I replaced the exhaust on my '91 V2500 Suburban a couple of years ago. The original large pancake cat is gone and replaced with a high-flow cat. If I cap the vacuum port on the EGR solenoid and delete the EGR valve will that lead to any issues or problems? Thanks.
CK5
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EGR Delete question
- Thread starter GaBnn3
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gmbellew
Registered Member
it will throw a code and SES light will come on when the system self tests and fails. If it is working, I'd just keep it functional. you will probably have less issues in the long run that way.
Thanks. It's time for a new EGR valve.
If yours was like mine, the intake passages are completely plugged with carbon so they tend to naturally delete themselves.
I'm not sure I'm on the right track, but the truck recently started to run like crap and dangerously stalled in a busy intersection a few days ago. There are no trouble codes, the timing is perfect, and plugs and wires are new. I just replaced the fuel filter and injectors. So by default I thought that the EGR valve is probably the problem. That explains my amateur understanding. I wondered if deleting the EGR valve would not only solve my immediate problem but prevent future issues also. Thanks for the input.
gmbellew
Registered Member
A quick test would be to take the vacuum line off the EGR that goes to the solenoid and plug it. The EGR shouldnt open on its own, only when the ECM commands the solenoid to aplply vacuum and open it.
You can also apply vacuum to the EGR with a mityvac and make sure it opens and closes properly. You could also remove the valve and make sure it isn't somehow stuck open.
But if it was a 1 time stall or otherwise intermittent, diagnostics get harder. Is the issue constant? Does it run bad over the full range, just idle, etc? Did it start immediately after your other work, or was the new parts an effort to fix an issue?
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to delete = chip burn to turn it off .
most likely plugged ports in the intake and head on that side of intake reducing or closing off flow .
also the buildup can chunk off from time to time and the egr can get hung part way open until it falls out and lets it close .
i would pull the valve and look in the ports and valve for massive build up . if so i say pull the intake and clean the ports all out good and shop vac or better compress air them out after a good scrub down . same on the ports on the head also . then clean the egr best possible and reinstall and run it with a good fuel cleaner additive a few tanks and see how that helps .
most likely plugged ports in the intake and head on that side of intake reducing or closing off flow .
also the buildup can chunk off from time to time and the egr can get hung part way open until it falls out and lets it close .
i would pull the valve and look in the ports and valve for massive build up . if so i say pull the intake and clean the ports all out good and shop vac or better compress air them out after a good scrub down . same on the ports on the head also . then clean the egr best possible and reinstall and run it with a good fuel cleaner additive a few tanks and see how that helps .
Circumstances of stall?
Accelerating ? Deceleration? Cruising through? At what speed? Did it restart quickly, or after 10+ minutes?
Egr can definitely cuase a stall.
If you force it open at idle enginevshould stall right away. If it does passages are open.
If you have a miss with a higher than normal idlectpm a light rap with a mallet, and it then smooths out egr is hanging open a small bit. Chases of this are carbon build up vacuum solenoid dirty blocked vent. Backed up exhaust, plugged cat etc
Accelerating ? Deceleration? Cruising through? At what speed? Did it restart quickly, or after 10+ minutes?
Egr can definitely cuase a stall.
If you force it open at idle enginevshould stall right away. If it does passages are open.
If you have a miss with a higher than normal idlectpm a light rap with a mallet, and it then smooths out egr is hanging open a small bit. Chases of this are carbon build up vacuum solenoid dirty blocked vent. Backed up exhaust, plugged cat etc
Wes, the stall consistently occurs when accelerating from the stopped position. It will start right back up but with a little more cranking than when running well. Thanks for that article shima and all for the input. I truly appreciate the help.
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Egr shouldn't be opening when pulling away from a stop.
Is the Catalytic converter original or very old?
High exhaust back pressure can unseat the egr pintle, under load typical of pulling away from a stop.
Another area to inspect is the electrical system. If low voltage to coil the spark may lay down under high demand, or possibly the coil itself.
Good battery cables clean connections all important.
Is the Catalytic converter original or very old?
High exhaust back pressure can unseat the egr pintle, under load typical of pulling away from a stop.
Another area to inspect is the electrical system. If low voltage to coil the spark may lay down under high demand, or possibly the coil itself.
Good battery cables clean connections all important.
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gmbellew
Registered Member
just for fun, you might unhook the vac line between the EGR valve and solenoid and plug it to see if that fixes the issue. if so, the valve is bad or it is the wrong type of valve installed
gmbellew
Registered Member
potentially it is dumping top much fuel for some reason, but you'd need a scanner (or ALDLDroid and a OBD1 Bluetooth plug) to see if any of the sensors are reading out of norm.
I took the EGR valve out and blew it out and checked it. It looked and worked okay so I reinstalled it. On a test ride the truck ran perfect. All issues including the stall problem is gone. The throttle response is great now. It never ran so good. But there is now an awful loud whine coming from the engine that it did not have before. The tone and pitch of the noise changes with use of the accelerator. So it seems to be an issue with the fuel delivery system. As I went over the whole deal in my head, the only repair that could have gone smoother was the new fuel regulator. Since I was taking it apart for the injectors I put in the GP Sorenson 800-243 regulator from Autozone. The replacement spring was half the size of the original. So I re-used the original spring thinking I was clever. It took a couple of tries to get it together. Has anyone ever heard of the fuel regulator causing such a noise and should I have used the replacement spring, which would have made it easier to assemble? Thanks.
gmbellew
Registered Member
I don't think the fuel regulator is making a whining sound. I'd be looking to make sure you didn't leave a vacuum line disconnected somewhere as a first step.
second step would be to try and isolate the noise source. this will be easiest if it whines at idle.
second step would be to try and isolate the noise source. this will be easiest if it whines at idle.
Exhaust Gas Recirculation valves pump hot, dirty exhaust back into the intake to reduce exhaust temperature by giving the engine a contaminated air fuel mixture. This can help the engine warn up, a little quicker, but they reduce the power output. Ie it reduces efficiency.
The computer only "sees" the solenoid curcuit, not the vavle position. So if you leave it solenoid and wires connected electrically the computer will be happy. Then remove all the rest of the JUNK associated with the EGR, and block off the ports you eliminate a huge inefficiency.
I have done this on several vehicles and had no problems. You can even just instal a plate in between the valve and manifold to keep it looking stock if you have to deal with inspections.
The solenoid keeps doing what the computer tells it to so there is no code. You have a cooler & cleaner intake charge for more power. You also can eliminate the potential vacuum leaks from the 2 lines you don't need any more.
The computer only "sees" the solenoid curcuit, not the vavle position. So if you leave it solenoid and wires connected electrically the computer will be happy. Then remove all the rest of the JUNK associated with the EGR, and block off the ports you eliminate a huge inefficiency.
I have done this on several vehicles and had no problems. You can even just instal a plate in between the valve and manifold to keep it looking stock if you have to deal with inspections.
The solenoid keeps doing what the computer tells it to so there is no code. You have a cooler & cleaner intake charge for more power. You also can eliminate the potential vacuum leaks from the 2 lines you don't need any more.
gmbellew
Registered Member
the ECM will test for EGR operation, or at least it says so in the 1990 service manual
Also changes timing and fueling strategy when it commands EGR, but hey...
EGR Delete (TBI) & Custom chips - Info/Links
This thread is NOT FOR ARGUING about what EGR does or if it sucks or whether deleting it has any benefits. This thread is only here to save people time, aggravation and money by providing links to QUALITY parts & services. Most of the pollution crap has been off my truck for years. I finally...
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I hate to admit mistakes, but for everyone's benefit here it is. Never having done injectors before, I relied on a Youtube video and didn't read the instructions carefully. I put the injectors in without knowing they must be aligned correctly. Upon review I realized my mistake and concluded that the whine/squeal would go away once I aligned them. One symptom of this whine is when the truck is shut off the noise lasts for a second, decreasing in pitch and volume until gone. So, the source seems to be either fuel pressure or vacuum. All vacuum lines checked, no problem. There was no noise until I did this repair on this end of the fuel delivery. I realigned the injectors. Sadly the noise is still there. I tried to think of all possibilities including that maybe a piece of old gasket some how is involved. I'd hate to have to live with my mistake. Any suggestions welcome. Thanks again.
Maybe a dumb question, but in an earlier post you mentioned that you removed the EGR in order to check it out. Then you blew it out clean and reinstalled it. EGR valves are annoying to tighten fully because of how awkward that space is for a wrench... did you get it tightened down fully, and is the gasket in place and in good condition?
