?

The car feels weak. It feels about normal on the lower RPM, but once I get over 3000 where boost normally is the car feels slow. Turbo spins freely. I checked that 2 days ago. There aren't any boost leaks that I know of. Car idles great and runs clean, just no boost.

I have a dual port LR wastegate to replace my stock one. If the wastegate is bad would that cause zero boost our just low boost?

If the wastegate valve is not closing/sealing, then it's very possible you'd have zero boost. A 951 will feel weak and slow without any boost. Is that what you mean, or does it feel like the motor is not running right even for a low compression n/a 4 banger?

I'm not sure what a low compression 4 cylinder should feel like. The car now feels slower than my 924s.

doesn't stumble out misfire

Hard to say without being there, but a solid 924S make 147-160hp, and in a slipperier/lighter car. Super ball parky, but if figure no boost will reduce your power about 40%-50% on a bone stock 217hp 951, then you're looking at only 110-130 without boost -- so you would indeed expect it to feel slower (up to 50hp plus more weight slower). So if the motor is running smooth with no symptoms other than no boost -- just gutless -- then I'd focus on making boost.

I just did a few checks on mine for comparison. Starting with a cold car (parked overnight)...after a few minutes of idling the crossover pipe is scorching hot, the crossover to wastegate piece is fairly hot but not too bad, but the dump pipe is as cold as ever. I went for a drive and used a little boost and checked again. Now the dump pipe is hot, but I can still put my hand on it. It's nowhere near as hot as the forward sections of the exhaust.

How does that compare to yours? If your wastegate dump pipe is hot to the touch from a few minutes of idling (starting with a cold car obviously) then your wastegate must be stuck open.

Yesterday before my test drive I was letting the cart idle to warm up. The dump pipe was hot to touch.

Your symptoms sound identical to when my boost was zero. It would pull great vacuum, but, no boost pressure. Check the balance of your turbo, as well as for play in the shaft. It could be the turbo on it's way out.

You have to have a GIGANTIC leak in your intake/vacuum system to create a zero boost situation.

With the wastegate pipe being hot to the touch just from idling, I'm betting it's stuck open. Did you get a chance to swap the Lindsey one in yet?

My turbo was rebuilt 2.5 years ago. It has maybe 15,000 miles on it. They are overall easy miles. I did pull on the shaft and it was tight still, spun freely.

I have not. I didn't get the new wastegate yet. I should get it tomorrow, then I need to get some time to swap it out as I can't do it in my small 1 car garage. I will be taking it to DIY to swap it out.

I haven't swapped the wastegate just yet. Could the Forge BOV somehow cause a 0 boost situation?

if your wastegate is not stuck open you might want to consider pulling the turbo out, your situation sounds very similar to what happened to doabarrelrrol

https://rennlist.com/forums/944-turb...ml#post9786157

Do rebuilt turbos fail that soon 2.5 years and low mileage?

Yes, everything is possible with a 951, oh man that sounds like a quote from the Bible, lol

+1

0 boost usually means your turbo is finished.

If its the wastegate, you'll still see boost. Even if it's stuck open. even if it's 1-2 psi.
the CV would do the same. You'll see some boost. not much though.

Or the Xover is collapsed and the wastegate is open all at once. That would be 0 boost.

If the turbo was toast would it go from one day boosting 10-11 PSI no problem to the car sits overnight in the morning it makes 0 boost? That just doesn't seem possible. I never heard any weird noise or anything. Also the turbo spins fine from the intake side where the J Boot connects.

Have you inspected the wastegate yet? Seem like a wastegate valve could indeed stick open or crack or the diaphragm could fail just about anytime, even overnight. Only one way to find out....

The wastegate and the wastegate valve are no longer connected...BTDT.

I have been crazy busy with work. I hope to pull this wastegate off sometime this week. I have a LR Dual Port wastegate ready to go. I really hope its the wastegate not the turbo.

Should I clean up these mounting surfaces on this used wastegate?

http://i856.photobucket.com/albums/a...ps7f973e63.jpg

http://i856.photobucket.com/albums/a...ps20f03f92.jpg

https://rennlist.com/forums/members/...s-exhaust.html.

This is how my down pipe looked when I had a no boost issue, Prior to my failure to place the air filter properly allowing my turbo fins to be destroyed. Had similar symptoms prior to blowing up my turbo.

I am afraid of the downpipe or crossover pipes being collapsed.

Why does that happen anyway?

It's double-walled.

I imagine that if the outer pipe cooled suddenly, it would shrink and crush the inner pipe. Like hitting a puddle of water or something. (?)

I guess this was the cause of my no boost issue.

http://i856.photobucket.com/albums/a...ps1a58b98c.jpg

http://i856.photobucket.com/albums/a...psfba4e887.jpg

I installed a used Lindsey Dual Port wastegate with an MBC. I haven't driven the car yet or even tried to set the MBC. I am still running stock chips so I will keep it at 10 PSI just to be safe.

Good luck on boosting! That thing looks like something salvaged from the Titanic... Is that valve seized like that?

It was until I hit it with hammer. I guess the diaphragm is busted. I am going to take it apart to see what really failed.

Just got it completely together. I have the boost set at 10 PSI. I couldn't remember if 10, 11, or 12 psi was stock. I figured 10 seems okay.

The car runs great and no longer makes a rattle noise when coming on to boost(maybe that was my wastegate slowly dieing).

Congrats on finding the issue!

This just happened to my '86 951 today.
 

I just had this very same situation happen to me this morning on my way to work. Started out and I was making boost fine (aftermarket boost gauge). The next thing I know, I have a smooth running NA 944. Great vacuum, still 20 inches at idle. Everything else is great, runs fine, accelerates smoothly, quietly, just makes zero boost.

I have suspected that the waste gate might be a weak link since I acquired the car back in May (previous owner shimmed it). Sometimes I would get inconsistent boost levels (have Lindsey MBC, 951Max chips, no cat). Last week it started suddenly increasing boost beyond what I had it set at, 17-18 psi vs 15 previously.

86 951 Driver,
I think I saw in your posts that you went with a Lindsey Dual Port. Sitll happy with this?

Thanks.
Roger

I'm using a lr duel port and love it. It definitely sounds like your wastegate is stuck open though

Is the LR Dual Port legal for use in PCA Club Racing, stock class? At some point down the road, I may want to do some Club Racing with this car.

Roger

I don't think you will get an answer as I believe his car burnt to the ground shortly after this from a fire in a garage.

Ouch! I hope it wasn't the waste gate that caused the fire :( As long as no one was hurt.

I think I will probably find one of the other threads that deals more directly with waste gate selection and get some info there. Probably more appropriate placement than in this thread. Thanks for the heads up.

Roger

The dual port is not CR legal. But they make a "clubgate" version which is a single-port version of their updated WG.

Thanks. If I do turn the car into a club racer, it won't be for another 3-4 years. I see a lot of positive info regarding the Tial. I'm thinking maybe I should just go that route now and worry about club racing when that time comes.

Roger

I just went out to the parking lot and confirmed that the wastegate is stuck open. I started the car and reached under to feel the dump pipe off the wastegate. It started to warm up immediately, within 60 sec it was hot.

I also got confirmation that Pauer Tuning is no longer making the Tial wastegate kits. If anyone has any suggestions on where to find the necessary adapter for a Tial 38mm wastegate, please let me know.

Thanks.
Roger

Send a PM to fejjj.

My advice: don't "build" anything. Buy a CR car that's already done and ready to race.

Just did. Thanks.

Are there different models of Tial 38mm wastegates? I thought I saw a Sport and a BV, etc.

Roger

His kit is on eBay ...well it was, just sold lol
http://www.ebay.com/itm/151416349416?redirect=mobile
And pauer tuning sold the f38 38mm tial duel port wastegate sport version, if your looking to go that route

I just bought the fejjj kit off Ebay. Now I need to find the Tial Sport 38mm.

Roger

This was pauer tunings previous distributor. So call them and they can get you what you need, you can order any color you want

Turbos Direct LLC.
3581 W Electra Lane* Suite 100
Glendale, AZ 85310
623-376-2562 (Sales*)
623-587-9848 (Fax)

I haven't been on here in a while. But I still check it from time to time.

My car did burn up in a fire shortly after this. Before that the car ram great. Boost came on a bit sooner than when it was stock, and it complimented my other mods. I would recommend it. For the money though you can get a nice tial with adapter plates.

Yes, I decided to go with the Tial. Sorry about your car. Hopefully you have a comparable replacement?

Roger

Tial is half the cost of the approved gate. The rules are now such that I do not understand a reason that PCA would continue the ban. Aftermarket chips are allowed and they allegedly have a way to measure boost, which is limited to 12 PSI but otherwise unrestricted. I have a Tial, though not on any of my cars, yet. I am hoping that PCA will consider allowing aftermarket gates in the future. I hope to lobby for it, but I will in all likelihood have converted by TUrbo to a 968, S2, or S if I can get enough weight out, and not be dealing with the complexity of a turbo in the future.

Yes, I ordered all the Tial components yesterday. All in, with gaskets, it was about $400, plus I can keep my stock wastegate. Hopefully I will get it installed this weekend. I'm keeping my fingers crossed that everything goes smoothly, even though it rarely does!

A quick reply to the suggestion of buying a race car. Yes, in the end that is usually the easiest and cheapest route. However, there are some extenuating circumstances here. The 951 will be my son's daily driver until he leaves for college. It has already been, and will continue to be (whether we like it or not!) a source for "father son projects". We will have some fun working on it, modding it, autocrossing and DEing it. When this phase ends, then I may convert it to a club racer.

Roger