Is there anyway to test the EGR Vacuum Solenoid?

Thanks so much for all of the replies.

dchavezo said:

Check the hose system for the EGR system. I'll bet the hose coming off the throttle body is cracked. The valve or solenoid could be at fault too

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Hmm... there is a hose that is running off of the back of the throttle body area, I cant remember if it is running off of the air cleaner assembly, or the throttle body itself, but it looks like that hose is running down to the valve cover on the back. It does have tape on it up where it connects to the back of the throttle body, as if it was cracked. Is that it? If so, would that cause a knock? Not sure where I could get a replacement hose.

mc_marto said:

Just remember, that the solenoid is energized to stay closed, and de-energized to open. Like others said, check the vacuum connections to and from the solenoid.

So, you're saying you don't hear "marbles in a tin can" type of sound, but a knock? If it's a knocking sound it could be fuel related (running too lean). How is your oxygen sensor? Did your mechanic check it when he replaced the injectors and EGR valve? A O2 sensor that's gotten lazy will make the engine run lean when hot (because of closed loop), and you may get a knock from it. To check the O2 sensor activity enter diagnostics (Off + Warmer), after 7.0 press Lo, wait for the display to change, then navigate to P.1.6 (o2 sensor cross-counts). Drive the car while observing the display - the counts should go in the 20s upon acceleration, and when cruising or idling should hit 0 occasionally, but not stay there most of the time.

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Nope, it is definitely not like a marbles in a can sound, I know that sound you mention though. I have no idea about the 02 sensor. I was assuming it was ok since there are no service engine lights on and the car only has 60k miles, but I guess that don't mean anything? I have no idea if my mechanic checked it or not. It seems like it didn't start though until I had him put in the new injectors and EGR valve. If it is too "lean" is there anything I can do? I know it sure don't get good gas mileage as if it was lean. I only average about 19-20 mpg, 80% highway driving, but on my dash when I am on the freeway, it seems to get around 25-26 on the highway on average, but guzzles gas I guess on what little city driving I do in it. Before the new injectors though I was getting about 6 mpg!

That hose mentioned by dch is cracked/taped up, so wondering if I should check that out.

I also have a new problem, there is wetness below my water pump, I THINK it is coolant, but the coolant level is full. I guess the water pump is failing at 60k. This poor old car. lol.

Cracked hoses need to get replaced. Just because it's taped it doesn't mean its vacuum sealed. Go to your parts store and get a couple of feet of vacuum hoses so you can replace anything needing a replacement (all vacuum hoses at this age are suspects).

If it is too "lean" is there anything I can do?

You can start by inspecting and replacing bad vacuum connections. Then observe the oxygen sensor's cross-counts as I described in my previous comment. See if you have an active sensor or a lazy one. If you find that you need a replacement go only with AC Delco; I'll tell you why. I replaced my AC Delco o2 sensor about two years ago (previous owners had that one installed not that long ago), because I thought the ground connection seemed to be no good (strap over the o2 sensor body). I installed a Bosch Premium sensor and everything seemed to be good. Well, when I was chasing some drivability issues of my own I decided to swap the old AC Delco sensor in there. Results - the Bosch sensor would rarely exceed 5 cross-counts and very frequently would stay at 0 when idling. The AC Delco sensor rarely goes to 0 cross-counts at idle and I can frequently see numbers as high as 25-30 cross-counts at acceleration. If you think about it that makes for a lot of activity, considering cross-counts are registered per second - meaning 25-30 swings between rich/lean conditions in a second.

I know it sure don't get good gas mileage as if it was lean.

I would actually expect worse mileage with a lean running condition. Anytime your engine doesn't develop it's full potential power you're going to work it harder - waste more gas. When your engine is running better you don't have to mash the gas pedal as much to obtain the same acceleration/cruising speed. Ideally, if you could improve the power output of the engine without adding any more weight you will gain fuel efficiency as well (again less load on the engine to deliver the same results).

there is wetness below my water pump

You'd have to inspect if it is the water pump or some of the hoses around there. There is a bypass metal line that runs around the same area, that some members have had problems with. The pipe would rust out and develop holes for coolant to seep through. Otherwise, a lot of people say these water pumps are not a good design to begin with, and so they frequently fail. I know mine was replaced at around 50K miles from the previous owner, and I replaced it around 100K mi.

Thanks. Well the photo of that hose in question is below. I looked in the FSM yesterday and it mentioned what it was called, but I already forgot. lol. It runs to the rear valve cover.

I don't think it was mentioned above, but if the o2 sensor was bad (or lazy) would my service engine soon light be on? I checked my MPG computer today and I am averaging 18.0 mpg and that was right on with my own calculation by using the trip computer/gallons to refill, so that thing is pretty accurate. That MPG is about 75% highway driving at 65 mph.

Another thing is that when I turn my car off when the engine is hot, I noticed a noise, like a "robot" was operating. One day I had the hood up and was running the car, shut it off and heard it again and it is coming from the cylinder thing in the pic below. I think it is the TPS? Anyway, it will make a whirring noise for about 5 seconds and that arm will move back and forth. Also it seems like when the engine is hot and started, the rpms kick up and then go down. Is that normal? Today it did that and I was too quick to put in in drive and it jerked the car. I thought I would ruin my transmission. I guess it is ok though.

*I did have a nice surprise though. I didn't think that my driver window worked... today I pressed the down button and it didn't click like the others do or even like the driver window does when you press the switch to go up... I pressed it harder and viola, the window went down quickly and went up quickly. I guess the switch is going out, or something. Still I will use it until it completely breaks. lol.

Now, here is that taped up hose. I don't think this would cause the engine to knock though?





Here is that thing that sometimes goes wild when I shut the car off...