BoostedDSM

iTrader: (6)

So this one has me at a loss for now. A bit over a month ago the car picked up a bad miss coming home one night, figured it was the plug wires like usual, as it was stumbling, and popping at low rpm. Well with a new set of summit 8.5's on the car, zero change. The weirdest thing to me, is it runs like **** in open loop, and when it warms up, it runs much better... Not sure what that is telling me, but I'm lost. I'm stuck 100 miles at my other house with the car, so I'm super limited on tools, and space. Very tempted to just drop it off at a local shop, and see what they can find. But I'd like to hear what you guys think first. It does run fine in the upper rpm's, but I'm only testing things at this point, not driving it at all.

it's worth noting I can hear it running off by a sound in the exhaust, which is how i've always known it to sound when plug wires got burnt up. I can post a video of that tomorrow.

JUST ADDED
Put a new TDR in today, new PN from GM blah blah blah. Car fired right up, shut it off, fired again but rather unwillingly. Now it won't turn over again, the purple wire at the TDR is getting hot, which makes me think power is not leaving the TDR? I've got it grounded out, the yellow and black wire already to the post under the hood. I've replaced the switch on the column too, but if I have power to the Relay but not the starter what other grounds/issues could this possibly be?

the car
95 Z/28 auto
222k on body 133k on engine
carries 40 psi cruising on the highway
stock longblock
longtubes, ory dumped (asshat stole my catback...)
no emissions
ls1 lid swap
I tuned the car, added a bit of timing, leaned out open loop, worked on the BLM's for better cruising afr's. I've had a AEM UEGO the entire time just after the o2's I have a mail order tune from solomon coming in a few days, finally.

ahritchie

iTrader: (1)

I would try changing out the plugs first; could be a cracked porcelain part of a plug causing the misfire. If that doesn't work and the wires were already eliminated, try a new cap and rotor.....hopefully the optical sensor portion of your opti is not on it's way out or got contaminated with water/oil, how old is it?

BoostedDSM

iTrader: (6)

Rebuilt it about 3 years ago, but I've worked on the car many times since. From the timing cover leaking oil etc etc.

I'll grab some new NGK's today, I will say with the bigger wires, it was a absolute PAIN to get cyl 5 on...

BoostedDSM

iTrader: (6)

New TR55's are in, gapped to .045. Car fired up, and let off a gun shot loud pop. It sounded better, no more "hollow" sound from the exhaust, made a few more loud pops over the next minute or 2. I noticed the WB was up in the 17ish range and shut it off, went to refire it.... not a damn thing, lights go dim on the dash and it won't even attempt to roll over.

attached what the plugs looked like as well. I've had this car for nearly 4 years, and I absolutely love driving it... But I'm ready to throw something at it right now.

BoostedDSM

iTrader: (6)

interesting, found I'm not getting enough power from the TDR. I've had this issue before, grounded out the yellow wire and it had been fine, if you fiddle with the key enough it'll try to roll over. But the wires coming to the TDR get hot, what else do I need to check, the car has a new ignition switch from last time too.

BoostedDSM

iTrader: (6)

I'm going to toss a new relay in it, this one is clicking and very minimal power is making it through. From what I can tell the part # is 12077867, yet searching around for a Theft deterrent relay yields very little.

Gmpartsdirect has a relay with that part number, just wondering if anyone has replaced one before. I'll be going to the dealer Monday to double check my part # if no one is able to chime in.

If it does not start after that, it would lead me to think the switch on top of the column is having issues, as Shbox's site says, the plugs are notorious for burning up. I even have a spare one here because of that. So if I understand my process here, tracing backwards would take me to that switch/plug, from there I'm not sure though. No Security light, even though it's popped up a few times recently after starting the car, then went away a minute later. Might be time to install my resistor under the dash, my tune from Solomon should be here soon, I possibly didn't disable VATS fully in my tune... idk lol

BoostedDSM

iTrader: (6)

updated the OP, anyone have any ideas?

Puck

iTrader: (17)

I had a no-start issue on my car after it sat for years. I had no fuel pump prime, crank, or anything with it hooked up normally. Grounded the yellow wire to a nut near the relay and it cranks right over every time now.

Purple wire from TDR goes to starter, jump 12v to it and your starter should engage so you can eliminate that. It getting hot may mean you have a shorted or frozen starter solenoid which will heat up when you give it power. This may explain the hot wire, and a short will drain the battery which may explain the dim lights.

BoostedDSM

iTrader: (6)

When I get the chance It's going on stands, so I can check out the wiring to the starter, just in case. If anything, I'll pull the starter and have it tested. I heard it pop when I gave it some gas when it did fire up, that'll be my next on my list of stuff to fix.

BoostedDSM

iTrader: (6)

Made a step in the right direction today, took the starter off and had it tested. Checks good, found oil caked on the purple wire to the starter. Needless to say, cleaned that up and it fires up again.... Damn rear main seal.

So back to my original problem, it still is popping and shaking really bad. The WB is showing lean all the time, just flashed my tune from Solomon on the car too. I let it idle and warm up, popped a few random times, went for a ride around the block and it was terrible. So I'm back to square one on finding my misfire issue, the engine is visibly shaking as is the whole damn car. Last time I had anything like this it was plug wires, the car has new Summit racing 8.5mm wires and TR55 plugs @ .045. I know I can't hear
#5 "click" on the plug when trying to get the wires on, but when I wiggle it compared to the others it feels fully seated.

BoostedDSM

iTrader: (6)

So it ran good for a little while tonight, figured out plug wires 6 and 8 were swapped.... even though I double checked after the plugs went in. Anyhow, ran great, pulled great, then acted like it's dropping a cyl and picking it back up on and off.

So on to the next problem, i'll double check wires tomorrow but did not see any arcing under the hood at idle.

hrcslam

When mine did that, it was an injector plug.

BoostedDSM

iTrader: (6)

Was it just loose, or did the plug go bad somehow?

BoostedDSM

iTrader: (6)

popped the injector plugs off and back on, checked plug wires. Found one laying close to a primary, didn't feel burnt or melted. Zip tied them away, still has this tin sounding note in the exhaust that it's not hitting on all 8. Drove it lightly, still stuttering pretty bad.

Going to datalog it later, if Bestbuy has the cord I need for my laptop. Still not seeing it arc out, which leads to me say it's not wires, but the way it sounds.... says wires to me.

At least it ran good for 30 minutes last night, was nice to enjoy it while it lasted again.

ahritchie

iTrader: (1)

Popping, shaking, stumbling, and hard starting are all opti symptoms...what opti are you running and how many miles are on it? I would try a new cap and rotor when you replace the suspect wires, it is a wear item and should be replaced after high mileage use. If it still has issues, uh...it's pretty self evident what your issue is!

BoostedDSM

iTrader: (6)

It turns out to be a head gasket going, but the opti is about 3 years old with about 35k ish on it.

Teardown starts tomorrow, will be running in about 3 weeks. Just in time for the Woodward Dream Cruise. Giving it a bump in compression while I'm at it, amongst other things.

I'll note, it dropped the cyl completely when warm. But would sort of try to pick it up with no throttle imput, I'm interested to see how the rest of the engine looks compared to 3 years ago and 30k of hard driving.

ahritchie

iTrader: (1)

Perfect time for ported heads/cam then!

BoostedDSM

iTrader: (6)

I wish it was in the budget right now. Saving to do a 355, and H/C/I at the same time. Figured it would be best to wait until I either found a 6 speed car, or can convert this one over. Really bored of the Auto, but man does it run consistent at the track.