legacycentral bbs

Cruising along and WHAM, WHam, huge letoff in power where the car bucks and surges. BUT, the tack stays right where it should be. AF ratios dive during this period. I am thinking serious lack of fuel during these episodes. I will be replacing the sock if available and the filter since I have an extra.

Sounds like the pump.

pump is a new walbro

A bad misfire causes a lean air/fuel ratio reading, since it leaves a lot of unburnt oxygen in the exhaust. I would actually suspect spark before fuel. But you might as well replace the filters if you haven't yet.

It was the plug wires.

I called it!

Unfortunately you didnt. Kinda

The problem is back.

I did have bad plug wires, once i replaced them, it was obvious I needed to. The wagon ran great. I ran out to PIR and watched Uber FAst twin turbo V6 Audi wagons rip the track up and then drove back home.

urp, lurch, misfire, lag. where the hell did this come from.

Out of the blue the problem resurfaced. It has nothing to do with boost, it just surfaces when cruising. Shifting seems to help. crap.

Have you read the plugs?

Steve

The plugs are new as well. And the old ones "looked" good.

So there appears to be no internal problem causing misfiring ... Could you be hitting some kind of errant rev limiter? Sounds like it's more than one cylinder that's a problem, so it would likely be fuel related other than a weird rev limiter. An ignitor would just fail, right? I think your instinct about the pump sock is probably right. In my experience, the filter would just cause hesitation (that's what I use to know when to replace it). Check for some kind of clog near the pick up tube, too.

Steve

D'oh.

An ignitor could just fail when it gets really hot or something. Or if something leans on it.

Did you end up changing the fuel filters out yet?

Dumb question - you used good new plug wires and made sure to install them correctly and securely, right?

Does the ignitor need to be grounded anyway? I say this because it has the metal plate on the back of it. Mine is just dangeling there without a plate.

That metal plate is for cooling. It's supposed to be bolted to a bracket that it uses as a heat sink.

It doesn't use it for a ground.

OK, you are right again.

The spark plug in on #1 cylinder had popped off and was just barely making contact.

I hope this was the problem.

Yeah, it can be hard to get them to snap on all the way sometimes... Let's hope that's it!

Yeah, I really have my fingers crossed since I am going to be tracking it on March 5th at PIR. It would really suck to have it misfiring at 100 plus mph.

I am going to be putting 8.5 mm wires on hopefully before then, and pulling these new ones off and installing them on the wifes car. I just have to find them locally first. That, and 5 gallons of race fuel!

You can get a set of Magnecor KV85s (arguably the best wires out there for us) for about $65 plus shipping from cyberauto.com. They can do 2-day shipping and whatnot if necessary if you call them up on the phone.

one of my plug wiress wasnt popped on all the way. That helped a lot, that and a new fuel filter, and I am a happy camper.

I use ty-wraps on the boots to make sure they stay after I had one do the same thing.

Steve

AAAAAAAGGGGGHHHH!

Its back again. Its worse than unpredictable. Runs fine this morning taking my kid to school. Fine later in the day going to the bank. two-three hours later, drive 2 blocks and it starts in with the "killed" feeling. I dont like to call it hesitation or misfiring because it sometimes goes for a full 20-30 seconds, sometimes for 1 second, and the whole time like someone just turned the engine off, not just a specific plug.

So it does this all the way, on and off, for about 5 miles. Pick my other kid up and presto, not a single problem on the way home.

And this happens off boost.

I hate it. There are so many variables and I am just going to have to try eliminating every single one.

I did order Magnecor wires today, they should be here Thursday.

I will also redo my positive and negative battery connections.

And check EVERY SINGLE CONNECTION in the engine bay. Crap.

It's far more dramatic than ignition retard, right?

Steve

Yeah,


Lets say if its running fine, you are....

b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,b,

missing would be

b,b,b,b,m,b,b,bb,m,b,b,b,b,b,m,b,b,bb,b,m

this is

b,b,b,b,buuuuuuuuuuuuuuuuuuuuh,b,b,buh,buuuuuuuuuuuuuuuh.

b = bang for that great bang of combustion!

I have just read both the sticky hesitation threads and it got me thinking.

Electricity is a good thing.

So, I will be yanking my old battery and cables and replacing them tommorrow. I have a new battery just sitting there but I never installed it because it is top mount versus the side mount I am currently set up for.

I would like to replace my alternator but I will have to wait on that.

New battery and new battery connections, removing all the corroded parts (not much).

Runs better.

Problem is still there.

But........

On the way home tonight, I was watching my digital O2 sensor signal. It was steady at .7 or so. I turned on my fog lights and AWIC pump (same switch). Signal dropped to .55. Turn it off and signal jumped back up. Did it a few times and the signal changed each time.

I cant remember if the fog lights were on everytime the problem happened though.

I will have to check all that wiring. The signal shouldnt change like that I would think.

Yeah, sounds like some iffy grounds. How are you grounding your oxygen sensor, intercooler pump, and fog lights, and the relays controlling the pump and lights)?