'87 GLHS turbo problem continued.....

[hemiman]

I still have a problem with my wastegate control solenoid. It is allowing engine vaccum to keep the wastegate open and limiting pressure to just 5-6psi. If I remove the vaccum line, boost jumps quickly, but has no limiter and will overboost (which is normal when you disconnect the wastegate vaccum line).

I need the wastegate to operate properly, ie. only open at the desired 14psi rating of my Stage II computer module. I pulled the solenoid out and cleaned the contacts. I can activate it manually with a simple 9 volt battery and verify the internal valve is working properly (it closes when powered). I cleaned the contacts on the plug from the harness and checked the voltage with the key in the "run" position (not running). I get 12 volts across the leads. When I plug the connector into the solenoid, I can hear it actuate for a brief moment, then it appears to turn the soleniod back off. Is this normal behavior?

Nevertheless, a quick drive still results in the 5psi max which tells me that the computer is not turning the soleniod back on. The solenoid must be turned on in order to keep the system vaccum "source" from opening the wastegate.

My problem is I'm not even sure the wastegate vaccum line is plugged into the correct solenoid. For all I know they could all be mixed up. Does anyone have a picture diagram detailing the operation of all four vaccum solenoids? I need something that coorelates a system diagram to the actual solenoid under the hood.

The wastegate solenoid is one of 4 solenoids mounted on the passanger side shock tower. Currently the wastegate vaccum line is plugged into the bottom of the solenoid closest to the outside (nearest the fender). Is this the correct solenoid? I guess its possible that the electrical plugs are mixed up too, but who knows.

I need some help. I know there are ways around this cat, but I want the computer to handle it the way it was designed too.

[mwinkle353]

ok here may be a silly question. But I just have to ask. Did you do any rework of the vacuum tubing/hoses of the wastegate system? If so, did you remember to put the restrictor between the manifold and the wastegate solenoid? Is it between the Solenoid and the wastegate actuator? Or is it not there at all?

I only ask this because I did a similar thing with my sundance when I was trying to sort out it's non-exhistant vacuum system. I found that if you don't have the restrictor in the right place or not installed, the solenoid can't bleed off the boost fast enough to allow boost to rise abouve 5-7 psi. The restrictor is there to limit the flow of air to the solenoid and to the actuator on the turbo. If too much air is supplied to the solenoid and actuator, you will never get boost above 5-7 psi without the use of other boost control means.

Remember this. Manifold-----> Restrictor ------> Solenoid -----> Acuator

I've seen that even some FSM's have the information wrong.

Just something to look into.


Wink

93 Lebaron Conv 3.0L 5 speed

89 Sundance RS 2.5L 3 speed

89 Shadow ES 2.5L 3 speed

[hemiman]

No, I bought the car this way. I've done nothing with it since it came into my possesion. I don't think this is a restrictor issue. The solenoid does not close when it supposed too to the best of my understanding. This is not due to either a mechanical issue or a problem with the solenoid or its electrical connection. Either the wastegate is hooked up to the wrong solenoid, or the computer is malfunctioning. At least the way I see it.

[85GLHT-Omni]

Is the boost guage shaking under boost, steady under vacuum?

[hemiman]

No, the boost guage does not shake. It don't think there is a vaccum leak. I believe this is an electrical issue, or the wrong solenoid is being used. Somebody do me a favor. Go out to your GLHS...follow the vaccum line from the wastegate to the solenoid. Tell me which solenoid your hooked up too and what the color are the wires you see plugged into the bottom. That should help me narrow it down.

[xtz]

I would check the wastegate solenoid to make sure the vacuum lines were not reversed. if I remember correctly this is what happens when you switch the lines on the solenoid - and the set up is different than the solenoids in the same bank. don't just eyeball it - compare it to the vacuum diagram under the hood. I'm guessing you already checked the condition of the lines, if not do so.

[Scottmon]

I borrowed this from Dempsey's Team Omni page. Turbo L body solenoid pack setup. Hope it helps: "Here is one great tidbit for turbo L-body owners. Ever had to try and reroute all the vacuum lines to the solenoid pack on the passenger strut tower? It can be intimidating. Here is a simple ASCII schematic to guide you along:"

[glhsken]

Quote:

Originally Posted by xtz I would check the wastegate solenoid to make sure the vacuum lines were not reversed. if I remember correctly this is what happens when you switch the lines on the solenoid - and the set up is different than the solenoids in the same bank. don't just eyeball it - compare it to the vacuum diagram under the hood. I'm guessing you already checked the condition of the lines, if not do so.

YEP, exactly what I was thinking. The 5psi boost is the hint. With the small can, this is the minimum boost the car will run with direct manifold source.

I've also fixed peoples cars that had the issue caused by incorrect solenoid hook-up. Most folks look at it and think, Hmmm it should be hooked up the same as the baro solenoid right??? NOPE.

[hemiman]

Quote:

Originally Posted by xtz I would check the wastegate solenoid to make sure the vacuum lines were not reversed. if I remember correctly this is what happens when you switch the lines on the solenoid - and the set up is different than the solenoids in the same bank. don't just eyeball it - compare it to the vacuum diagram under the hood. I'm guessing you already checked the condition of the lines, if not do so.

Did that, see post above. I know which way the lines need to be based on observed operation of the solenoid. Now, about verifying my solenoid selection against someone elses.....

[hemiman]

Quote:

Originally Posted by Scottmon I borrowed this from Dempsey's Team Omni page. Turbo L body solenoid pack setup. Hope it helps: "Here is one great tidbit for turbo L-body owners. Ever had to try and reroute all the vacuum lines to the solenoid pack on the passenger strut tower? It can be intimidating. Here is a simple ASCII schematic to guide you along:"

Ah, now thats what I'm looking for! Thanks! If this is true, then my solenoid hook up arrangement is all wrong. Currently my connection for the wastgate is as follows...

"vac" is connected too "evap can" (solenoid on tire side)
"waste gate" is connected too "vac" (solenoid on tire side)

This would indicate that the vaccum lines that operate the wastegate are not only improperly connected, but connected to the wrong circuit! I noticed that 3rd solenoid from the left on my car is completely disconnected (which according to the diagram above is the wastgate solenoid). I'm going to have to check all of these.