Fosnot

iTrader: (15)

Alright, long story short, I put a cam in and didn't take the time to double check the direction of the head gasket it on the passenger side, and it blew out.
I took the whole side apart to replace it, as well as took the drivers side valve cover and coil set off to take a look at the rockers with the new springs just to see how they were doing.

Now buttoned everything back up and I have a backfire (sounds like a gunshot) coming from the drivers side (dual exhaust, dumps, bullets, non X pipe) when idling, but only has happened when the car is warming up. And it has a really really bad miss if you drive it around the block. Additionally, the 'check gauges' light flickers, almost like a short, but goes away if you rev the engine without load.

Car was running fine (despite a horrible coolant leak after the dyno session) and had no backfire prior to me disassembling the top of the engine. For what it is worth it currently has a speed density tune, effectively nullifying the MAF.
Also, no AIR, EGR, or other emissions systems.

Is there something I could have done wrong or missed to cause that to miss and backfire? Could one of the coils be bad (the coil rack was knocked over when leaning against the wall?), or one of the wires be bad?
It is not throwing any SES codes, only triggering the Check Gauges light as a flicker.

01transampower

iTrader: (9)

Did you makesure to line the timing dots back up perfectly when you put the timing gear back on?

Fosnot

iTrader: (15)

yes, the cam install itself was done to a T, and the engine ran perfectly prior to this 2nd disassemble.

01transampower

iTrader: (9)

I would pull your plugs. Ibet one of the plugs is cracked

Fosnot

iTrader: (15)

Just for sake of other possibilities... are there any other possibilities?

01transampower

iTrader: (9)

Coil pack could go bad but that is rare. Or a plug wire. My best is one of the 3. Plugs are what id really check first. They break fairly easy.

poltergeist 02

iTrader: (65)

there are many stories about poeple not pushing the plug wires all the way on. sometime they can be a pain in the a** to get them to clip on the coil or spark plug. this would cause a missfire. also where was your car leaking coolant from?

Fosnot

iTrader: (15)

I guess I'll work my way up... plugs, then wires... then coils

baxsom

iTrader: (6)

is is backfiring through the exhaust or intake? an exhaust leak can cause it as well

01transampower

iTrader: (9)

Do you have the block off plattes on the headers? I remember mine not being sealed and back firing under the hood through the air hole on the header

gMAG

iTrader: (1)

When I first fired up my engine last year, it backfired intermittantly, and the driver's header was relatively cool, compared to the pass side header.
Someone suggested to verify that the driver's coil harness was not reversed......instead of 1, 3, 5, 7, I had it connected 7, 5, 3, 1.
The color code on a 98 (mine) may not be the same as yours, so I'm not gonna say what colors to look for.
If I read your post correctly, you said that you had removed the coil packs?

Fosnot

iTrader: (15)

Backfiring thru the exhaust.
And my headers have no provisions for egr so no block off plate is needed.
How would I reverse the harness for the coils, I also have a 98.

gMAG

iTrader: (1)

The coil harness is detachable, and separate from the rest of the harness.
If you removed your coils, then you had to disconnect the coil harness.
In my case, the main connection on top of the head was plugged in, but the coil harness had been turned over.
For reference,
#1 blk--brn--ppl--pnk
#5 blk--brn--drk grn--pnk
#7 blk--brn--red--pnk

#2 blk--brn/wh--pnk--red/wh
#4 blk--brn/wh--drk grn/wh--pnk
#8 blk--brn/wh--ppl/wh--pnk

The colors can fade over time, so telling the difference between orange & red, or, ppl & red can be difficult. For this reason, I've included an extra cylinder per bank, to help differentiate.
Hope you find the trouble.

Fosnot

iTrader: (15)

Alright well I'm 3 hours away from my car at college right now, but I'll check this when I get back.

Only thing I'm confused about is the harness you're talking about... how can you not connect the harness correctly? by switching sides? I took the whole bracket off... and the plug only goes in one direction right?

Any way to clarify without looking at my LS?

LS1WS6dreamer

iTrader: (1)

I went down the ole coil pack harness is backwards road. Backfired, ran rough, sounds like your issue. As to how i did it. it was just reversed. turned it around and bam it worked. First start after installiing LT"s. man was i freaked. lol

gMAG

iTrader: (1)

The main, large grey plug for the coil harness plugs in only one way. The main grey plug went in, but I erroneously plugged the separate, driver's coil plugs in 7/5/3/1 (by color code), instead of 1/3/5/7. All you have to do is turn the harness over. The separate coil wires are flexible enough to do this. This changed the firing order from (correct) 1-8-7-2-6-5-4-3, to (incorrect) 7-8-1-2-6-3-4-5. No doubt, there was backfire on start-up, under acceleration, along with plenty of unburned fuel!

I'm looking at both harnesses. I marked them with tape this time to help identify driver's & pass side, along with correct cylinder location.
If your harnesses are unmarked, it is quite easy to reverse driver's & pass sides (instead of just the driver's, as I did!), so that when they are reinstalled, you create a firing order of 7-2-1-8-4-3-6-5.
While this is extreme, it can happen. I'm not sure that the car would run in this condition.
A simple check of the colors, as I posted, will prove these harnesses.
To begin, the driver's side has a solid brown on each cylinder.
The pass side has a brown/white on each cylinder.
If they're off, it's a quick fix!

Fosnot

iTrader: (15)

So I need to flip the coil bracket over, or switch the coil sides (passenger to drivers side, and drivers to passenger side?)

waterbug1999

iTrader: (3)

i did that when i did my build, but had them both *** backwards and the car wouldnt even start and backfired while cranking it. I eventually got smart and flipped them all around. If u have it like that with one side it will start and backfire.

Make more since?

Fosnot

iTrader: (15)

Ohh... ok, I just thought the orientation of the plug made it so you couldn't put them on reversed like that.

waterbug1999

iTrader: (3)

well, u cant plug say coil connection "A" into "C" due to the length, but you can have them all flipped around and they will all plug in fine and look normal. Not sure how u took it all apart but if u did have it torn down all the way it could be switched and will backfire while running. Both sides like that it wont start. .

But still check your plugs, plug wires to make sure they are seated all the way as well.