Tracking down a code 32 on my L98, and am replacing the egr solenoid connector. Trouble is, some PO has put in a different connector that simply has two grey wires, so you can't differentiate which one is supposed to go on which side of the harness. Now I can see far enough down the harness to see where they've spliced in the new connector, so I can see pnkblk and grey in there and follow them up. My problem is, the PO used a solenoid made for an LT1, which is not supposed to be put on an L98, I've been told they work opposite. I've got the proper solenoid now, but my questions are about the wiring. The connector can only be put on one way because of the clip, so then does it matter which side of the connector the pnkblk and grey wires are wired to? I would think it does. I say this because I got continuity between the computer and egr connector when I used a jump wire to connect ECM port GE9 to the pnkblk connector wire, but not the grey one! This doesn't seem right to me. I thought pnkblk was power and the grey (sometimes called "green"?) talked to the ecm? So I should get continuity at the grey wire not the pnkblk right? Did the PO get the wires crossed at the solenoid, or am I not understanding something? Or did he reverse them because he knew he had an LT1 solenoid that "worked the opposite"? I've seen several pretty goofy things done on this car, anything is possible. My new connector has pnkblk and grey, so it will be easy to reconnect properly when it gets here, but am I understanding this right? The one I ordered has pnkblk on the right side and grey on the left (looking at it with the clip on top), but the PO connector I just pulled off my car had it looped back to where pnkblk was on the LEFT side of the connector--like they were swapped. Does this matter?

 

This is what I just bought. The one I just pulled off has grey on both sides.

 

No it doesn't matter. The solenoid is dirt simple: just an electromagnet that works a little valve. Doesn't care which way the current flows through it.

 

Ok thx. Every flow chart I test I do comes to "bad solenoid or solenoid connector", and I have a new solenoid, so the connector was next.

 

The solenoid merely operates a valve. Electricity applied = valve open. Valve open = vacuum gets from one side to the other. Vacuum gets through = EGR does its job.

Don't forget the solenoid also has a 3rd port, which is open to the EGR valve when electricity is not applied; its purpose is to let the vacuum escape so that the EGR itself can return to its "rest" position. The ports all look like hoses would go on them. Make sure you correctly identify which port is which.

 

Now my solenoid only has two ports, one to the egr, and one to the tb. IIRC, the open one goes to the tb and allows vacuum into the solenoid to be used as needed, the controlled port goes to the egr and is opened or closed as needed by the Ecm. Am I right, or should I be connecting the controlled side to the tb? The vacuum does release though when you turn the key off, that was one of the tests the chart had me run.

 

It has 3 ports. Blee dat. The 3rd might not look like a hose nipple, but you can be sure it exists, somewhere somehow.

Since there is a 3rd port, then yes, it matters which of the 2 active ports goes to the vacuum "source" (TB or plenum) and which to the "destination" (EGR valve). The one that goes to the EGR valve is connected to the TB when the solenoid is energized and to the 3rd port when it is not.

 

Right, I get that, but am I correct about the open side to tb and controlled side to egr? That at least makes sense. Here's a pic of my solenoid. As you can see there are two ports, but jutting out from the side of them there is something else that you can't connect a hose too. The vacuum bleeds off when the key is turned off, this could be how/where. Although, it doesn't look open, there may be a small opening. Btw, I just got everything hooked back up and took it out for a test drive. After about 6-7 miles guess what? SES. I am at a loss. I have a new egr, new egr solenoid, new connector, new ecm, continuity at the connector, 12v at the connector, and still SES. I may pull the plenum and runners, then use a rifle cleaner and shop vac to see if I can make sure all the passages are clean. I really don't know.

 

Not sure what you're asking about "open" and "controlled".

It's a VALVE. That's it. Just like the one on your garden hose, except even simpler: it's either open (allows flow) or closed (doesn't allow flow), with no in-between or gradual opening like a faucet. It's operated by electricity instead of by hand: apply electricity = open; remove electricity = closed. Kinda more like the ones in your washing machine that either let the water in or turn it off. It does have one minor "complication", in that it's a "changeover" function; such that if you look at it from the point of view of the port that's supposed to go to the EGR valve, its logic is: apply electricity = connect EGR to vacuum, remove electricity = connect EGR to outside air. The EGR <-> vacuum connection is what you would consider either "open" or "closed".

"Vacuum bleeds when key is off" doesn't make a whole lot of sense either, partly for the same reason. "Key on" or "key off" isn't the condition that distinguishes whether it should operate. "ECM says it's time for some EGR" is when it operates.

It's EXTREMELY unlikely that your problem is caused by the solenoid, except possibly from having its vacuum lines hooked up wrong, which can be checked as above. There's just nothing to fail except the winding, and that's just a piece of copper wire, nothing too likely to go bad. The whole thing is about as simple as those electromagnets you used to make in grade school science class, where you wound a bunch of wire around a nail and picked up stuff by hooking it to a battery; except that in this case, instead of picking up a BB or something, it moves the little valve. Not much more complex than a ball of mud.

Cleaning the passages in the intake is ALWAYS a good idea. They invariably get all coked up and blocked with exhaust funk over time, in every car of every kind. You can change solenoids and EGR valves every single day, and twice every Sunday just for good measure, but if those passages are blocked and don't allow exhaust gases to flow, it will make not the slightest difference whatsoever. The ECM will remain unhappy that no exhaust gas recirculation is being detected.

A plain common ordinary coat hanger wire is usually the tool of choice for rodding out the passages.

 

What I mean by open and controlled is if you look at the picture I posted, the "open" port seems to allow the vacuum into the valve. That would connect to the tb? The other port that's yellow in color does not seem to be open all the time. Even with the valve out of the car it seems closed. That's what I meant by controlled. If that is the port connected to the egr, then that is the port that would open and close as commanded by the ecm. I don't know if mechanics actually use the word controlled, but that's just the best one I could come up with seeing that I don't know the nomenclature. But I did also have the thought that if the solenoid is a valve it wouldn't matter which side the hoses were hooked up to as long as the vacuum passed through to the other side to do its job. I have that thought, but didn't know for sure if it was true.
What I mean by the vacuum bleeding off when the key is off comes from one of the diagnostic tests I did. It told me to put a vacuum gauge one one side of the solenoid, a vacuum pump on the other side, put 10" of vacuum on it with the aldl grounded and the key on. It said to unground the aldl/turn the key off and see if the vacuum immediately bled off, and it did. I took this to mean that the solenoid turns off and opens up allowing vacuum to drop so the egr will re-seat when power is off--which would make sense. The egr would need to be seated at next startup. If vacuum stayed on in the solenoid when the key was off, the egr might be open the next time you started the car, depending on how much later that was. It was just how I interpreted the data, seeing as I don't know much, I may have interpreted it wrong. That's why I'm on this site. But yeah, 22 years and 156k miles, I'm sure the passages need to be cleaned. I'll do it next time I have an afternoon off with decent weather.

 

Btw, speaking of exhaust passages..... I don't know what this says about how open they are, but one test I did was reaching under the egr with something and lifting it with the car idling. When I did the idle became erratic, which means they are at least partially open.