wired open secondaries=misfire??

[SuperHO]

Got froggy today and wired open the secondaries on the 98. It showed the rough low idle that I've read about. I took it out for a lil drive (about 15 miles worth of city driving) just to see how it was. Everything was fine. Power all over the rev range, stomped some tool in a riced out civic and all was well. Stopped at the smoke shop to pick up some filters and left it idling. Came back out about 5 minutes later, hopped in and mosied off. That's when I noticed it was stumbling, down on power and just all around unhappy. Did it the whole way home. Got out on the highway and pinned it....it struggled to get past 80mph at WOT. What the **** is wrong with my car?????/

 

[nothingtoseehere]

bad coil pack

 

[SuperHO]

that's kinda what I was thinking.....that a coil pack took an inopprotune time to **** it's life away. I do have two codes currently circulating through the system...

P0411 I believe the secondary air pump
P0172 I can't remember if it was lean or rich on bank 1...which 02 sensor's shot?

them's the only codes. SES light don't work, but i had the codes pulled about 15 minutes before the car started acting the fool. Could either of these be causing said misfire?

Also, is there any way to tell which coil's bad? I'm hopin it's not in the rear bank, cuz I've never yanked the intake off a gen III before, and I'm not really in any hurry to learn how the hard way like I did with the gen II.

I'm kinda dumb with V8s. I've not learned all I can yet, as I've not really had to touch this car in the past two years. The only thing that's been done since I bought it was a cam weld/100k done by FPS, an alternator and a fuel pump. All of which was done well over a year ago.

PLEASE HELP!!!!!!!!!

 

[me6894]

a lean/rich code doesnt mean you have a bad O2 sensor... it can, but a rich code can, and is usually caused by a misfire

if it hasnt thrown a code yet theres not much you can do until it does unless you wanna hook the spark tester up to each one one at a time

 

[NebraskaSHO]

Yank the intake off, and replace all four rear coils.

http://www.shoforum.com/showthread.php?t=78997

 

[chrome_rust]

the intake isnt that big of a deal, there is 2 12mm bolts behind the surge tank that hold the intake to the rear valvecover ( wouldn't it be a CAM cover?), they can be a PITA to get too if you have big hands. Invest in a 12mm ratchet wrench. Also there are 2 10mm bolts that hold the EGR flow sensor to the rear of the surge tank, you can get to those pretty easily. Also you dont have to disassemble the entire intake to remove it. just remove the bolts that are holding the metal straps at the ends of the runners on both the passenger and drivers side of the intake. Then loosen all the clamps, and remove the EGR's 10mm bolts and the bracket near the EGR, and you can wiggle the intake free in one big chunk. It took me 30 minuted to do my last tune up... Do it once, and it is easier the nest time you do it. I can do a Cam weld in 3 hours. (I have 4 under my belt now)

 

[SuperHO]

eh, maybe I'll rip this pig apart tommorrow (since I gotta be back to work thursday) and see what the problem is. Guess it's time to head back to advanced auto and have codes pulled again...

BTW....the code's telling me the system's running rich on bank 1. what could cause that?

 

[nothingtoseehere]

Remove vanity cover, start car, let idle, unplug one front coil, wait to see if the idle changes, if so, reconnect and unplug the next. if all four front check out ok, swap them front to rear and start over.

 

[me6894]

a rich condition can be cause by a misfire, even a misfire that isnt yet throwing a code

 

[SuperHO]

Thing is, it wasn't misfiring before I messed with it. It had a very minor hot idle skip that it's had since last winter. it wasn't until after I tore it apart to mess with the IMRC that it started puttering really badly. Could I have knocked something loose?

 

[SHOZ123]

Probably not but if a coil is weak and you now have a diffrent air flow than usual entering the engine at idle this may aggravate the missfire problem.

Did you pull the battery to clear out the KAM ? This will cause the car to revert back to the stock fuel tables. With the secondaries open all the time it will idle rough for a day or two but will soon learn the idle mix and smooth out.

 

[SuperHO]

K, so I swapped coils from back to front after unplugging the fronts while the car was running. All the plugs looked good (although a couple from the front bank had some small deposits on em). Fired it up and started unplugged coils. Got to #7 and it didn't seem to bog down nearly as bad as when I disconnected the rest. Took it for a drive to Auto Zone (I hate that place) and borrowed their code reader. Turns out there's stored codes for misfires on cylinder #3 and cylinder #7. Since I swapped the packs straight from front to back (1 to 5, 2 to 6 etc), that tells me the coil on 7 is shit.

So how bad is it to run the car with one bad coil? Just power loss and crappy fuel economy?

 

[SHOZ123]

Depends whether you do it for a day or two or for a couple of months.

FWIW I'm not a fan of the swapping of the coils. I've found the coils under the vanity cover in front get just as hot as the ones in the rear. If the case on the coil is cracked then handling them is asking for making the situation worse.

I would just pony up for 4 new coils and put them in the back. Then keep the other ones for misfire hunting replacement TSing for the front.

 

[SuperHO]

I'd only be doing it for the rest of this week/beginning of next week. It'd be fixed by wednesday of next week at the absolute latest.

Only thing is, I don't have the scratch for 4 new coils at the moment. unless I'm looking in all the wrong places. Wanna point me in the direction of some coils that don't cost half of what I paid for the 95?

 

[SHOZ123]

AZ has them for about $75 apiece.

 

[SuperHO]

I know...i just don't care for duracrap brand stuff....

 

[Ian Macoomb]

With the coils it doesn't matter. The Ford coils suck just as bad as anything you'll get aftermarket and most of the aftermarket coils are either rebadged Motorcraft coils or they still have a Motorcraft sticker on 'em.

 

[NebraskaSHO]

FWIW I was able to buy a new Ford coil off of eBay for $45 shipped. Yes, I got lucky.

So If you have time try that. But I would suggest getting a replacement, and then lurking on eBay for another back up coil.

 

[Motoman991]

I'm glad I have 8 extra spare coils that still worked when taken off my bad engine.

 

[SHOZ123]

I got 8 new ones off eBay for $25 each.

And I second Ian's comments about Ford coils. In fact I would choose an aftermarket coil over OEM.