I've been driving for almost 20 yrs and i've never broke down and needed a tow. But today i took off from a stop sign a few miles after leaving work and she died on me. I was able to coast into the nearest parking lot. Tried starting it after a few minutes and it fired right up idled for fine for about 10 seconds then died again. Got the tow truck there and towed it back to the house where of course it started and idled fine for 2 minutes until i shut her down. The temp was low at the house so i'm assuming it's running fine cold but dying when it gets to temp which makes me believe Opti is the cause of my troubles, don't want to jump to conclusions though. Anyone with similar experiences chime in please. Thanks

 

I was in a similar situation 3 months ago. What I noticed when stranded was the familiar sound of the fuel pump priming the fuel system when the ignition was turned on before actually cranking, was missing. When I was able to get her started only for a few seconds before dying, the fuel pump did prime but it sounded very weak. I was able to drive her home the following day but once again after parked and shutdown wouldn't start again. I ended up cutting a trap door in the rear cargo area to access and replace the fuel pump. Also, I replaced the fuel filter. Found it was getting plugged up and restricting fuel flow. Those two pieces lasted 16 years and 150K miles. Lol! I never changed the fuel filter for that long!

 

I just looked at your other posts and saw you did a fuel pump replace before. LOL! I'm a noob!lol:

 

When my fuel pump went out and I was able to start and drive the car after dying on me several times. I got home about 15 miles away and was dead forever. If you could hook a fuel pressure testing and run it, that would be a big help in figuring it out. The opti could be, but I would check the cheap stuff first.

 

check the fuel pressure for certain. Brand new pumps fail, hoses fall of the pump etc. If it seems like it's running out of gas.....it probably is.

 

The fuel pump is solid and about 14 months old i hear the very distinct whine of it priming every time i turn the key on. I don't have any way to check it other than pulling the line off and turning on the key. I know that won't give me the pressure but if it's priming then i'll at least know that. I'm going to look at this trouble shooting the opti sticky and see what i got.

 

Scan if for codes. One code that will shut the engine down is loss of low resolution signal from the cam position sensor in the Opti. That sets DTC 16, which shuts down the fuel system. And it doesn't turn on the SES light, so the only way to find it is a scan.

If the scan shows DTC 16, but the engine is running, its a stored code. In that case, clear the code (pull "PCM BAT" fuse for 30 seconds) and see if the code reappears after it shuts down.

 

Had it idling in the driveway for 25 minutes perfectly. Even held it at 2500 rpms for 5 minutes. Nothing! I was raining pretty hard today when it shut down. Also noticed what felt like a missfire yesterday twice and twice this morning on the way to work.
Injuneer- where do i get a code scanner for an OBD1 car? Is there a way do do it without one?

 

You need an OBD-I code scanner. No other way to pull codes. Shorting the ALDL pins to flash the codes won't work after 1993. Do not be fooled by the $30 Actron unit - it's just a switch in a box that shorts the ALDL pins, and even though it says on the box it will work on your 94, it won't. There are some older AutoXray units that work best.

The alternative is scanning/data logging software. Free downloads. Just need a laptop and a cable.

TTS DataMaster (free download, 20 free uses)

http://www.ttspowersystems.com/DataMaster.html

FreeScan (totally free)

http://andywhittaker.com/ECU/FreeSca...0/Default.aspx

http://www.akmcables.com/

 

Thank you very much. So i order the cable, download the software and see what i got? I guess she's staying home for a while until this cable shows up. Guess i'll have to cruise around in the Denali, rough life.

I'm sure i'll be in touch Injuneer.

 

Ok got the cable and the software. Ran it with zero codes. Suggestions?

 

A fuel pressure gauge is pretty cheap and can be used over and over again. Some places let you barrow or rent them cheap. Get one with the longer hose so you can drive it and watch the pressure under a load. It will run up through the cowling and you can use the wiper to hold it in place.

 

Ok here's what i got. I don't know much about this open loop/closed loop thing. But i started my car with the datamaster software recording and it was open loop until about 135 degrees engine temp then it switched to closed loop. Drove it around varying rpms and as soon as it switched back to open loop it shut down. I waited a minute in the parking spot i was in and it started back up and was in closed loop for the rest of the drive. Pulled into the driveway reved it a couple times and bam, it jumped into open loop and shut down.
So what does this mean? What's causing it to come out of closed loop? Like i said i don't know much about this particular but i'm leaning toward some sort of electrical prob with the icm or opti?

 

https://www.camaroz28.com/forums/sho...ight=open+loop

Did some searching for you. Actually found my old post I forgot about. Should help you.

If you can check the O2 sensor reading, that will answer the question if they need replacing. You want them to change rapidly and see higher and lower numbers and 9xx when under full throttle.

 

You talking about the "O2 mV" blocks? Right before it switch to open loop and shut down while driving the readings were 84 and 107 so that seems like it might be it. During heavy accel they remain in the 900 range but reading the log they went from the 900s to the 84 107 and shut down. This is awesome info i would have been beating my head against the wall with this problem and no check engine light. I'll try the O2 sensors tomorrow. Any brand that you would recommend staying away from? And thank you for this info.