1991 ZR1 Restore - Help!

[kapkanimd]

My sending unit definitely has seen better days, but I replaced the hoses, pumps, and screens on it. There was a lot of rust so I can't rule out pin holes in the metal.. the fuel pressure regulator is new like I mentioned so I am assuming that it should be fine (hopefully).. I can start look for a new sending unit and keep trying other things as well. Fuel filter should be on correctly, but I will check again to be safe. THANKS!

[Corvette95]

18 psi? Could you have the fuel line connected in right direction or and pumps plugged up right? You have a fuel problem which is one of the more user friendly systems to check quickly. Also, since you have Phil's fuel pressure regulator, are you sure the fuel rail is connected/assembled correctly?

[kapkanimd]

I put the fuel pressure gauge right after the fuel pump/sender outlet and was still only getting 18psi. So definitely issue with the assembly. I posted a WTB and if anyone has any leads on a replacement fuel sending unit let me know. (Fuel filter is on in the right direction )

Also now for some reason my a/c unit in the car stopped working.. was working fine until today

[kapkanimd]

Sooo.. I decided while I am waiting, to finally put the wheels back on and get it on the ground and moving.. pulled it out the garage and it was clearly not driveable the way it was still stuttering (with I assume lack of fuel).. I let it run outside while I cleaned out the garage, and when I went to move it back it, it was running completely normal (normal idle, rev'd up with out stuttering, etc.)!

So I took it for it's first drive in years! Got back and started airing up the tires and then randomly I could hear the idle drop and it started running rough again Got it and it was back to the way it was where it was stuttering and undriveable.. It through a SEL which was Right O2 Sensor too Lean, which I checked values and it was randomly showing 0mV..

So now I am thinking it may not be the sending unit after all... Any thoughts? could it be the 02 sensor this whole time? relay? ecu? I guess I could start with 02 sensors.. I was thinking of doing headers anyway..

Either way, happy to see this thing moving on it's own power for the first time in years

[viper107]

If it's acting possessed,put in a few new gm o2 sensor's,they need it anyway,if still persistent,I say ecm

[kapkanimd]

I swear this car will be the death of me..

Yesterday I put the hood back on, started it up to check the lights, and now I am getting a battery light on... drove it today to the gas station and back and am only getting 11.4v per the computer.... The only other thing different is that I left the trickle charger leads on the battery (not plugged in) when I started it.. I keep reading about fusable links on this car but seems like no one really can identify it.. I am hoping it is not the alternator, any thoughts? When I get time I will get a meter out and start testing what I can. I see a lot of instructions for regular C4s.. is it the same for the ZR1?

Today I changed out the 02 sensor before driving it, and the data from the computer looks normal now, but it didnt really change the way it was running like I would have hoped. However, now I am throwing another code:31 (Cam sensor diagnostic error)..

I was reading another thread on here: http://zr1.net/forum/showthread.php?t=25747 that was getting similar symptoms to me (my car does not like to start when warm/hot, I have to wait until it cools down and then it fires up on the first try. I also get random stalls when starting - cranks up idles high then when it drops it just goes straight to stall. This goes away usually after it gets warmer/runs for a bit)

I can test the cam sensor, and it was also mentioned that I could be chasing phantom things that is being caused by the ECU... I have been throwing money at this thing like water, and am just trying to get it reliable at this point... I am over the budget I was expecting to get this thing going and i havent even made it to the body/paint shop..

[Young1]

The cam sensor code 31 can cause intermittent stalling and restarts. The only replacement is one built by Jagpanzer here on the forum. I have been running Jagpanzers prototype for I think four years now. Cam sensor does not exist NOS, unless a forum member lets go of one stored on a shelf. Be patient, these cars are reliable fun once all the 30 year old parts are replaced.

Plugs, wires, coils, injectors, vaccuum valves, clean up starter solenoid, vacuum pump, cam sensor, O2 sensors, fuel pumps.

Either nickel dime it or do it all at once and be reliable.

I would not hesitate to drive mine to the west coast at this moment.

[kapkanimd]

Small update: I have since replaced the fuel sending unit, swapped out the pumps for two new ones under warranty, the second 02 sensor, buttoned up the exhaust, and today changed the alternator..

Car runs a lot better, but still not right.. I am still getting the SEL as soon as the car gets hot and it is throwing the cam positions sensor code again. then once I turn off it will no longer start until it cools down completely..

I messaged Jagpanzer (who I also got the new fuel pressure regulator from) to see if he is still doing the cam sensors.. Not sure what else I have left to try..

[Young1]

Replace the crank position sensor. Car will not start if it is bad. Most likely the sensor gives bad signal when hot. They are readily available. The car does not need the camshaft sensor to start but to increase timing accuracy. I left mine unplugged one time is how I know.
You will need to grind it to fit into the recess in the block. Also apply some RTV to keep the oil in for good measure.
PM me with your phone number and I can talk you through some stuff. I have a daughter on the north side of Tampa too.

[kapkanimd]

Replaced the crank sensor, no change. Replaced the cam sensor, no change....

today, I checked the the injector relays and injector resistance, all checked out good

All that is left is the ECU or the fuel pumps themselves (which are both new - advance auto suburban pumps).. I am going to grab the fuel pressure gauge again and start testing everything per the manual..

The sad thing is, I have found a TON of threads on here and other forums mentioning the exact same problems an no one ever comes back and updates their solution...

Current Major Issues remaining:
1. Anything but minor throttle input will bog the car down. I can only slowly accelerate smoothly with small throttle input. If I push harder it just putters...
2. Once the car gets to temperature (higher range) the car starts running very rough, will eventually die, and will not restart until cooled off significantly (hours later)

If everything with trouble shooting the fuel system checks out, I will pick up an ECU if I can find one.. I did take mine out, clean it, and reinstall with no change...