EGR valve problem
08-24-2001, 08:40 AM
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EGR valve problem
The other day I was trying to test the EGR valve on my ’91 Formula 350. I unhooked the vacuum line and applied vacuum to the EGR line and was watching to see if the diaphragm moved. It moved a little and then got stuck up in the valve after I released the vacuum. I ended up carefully pressurizing the EGR valve with air from the air compressor and it popped back down. Should the valve stick like this or did I apply too much vacuum? The car also stumbles real bad sometimes, especially around 2000 rpm, that’s why I was testing the EGR. Any help would be greatly appreciated. Thanks
Chris
Chris
08-24-2001, 03:31 PM
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It does sound like you have a bad valve , when you apply vacume to it it should hold as long as it has vacume , when you release the vacume the diafram should go down it should stop or get stuck , I had a big egr valve problem last year it ened up being a bad valve and my exhuast was to free flowing , There are two different types of valve there is a negative valve wich work with back preasure from the exhuast which is what I have and a Positive valve which doesnt use back preasure , I solved my problem by using a 20 dollor muffler havent had a problem since , if I end up putting mu slp system on Ill have to have my egr valve switched to a positive valve.
08-24-2001, 09:44 PM
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Its about 60 bucks for the EGR (last time I checked anyway) and you will want an AC Delco replacement, dont even bother with aftermarket stuff unless you like picking washer sizes and jamming them into place.
Its probably about a 2 hour job, more or less, depending on your experience.
Its probably about a 2 hour job, more or less, depending on your experience.
08-26-2001, 01:59 AM
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The EGR Valve may have a weak spring(wore out)so the Diaphram may seem like it's working right but is still bad. Check out this link for more info on my troubleshooting https://www.thirdgen.org/messgboard/...ML/006739.html . The EGR Valve cost me $50.00 at Autozone and it was in a Wells bag with GM logo stamped into the EGR Valve. The OEM # for your EGR Valve is 17087263 and Autozone's part # is EGR1008. Don't forget that you'll need Gaskets for your Plenum. I had to buy the whole Intake Gasket Set for $33.00 because just the upper was no longer available. If you have any questions feel free to email me or just do a search in this form for my name and egr valve. 
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08-26-2001, 02:29 AM
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When I had my car smogged a month ago it passed emissions easily, but the tech said my EGR valve was not working properly. I noticed that he had two guys with rags try to plug up my exhaust while he was checking EGR valve. Could it be my exhaust is to free flowing as I have the negative back pressure valve. If I wanted to switch to a positive valve what would I have to do? And how would that be better? Thanks for any info. Also if the EGR valve was not working right how come my emmisions were so clean?
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SLP 1 5/8 Headers,Dual Catco cats,ATR catback exhaust,SLP cold air box,Crane 1:6 roller rockers,Bosch plugs and MSD wires,MSD Coil,Fastchip,Underdrive pulleys,Borg Warner 9 bolt 3:27,Corvette Servo,ROH ZS 17X9.5 Goodyear GSC,s 275/40/17
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SLP 1 5/8 Headers,Dual Catco cats,ATR catback exhaust,SLP cold air box,Crane 1:6 roller rockers,Bosch plugs and MSD wires,MSD Coil,Fastchip,Underdrive pulleys,Borg Warner 9 bolt 3:27,Corvette Servo,ROH ZS 17X9.5 Goodyear GSC,s 275/40/17
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08-27-2001, 04:12 PM
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thats exactly what it is , free flowing exhuast , causes a negative preassure vale to not work properly , Iv been told that it can be switched, thats what the guy that worked on mine said he told it can be done didnt really tell me what hast to be done , i think it has to be a different vacume solinoid . and egr valve. as soon as i find out ill let you know
w
w
08-28-2001, 03:18 AM
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Thanx for the info Pino. When I had my car smogged two years ago I had the headers and catback system and had no problem with EGR, but a week before I had it smogged this year I had the Catco Cats put on could they of made that much difference? Is there anyone that has changed their exhaust and still using the negative EGR with no problems?
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