Jump to content

Sporadic dip or surge in idle


Recommended Posts

Just thinking about it logically, I can’t imagine how it could be off that much and not be the harmonic balancer. The thing is that I’m not driving this truck right now until I can get the closed loop issue figured out. I’d rather not throw money at it right now unless it’ll improve how it runs. The fiancé is asking how much more money I’ll spend on this broken truck 😢 once it’s running good, she won’t worry so much about how much $ I spend on it 😈

Link to comment
Share on other sites

  • Replies 144
  • Created
  • Last Reply

Top Posters In This Topic

8 minutes ago, PhilisDiller said:

The trailing edge of the rotor is just a hair before the beginning of the metal for spark 1.

Where would the rotor be if you were at TDC or 20°BTDC. Possible cause for weak spark.

Link to comment
Share on other sites

34 minutes ago, PhilisDiller said:

I just confirmed true TDC using a screwdriver and got an average mark between the marks I made with the screwdriver maxing out both CW and CCW. The notch in my harmonic balancer is at 20 degrees. 

Isn't this TDC.

Link to comment
Share on other sites

So the markings read 20 when the motor is at true TDC. I took the picture of the rotor when it was in that position.

 

when I moved the marking to line up with 0 and it is beyond true TDC, the trailing end of the rotor is passing about midway through the metal for spark 1

Link to comment
Share on other sites

I’m with you. Okay, when I get back on Sunday I’ll adjust the distributor to be just barely gapped past the end of the metal tip for spark 1 and I’ll do that at true TDC. 

 

I’ll test vacuum using a gauge then too. 
 

Something interesting did happen yesterday when stopping by the store. The RPMs shot up and got stuck around 1400rpm. I shut it off and then back on. Same thing. Drove it 50 feet, shut it off and back on again and the RPMs stuck at 3000 for a minute before eventually dropping back down to 1100. My RPMs have been averaging 1100 after the injector swap. Before it was at 750. I wonder what happened there

Link to comment
Share on other sites

Alrighty, so the dizzy has been properly indexed now. 
 

I’ve also hooked up a vacuum gauge and the readings align with the REM. 
 

I'm wondering if I have some sort of exhaust/vacuum leak. I’ve retightened the top bolts and the two bottom outer exhaust bolts. But I haven’t retightened the bottom 3 bolts that are difficult to access. I’ll give that a go when it cools down. I’ll also confirm the tightness of the Downpipe bolts.

 

it has a pretty loud tick on first startup and then it quiets. but once it’s really warmed up, it almost sounds like it has an exhaust leak? I can’t tell if it’s just the motor internals or exhaust. I am ordering a mechanics stethoscope to help me identify the source.
 

 

Link to comment
Share on other sites

Is there a good way to test for that? I’ve tried depressing it while idling and it stumbled hard. Do I just have to take it out and inspect/clean it? I’m thinking of removing/capping the EGR because I just found out I don’t have emissions testing because she’s over 20. Doesn’t make sense to me, but I’m all for it 👍

Link to comment
Share on other sites

Nothing the matter with running the EGR. It only comes ON under certain conditions. As for testing, IDK, you say depressing it make engine stumble. That's what you'd expect. I guess, the question is 'does it seal completely when CLOSED?

Link to comment
Share on other sites

  • 3 weeks later...

Hey all, I had surgery 2 weeks ago and just got around to getting the EGR off yesterday. Freaking PITA to get those bolts out.

 

It's hard to see really well inside the EGR to see if it's sealing BUT I cleaned up the outside of the nipple that goes into the intake and sucked on it to see if it could hold vacuum. It does NOT hold vacuum, it looks a small amount of air is able to pass through but it's still a significant amount. Oh man I hope I'm understanding how this EGR works properly because this looks like it could be the source of my vacuum issue.

 

Any recommendations for how to clean out the inside of this to allow a proper seal? The valve doesn't seem to be centered perfectly. Here's some pictures to show what I'm talking about. That’s also where I applied vacuum

 

 

FF2DFB21-56EF-4656-AB36-66599F5C8033.jpeg

CD1CA700-B194-4FF8-B863-5EE99001D3AA.jpeg

Link to comment
Share on other sites

I’m exempt from emissions testing. I’ve thought about removing it, but have heard it keeps engine operating temps down. (Now my low operating temps make sense with the EGR being stuck partially open). I’m open to blocking it off, but would like to keep it if possible to repair. At $60 though, it’s not too expensive...

Link to comment
Share on other sites

This block off plate looks like it should work. https://www.ebay.com/itm/AMC-6-CYL-V8-EGR-VALVE-STAINLESS-STEEL-BLOCK-OFF-PLATE-With-GASKET-MADE-IN-USA-/283740262656?_trksid=p2349624.m46890.l49292
 

i was hoping I could slip the plate in between the EGR and the intake to have it retain the OEM look, but don’t see how I can do that with the way there’s the nipple on the EGR that sits inside the intake. 
 

$15 and peace of mind it won’t leak again vs $60 knowing it’s operating as it was intended to from the factory. I also would like to keep pollutants low... ah the great debate. 

Link to comment
Share on other sites

12 minutes ago, PhilisDiller said:

What do you mean by this? Are you saying there is no benefit to the egr?

I've seen no benefit.  I feel I benefit by not having it.  It is so much easier to see and to reach around in this area now.  And no worries about a 30+ year old EGR inevitably interfering with drivability.  I'd deleted mine back in 2018 and haven't looked back since.  If there's a disadvantage, I hadn't be able to tell.  Here's a pic of what it looks now:

 

egr.jpg.569184d0a3e075b4f4055ffa5cf5cd1c.jpg

 

I had been doing some work on my header, repairing cracks, adding gussets.  While in there, I cut the tube connecting header and EGR.  Welded header at pipe opening.  I removed, then cut off all of the stuff attached to the cast iron EGR housing.  Using a piece of scrap flat metal, I cut it in the same profile as the EGR housing.  I then smeared some RTV on one side of my sheet metal and used the EGR housing to sandwich it to the intake manifold.  Prior to, I painted it red just for fun.  

 

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share


×
×
  • Create New...