Rough running - Need help and advice

[tccrab]

Update 2

The plenum is off. I found good and not so good.

The good:
All of the injectors test with 12.1-12.6 ohms resistance.

This is great news! Guess I'll have to eat that darned hat after all. Anybody have a good recipe?

I don't see any oil leaks down in there. Though there is some shredded insulation way down in the valley. I guess some critter once called that home?

This is more common than you'd expect. Something about this engine attracts those little critters.

Not so good:

<snip>

Set up a free account with http://www.photobucket.com and upload the pictures there. Then cut and paste the links for the pictures into your post.
The online services like Photobucket automatically size the pictures for you so that they display correctly in a forum format.

It's common to find a little oil inside the plenum and also down in the valley below the plenum. Retorque the bolts to the breather box and check the hose clams on the breather box hoses (it's common for them to come loose). Give it a good clean under there, take the time to follow all the hoses and pipes and get to know what's going on under there. Check the secondaries for proper operation, all you need is one of those hand held vacuum pumps to apply vacuum in the appropriate places.
Hopefully JeffVette will chime in on the charcoal issue, there wasn't any in mine, but I have a '90, my systems are slightly different than yours.

TomC
'90ZR1 #792

Originally Posted by SharkPilot

Update...

I just pulled off each plug wire with the engine idling and there was no change when #'s 1 & 6 were pulled. Those two share a coil. So it looks like I have a failed coil. Either that or a very coincidental failure of two injectors. With the plenum off I will check the reistance through all of the injectors just to see what I have.

Keep diagnostics simple.

Jeff,
If you'd like I will try to capture some images of the charcoal. I already have a new evap hose for under the plenuim along with a new canister. I can photograph what comes out of the tubing along with what I blow out of the hose leading up to the engine.

I'll pm you my email and you can send the photos over and I'll host them.

Originally Posted by SharkPilot

Is it normal to have some oil in the plenum? I have oil in the end of the purge tube and can see evidence of oil on the secondary throttle plates. There is a film of oil inside the plenum.

Small difference between a little oil and excessive. You should have a light coating on the inside of the plenum. You can start by replacing your PCV valves, and then go really wild and make a oil/air sperator catch can.

Want to bring this one back up to the top.

So what did you ever find on the charcoal? Replace the lid on the canister? or?

[SharkPilot]

I replaced the complete canister along with the evap valve under the plenum. The hose going from the canister toward the engine was packed with charcoal so I worked to blow that out. That took some doing because of how packed in there it was. I had to remove the rear wheel housing to get at the pipe. After shaking it around to loosen up the charcoal it fianlly all blew out.
That charcoal is pretty soft so I doubt that it caused any trouble going through the engine. At first I was concerned about that.

Jeff, I sent you a few photos of the charcoal last year. Did you receive them? If not I still have them on file.

Jim

[ZWILD1]

Hey Jeff, This all sounds like what I have been seeing in my car. I have spark to all plugs. No matter how I drive it all plugs are white and clean. Car just seems off and after replacing fuel filter and then both O2 sensors I get the rough idle and mis after it warmed up. I am going to test injectors, wires and coils. Coils and wires were replaced at 78,000 to 80,000 miles car now has 103,000.

[karterdon]

If you are going to replace 1 coil - I would replace them all - MSD has a replacement coil - I found them from summit racing for about $46 per coil. And since I have the plenum off - I would also replace the injectors - Since the originals were prone to failure due to age and ethanol.