lt1 has misfire after bbk header install???

[93formulalt1]

Do you have the capability to read sensor data with the car running? ALDL cable, free scan, a OBDI scanner, anything? I found out my off-idle hesitation is caused by a bad MAF Sensor today, it's reading 2-3GPM higher than it should. Swapped a known good unit in, the car ran better off idle, no more hesitation. (Thanks for loaning me the MAF for a few minutes, Steve!)

Also, trust me when I tell you this, having just diagnosed similar issues and wasting HUNDREDS of dollars doing it, I would really think about things before you decide to ignore the advice of the folks here. They can save you a ton of money and headaches, but you have to give them enough info to work with.


What is your spark plug gap set at? You should have them gapped to .045-.050, if you installed them without gapping them, you might as well buy a new set, set the gaps at .045, and get ready to replace them again. Most of the plugs I've bought were factory set at .060".

If you need a hand, I'm willing to help out, since I know exactly what you're going through, but I'm only on this side of the state once every couple weeks for maybe 2 days at a time.

[meissen]

Has anyone really noticed that much of a difference with gapping the plugs? I can honestly say I've never paid that close attention to plug gap

[mazakman]

Could it be a dirty injector?

[93formulalt1]

Has anyone really noticed that much of a difference with gapping the plugs? I can honestly say I've never paid that close attention to plug gap

I have, because the previous owner didn't, and the car ran like hell. I found gaps as large as .076 and as small as .040 in the plugs I removed from my car, and it seriously felt like it could blow up at any moment when driving it. Properly gapped plugs won't make the car run any worse, and they make combustion as even as possible across all 8 cylinders. Proper plug selection and gap plays a big part in effectively igniting the air/fuel mixture, so really, it's a critical part of making our cars run properly.

[Gregs_gsxr]

Could it be a dirty injector?

it could be dirty or just not working at 100%

[JoeliusZ28]

Has anyone really noticed that much of a difference with gapping the plugs? I can honestly say I've never paid that close attention to plug gap

Yes ive noticed a difference. A conservativr gap is better. less resistance = more consistent spark. I think it would be less of an issue on a coil per cylinder setup.

Also check your wires near the accessory belt. If you dont route the passenger side wires behind the accessory bracket they can get fubarred up by the belt pretty easily.

[9302z28SS]

well on a cold start it runs bad, hesitation, lack of power, but when it warms up it seems to run alittle better, little hesitation off the line has power but i can tell its
not running at full power,

i didnt pay attention to spark plug gap at all ill be honest there, i cant check to see if the wires are on the right cyl for the passenger side, theres so much
crap in the way its impossible, (ill just have to bite the bullet and do it)

the thing still has balls i can leave as much rubber down as i please but its getting shity gas mileage and missing all over the place (not at an idle??)

my car is a 93 so i dont think i can watch it with an ALDL like the 94+ guys,

i bought a 7/8s 02 socket today so hopefully i can tighten that and it help my problem,

i did notice that the little metal/tin cover that the single wire comes out of on the o2 sensor is broken, i can slide it completely up the wire to the connector,
is this helping my problem?????

im thinking if i mixed any wires up it would be the number 2 and 4 plug wires,

[9302z28SS]

pics

Took a pic of the o2 and just how far backed out it is.
I need a 7/8s ratchet wrench and I can't find one anywhere.

Its tight ish right now but I can take it and unscrew it by hand
And remove it no tools needed. I'd say its a thread maybe two
Into the header.

20130701_161208.jpg

[9302z28SS]

Tightened up the o2 and now there's very very little to no
Hesitiation off the line. Shifts great.

But at 40mph I'm having an issue with how its riding

Only way i know how to explain it is.and anyone who has
Or has ever driven a manual car will understand me.

Ever drive your manual car in too high of a gear at too low
Of a speed??

You know how it kind of sputters? Not the sound but the
Jolts? That's what I'm having.

[JoeliusZ28]

Like this?

[ruckusz28]

No bueno! Cool shifter!

[9302z28SS]

yup

Yup just like that. Just not as severe. I'd say 1-10 on how
Bad it is I'd say a 3 maybe a 4. Going to drive it now
That its been sitting all night and everythings cooled down

Thinking about a T-56 swap soon anyway. So I'm acually
Hoping its the trans messing up. Ill drive it till it won't
Move then rip it down and swap it all over.

[JoeliusZ28]

that video was plugs and wires, mostly wires causing the problem.

[9302z28SS]

Thank you! Lol ill try those tomorrow. Just replaced the tensioner cause it was knocking.

Found out I was a full quart low on trans fluid. Filled it up.

Now the car doesn't miss in gear underload. But still has the jolting
At 40mph.

So