RT808

Hi, my 94Z just sputtered and stopped running on a city street last month. would not restart and it sounded like misfire, bad. Had it towed home.

Got fuel pressure tester today and it went straight to 42 psi and held. 3 min later still 40 psi. fuel pump sound on start up loud and normal. But still cannot start. turn over and over. tried 3 times and removed key complete start on 3rd try. Fuel pressure was still at 42psi after. Fuel tank is at 3/4 full. battery charge at 87% on my tender.

i replaced the opti in 2014 with a delphi $300 something opti from partsladdie a year before. Was running fine until last month i hit the gas to accelerate in 2nd from 25 or 30mph and it just stumbled and died. Vacuum tubes and elec connectors all tight that are readily visible. Also new plugs/Taylor thundervolts with the longtubes in Nov 2014 help

timnfxr

SES light on? Have you scanned it for DTCs? Not all errors will set the SES. Have spark?

JakeRobb

You checked the fuel pressure, but you’re just assuming you have spark. Start checking for things. Tim’s suggestions are a good start.

If you have fuel and spark and still no start, check compression.

Injuneer

Isn't unheard of for the rotor screws to fall out, even on the Delphi. Might even get a bit of spark, but the timing will be way off. Does it at least sputter like it's getting a random spark or two?

And, with DTC 16 the SES light does not come on, the fuel pump will prime to correct pressure, but at that point the PCM disables the injectors, and the pump will not continue to run?

RT808

thanks, ok i have an old laptop that had scanning software but havent fired it up in 5 years. i have the old OBD-1 data cable with serial connector for that. it might still work. i'll charge it.

SES light is on. but cant remember if it always comes on before starting. i checked the power junction yesterday and what i could see from the coil. looked good. need to go under and check the cable to the opti and those cables.
and i did not loctite the screws in the opti. i think i only put 3K on the car in 2015 but driven 4-5 times a week short trips.

yesterday, no sputter just would not start. When it happened, it seemed to struggle to start but made bad sounds like misfire for half sec and stop. now just crank

gaedbo

I had a similar issue this fall. Turned out it was the ground wire and wires that connect onto the stud that mounts the ICM/coil were loose making contact sometimes. Hope yours is that easy to correct.

RT808

Update, my old laptop was thrown out, i forgot. My OBD-1 data cable had a serial connection. will buy the correct USB cable for my new laptop and get that free software i saw here.

so i bought a cheap OBD-1 scanner at Oreillys. Bosche OBD 1001. no screen, it relies on making the Check Engine or Service Engine Soon light flash a morse code for each code. it doesnt work. I plug it in, turn ignition on and the cooling fans come on full blast and the only gauge light on is Check Gauges and it doesnt blink. left it like that for 60 sec no change. tried several times.

used the battery tender to bring batt to 100% before starting. i'll get a cable and return this scanner. The scanner manual said if you dont get flashing Check Engine or SES or the basic code 12 flash, then

1. You have a problem which needs repair before using the Code Scanner.

2. Refer to "Diagnostic Circuit Check" chart in vehicle service manual.

Tomorrow i'll lift the car and check the wires to the coil and opti. can you think of anything else i should check? and grounds thanks

gaedbo

I would try and do what the Moderators at this site reccommend, they are really extremely knowledgeable. My knowledge and experience is not even close.

Injuneer

That Bosch scanner simply shorts the pins in the ALDL connector to flash the codes on the SES light. Same thing you could do with a paper clip. Unfortunately, 1993 is the last year LT1 that works on. You need a real OBD-1 scanner. And that scanner has to have an internal battery, or an adapter to provide 12V to the scanner. There is no 12V pin in the LT1 OBD-1 connector.

Way better than that:

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

blac94Z

will it restart after it cools ?

RT808

no, it just cranks normal sounding but no fire. i lifted the car yesterday, disconnected the battery, and all wires, plugs are tight. i also armed/disarmed the alarm to make sure it wasnt locked down. alarm is off.
I ordered an OBD-1 cable usb from that site for $60. Thanks Injuneer, i'll return that box and install scan9495. Next post will be the scan codes. thanks

RT808

oh, is it normal for that red oval plastic junction box to wobble? by the battery? i felt under in the wheel well but theres a spashguard. The wires are tight on the post but the whole thing can rock a little, maybe 1/4" either side. i thought it was not moving before. also not sure where the ground wire is

RT808

i finally got the OBD-1 cable to work with my Win7 laptop. I should not have disconnected the battery. No codes.

I cranked it a few times. Scan9495 looks nice but no codes. i also have Freescan by Andy Whittacre installed. it made a log file

25 Jan 16 14:24:05 - 0x0A 0x58 0xFF 0x00 0x00 0x9F
Supervisor: CSupervisor- Com Port stopped
Main: Model GM 1994 Camaro Z28 - Impala SS - Corvette (LT1) selected.
Supervisor:
Supervisor: Initialising selected protocol...
Supervisor: CSupervisor- Com Port stopped
P: Creating GM1994CamaroZ28 Protocol Window
P: Com Port initialised
P: In monitor mode, no interaction with ECU will be done.
Main: Temperatures will be in degrees C
Main: Speeds will be in mph
Supervisor: CSupervisor- Com Port restarted
P: 0a - Finding start header
P: 90 - Finding start header
P: f0 - Found main start header
P: From OnIdle - Idle Header Detected but not in Interactive
25 Jan 16 14:24:15 - 0xF0 0x56 0xF4 0xC6
P: 90 - Header sent by ECU
25 Jan 16 14:24:15 - 0x90 0x5A 0x02 0x08 0x59 0x08 0xFF 0xAC
P: 0a - Header sent by ECU
25 Jan 16 14:24:15 - 0x0A 0x58 0xFF 0x00 0x00 0x9F
P: 90 - Header sent by ECU
25 Jan 16 14:24:15 - 0x90 0x5A 0x02 0x08 0x59 0x08 0xFF 0xAC
P: f0 - Header sent by ECU
P: From OnIdle - Idle Header Detected but not in Interactive
25 Jan 16 14:24:15 - 0xF0 0x56 0xF4 0xC6
P: 90 - Header sent by ECU
25 Jan 16 14:24:15 - 0x90 0x5A 0x02 0x08 0x59 0x08 0xFF 0xAC
P: 0a - Header sent by ECU
25 Jan 16 14:24:15 - 0x0A 0x58 0xFF 0x00 0x00 0x9F
P: 90 - Header sent by ECU
25 Jan 16 14:24:16 - 0x90 0x5A 0x02 0x08 0x59 0x08 0xFF 0xAC
P: f0 - Header sent by ECU
P: From OnIdle - Idle Header Detected but not in Interactive
25 Jan 16 14:24:16 - 0xF0 0x56 0xF4 0xC6
P: 90 - Header sent by ECU

any suggestions please

Injuneer

Scan9495 documents codes. You may have missed a check box or something. Send a PM to "GaryDoug" if you can't figure it out. He is a member, and he wrote the program. There are codes that can set when attempting to start the engine, but many others have to have the engine running, under very specific operating conditions to run the diagnostics. Disconnecting the battery was a mistake.

What you copied and pasted above is not a scan data log. Appears to be a record of the Freescan setup data or something.

Over the past 15 years or so I have reviewed upwards of 1,000 scan data logs for LT1 owners. Scan9495 is by far the best system available.

RT808

Ok thanks Injuneer. Will try again and PM the creator