Opti low res"noise"

[LeadfootLT1]

Ok amigos. So My car has been on and off the dyno for a few days now trying to figure out where my prob is. I'm going to the same place that Popo is going to and I Amsterdam to be having similar issues

Long story kinda short. First runs on the dyno I seem to be getting a high rpm miss. Some runs worse than others. So yesterday we put a scope in the hi and low res wires from the opti. And did 2 dyno pulls just watching the scope and seeing what was happening when the breaking up started happening. Suprisingly all looked fine and dandy. although there was a very small amount of "noise" on the low res side. Kinda like very small littler blips in the low res line(if that makes sense). Can this cause a Hugh rom misfire? I have a photo of the dyno sheet from one of the runs running fat where the miss looks alot worse. And than another one where it was running more lean and seemed quite a bit smoother. I'm gonna do my best to get that pic up. (Popo help me out here!!)

Either way I feel like a chicken with my head cut off. I don't know enough about any of the tuning aspect of this and I'm just trying to eliminate some issues I'm more familiar with. I talked to the tuner and asked if we can pull fuel back out and see if it smoothes it back out again. So that will be happening tomorrow.

Again sorry if i seem like I'm rambling. I got a million things going through my head with this car and don't know where or how to start getting this solved.

[LeadfootLT1]

9268

[LeadfootLT1]

Ok seems like tapatalk app makes uploads easy! So that dyno pic shows the 2 runs. Blue was a run last week when he was tuning the car. . Since that run more fuel was added. The red run was today.

[95ImpySS]

Whats your fuel pressure and fuel system like? That's an odd issue. Could be a chance that the optical sensor is on its way out or the coil is weak. But if the O scope is showing noise on the optical signal there's a good chance that its an opti or connection problem.

[popo8]

Its not the opti.... Thats our tuners first answer ti everything..... my car.... Leadfoots car and even blue bottlezs xar are all "stumbling at the same rpm range..... not one build is identicle. the prob is the only parameters that are being messed with are fuel and timing...... according to some of the ltx tuners ive spoken to on here.....there are other things that need to be addressed that
Just are not.....

[popo8]

Here is leadfoots pic.....

[LeadfootLT1]

Fuel looks good and we added 5 gal of 116 to make sure it wasn't an octane issue. I'm not really sure how to tell of the noise that we suspected is even out of the ordinary. I'm gonna go over today and double check all grounds and whatnot. And I may throw a fuel press gauge on it just to make sure were not loosing it. It's nt really a super crazy build so i should be ok with factory pump,reg, and injectors.

Cc306
Hooker LTs
Catless y
Ported heads and intake
1.6rr
58mmtb
Ported maf(could this cause any issues? Was like it when I bought it)
Rebuilt stock bottom end
Msd opti

[LeadfootLT1]

Larry I brought up to him that I gathered some info from moe about what we talked about. He said he still doesnt think it's in the tune but he's gonna tweak it tonight and see what changes. I don't know enough about any of this to say hey try this. Or try this.

[LeadfootLT1]

Impy does it make sense that it could be the opti even after lookin at the dyno chart? Cause it seems to me that with it not as fat it smoothed out the miss quite a bit. Makes me take Larry's side cause to me a bad opti couldnt be smoothed out with a tune.

Just shooting out ideas here. But that kinda makes sense to me. Please tell me if I'm wrong

[AdamG]

if you check your grounds check your opti harness and icm harness. a poor connection or bad wire in those could mess the signal up. I could be wrong so someone correct me if I am. the opti acts like a cam positioning sensor. It gathers the signal for the injector pulses and inginiton firing order. It takes the signal and sends it to the pcm and from there to the icm and then to the coil. Its important to make sure that signal is for the lack of better words clear and unobstructed.

I find it odd that 3 cars with almost nothing in common all have the same symptoms.

[popo8]

And three very different builds....

MIne is a boosted stroker with ignition box and dynaspark...tuned with LT1 edit.

Leadfoots is a freshened 355 (I think) with H/C/I and a freshly rebuilt BILLET MSD opti, tuned with LT1 edit.

BlueBottlez's a fresh 350 or 355 (H/C/I) with a GM opti with unknown miles on it, tuned through a stand alone MEGASQUIRT system.

[Spartan7]

I'm going to say opti. That's what mine was.

http://i238.photobucket.com/albums/ff114/malomanm/LT1.jpg

[LeadfootLT1]

Just seems odd to have 3 bad Optis all diff brands.

[popo8]

I'm going to say opti. That's what mine was.

http://i238.photobucket.com/albums/ff114/malomanm/LT1.jpg

SO his freshly rebuilt BILLET Opti... My NEw Dynaspark opti with the "good" OPTICAL sensor, and a GM opti... all malfunctioning in three builds at the same time....????

[firebird_1995]

Im not one to jump on the blame the opti bandwagon but I had a high (4500-5000) rpm miss also. Changed plugs first with smaller gap and it helped. Then i changed the wires, and opti and it went away. Looking back i wish i would have changed the wires and gave them a chance before changing the opti. I had Taylor wires and at night you could see them arcing almost everywhere they touched ground. I can't say for sure what exactly healed it but I even put a "junk" autozone opti back in and haven't had a problem since. They all have the same Mitsubishi optical sensor in them....

[Spartan7]

SO his freshly rebuilt BILLET Opti... My NEw Dynaspark opti with the "good" OPTICAL sensor, and a GM opti... all malfunctioning in three builds at the same time....????

What are you looking for, a spiritual connection? I'm just saying what my issue was, and my dyno chart looks pretty similar. It would run perfect before 4500 and then go to shit, like hitting a rev limiter. And it was the cap that went out on mine.

[95ImpySS]

TESTSo to clarify. You used an oscilloscope to watch the frequency of the pulses on the opti signal wires. And when the "noise" was seen on the waveform of the oscilloscope. It corresponded to where the dips are on the dyno graph? If so, the oscilloscope does not lie. There is a problem with the signal or the connections. Weather the PCM can see though the noise. I know not. Do you have any outrageous knock counts or knock retard? 1badz had an issue during his dyno runs. Cars power and RPM fluctuated up top. After looking at the datalog in datamaster, he noticed that the car threw an error code momentarily many times wile up top. IIRC that error code causes the injectors to stop pulsing.

[popo8]

SO his freshly rebuilt BILLET Opti... My NEw Dynaspark opti with the "good" OPTICAL sensor, and a GM opti... all malfunctioning in three builds at the same time....????

What are you looking for, a spiritual connection? I'm just saying what my issue was, and my dyno chart looks pretty similar. It would run perfect before 4500 and then go to shit, like hitting a rev limiter. And it was the cap that went out on mine.

Im not sure what that means... "spiritual connection." im saying its tge tuner.... Not 3 different optis on 3 different builds.