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Technical EGR questions[700/90] posted by David Harris on
Sunday, 14 October 2001, at 12:12 a.m.
Recently I've been getting an intermittent "Check Engine" lamp. I've run the EZK (terminal 6) fault code and I get a 2-4-1 which appears to be an EGR problem. I have tested the EGR valve under the intake and with manual vacuum applied, it opens properly and holds vacuum. I do not know how to test the electromagnetic vacuum switching valve on the left strut tower but it does not seem to manage the vacuum signal to the EGR valve at various (warm) engine speeds. The "Check Engine" lamp is intermittent because when I have driven the car and made several shut downs and restarts over the course of an hour or so, the lamp goes out. When I check the input voltage to the EGR vacuum switching valve at 2500 rpm, I get very fast, mixed voltages of 1 volt down to .25 millivolt repeating in a fairly concise pattern. I'd really like to avoid paying $160 for a new ($60 used) EGR vacuum switch but don't really think its the problem. BTW: I have new temperature senders on the block under the intake and warm idle is only occasionaly rough.
Any suggestions on EGR input voltages or likely problem areas?
Muchas Gracias
--Dave
Re: Technical EGR questions[700/90] posted by Bill D. on
Sunday, 14 October 2001, at 12:34 a.m.
You say the egr valve diaphram holds vacumn. With the engine running apply vac to the egr. The engine speed should drop noticably. If it doesn't the egr passages are plugged with soot. The valve may function perfect but if no exhaust gases are getting to the combustion chambers the 02 sender will see no change.
A freinds Pontiac set a egr trouble code because the vac hose fell off. The computer didn't know about the vac leak, no vac sensor, but it knew the o2 reading didn't change when it energized the egr valve.
Bill D.
Re: Technical EGR questions[700/90] posted by David Harris on
Sunday, 14 October 2001, at 11:41 a.m.
Bill,
When I apply manual vacuumm to the EGR valve under the manifold while the engine is running, the engine speed does indeed drop significantly, especially at idle. I have run all the (new) vacuum hoses and found no leaks or disconnects. I suspect the EGR vacuum switching valve or the signal to it is the problem. Still, the parts are so expensive. I may try to find a used Toyota EGR vacuum switch to replace the Volvo part. It appears both are made by Aisin (Toyota supplier) and see what happens.
Dave
Re: Technical EGR questions[700/90] posted by chris herbst on
Sunday, 14 October 2001, at 1:03 p.m.
Yes, it's an Aisin controller... you could probably get it elsewhere cheaper.
On the plus side, they are pretty reliable.
--chris herbst, near Chicago ---- 91 245, 87 244, 90 245, 87 245, 88 744, 93 944