240sx KA24E EGR Problem

[shiro_neko]

Im currently troubleshooting my slight hesitation high idle problem. I have done some checking and cleaning and Im in the point of checking my EGR. My EGR is not functioning so I tried testing the EGR valve and the diaphragm lifts when I suck on the vacuum hose. So I checked the vacuum hose to the BPT and no vacuum is present when racing the engine. Then I tested the EGR control solenoid and this is where Im confused.

I measured the voltage of terminal a (lg color) and its 0.8v at idle and battery voltage while racing. But the 89 FSM says its the other way around. However in the "Electrical Components Inspection" section its 0.7-0.9v engine running and battery voltage engine running (racing)

Furthermore, in page EF & EC 149, its illustrated that air passes in vacuum lines going to BPT and P.R. solenoid when 12v current supplied, and air passes in lines going to BPT and intake collector when there's no supply.

To make my post longer, its also weird that there's no vacuum when I check the line coming from the Intake collector weather its in idle or not. If I understand this correctly this is the vacuum that supplies the line going to the BPT then EGR valve. Even though the signals might be reversed I should have a vacuum in one of the conditions.

[shiro_neko]

I forgot to mention I dont have any ECU codes

[seang]

Is the vacuum line plugged?

[vancouverbc]

the following link is vacuum lines for ka24de. the swirl control valve has to send the right message to the egr solenoid before it sends vacuum to bpt. check the vacuum source that enters the egr solenoid. it should be constant vacuum. it is line 1 coming into egr solenoid.

zerothread?id=481398
Modified by vancouverbc at 11:20 PM 3/7/2010

[shiro_neko]

Everything is plugged in. I've put together a diagram for reference. The layout of the SOHC is different from the DOHC. The egr solenoid is under the TB. PR solenoid and SCV solenoid are behind the block.



Here is how I understood it:15-a needs vacuum to lift egr. 15b gets vacuum from 16 but 21 must not have pressure for it to pass through (not sure abotu this though). 16 leads to 7 and 10. 7 goes to dist of canister and 10 goes to A (egr solenoid). If no current is supplied to the egr solenoid A goes to C then to 12 (collector), if there is current it goes to B then to 11. 11 shares the same line that goes to 9 (connects to the air intake tube and AIV) and 3 (PR solenoid. Ive traced it up to this point only)

So if Im in idle (no supply) 15-a goes to 12 of collector and If I race it (current supplied) 15-a goes to 3 (PR solenoid) so my vacuum source is the pressure regulator? is this right? I should check the pressure regulator and control solenoid? BPT? (FSM is not clear on BPT testing)

BTW, my AIV has been removed so 6 and 5 are plugged by screws. Also before I checked my EGR I found that 8 is plugged up by a bolt so I removed it and connected it to purge. Have no idea why it was like that.

Edit:diagram resolution got compressed when I uploaded it. if its too small to view I'll upload it again

Edit: updated the diagram resolution
Modified by shiro_neko at 7:09 PM 3/8/2010

[shiro_neko]

I re-checked 12 again and there was vacuum. it was those material that covers the hose that's obstructing the vacuum. anyway I've pinpointed where the vacuum stops. 7 (canister) has vacuum when raced. so egr solenoid is working because vacuum from 12 passes to 10 then 7. however, there is no vacuum in 16 so the tube from 10 to 16 might be clogged. Its hard to blow air in there as its under the TB. Can I just pour seafoam in 16 to clear it? if not I might remove the air intake tube to check those vacuum lines

[seang]

I would take it apart manually. The only way I would do the seafoam way is if the line itself went into the collector (intake manifold), then it would be alright, I guess. Don't want stagnant seafoam sitting in the individual components.

[shiro_neko]

Thats what I thought. Dont have time to do that until this weekend though. I'll post back afterwards

[shiro_neko]

I took out the vacuum tubes today and it was a PITA! after several hours of figuring and yanking I finally got it out only to find out that there was no clog. I put the vacuum tubes back and tried testing the solenoid with another vacuum line. And I found out that the vacuum was going out the airduct (9) the vacuum hoses are plugged to the wrong hard lines so I switch it and the EGR works now

unfortunately it wasnt the cause of my high idle slight hesitation. oh well, back to the FSM