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Mr. M3

02-11-2018 07:54 PM

88 Suburban V10 EGR removal for an idle misfire

So to start the previous owner of my Suburban replaced the exhaust from the manifolds back. Recently I have noticed an inconsistent misfire when idling and it has been suggested that the old EGR is a possible cause, as all cylinders have spark, plugs are new, and the ignition module tests good at the part store, I installed a new cap/rotor and timing is good. So I figure I will remove the EGR and plate it. The big item that I am unsure of is all the plumbing coming off the manifolds. Can I just plug the ports on the manifolds and cut out the old plumbing? This is the youngest Chevy I have owned and the only TBI I have owned. What suggestions can you guys give me to correct this misfire?

95 S_Trucker

02-11-2018 10:30 PM

Re: 88 Suburban V10 EGR removal for an idle misfire

The exhaust passage for egr is in the intake manifold.

The pipes going into the exhaust manifolds are for secondary air injection. It's a completely different system.

Kudzupatch

02-12-2018 10:37 AM

Re: 88 Suburban V10 EGR removal for an idle misfire

You can just plug the vacuum line on EGR and see what happens. No need to remove or block it to test it.

But, you will see a lot of people with an misfire/unsteady idle with TBI that runs well otherwise. Mine does this and I have given up on finding the reason. ChevyTech suggests that alcohol in the fuel can contribute to this. I don't know but we do have it in our fuel. I just know it is common and I have never read about anyone being able to figure it out.

Mr. M3

02-12-2018 11:20 AM

Re: 88 Suburban V10 EGR removal for an idle misfire

Quote:

Originally Posted by 95 S_Trucker (Post 8185495)

The pipes going into the exhaust manifolds are for secondary air injection. It's a completely different system.

What exactly is the purpose of the secondary air injection? Emissions related?

95 S_Trucker

02-12-2018 11:57 AM

Re: 88 Suburban V10 EGR removal for an idle misfire

Quote:

Originally Posted by Mr. M3 (Post 8185897)

What exactly is the purpose of the secondary air injection? Emissions related?

To aid in burning unburned fuel in the exhaust system.

Mr. M3

02-13-2018 09:16 AM

Re: 88 Suburban V10 EGR removal for an idle misfire

Quote:

Originally Posted by 95 S_Trucker (Post 8185934)

To aid in burning unburned fuel in the exhaust system.

So it is not necessary on mine, as it has no Cat installed. So I can simply remove it and plug the ports on the manifolds then.

95 S_Trucker

02-13-2018 10:07 AM

Re: 88 Suburban V10 EGR removal for an idle misfire

Quote:

Originally Posted by Mr. M3 (Post 8186745)

So it is not necessary on mine, as it has no Cat installed. So I can simply remove it and plug the ports on the manifolds then.

That is correct, unless you state has emissions testing or anti-tampering laws.

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