Replacement EGR Valve Has Smaller Port

krathone · 08-15-2008, 03:12 PM

I just replaced my egr valve on my ’95 blazer, 4.3 vortec. The valve has been replaced before. Before replacing valve this time, I tried to clean the existing valve (which I have cleaned before) The pintle was really sticky and I could never get it to operate smoothly. When I got the replacement valve, I noticed the pintle opening was smaller than the exiting valve I took off. Everything else about the valve was identical, other than the electrical plug hook up which on the new one sits counter to where it was located on the old valve. This aspect was better because on the old valve, the plug connector sat almost against the belt tensioner. The new valve ran fine for a day, then it began to stick. A peck on the valve with a wrench freed it up again and it ran fine. I’m assuming more carbon in the pintle. It’s a “drive to work” vehicle so I’m just going to put a tomco screened gasket on the valve. When I replace the gasket this time, I’m going to run the truck while the valve is off and try to blow some carbon out.

I suppose my question is this: Did they decide the pintle hole should be smaller on the replacement egr valves, or do I have the wrong valve?

Thanks

dagan06 · 08-22-2008, 02:32 PM

I have a 94 and they produced 2 different erg valves in 94 but local parts store only carried 1 style. I had to contact a local dealer and got the OEM part number for the erg valve that was originally on my Blazer. Then cross referenced it with local parts store to see if they gave me the correct valve I found this web site http://www.discountpartshub.com/Default.aspx to get dealer parts at a discount all you have to have is OEM part # and sign up for an account but its free and they don't send you junk mail. When I got my blazer it had the wrong one on it and as soon as I put the correct one on it ran great. I hope this helps you.

blazes9395 · 08-23-2008, 12:52 AM

The two valves in '94 were for two different engines. The TBI used a vacuum opertaed EGR, the CPI engine used the digital valve. You cannot mistaken these two for one another, they are totally different.

If the EGR valve fits, and the connector plugs in, chances are you have the correct one. As long as the Service light is not coming on, a smaller hole will not harm it. It will actually improve performance for that matter. For it to be carboning up fast like that, you may have a leaky regulator or injector.

dagan06 · 08-23-2008, 12:57 AM

No I have the Vortec 2 different EGR valves were produced the 2 links below are pictures of the 2 EGR valves that were produced for the CPI models. You will notice the difference in the way the electrical connector plugs in. They also have a huge effect on the performance. Having the wrong one caused my Blazer to misfire, die, barley idle, and it was hard to start.
http://info.rockauto.com/Airtex/Detail.html?4F1137.jpg
http://info.rockauto.com/Airtex/Detail.html?4F1138.jpg

This link is the tbi models
http://info.rockauto.com/Airtex/Detail.html?4F1019.jpg

blazes9395 · 08-23-2008, 01:15 AM

I stand corrected, there are two different ones. Sorry about that dagan06, I thought you were comparing the CPI and TBI valves. I personally have not seen two different digital, CPI ones. The pinouts look the same, I'll have to take a better look and see when I get a chance. Maybe one was used for the s-series trucks and the other valve used for the M body vans...interesting, learn something new everyday....

dagan06 · 08-23-2008, 01:24 AM

If you go to a parts store like AutoZone they will give you the one that plugs in from the top. Mine of course is the one that plugs in from the side. It is a special order and about $250. I found that website I listed in a previous post and found it for $80 at a local dealer. It took me nearly 6 months to find out that they produced 2 different EGR valves.

krathone · 09-06-2008, 10:23 AM

Update on the replacement. I installed the new valve. Within a day, I was back to the missing and rough idle. I removed the valve again, started it up with the valve removed, blew out the carbon, installed another new gasket, this time I used the one with the screened port hole and put it back together. This took care of the problem. The smaller hole doesn't seem to be an issue at all.

I do have an intake manifold gasket leaking coolant. This week, I'm changing that. Hopefully after that job, things will settle down with my Blazer...... at least for a while.

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