I changed the plugs in my car the other day and it started running poorly. I'm running the BUR9EQ plugs in the leading and trailing (which is what I was doing before the car started this crap). I thought I may have gotten a bad plug, so I reinstalled the ones I had just taken out to see if the problem cleared up, but it didn't.

Now, the car is running real rich (you can feel it and smell it). Rich to the point that I can hear fuel igniting out of the exhaust. When boost starts to build, it's like someone has tied a rope to the back of the car. It's like it's having to try and build boost. I had the car checked for boost leaks (with a smoke machine) and found none. I looked at the new plugs I pulled out and the two leading are REAL black (I think too black to have only had less than 10 miles on them) and the trailing appeared fine.

Looking at EGT temps, the car normally runs around 600. Today on the Interstate, the EGT was consistantly about 750 while running 80 mph in fifth. The EGT was about 650-675 while running 60 mph in fourth on a highway, which it normally runs a little below 600 normally at that speed. I don't know if this is due to fuel igniting in the exhaust causing the temps to raise or not.

I couldn't find anything unplugged except for a black wire with a flat looking end piece close to the front housing. I don't know what it is or where it goes, so I put electrical tape around the metal piece so it wouldn't rub against the housing. I don't know if that wire has always been unplugged or if I knocked it loose while changing the plugs that day.

The car sounds fine at idle. It normally pulls around 15-17 vacuum, but right now it's pulling about 10-12 vacuum at idle. Sometimes when I'm going down the road, I'll push the clutch in and the vacuum creeps to around 5, then will settle back to about 10-12.

I'm at a loss with what's going on. Does anyone have any ideas or suggestions? What does it sound like is happening? What do I need to check? I'm going to plug in my Power FC Datalogit today and save some logs. Is there anything I need to check when doing this?

~RJJ~

 

Have you checked the MAP sensor?

Can you take a pic of that wire? Not sure what it is - could be the wire to the oil pressure sender or something.

Dale

 

I'll try to take one in a minute!

 

Make sure to check the vacuum hose going to the MAP sensor - it's real easy to knock that off when changing plugs, and that will give you exactly the symptoms you described.

Dale

 

I checked it and it's plugged in good.

 

I just realized my digital camera is at the house, so I can't take a pic right now.

 

The connector you are talking about probably goes to the oil pressure sending unit, or the water temp sensor. Check the plug wires going to the leading coil. Also, check the wires in the coil harness. The plug that goes to the leading coil could have gotten pulled off.

 

I will check them. But, since all four spark plugs showed to be firing, wouldn't that eliminate plug wire connection as the culprit?

 

Is there a way to find out if a coil pack is doing a proper job or to test if it's beginning to fail?

 

Cant answer your question Roy but when is SCF gonna be back up damnit. Free bump for you.

David Jerome

 

Hopefully today or tomorrow (my fingers are crossed).

 

I know this sounds obvious, but did you switch the Trailing with the Leading plug wires?
More than likely you didn't, but it's worth checking while you are checking the coils.
Did you change them from the bottom of the car or top of the car? I found they were easy to change when the car was on ramps and I could access them from the bottom of the car.
Good luck man.
Ralph

 

I have ensured that the plug wires are connected properly. I have always changed the plugs from the top of the car. I remove the elbow and I can usually have them changed out within 45 minutes. Is it much quicker from the bottom?

 

any of the sensors on the PFC highlighted?

Tim

 

Only this one: FUEL: 4.98

But I've been told that was expected since I'm running with a custom secondary fuel rail.

 

Is the idle smooth...?

 

For the most part, yes. Two days ago, I started it up (it had been sitting for several hours) and the motor was still cold and vacuum fluctuated between -12 ~ -10 for a bit, but finally started idling smoothly. The vacuum may have fluctuated because the rpms were going up and down, up and down. But, once the motor was warm, the idle smoothed.

 

So did they happen when you changed the plugs....or did you change the plugs because this was happening.

If it happened when you changed plugs you probably dislocated a plug wire boot when pulling it off of the spark plug. I'd test the wires

 

The car seemed like it was loading up with fuel in high rpms, so I changed the plugs. It wasn't until after I changed the plugs that it started running worse.

What is the best way to test the wires?

 

grasping here, stuck 1600 injector but then again, it would have to be both of them. Fuel pressure regulator **** up and pressures through the roof?

Tim

 

I can feel the secondaries coming in at 4k rpms. My fuel pressure shows 38 at idle (why am I thinking it should be around 45?). I had a radiator put on my car the other day and that guy said fuel pressure at idle then was showing 38 at idle. The car ran fine after the install (the radiator has been in for several weeks).

 

Yeah Actually man. If you pull the car on ramps and reach in through the a-arm with a plug socket and wrench that fits on the end of it, you can change plugs in less than 10 mins. Really a piece of cake, in comparison to pulling the elbow off.

 

you can check to see if the injectors are leaking. just prime the system ad pinch the feed and return lines then watch the gague. if it drops you have a leaking injector/fpr. are you sure the spark is good. did you accidently change a setting in the pfc?

 

Nothing has changed in the PFC. What is the best way to check the coil packs and plug wires for proper functioning?

 

Honestly, the best (and easiest) way to check your plug wires, coils, igniter, and coil harness is just to switch them out for a known good set. If you have a friend that will let you borrow his parts, just undo your plug wires and the coil harness connector, and then plug his whole assembly up. You can have his sit next to your intake elbow, and not even have to take yours out.