M30 Running rough

[NE32]

Hey everyone,

Finally got my 7 out of storage. Excited to cruise in this warm weather but the engine is running rough. Definitely misfires/runs lean. It idles fine. When you blip the throttle, it'll seem like it will stall then rpms will go up. From the little drive I went on, car will just shake when on the throttle. Especially around 40-60mph. Once you let off the throttle it's smooth as if nothing is wrong. CEL isn't on and stomp test brought no codes up. Injectors were rebuilt and intake gaskets were replaced in November. Distributor, rotor, and spark plug wires replaced a year ago. Spark plugs changed in august with Bosch 7909. They were carbon fouled when I took them out so I will replace in the next few days

So what should I be looking for here? Did some reading around forums and saw I should disconnect the afm to see how it runs? Also told it could be reset? Don't have any clue how to do that. Don't want to start ripping it apart just yet.

[shogun]

Maybe first keep on driving, as the battery could have been a bit low after long time storage.
Resetting the DME is done by disconnecting the battery for some time like 30 minutes so that the DME is cleared. But before you disconnect the battery make sure that you have all necessary codes noted down like for radio, aftermarket drive away protection or whatever needs a code. Also the OBC has to be set new with time, date.

[NE32]

Should I still try this even though I had it on a battery tender?

[shogun]

A battery tender will not help much in case one of the cells is dead. In case you have a load tester, you can make a battery load test. This gives you a good idea: Testing procedure for field-returned batteries. This procedure should help determine whether the battery returned by the customer has reached its end of life or simply needs a full recharge http://www.batteryweb.com/pdf/Odysse...Procedures.pdf

[NE32]

Okay I disconnected the battery and changed the spark plugs. Still misfiring. I drove for about 2 hours to see how it it ran. Was better than yesterday but apparent it's not running as it should. Since it isn't throwing codes, I'll go and check over the intake gaskets and some other stuff.

[SergeBMW]

How do you know it is running lean and not rich?
Try this, let the car idle, and disconnect one injector wire harness and listen for a change in rpm. It should drop. Reconnect and try the next, if there is no drop, then you know the injector is faulty or spark plugs or leads.
I know you mentioned you had it all replaced but it's not good to assume they all function without knowing for sure.

You might want to check the distributor as well, I had a new one that cracked within the first month... open them up and make sure they are ok.

[shogun]

Besides the distributor and the rotor, vacuum lines to be checked, they also control the fuel pressure http://www.nmia.com/~dgnrg/hose_map.jpg
spark plugs fuel fouled or carbon fouled???

Plug Tips Tell the Story
1 NORMAL
Appearance: Grayish-tan to white color
Recommendation: Correct heat range of spark plug is being used. Replace spark plug at the proper interval.
•2. NORMAL WITH RED COATING
Appearance: Pinkish-red color on the ceramic insulator tip, the center electrode, and the ground electrode.
Recommendation: Normal - coloration is from the use of additives in unleaded fuel.
•3. FUEL FOULED
Appearance: Firing tip is damp with gasoline, usually the odor of fuel is present on the spark plug. The insulator is often tinted the color of charcoal.
Recommendation: Indicates the cylinder from which the spark plug came is not using all the fuel supplied to it. Check for faulty or sticking choke, overly rich fuel mixture, ignition problems, leaking fuel injectors, or spark plug heat range is too cold.
•4. DETONATION
Appearance: Insulator is usually cracked, chipped, or broken. Ground electrode can also exhibit damage.
Recommendation: Caused by low octane fuel or over advanced timing. Can be noticed as engine knock. Check for faulty EGR system, detonation sensor, and correct spark plug heat range.
•5. WORN OUT
Appearance: Center and ground electrodes are eroded, have rounded edges, and are excessively worn away. Difficulty starting engine and misfiring during acceleration may occur.
Recommendation: Spark plug used beyond its intended life. Replace with a new set of spark plugs.
•6. GLAZING
Appearance: Ceramic insulator tip appears to have a melted, glazed coating.
Recommendation: Spark plug is operating too hot at high speeds. Replace with a colder heat range of spark plug.
•7. CARBON FOULED
Appearance: Black, sooty coating on firing end.
Recommendation: Spark plug heat range is too cold and/or caused by extensive low-speed, short distance driving. Replace with the correct heat range of spark plug. Also caused by weak ignition system and/or rich fuel mixture. Fuel injection engines would produce carbon fouling from clogged fuel injectors, vacuum leaks, and/or problem with carbon canister/purge valve operation. Carburetor equipped engines cause carbon fouling from improperly adjusted or malfunctioning choke.
•8. SUSTAINED PREIGNITION
Appearance: Melted center and ground electrodes and damaged ceramic insulator tip. Initial and sustained preignition are two extremes of the same engine problem.
Recommendation: Check for correct application of spark plug (heat range too hot, wrong spark plug for engine), cross firing of ignition cables, over advanced timing, lean fuel mixture, defective EGR valve, accumulation of combustion chamber deposits, hot spots in the combustion chamber due to poor heat dissipation, improper installation torque applied to spark plug, and/or head gasket protrusion into the combustion chamber.
•9. ASH DEPOSITS
Appearance: Center electrode, ground electrode, and/or ceramic insulator tip are coated with tan colored deposits.
Recommendation: Caused by the use of leaded fuel, fuel additives, and/or oil additives. Check for worn piston rings and/or valve guides. Misfiring may occur due to the deposits on the electrodes.
•10. OIL FOULED
Appearance: Center electrode, ground electrode, and/or ceramic insulator tip are coated with a black, oily substance.
Recommendation: Caused by presence of oil in the combustion chamber. Check for worn rings, worn valve guides, and/or worn valve seals.
•11. MECHANICAL DAMAGE
Appearance: Center electrode and ground electrode are bent out of position, down or to one side of the spark plug. Ceramic tip is broken and missing from the firing tip.
Recommendation: Locate and remove foreign object from inside of cylinder. Check catalog for proper spark plug application. Improper spark plug thread reach can protrude into cylinder and sustain damage.
•12. LEAD FOULED
Appearance: Ceramic insulator tip is coated with a brownish-yellow glazed coating.
Recommendation: Occurrence is from use of leaded fuel or fuel additives containing lead which become conductive over the firing tip. Install new spark plugs.

see under troubleshooting the pics https://www.carid.com/autolite/info/installation.html

[NE32]

You're right, I was thinking that while I was driving around. Just my first thought when to "well it was replaced so it should be good." I will try that when I get off! Took it to work this morning and running much better. Granted it was a short 2 minute drive but I could still tell.

@Shogun I was thinking I could have a vacuum leak somewhere so I'll be poking around.

How do you know it is running lean and not rich?
Try this, let the car idle, and disconnect one injector wire harness and listen for a change in rpm. It should drop. Reconnect and try the next, if there is no drop, then you know the injector is faulty or spark plugs or leads.
I know you mentioned you had it all replaced but it's not good to assume they all function without knowing for sure.

You might want to check the distributor as well, I had a new one that cracked within the first month... open them up and make sure they are ok.

[NE32]

Little update...Checked the gaskets and they were all good. I think it was the vacuum line from the Valve cover tee. Also just going to replace the spark plug wires, distributor, and rotor. I know PO did them but I know they aren't OEM or even a good aftermarket. Give me more peace of mind.