Jeff1904

Ok guys here I am back again. Here is some info about my car first 1994 Z28 M6 , headers, air/egr delete, (also tuned out) cold air intake. Stuff that has been replaced within the past year, Opti, wires , plugs, ICM, coil, water pump that's about all I can remember engine wise will edit if more. I also just changed the spark plugs again about 1000 miles ago and the car has been running great until now. So I was just cruising and the car gave me a little hesitation when I was accelerating very slightly I have felt the car give REAL acceleration hesitation problems on a different problem but this was not that type, ok so continue driving slowing down I had to shift to second once I did is where I remember the huge problems start occurring first off I could no longer accelerate at all extremely sluggish even worse then when you have 02 sensor problems there was no such thing as it all of a sudden working at WOT even at WOT the car had these symptoms I had to keep shifting from first to second to keep the car alive at this point my RPMS was literally bouncing around on the tachometer I was extremely impressed by how fast my rpms were bouncing up and down it look like a show, when I would accelerate some back firing noises periodically, because of all of these problems I figured it would be best if I could let the car coast/idle as much as I could before I could get home on my way there even during coasting in neutral the car would rpm below 500 periodically nearly stalling out then it did stall out over and over during my ride home I had to turn it over start accelerating as much as it would let me so I could get to coasting again my car kept dying/ stalling out so much that towards the end when I got close to home if I got lucky enough for the car to start and not shut off immediately I could accelerate and then coast , note that during all these times the cars was backfiring and sluggish at accelerating with the rpms bouncing all around I literally coasted my way home most of the way with the car off because it could not keep its self running. One time It started it had the SES light but stalled so quickly it shut off the SES light luckily I got the codes more down in the post. So when I got home I checked the plugs and wires to see if they were burned which is what I was hoping for they were not. I then data logged my car after letting it sit for 3 min it did fine idling and running this time not a problem really BUT once I revved past 3000 rpms the problems came back not nearly as bad but I can for sure confirm that every time I got to 3000 rpms in any gear the bouncing and backfiring came back again not nearly as bad as the first drive but it was there once that happened I knew I had to get home again before it got worse it never stalled out on my way home the second time note both of these "rides" home were in a span of 10 minutes I live in a very small town. It never staled out until right before I got home luckily which was caught in the data log I then restarted the car let it idle without me moving for about 10 seconds and it continued to idle around 2000 rpms for that long then it came back to normal parked the car started to idle funny again let the data log catch it then I shut the car off note that in the data log the car stalling out and me restarting the car is right before the end of the log. The problem is I did not use SCAN 9495 to scan my car I was so worried I didn't think about it I used $EE hack or EE hack, which saves it in a different file extension then scan tool does so will you guys still be able to read this? Thanks for the help any input is greatly appreciated here are the codes I was hit with during the first ride home. Also as a side note for the past 2 months sometimes only sometimes when I would start my car it would start fine but stall right away or it would stall BUT catch its self and continue running but all the times this has happened I would just re start it and has runs fine every time.
16-LO-RES failure
41-EST OPEN
36-HI-RES failure
48-MASS AIR FLOW SYSTEM failure
51-PROM/FLASH ERROR
Just realized I cannot upload a .eedata file is there any way to convert it or send it threw a different method?

moparman

Codes 16 and 36 point directly to the opti.

Jeff1904

Update the next day. So took the car to work ran fine then the store ran fine, once i left the store my jumping rpms were back made it home with a struggle then I tried to start it again wouldn't start for 20 minutes then i finally did get it to start and it was running worse then it every had before I am very fortunate that i was able to make it to my shop and get it in there the car was stalling over and over luckily i could pop the clutch to get it started again rather then trying to turn it over or i dont think i would have made it pulling and stopping from all the miss fires it sounded absolutely terrible.

You say the codes point to the opti? Ah the famous LT1 opti spark that i just replaced within the past year except i dont doubt it at all I too believe its the opti again it sure is acting like it is Ive experienced a failed opti before. Thanks for the input.

So now the car is in my shop I guess whats next on my list of things to do is replace my opti im also going to replace my timing chain and sprockets along with the seals because i have a oil leak in the front bottom of the timing chain cover I will post back with my results whenever it gets done I have to leave to Texas for a week next week so i hope i can get it done before then as i have to order the opti still any more input on my situation is appreciated thanks.

Injuneer

What brand Opti did you install? Anything other than a Delphi or AC Delco is a crap shoot with regard to failure rate. The less the aftermarket replacements cost, the more likely they are to fail in a short period.

The tach gets it RPM signal from the PCM, the PCM gets it from the optical cam position sensor in the Opti. A data log using Scan9495 would show this. Seems like an erratic signal from the sensor.

https://www.camaroz28.com/forums/com...95-lt1-874306/

Always a good idea to check before buying parts.

Jeff1904

I got it from my local oreillys store I believe it was spectra premium was the brand name it was not there most expensive one either i got it for 165 but i should have a lifetime warranty for it but if this brand is no good should i look for a different one as Im not trying to do this as general maintenance every year haha. Also okay I will try to scan it later today with scan tool hopefully I can get the car running long enough to get some valuable information I wont be able to move it as I dont think ill be able to get back in the shop under its own power but I will try to log it later today when I get to the shop.

Injuneer

You figured it out...... cheap part with a lifetime warranty, change it out every year or two, AC Delco or Delphi and you have significantly reduced the odds of having to do that.

Jeff1904

Ah okay I see well that will be on my list of things to get I guess for now since this is my daily driver car if they support my warranty Ill put it on if it works for now great but I will DEFINITELY get one of the better ones when I get the cash for it and throw this one out real soon.

GaryDoug

For future reference, EEhack is a good tuning tool but it is not set up to share log files with most people. It doesn't even have a text output conversion feature.

Jeff1904

Thanks for that, Gary. Update got the opti installed car runs brand new again I drove it all day today no back fires or miss or studering pretty sure I got my problem fixed so far. I have a question tho about my water pump I got a new water pump when I replaced my opti last year it was just like this last year too my water pump has only has 5 bolts, 3 for the right side with 2 long ones and 1 long stud bolt in the middle right as if you were standing in front of the car, my left side has 2 long bolts one for the top and the bottom the middle bolt hole on the left does not thread a bolt in it as if a bolt was broken inside of it by the previous owner or does my car just not have one thats specific to my car, if there really should be 6 bolts should I be worried? It didnt leak at all last year and its not leaking now but every time I look for replacement bolts I find 6 with 4 long and 2 short I would like to know so I know that someday thats a problem I need to tackle. And also thank you Fred for the advice.