Mississippi

Ok, so I just pulled THREE injector plugs. I didn't notice ****. Idle stayed the same. There was a slight shutter when I pulled number 3 injectors, but nothing when I pulled 2 & 4. Is it gonna be a noticeable change when I unplug them?

draggin97s10

iTrader: (2)

yes, when you pull them it should be running completely different then when you have them plugged in........(way worse) sounds like bad injectors. Do you have a buddy with 26 lb injectors in his car trhat you can try out..before you go buying any?

Mississippi

Is it normal for a shitload of injectors to go bad at once? I mean I overheated the car ONCE but why the hell would 3-4 injectors go bad all at once? I might buy some cheap autozone **** and put them in their to see if it fixes the problem. If not, I'll get a refund. All my lt1 buddies have either become traitors and gotten an ls1, a mustang, or just gotten out of the sport car world all together.

draggin97s10

iTrader: (2)

as long as theyt are 26lb injectors or close(28 or 24) IT doesnt matter. But yes its possible to go bad in a batch...they were made at close to the same time right???? anyhow yea replace them and try it out...

z_speedfreak

iTrader: (3)

I was gonna suggest the same thing, some times when fuel pumps are on their way out they run fines some times and randomly takes ***** here and there. when you say its really loud have you noticed a change in pitch at all?
next thing is that I'd def check the injectors like how BADHAWK was saying,.
If still nothing still I would also go through and disconnect different sensors one at a time, MAF, O2's.. still nothing try deleting the ERG -and AIR while your at it
you've verified every cylinder is getting spark right? checked how all your spark plugs look?
and before you even think about touching the opti make sure you do the opti test(which is a how-to on shbox's site) first

Mississippi

I'm about to give the car to a shop and see if they can figure it out. I've tried everything I can think of short of throwing parts at it. I'm pretty certain its fuel injectors now but I want an expert opinion before I start throwing cash away. Anyone from the Memphis tn area? Or willing to make a trip? If you can diagnose the problem I can swing some cash your way. PM me if interested. That's how out of ideas I am.

Big Al

iTrader: (1)

About the rattle, remove the belt and see if it goes away.

Al 95 Z28

Mississippi

Good advice al. That would definitely narrow the search if the noise goes away with the belt. I'll test that tonight. If that doesn't give me some revelation, I will be installing a new opti tonight. Along with plugs, wires, fuel filter, and possibly O2s. If that doesn't clear my problem, I'll move on to coil, icm, and injectors. If its still fucked up after all that, fuel pump. At that point if its still toast, I will be doing the 9mm mod and possible the "oh **** there's a tree" mod. Followed by the "test how good my full coverage is" mod.

popethe5th

iTrader: (2)

run the car with out the cats on open manifolds are fine, does it only do it when it gets hot if so its the cats no question. belt tensioners will rattle when the spring comes loose, pull the belt off does the rattle go away?? does it run better? check the opti if the opti is bad check the water pump, when the water pump fails it so kindly leaks onto the opti destroying it forever.

popethe5th

iTrader: (2)

BTW its your opti!

Mississippi

Putting an opti on now. Reassembly beginning now. Hopefully its fixed...

Mississippi

Just got the car started after the new opti install. Didn't fix ****. Same bull ****. You know how when you cut your car off the exhaust ticks a little while its cooling down? Mine does this loudly and aggressively. Possibly indicating that my car is running super super lean which would make exhaust temps much higher (I'm correct on that aren't I?) Which would make them louder when cooling down. The exhaust piping is very hot. I can't ******* figure this **** out....

IronOutlaw

iTrader: (4)

How did you tell the cat was clogged by looking at it?

Mississippi

Well from what my this old "shade tree" mechanic told me, once I unbolt it I can look into it and it should be relatively clean. He said if it was filled with black ****, or all of the filter screen **** in the cat wasnt clogged with **** then I'm fine. Idk if thats correct of not. I just took his word for it. But its obviously not the cats. I busted them up anyways. Haha. I think its fuel related. I think number 2 and 4 injectors are fucked up. I can unplug both of them and BARELY notice a difference in idle. If I unplug any of the other injectors, it is a noticeable change in idle. I'm dropping it at Powers Automotive tomorrow night if I can't figure it out before the weekend is over... Bye bye money....

SS RRR

iTrader: (2)

Don't be surprised when you get a completely inaccurate diagnosis and ungodly expensive estimate. Give a car to a garage with an unknown problem usually never turns out well for the customer. Especially at a $90+ hour shop rate...
Good luck.

Mississippi

Well the guy who runs the place is a friend of my family. He is not one of these shady *** price jacking mechanics. If he cant figure it out, then I dont have to pay him ****. He is the best around. He is a good old man. I wouldnt drop my baby off with just anyone. I'd buy a motor and put that bitch in there before I took my Z to the local Meineke or Pep Boys. I know this guy isnt gonna **** me. The problem IS FUEL RELATED. I'm certain of that now. I just dont have the time to deal with it right now. Work, military, family. I just dont have the time.

nascarnate326

iTrader: (1)

Love my CMS opti. Taken it to 6k rev limiter plenty of times with no issues. I wouldnt consider buying a GM unit even if I did have to change it once a year.

Is your MAF clean?

Mississippi

Yeah maf is clean. Little problems like o2s and mafs and **** are pretty much out of the question for the problems I'm experiencing due to how bad my car is actually running. I mean you could unplug the maf on any LT1 car and it would still be 10 times faster than mine and it would run way better. I'm missing on all cylinders. Cant pull over 4k rpms, even in neutral. Missing like crazy from 1200 to 2200. No power at all. 7 mpgs. The list goes on and on. My car sounds like a 4 cylinder. I ran my first LT1 fbody with no o2 sensors and a fucked up maf for a month (I was young and stupid) and that car still ran better than this one.

96famaro

Go and rent a Stethoscope and listen to each injector at idle. It should have a slight ticking noise and with a little rev up it should grow more rapidly as rpm increases. If it is a injector problem they could be dirty or dead. You can also check the injector fuses just to make sure nothing shorted out for some reason. Try a spark plug change its always a good start when needing to find a misfire solution. The front O2 sensors could have gotten damaged from the over heated exhaust temps its possible but doesn't really sound like it in your case. I'd really look into the cat some more well best of luck to you. Ernest

gatorhead

iTrader: (4)

For all the trouble you have gone through Rob's site is setup so that if you follow his instructions you can test every system and component on the car. Digital multimeters are cheap now and required if you are going to work and maintain your own vehicle. The test procedures would have shown whether or not it was the opti, coil, or ICM. Now the ICM has to be tested by Autozone. Have them run the test 5 times in a row.
I have a hard time saying more than one injector has failed at the same time. Only if there was one down before and you just didnt notice until the other dropped out.

All that being said I would not use any other opti except DELCO or Delphii which bought Delco out.

It is only educated gues based upon your description, it is hard to tell you what it is from the keyboards. Hope you get it figured out and when you do POST what it was so the next guy can search and see this thread. Too many times folks ask, find out and never tell lol Best of luck getting her done