SpeedOfLife

iTrader: (16)

I'm running a completely stock '87 TII and went autocrossing today. When it happened I had just accelerated real briefly then hit the clutch to brake, and as I started braking I heard a distinct pop. The car seemed fine so I just kept going and it drove home fine, all except for no longer being able to boost to 5+ psi. I couldn't see anything visibly wrong in the engine bay, and if the turbo's oil seals went or the turbo got stuck or a motor seal went, the car would NOT be driving like it is. Like I said, it drives PERFECT (ignore the fact that it doesn't idle just right, I'm working on that) except for not making significant boost (significant for the stock configuration). I suspect my waste gate is broken or stuck somehow, but am I on the right track or has someone else had this happen? My Haynes manual doesn't seem to have any particular insight on this, either.

TehMonkay

iTrader: (-1)

Chek the plumbing between the turbo outlet and throttlebody elbow. Loose clamps, holes in the hose, bad tbe lbow o-ring maybe.

check to see if the waste gate actuator is working properly.

SpeedOfLife

iTrader: (16)

I wonder if I had boost spike real hard when it happened, if it would spike much at any point that would be the right moment for it to do so. I'm just disappointed I'll probably have to tear out a bunch of stuff again so soon, not to mention I won't be able to do this with the engine warm/hot.

SpeedOfLife

iTrader: (16)

could you describe where that is? (and I can't tell how much of that was mistyped)

TehMonkay

iTrader: (-1)

TB elbow o-ring, seal between the throttle body and the elbow that bolts onto it.

But i'd look at the actuator and rod and the hoses first.

hurleysurf24

iTrader: (3)

did you check the intercooler hoses yet ?

ivegonemad

does the turbo do any noise while driving or idling?? also is there any leaks that you can hear?? vacuum leaks on the uim, TB??

SuperRotorMan

i had the same issue, took me days to track it down... check ur spark plugs... 10 bucks says your trailing plugs are shot

SpeedOfLife

iTrader: (16)

they appeared fine, I figured with a noise that loud I'd see something split/popped off.


no noise, no audible leaks

interesting, I'll check them, but my question is how would that cause this problem? the plugs are also pretty much new NGK's.

SuperRotorMan

when mine went, they were only 4 months old...

ivegonemad

check the trubine shaft....yeah and the wastegate actuator...

mort2002

iTrader: (1)

i say you have a bad intercooler pipe, one of your connections poped off, or split, check your BOV too. since you have a bad idle too that is screamin vac leak before the AFM. check and double check all of your intercooler piping, and BOV.

SpeedOfLife

iTrader: (16)

thanks for the pointers, I'll get back with results asap. although deep car work usually doesn't happen during the week, which sucks. I'll check the plugs first since that's the easiest.

SpeedOfLife

iTrader: (16)

I checked the plugs and compression today, the plugs are fine (showing a little bit of visible wear, but still fine). Compression is between 80 and 85 for all faces front and rear. Yes, I know that's low, but it's better than the last time I checked it. This time I had the engine warm plus a stronger charge on the battery, so I trust these numbers are pretty accurate.

However, as far as I can tell that doesn't do much in the way of determining the boost problem. But I figured I'd give you guys an update on what I'm doing to get there. Tearing it down to the turbo will take some time, especially with that cursed air pump in the way. When I start digging into performance mods that and the crappy exhaust manifold will be the first to go.

SpeedOfLife

iTrader: (16)

I worked on the TPS today in the hopes of helping the idle and light throttle response (yeah, I adjusted it with the engine warm and a TMIC bypass), but it appears the power line to my starter is crappy so it just so happens I can't start it at the moment. I hope to get up early and maybe find a fix for that... Any suggestions on how to fix a poor power line? The starter solenoid and starter are both new and I tried grounding the block to the negative battery terminal with no change, so basically I'm led to believe it's a power issue. Also seeming to point that direction is when I was fiddling with the starter (without it being jacked up, so I couldn't see real well what I was doing) I accidentally arced power to the starter with my ratchet so I figured "hey, it turned over, let's give it another shot" and sure enough it fired up, however I had to let it die to continue adjusting the TPS since it was at that point so far out of whack, and I couldn't get it started again.

Smoken'

iTrader: (1)

Sounds like you may have a crack in one of the intercoolerhoses. Check all the rubber pieces to make sure there is no cracks in them.

SpeedOfLife

iTrader: (16)

I got it started up this morning and the TPS adjustment I made paid off, it doesn't buck nearly as bad at light throttle, however the idle is still slightly rough but could be caused by a number of things. I'll worry about the boost problem now.

SaabGuy

Does your turbo spin? Wastegate close?

Did you megasquirt yet or are you still using stock ecu and afm? Does your car idle? check intake leaks.

My guess in order of most relevant are the following:

1. Intake leaks
2. Wastegate stock open or opening to soon
3. Turbo blown

SpeedOfLife

iTrader: (16)

I assumed the turbo was ok because everything sounds normal, I don't get any smoke from anywhere (including exhaust, every once in a while a little on startup and that's it), nothing lags as if the turbo were stuck, and I know I wasn't pushing much boost. Everything is stock and currently in the stock configuration. I also noticed that whatever intake pressure I can build INSTANTLY drops once I hit the clutch, it's an extremely fast drop.

TehMonkay

iTrader: (-1)

Leaking hose or bad wastegate. Used hose is an option or samco sells new silicone version for $99.

SpeedOfLife

iTrader: (16)

If it's a hose I'm sure I'd go used. Or repair it somehow. I couldn't bring myself to pay $100 for a 6" rubber hose, especially right now.

Since it's been brought up though, what symptoms does a blown turbo usually cause?

mort2002

iTrader: (1)

i still think you have an intercooler hose messed up.....

SpeedOfLife

iTrader: (16)

that's fine, I'm going to look into it and check out my waste gate. I don't think my turbo blew, I'm just curious what typically happens when one goes.

SpeedOfLife

iTrader: (16)

worked on it today, found a nasty split in the rubber hose that fits on the turbo inlet. kinda hard to find something to replace so for now it's sealed with black RTV. that made my idle really smooth, but I'm pretty sure on my test drive, after I let it set for a while, blew it back open. regardless, I can't boost past about 1 or just over 1psi now, which is about what it was before I worked on it today. sometime this week I was able to boost just barely more for no apparent reason. I did check ALL the intake lines and secured nearly everything with clamps, there should be NO intake leaks (aside from the turbo inlet) now if there even were before.

that said, would that inlet crack make the ECU keep the waste gate open since I'm probably running lean? or does this sound like something else? in the meantime I'm going to look for a replacement for that tube... when I got down to it, the clamp seemed to be loose which is why it might have been able to crack in the first place...

TehMonkay

iTrader: (-1)

The inlet or outlet? You mean the hose from the turbo to the intercooler?

Ecu does not control the wastegate.