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Discussion Starter #1
I've been struggling with an EGR valve issue for a few years now. I've replaced the EGR valve, the solenoid and all the tubing. We've also checked for blockages where the EGR valve is attached and in the aluminum tube that runs to the manifold. All components function according to the two manuals I have, so at this point I'm at a loss of what to do next. Does anyone have any more suggestions on how to troubleshoot, or what could be going wrong?
 

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I've been struggling with an EGR valve issue for a few years now. I've replaced the EGR valve, the solenoid and all the tubing. We've also checked for blockages where the EGR valve is attached and in the aluminum tube that runs to the manifold. All components function according to the two manuals I have, so at this point I'm at a loss of what to do next. Does anyone have any more suggestions on how to troubleshoot, or what could be going wrong?
You never mentioned why you think you have a problem. Year, make/model, miles, and location are also helpful tidbits.
 

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Discussion Starter #3
Sorry. It's a 1998 Suzuki Sidekick 1.6 liter 16 valve JX with just under 110,000 miles on it.

I'm getting the engine warning light and using a scan tool it says it's an EGR malfunction.
 

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Sorry. It's a 1998 Suzuki Sidekick 1.6 liter 16 valve JX with just under 110,000 miles on it.

I'm getting the engine warning light and using a scan tool it says it's an EGR malfunction.
What is the exact code? And did you clear it with the scan tool?
 

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Do you have an EGR thermoprobe and is it connected?
 

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Are you getting p0400? Have you pushed the EGR valve forward to see what happens to the car's idle?? No thermoprobe on your car, I don't think. A harder test is to get one of your rear tires off the ground, with a hot engine, rev the car and check to see if the diaphragm moves forward (it should). Your car has a couple of VSV's. The one by the EVAP VSV should measure about 30 ohms across the two pins if you test it with a DVM. You also have a another VSV which would be near to the EGR modulator, which can also be checked, which should have a similar resistance reading as well. Normally your solenoids will be in the open default position, until the ECU comes on line to close them. And then, there's also the EGR modulator, which can be checked for air flow, blockage, etc. The top of the modulator comes off - note that 'Q' is toward the EGR valve and should be that way when you replace it, and make sure you note which vacuum hoses go where - When you take the top of it off, you will see a filter in there, which you should check to see if its clogged up. With the cap back on, if you blow into one of the side nipples, with the other one blocked with your finger, you should feel air coming out the nipple on the bottom. You should also check the hoses at the modulator as well.
I'm assuming that the 2 manuals you are using may be Chilton's and/or Haynes? You'd be better off either searching the forum for your info, or going over to Ack's FAQS which has the 1996 Tracker FSM free to download (much, but not all, of the info will be the same for your car), or getting an proper FSM.
 

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You left out two sources of blockage that you may not have checked. Did you remove the intake hose to the throttle body, open the throttle plate and check the hole in the back of the intake manifold. It connects to the steel tube that goes down to the EGR valve and it has to be completely clear.

The other blockage location is the exhaust manifold tube that runs through the back of the head. You can do what's called a "bark" test, coined I think by kickfix, by removing the EGR valve and plugging the intake port. I used a piece of Gorilla tape to cover the port. Start the engine and exhaust should come out of the other port. If it doesn't, the port is plugged and the exhaust manifold will have to be removed.

I suffered from a P0400 code for a couple of years and finally cured it by replacing all of the vacuum hoses and both VSV solenoids.
 

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I think that barking or perhaps more specifically turbo bark is a concept that has been around for a long time - it is basically when the pressure on the intake side is higher than that of the exhaust side.
 

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Discussion Starter #9
Sorry for the delay in replying to these messages.

Error code is P0400 - Exhaust Gas Re-circulation Flow, according to my software (ScanTool.net version 1.20).

Yes, I have reset the error many times in the past couple years as I've tried different things to fix, but it always comes back within about 200 miles or so.
 

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Discussion Starter #11
Yes, I'm getting the P0400 message. Yes, I've manually depressed the EGR valve with the engine running at it causes the engine to stumble. Not sure about the thermoprobe on this model. I've replaced the valve at the back of the engine (the EGR vacuum solenoid) at the recommendation of someone at the auto parts store even though it didn't appear to bad but it made no different, the light came back on within about 200 miles. I've checked the resistance on the front valve and it was right around 30 ohms. We've replaced all the vacuum tubing. I've also checked the EGR modulator per the manual and everything seems to work properly. Yes, the two manuals are Haynes and Chilton.
 

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Discussion Starter #12
You left out two sources of blockage that you may not have checked. Did you remove the intake hose to the throttle body, open the throttle plate and check the hole in the back of the intake manifold. It connects to the steel tube that goes down to the EGR valve and it has to be completely clear.

The other blockage location is the exhaust manifold tube that runs through the back of the head. You can do what's called a "bark" test, coined I think by kickfix, by removing the EGR valve and plugging the intake port. I used a piece of Gorilla tape to cover the port. Start the engine and exhaust should come out of the other port. If it doesn't, the port is plugged and the exhaust manifold will have to be removed.

I suffered from a P0400 code for a couple of years and finally cured it by replacing all of the vacuum hoses and both VSV solenoids.
I don't believe I've checked either of these things, definitely not the bark test. The bark test sounds fairly straight forward but can you give me more details on the throttle body test?
 

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I don't believe I've checked either of these things, definitely not the bark test. The bark test sounds fairly straight forward but can you give me more details on the throttle body test?


Black arrow is pointing at the nipple that gets clogged with carbon. I just cleaned it out this weekend. I blew into the nipple going into the throttle body and felt blockage, then I really put my lungs into it and felt something shoot out and then had air flow. Took off the intake and holy crap was there carbon. Everything from behind the plate was covered and thick.
 

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Don't know if I have an "EGR thermoprobe", where would I find that?
If the EGR valve has an electric connection, then it has a thermoprobe.
 

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Discussion Starter #15
I blew into the throttle nipple you suggested and there is definite air flow. Not sure if you got the other posts I tried to send.
 

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I blew into the throttle nipple you suggested and there is definite air flow. Not sure if you got the other posts I tried to send.
Something is messed up with my account. Make sure you secure the rubber hose around the throttle nipple by pinching it hard, else air will just escape around the hose. Once I pinched it, I felt a blockage then a sudden un-blockage. Have you looked inside the TB yet?
 

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Discussion Starter #18
Something is messed up with my account. Make sure you secure the rubber hose around the throttle nipple by pinching it hard, else air will just escape around the hose. Once I pinched it, I felt a blockage then a sudden un-blockage. Have you looked inside the TB yet?
No I haven't looked inside the throttle body yet as I don't have the tools for that right now, but I will.
 
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