EGR will not hold vacuum

Tiny
SMILINGDAWG
  • MEMBER
  • 1979 FORD F-150
  • 5.0L
  • V8
  • 2WD
  • MANUAL
  • 200,000 MILES
Vehicle has strong spark knock. Tested EGR with vacuum and tester showed it wouldn't hold vacuum. Bought new EGR from Standard motor products. Tested it with vacuum pump. New EGR would not hold vacuum. Returned EGR and got a replacement. Second new EGR would not hold vacuum. Vacuum tester works good. So two new EGR valves would not hold vacuum or open it's valve. Am I doing something wrong?
Friday, July 23rd, 2021 AT 4:28 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

When the vacuum is applied, the pintel should open and the EGR should hold and maintain the vacuum. It doesn't sound like you are doing anything wrong.

If the original one is holding vacuum, does the pintel move when vacuum is applied? If it does, then it's likely good. If that is the case, inspect where it mounts in the intake. See if there is excessive carbon or corrosion that would block air flow.

Take a look at the attachments below. They are the basic diagnostics for the EGR on this vehicle. Hopefully, they will help you.

Let me know what you find.

Joe

See pics below.
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Friday, July 23rd, 2021 AT 10:28 PM
Tiny
SMILINGDAWG
  • MEMBER
  • 2 POSTS
I've returned the first new EGR valve, the replacement that I received acts the same way (won't hold vacuum). Since the vehicle is over 40 years old is it possible that EGR valves that have been on the shelf for 40 years could have deteriorated? Is it possible they have a shelf life? These valves were from Standard Motor Products who I thought were a good manufacturer. Having had two new valves fail has got me stumped. The original would not hold vacuum. Do you know of another aftermarket EGR valve manufacturer?
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Saturday, July 24th, 2021 AT 7:58 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Anything that is rubber will eventually dry out and fail. It's hard to believe they gave you two bad ones. Also, Standard is a well-known name.

The OEM part number is E3PZ-9D448-C. I saw a few on eBay that were Motorcraft.

Also, Dorman, Federal Mogel, and so on are all good. Take a look at this:

https://www.ebay.com/itm/380813814147?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=380813814147&targetid=1264870805984&device=c&mktype=pla&googleloc=9006104&poi=&campaignid=13918136049&mkgroupid=126556538764&rlsatarget=pla-1264870805984&abcId=9300613&merchantid=137686692&gclid=EAIaIQobChMI0ueOq4r98QIVHmxvBB3fYAPSEAQYAyABEgLt0_D_BwE

That's an eBay link.

Let me know.

Joe
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Saturday, July 24th, 2021 AT 6:42 PM

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