First Drive...'87 GLHS puts out only 6psi

[hemiman]

I just bought this car. Finally got it road worthy. It seems to run fine, however the boost guage never goes beyond 6psi. It could be the guage, but it doesn't seem to pull like its getting the factory 12psi either. What could be the cause?

Be very descriptive, this is my first GLHS in quite awhile and the one I owned years earlier I never worked on, only drove it.

[Mystryguy]

most likely vacuum lines to wastegate can. trace the lines using your diagram under the hood or here: http://www.thedodgegarage.com/turbo/turbo87.jpg

[hemiman]

Quote:

Originally Posted by Mystryguy most likely vacuum lines to wastegate can. trace the lines using your diagram under the hood or here: http://www.thedodgegarage.com/turbo/turbo87.jpg

Ok, I checked it. The Vacuum line appears to be in place. I see no cracks or breaks along the line to the vaccum solenoid (following your diagram). Could the solenoid by the issue? What usually is the culprit here if there are no leaks. Would like to try there first.

[glhs727]

check to make sure the wastegate actuator rod is attached to the wastegate flapper, and that the wastegate flapper isn't stuck. Check vacuum lines from manifold to solenoid and solinoid to wastegate, usually if you have a broken vacuum line to the wastegate actuator, you will experience overboost. Also reset your computer after you change a bad vacuum line or reattach a rod to the flapper. later,
Cindy

[hemiman]

Quote:

Originally Posted by glhs727 check to make sure the wastegate actuator rod is attached to the wastegate flapper, and that the wastegate flapper isn't stuck. Check vacuum lines from manifold to solenoid and solinoid to wastegate, usually if you have a broken vacuum line to the wastegate actuator, you will experience overboost. Also reset your computer after you change a bad vacuum line or reattach a rod to the flapper. later, Cindy

Ok, I checked all the vaccum lines and they appear ok. I see where patches were done, probably should be done again and done right, however they don't appear to leak. I can see the wastegate flapper rod is attached, however I can't move it. Should you be able to move it freely with the engine off? How hard is it to overcome the spring inside? If the rod is stuck would this be a cause?

The engine builds boost quickly, but levels off right at 6psi. Its spirited acceleration, but not GLHS acceleration

[glhs727]

Yes, there should be some tension but you should be able to open/close the flapper. If it is stuck, you will lose boost and that could be your issue. I would spray it will PB blaster or wd-40 a few times and try to work it back and forth until it is operating correctly. I had that happen to a t-1 turbo car I had after it sat for a year untouched. I few squirts of PB blaster and working it back and forth with a vice grip (so I could grab it better and all was well. I would also replace the bad vacuum lines, because they will just get worse over time.
Good luck

[hemiman]

Ok, I worked the wastegate rod back and forth. Didn't read the last post until just now. I took the liberty to install a Stage II MP computer while I had the battery disconnected. I can move the rod with a little more "energy" in my fingers. I was afraid of trying too hard and risking pulling the thing off. It does move. After reconnecting the battery and taking the car out for a quick drive, things haven't changed. Even with the Stage II Computer, I see only 5-6psi on the turbo guage. She can't even spin the tires all out in 1st gear going around corners. Hell, even the minivan can do that. Probably indicates the turbo guage isn't lying.

I'm done for tonight, I'll try lubing up the wastgate with some WD-40 tomorrow.

[GLHNSLHT2]

Either the lines are on the solenoids backwards or the solenoid is stuck OPEN sending full intake pressure to the actuator/can and opening the wastegatev at 6psi. On garrett T2 and T1 cars the solenoid restricts pressure to the actuator until close to the boost limit then sends some pressure to open up the flapper. If the rod wasn't attached to the flapper then you'd get 0-1psi of boost and you're really have to flog it to get there. Been There Done that. If you supply 12v to the solenoid it should open and shut.

[Ben]

Think of checking for boost leaks? Check your hoses and clamps from the turbo to intercooler to airbox to throttle body. Make sure there's no splits in any of the hoses. You'd probably hear a good hiss.

Exhaust clogged? Does it rev up nice and freely?

[tonyz2897]

Another thing you could try is disconnecting the vac. line at the solenoid and drive the car. Be EXTREMELY CAREFUL if you try this as it will be easy to overboost. The computer should protect the engine (overboost cutout) but I wouldn't rely on that. Keep a close eye on the boost guage and let out of the throttle if you see the boost coming above 10-12 psi. Trying this should narrow things down. If the boost comes up with the line unhooked, then it's likely a problem with the solenoid. If the boost is still low, then I'd look to the wastegate or plumbing for the problem.
HTH,
Tony

[hemiman]

I disconnected the wastegate soleniod vaccum line and just tried it out in front of my house in 1st gear. I saw it jump to 14psi before backing off the throttle. I wasn't sure where the overboost would kick in so I got out of it quickly. The MP Computer is designed to requlate 14psi. I've also been informed that my stock computer has been remapped to regulate up to 15psi. I may put that one back in. I guess this narrows it down to the solenoid. Maybe its stuck open. I'll try tapping on it. Is there a source for replacements?

[tonyz2897]

Should be able to pick one right out of your local junkyard. Another option would be to plumb in a manual boost controler. The "grainger valve" is a pretty popular unit and there are always a few different other styles of mbc's available on Ebay for not much money.
In a pinch, I've even made a simple bleed type boost controler out of a fishtank air valve.
HTH,
Tony

[Putter]

You could always just try freeing the solinoid, carb cleaner or intake spray works wonders on sticky solinoids, run some through it and actuate it with a pair of wires a bit and run some more through it, it should come out of it and start working again if it isn't in really bad shape. Make sure its hooked up to the proper solinoid if someone has been in there patching things.

[hemiman]

Ok, took it out on a high speed road, she pulls upwards of 18psi. I didn't stay there but for a sec since that is way past the computer regulation pressure. I tried tapping on it. That didn't work. I'm not even sure that it is hooked up to the right solenoid. There is another here with nothing connected to it. I tried moving both the lines to it. Nope, that didn't work. Still only 6psi with it hooked up.

Someone suggested that the soleniod could be hooked up backwards. I don't think so. The lines here are original and are routed such that they make sense how they are currently plugged in. Trying to swap them would require loosening them from their bundle, I don't think they are plugged in backwards. They are in uniform with other vaccum lines plugged into solenoids.

Nevertheless, they could be swapped out with the wrong solenoid. Does anyone have a picture pointing out which is which that I can use to verify?

[hemiman]

Just for giggles, I went ahead and tried swapping the vaccum line direction on the solenoid. This didn't work either. The solenoid must be really jammed. the car was sitting for months. It sat about 50 miles from the ocean and I notice there is surface rust here and there. The A/C clutch for instance is rusted engaged and spins the pump whether the A/C is on or not. I'm quite sure its low on refrigerant and should be off due to the low pressure cut off anyway. This probably what has happened to the solenoid.