IN NEED OF SOME HELP PLZ

[LTX_OUTLAW]

hey guys i'm in need of some great help recently my 93 formula has been running on the rough side while i am driving the car it seems to hesitate randomly or even completely shut off with out any notice some days it runs great and some not so well and sometimes it takes a few minutes to start after driving for a short distance i recently replaced the fuel pressure regulator, fuel filter and even the fuel pump assembly the car has a msd distributor that has been running great since i bought the car right now i am just stuck on what could be possibly wrong with the car and any advise or troubleshooting procedures or where to start looking would be a great help thx

[CamaroZGuy]

Coil? Plugs? Wires? ICM?

[casey20000007]

O2's , and or water temp sensor in the head and water pump (its one of them)


SMOKE TIRES NOT DRUGS

[Fastbird]

These moments when it seems like the car completely shuts off then comes back........what conditions are you under here (throttle, RPM, load, etc). I'm thinking opti for that one just due to personal experience with the same things.

[LTX_OUTLAW]

Coil wires and plugs all are new and it usually happens at random moments I can be driving at highway speeds or in town errands just a example a few weeks me and a co worker went to the track It drove great and then I turned it off about 20 minutes later I decided to run the car and it ran great but when I got done I parked the car for about 15 minutes to get ready to head home it would not start I sat at the track for about 30 minutes and then it finally started? Lately that's been the trend whenever I does it may take a few minutes before it restarts but something else I noticed when it does die sometimes every other starts I didn't hear the pump? Is there a relay or switch that may be bad? I just about replaced almost all of the major components relating to fuel

[CamaroZGuy]

Coil wires and plugs all are new and it usually happens at random moments I can be driving at highway speeds or in town errands just a example a few weeks me and a co worker went to the track It drove great and then I turned it off about 20 minutes later I decided to run the car and it ran great but when I got done I parked the car for about 15 minutes to get ready to head home it would not start I sat at the track for about 30 minutes and then it finally started? Lately that's been the trend whenever I does it may take a few minutes before it restarts but something else I noticed when it does die sometimes every other starts I didn't hear the pump? Is there a relay or switch that may be bad? I just about replaced almost all of the major components relating to fuel

ICM could be overheating, and yes there is a fuel pump relay in the fuse box under the hood.

[BaddAss93TA]

Do you have headers? Make sure you didn't burn a plug wire. Been there done that. Also make sure all your plugs are properly tightened. Then I would go to the Opti and the 02s

[cholmes729]

I am going to repeat myself multiple times again. Throw the junk MSD opti away and put a known good stock one on.

[LTX_OUTLAW]

Hey thx guys for the help but I was wondering how could you tell if your opti went out? Way back when in high school I was riding around and out of nowhere my car just died but in this case I can drive the car all day long back and forward to work no issues but it happens at the most unexpected time I usually have to wait 5-10 minutes and it restarts again? But one thing I did noticed that when this does happens some of the times the pump does not come on heck it brand new I replaced it this past Saturday I'm really interested in this relay does anyone have and troubleshooting steps to test it or even have the gm p/n for a replacement? Thx

[CamaroZGuy]

I am going to repeat myself multiple times again. Throw the junk MSD opti away and put a known good stock one on.

this is an unhelpful post, not every MSD unit is crap, there are several people using them with success. we know you had problems with one, but why not help the guy troubleshoot it before throwing a $300-$400 part at it.

[CamaroZGuy]

Hey thx guys for the help but I was wondering how could you tell if your opti went out? Way back when in high school I was riding around and out of nowhere my car just died but in this case I can drive the car all day long back and forward to work no issues but it happens at the most unexpected time I usually have to wait 5-10 minutes and it restarts again? But one thing I did noticed that when this does happens some of the times the pump does not come on heck it brand new I replaced it this past Saturday I'm really interested in this relay does anyone have and troubleshooting steps to test it or even have the gm p/n for a replacement? Thx

do you have a mech. FP gauge you can put on when you drive it? see if you are losing FP

[cholmes729]

this is an unhelpful post, not every MSD unit is crap, there are several people using them with success. we know you had problems with one, but why not help the guy troubleshoot it before throwing a $300-$400 part at it.


The symptoms he is describing sounds like an opti issue, I never said they were all crap. Just most!. I have heard of 2 units that failed on a dyno back to back, they put a GM one on there, and it was fixed. If you know how to troubleshoot his problem, then troubleshoot on. I am all about troubleshooting before throwing parts at it. I troubleshoot heavy duty electrical problems for a living, and I am good at it. His problems are intermittent, and chances are he does not have access to a scan tool, so its tough to troubleshoot right now unless something completely fails. So you have to troubleshoot by symptom.

[LTX_OUTLAW]

well guys the news is in apparently there is some sort of diode or electrical circuit inside of the ecu that went out and that is tripping the fuel pump relay which in turn killing the pump??? a local performance shop here in town ruled that to be the problem and said that the easy fix was to run the wire as a constant switch hot so it won't cut off while the switch is on (not too sure how safe that is but ok) if someone has a ecu for a 93 that would be great or any recommendation's on any aftermarket tuning companys like fastchip or pcm for less that can maybe offer a slight performance gain???

[LTX_OUTLAW]

hey guys a while ago i decided to go outside and try the car hoping i would get a different response and it did it again but this time i pulled out my code scanner and pulled the codes something my mechanic didn't do it flashed the 3 code 12's and then it flashed a code 16 3 times what is a code 16??? it must be a active code due to the car battery being disconnected for several days plz let me know what this means now thx

[cholmes729]

Code 16- Low resolution pulse (distributor). ECM is not detecting the 4X pulse from distributor. Check wiring connections, especially the pigtail connector from the optispark to main wiring harness. This is the black/red wire that goes to terminal "A" on the pigtail connector. On the 1992-93 ecm, this is wire C5 (green connector). 1994-95 ecm, this is wire B2 (black connector). If wiring checks out, you will have to replace the optical sensor module in the distributor

[cholmes729]

Here is some more interesting info:


Is Your Opti-Spark Failing?
LT1 owners have dealt with the Opti-Spark distributor for 11 years now, but there is still much confusion regarding the causes and symptoms of a failing unit. Tapping into the PCM with a scan tool is a good way to start, but sometimes no codes will be set. Before diving into the Opti-Spark, be sure to verify that your grounds are good and the coil and wires are not the source of the problem, as they are much easier to change.
Symptoms: * Car suddenly dies and won't restart
* Starts but immediately dies
* Extended cranking to start
* Rough idle
* Sputtering
* Backfiring
* Trouble reaching higher rpm
* Black smoke from exhaust
* Poor performance with car warmed up
* Weak plug wire spark
* Codes 16, 36, and 42 may be set


Read more: http://www.gmhightechperformance.com/tech/0310htp_lt1_ignition_system_understanding_modifyin g/viewall.html#ixzz2QgF9GiZC

[LTX_OUTLAW]

I may be opening a bunch of different comments but what would a good replacement be just in case??? I have read several different post on people saying the msd isn't good but on my other car I bought I brand new several years ago and I wouldn't run anything else on it the one on this car came with it the previous owner put it on just before I bought it let me know what you recommend

[cholmes729]

Stock gm ac Delco, look for one on here. I got mine used sealed and loctited for like 175 I believe.

[LTX_OUTLAW]

Hey guys what a day several days ago the mechanic at the local shop told me it was a fuel related issue with the car and he jumped a series of wires and the car ran for several hours with no problems??? But skipping ahead a few days later this past Sunday I checked continuity with all of the wires and everything check out great so I let the car idle for about 30 minutes within the first five minutes it stalled then I restarted it and it ran normal for about 20 minutes then started to stall repeated? But get this today I had a lil bit more time and also the remanufactured ecu and the stage2 performance chip from Fastchip came in the mail so I had nothing to loose so I tried it at first it seemed to idle a lil bit different but there was no engine lights or warnings to show anything was wrong so I let it run starting at 5pm I noticed he adjusted several things with the fan temp so it helped the car cool alot better so 6pm rolls around and it never stall not even the smallest hick up so the biggest trial came by fire I loaded the kids up and went for a drive once again no problems??? I did some highway city some some low speed passes it ran great then 730pm rolls around and I'm still driving and realized I'm almost out of gas I started with a half tank so I stop got some and when I got ready the car started right no problem I brought it back home and let it idle from 745pm-815pm once again no issues I think the car ran better today than any of my other trans am so this is the question??? What the heck happened? The other day I gave me a code 16 and after I replaced the ecu and added the performance chip there was no more codes in the system after today's trip? I'm really confused about this whole opti spark fault it would just seem if this optical trigger was so bad it would be consistently bad or if the code 16 means low resolution pulse to ecu it would make sense if was a two way street if the ecu is working properly it could read this signal better I'm not too sure plz let me know what you think because as of this morning before the work I did this afternoon I ordered another opti for 500+ so plz let me know do you think how well the car performed today with no faults stored I have a bad opti or there may have been something wrong with the ecu or do you think adding the performance chip adjusted something within a certain operating range to run let me know what you think thx

[cholmes729]

Maybe somebody else will chime in here, sounds like it is all over the place, maybe the pcm was bad, maybe it was a coincidence. Optis are weird, thats why people get rid of them and go 24x or ltcc coil conversion to eliminate 99 percent of the problems with these cars. I would hang on to your new opti, drive on your new pcm for awhile and see if it acts up, and if it does not, send it back and call it fixed!.