Greetings, In testing my EGR valve on a 91 SC (vacuum type). I am seeing something that strikes me as odd, unlike the EGR valves on the older Honda A20 motors. This one seems to hold vacuum and stay open with the engine off, however if the engine is on with pressure on the exhaust side. It leaks back to closed within about 1 or 2 seconds. This was tested with a handheld vacuum pump and not the supply from the TB. Most of my experience is with Honda engines. Is this the normal behavior for the Saturn 1.9 DOHC vacuum type EGR valves. Or is this just a dead EGR. Don't want to drop $99 if I don't really need to.
Thanks:
-HeadTrip

honestly i'm not sure, i have the linear style myself, but it does sound like you have a problem. i can only assume the EGR solenoid is designed to vent vacuum when it is commanded off by the PCM. if some one else with a vacuum EGR can confrim that it would be great. in the mean time, cleaning the EGR and solenoid can't hurt, use sensor safe carb and choke cleaner, but keep in mind if the EGR gasket is 14 years old it will most likey need replaced when the EGR is removed to clean it. is this concern related to a code 26 or 32?

Thanks, No codes. Just a strange idle surge at highway speeds when I push the cluch, and some dieseling when I cut the ignition. I did that first. replaced the gasket too, It was NASTY! but after having my same dieseling issue after cleaning the EGR. It's still there but not as pronounced. I decided to test it while running and that was what I came across. Already replaced the ECTS and the IAC. ECTS was the old plastic style and was split right down then center.. IAC was just worn and slow to respond to signal. At this point It's got to be the EGR or an intake leak somewhere I'm just not finding with spray around the gaskets. ahhhh the joys of getting a 91 for $600 and bringing it back to life.. aparently when the ECTS went out, the brain surgeon that worked on it, rather than replace the sensor. Hot wired the cooling fan to the ignition switch to prevent the overheating. wonder what else they "fixed". I think I will replace it just to be sure anyway. On another note has anyone tried converting the OBDI engines to OBD2. will the electronic EGR bolt on to the same head, or are they too diffrent?
Thanks again:
-HeadTrip

desieling is a sign of a leaking injectior on EFI cars(since when the ignition is turned off power is cut to the injectiors, and unlike carburated cars engine vaccum won't suck gas into the engine). a fuel pressure leakdown test may be helpful in diagnosing this.

also i did some research and found the vacuum bleed is in the EGR, not the solenoid. i wouldn't jump to replacing the EGR at this point.

Don't want to drop $99 if I don't really need to.

wasn't that your goal? but the one thing i'm not sure about is that something i read today said the EGR should stay in vaccum for at least 20 seconds, but i can remember if that was engine on or engine off. maybe you should cap off the vacuum line to the TB, and install a block off plate under the EGR and go for a test drive, see if the problem remains(from what i'm told you don't even need to make a block off plate, and that placing a quarter or two in the head passage works just as well)

i wouldn't think to hard about converting your car to OBD-II, of all the components that would need replaced, the crankshaft is the big one (different toner ring for CPS), also there where some OBD-I saturns with the linear valve, but again, crankshaft is different. but there is a adapter plate to use Linear EGRs on vacuum EGR heads.

just for the hell of it you may want to read these links -
http://www.saturnfans.com/forums/showthread.php?t=25237
http://www.saturnfans.com/forums/showthread.php?t=23668

when slowing to a stop in neutral, what is the idle RPM while you are moving then right as you stop.(the idle RPMs should drop a little right when you hit 0 MPH)

did you reset the PCM after changing the ECT and IAC or after cleaning the EGR?

Rolling idle is at about 1500 drops to 750 to 800 at 0 mph. I'm still looking at the OBDII hack, but not a saturn PCM. a modified Honda so I can use RS232 for the OBD interface. and the ability to tune with tools like hondata. after mating the PCM harness it will probably be a bitch to create the new fuel tables and such, but not impossible. The question about the newer EGR was just curiosity. I can use a microcontroller to translate the EGR signal into an EGR solonoid signal. not sure about the details of the whole project yet tho. May even use a RS/6000 43p running RTLinux as the new PCM :) But thanks for your response about the EGR. and I dont know why I didn't even think about the Injectors.. I ave been looking at some after market injectors anyway, after I get the computer where I want it I do plan to force induction. Planning on the SPS top end package anyway. It rides fine for now, so I may wait and revisit all this after the overhaul. If that dosn't resolve it anyway.
Thanks again:
-HeadTrip

FYI the stock injectiors are quiet powerful you shouldn't need aftermarket injectiors unless you are boosted.

you may want to check out turbosaturns.net

Ohhhh no doubt I plan to boost it. Just want everything else perfect first. well as close as posible. Still arguing super vs. turbo with myself tho. But the super looks like there will be ALOT more custom fabrication. only time and $$$ will tell.

Turbosaturns.net is more then just turbos, they also have pletty of supercharged, NOS, and N/A saturns, the forum is mainly about power. tons of good info even if you are not going turbo.