V6 Discussion and questions about the base carbureted or MPFI V6's and the rare SFI Turbo V6.

Rough idle, 3.1 MFI V6

Thread Tools
 
Search this Thread
 
Old 02-16-2012, 01:30 AM
  #1  
Member
Thread Starter
 
Dead Reckon's Avatar
 
Join Date: Aug 2011
Location: Roanoke "Roa-Joke", Virginia
Posts: 118
Likes: 0
Received 0 Likes on 0 Posts
Rough idle, 3.1 MFI V6

Alright, so, my '92 Camaro RS, 3.1 V6 LH0 MFI, is idling rough.

It don't think it's the plugs, 'cause it it's only idling rough, if it was bad plugs, it would be rough at other points too. I think it would at least, I'm not very familiar with TBI or MFI engines.

It did this before we replaced the ignition coil, so I know it isn't the cheap ignition coil, though I am putting a factory replacement on as soon as possible. The cheap one was a quick patch over that never got re-replaced. It's been on there for about 3k miles, I'll be surprised if it lasts another 3k, though it won't be on that long.

I haven't checked to see if the EGR pipe is clogged, could that be it?

Also, the EGR plug is bad, I haven't been able to replace it yet, it works, but it's patched with electrical tape.

The check engine light is not on, I'm not sure if the sensors are working, I'm not even sure where most of them are, or what they do.

The car was swapped from a 5spd to a auto, and it's going back to a stick soon.

Also, it doesn't quite accelerate right sometimes. Sometimes it'll open up if I stand on it, kind of like a four barrel does, but sometimes it won't, it's very unpredictable, which I don't think is normal.

I don't see how flooring it from a stop would cause it to open sometimes, and not others. And yes, I'm accounting for the amount of time it's wide open, it usually picks up about 35-45MPH, but it hasn't been doing that as often lately.

It is due for an oil change, I'm gonna change the plug wires, dis cap, button, ignition coil, plugs, and check for any bad wiring on the sensors. Is there anything else I should look for?

Would a leaky exhaust cause it to run funny? The catalytic converter is solid, but the rest of the exhaust, except the muffler its self, is rotted out.

Another thing to account for (maybe), the PO's hardwired the fan to the hot side of its fuse. Really stupid job, our cars deserve better than the life this one has had.

Last edited by Dead Reckon; 02-16-2012 at 01:37 AM.
Old 02-16-2012, 06:24 AM
  #2  
Supreme Member
 
ex-x-fire's Avatar
 
Join Date: Jan 2011
Posts: 1,727
Likes: 0
Received 1 Like on 1 Post
Re: Rough idle, 3.1 MFI V6

Remove the egr valve & see if its stuck open.
Check fuel pressure, tps for smooth operation. Any codes?
Old 02-16-2012, 07:48 AM
  #3  
Junior Member
iTrader: (1)
 
Brett68's Avatar
 
Join Date: Feb 2007
Location: Boise,ID
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
Car: Camaros 92 RS, 68 Project
Re: Rough idle, 3.1 MFI V6

I just changed the plugs and wires in my 3.1 and it cleaned up the rough idle I had. It was even producing an erratic tach indication. But these were the worst(condition) plugs I have ever seen. One of the plugs had gunk across the gap. It may be worth a look.
Old 02-16-2012, 02:02 PM
  #4  
Member
Thread Starter
 
Dead Reckon's Avatar
 
Join Date: Aug 2011
Location: Roanoke "Roa-Joke", Virginia
Posts: 118
Likes: 0
Received 0 Likes on 0 Posts
Re: Rough idle, 3.1 MFI V6

No errors, I was gonna check the EGR hose and valve today but it's raining. I'll check it tomorrow if it isn't raining.

As for the plugs, I'm going to replace them when I change the oil, hopefully put a new cap, button, and coil on it, as well as new plug wires, and a new coil wire.

I know to check the plugs, it's just the other area's I'm not sure about. I learned to work on cars which had two and four barrel carb's, so this is a bit new to me.

How do I check fuel pressure on this car?

EDIT:

If the EGR valve is bad, I've noticed the solenoid can cost upwards of $300, is there any way to delete it?

Last edited by Dead Reckon; 02-16-2012 at 03:14 PM.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
GeneralIesrussi
Carburetors
5
01-20-2020 01:06 PM
IROCtometal
TPI
2
09-20-2015 11:08 PM
IROCtometal
TPI
3
09-09-2015 10:01 AM
IROCtometal
TPI
0
09-02-2015 02:01 PM



Quick Reply: Rough idle, 3.1 MFI V6



All times are GMT -5. The time now is 11:54 PM.