1996 Z28, LT1, stock, 178K miles.
Background:
Changed waterpump about 2 months ago. Noticed oil leak from water pump area - I suspect the water pump drive shaft seal. "Will get around to it."

Probably 1000 miles after the water pump R&R, driving home from work, the car would hesitate and buck in higher gears/lower RPM while trying to accelerate. Got home, turned the car of, etc.

The next morning, the car will not start. The engine turns over just fine, but will not fire. After extended cranking, the engine might "hiccup" - almost like a backfire. But will not start.

I have checked:
1. Codes. I have two eternal codes from a misbehaving AIR pump. P0417 and P0410. No new codes.
2. Fuel delivery. I disconnected fuel lines from the tank, turned the key to "on" and verified fuel is coming out. Fuel pump is running. I do smell fuel when I'm turning over the engine.
3. All fuses good.
4. While turning over: Tested LV signal to coil, good. Tested HV output at coil, good. Tested spark at driver-front plug (easiest accessible), good.

I am thinking at this point either:
1. My opti is bad, because of the oil ingress from the leak, or delayed water damage from the water pump failure, or...
2. Insufficient fuel delivery to the fuel rail. I read about a "schrader valve" where you can check the pressure, but have yet to find it. Would love to see a diagram?

Any thoughts or recommendations are appreciated!

Thanks,
Drago

 

If the oil had affected the optical cam position sensor in the Opti, you would have 1 or 2 codes related to the high and low resolution pulse signals. You don't indicate finding either of them.

Shoebox can help you with the Schrader valve. You have to unscrew the plastic cap to access the valve. Using a pressure tester is the only way to verify fuel pump/regulator operation. Letting fuel run out doesn't confirm adequate flow/pressure.

http://shbox.com/1/fp_reg.jpg

 

Injuneer, thanks for your quick response.

I just rented a fuel pressure gauge kit from Autozone, Acton brand I think. Once the rain stops I will check the pressure.

I did locate what I think is the schrader valve. It's at the very back of the engine, on the top, just a bit on the passenger side of middle. Looks like a slightly smaller version of the AC valve fitting, or a slightly large tire valve.

I verified spark using a homemade spark tester. Basically a pair of neon lights in series with about 15 resistors in series, each 100K. I also bought a "real" spark tester, which is just about the cheapest, flimsiest thing I've ever seen, but at least it's something I can gap...

Thanks,
Drago

 

Okay, fuel pressure comes right up to about 42PSI and holds when the ignition is turned to "On." When turned to "Off" it holds right around 40-42PSI.

I am leaning heavily toward Opti and/or weak spark.

 

I mentioned before I only had two codes, P0417 and P0410. They were actually:
P0410 P1441

That P1441 looks new to me - I've never seen it before.

I tried to start the car again to get it to throw any new codes. It did not, but my scantool (freediag software, talking to BR-3 on this page http://obddiagnostics.com/order.html ) told me:
Trying SAEJ1850-VPW ... connected!

Connection to ECU established
MIL light ON, 2 stored DTCs
P0410 P1441
ECU 0 is OBD II (California ARB) compliant
4 Oxygen (O2) sensors in vehicle
Oxygen (O2) sensor tests not supported
Currently monitored DTCs: P1333
Non-continuously monitored system tests (failures only): -
ECU doesn't support non-continuously monitored system tests

I cleared the codes, to try and get any new ones; and it still tells me P1333 is a continuously monitored code.

I then put the software in "monitor" mode, and it told me:
Parameter Current FreezeFrame
Fuel System Status Open -----
Calculated Load Value 0.0% -----
Engine Coolant Temperature 26C -----
Short term fuel trim Bank 1 0.0% -----
Long term fuel trim Bank 1 0.0% -----
Short term fuel trim Bank 2 0.0% -----
Long term fuel trim Bank 2 0.0% -----
Intake Manifold Pressure 101kPaA -----
Engine RPM 0RPM -----
Vehicle Speed 0km/h -----
Ignition timing advance Cyl #1 -12.0 deg -----
Intake Air Temperature -40C -----
Air Flow Rate 2.72gm/s -----
Absolute Throttle Position 0.0% -----
Bank 1 Sensor 1 Voltage/Trim 0.095V/ 0.0% -----
Bank 1 Sensor 2 Voltage/Trim 0.010V -----
Bank 2 Sensor 1 Voltage/Trim 0.205V/ 0.0% -----
Bank 2 Sensor 2 Voltage/Trim 0.085V -----
Currently monitored DTCs: P0200

During the start attempt, it told me:
Parameter Current FreezeFrame
Fuel System Status Open -----
Calculated Load Value 0.0% -----
Engine Coolant Temperature 26C -----
Short term fuel trim Bank 1 0.0% -----
Long term fuel trim Bank 1 0.0% -----
Short term fuel trim Bank 2 0.0% -----
Long term fuel trim Bank 2 0.0% -----
Intake Manifold Pressure 101kPaA -----
Engine RPM 116RPM -----
Vehicle Speed 0km/h -----
Ignition timing advance Cyl #1 -12.0 deg -----
Intake Air Temperature -40C -----
Air Flow Rate 2.72gm/s -----
Absolute Throttle Position 0.0% -----
Bank 1 Sensor 1 Voltage/Trim 0.105V/ 0.0% -----
Bank 1 Sensor 2 Voltage/Trim 0.010V -----
Bank 2 Sensor 1 Voltage/Trim 0.215V/ 0.0% -----
Bank 2 Sensor 2 Voltage/Trim 0.115V -----
Currently monitored DTCs: P0200

Do I worry about the P1333 and the P0200 being "continuously monitored"? They do not seem to have set the MIL.

P0200 comes up as an injector open circuit...

Any thoughts?

Thanks,
Drago

 

I'm no pro, but i can tell you that your intake air temp sensor/wiring is no good. -40 celicus (however you spell it) is the same as -40 farenheit. so unless it's that cold out, that sensor is either bad or the wiring is. If my memory serves correctly, you should read 5 volts if you test across the 2 terminals to check your wiring. This, however, likely isn't why the car won't start. Just something i noticed.

 

Thanks Dookie,

I actually had the breather assembly off during these tests, so the intake air sensor and others were disconnected at the time.

Thanks,
Drago

 

well now i feel redundant.... haha. sorry i'm no help

 

No worries, Luke!

Is there a possibility that some common thing to all the injectors are causing my problem? A bad ground or bad +12V? I checked the fuses, which are fine. Guess I have more digging to do.

Still feels very much like an ignition failure.

Thanks,
Drago

 

http://www.obd-codes.com/p0200
If Shoebox doesn't have anything (sorry, i don't know) this might help.

 

Final update.
I worked on this car for a month. A MONTH!
Due to oil leaking from the water pump drive seal, and coating the optispark and everything else with oil and filth, I was convinced it was the optispark, even though I got no codes, and seemed to have good spark with my homemade HV detector (a couple of NE-2 neon lights in series with a large amount of resistance).

I tore down the whole front of the engine, removing the fairly new water pump, the belt and harmonic balancer, the opti. I replaced the spark plug wires and spark plugs, as it had been 100K miles since the last tuneup. New seals for the water pump drive shaft as well as the opti. New opti. All pretty and clean, now.

In other news, I hope to the great Engineer In The Sky NEVER to have to change wires on a car like that. Ever. Again.

Got it all back together with new belt, new radiator hoses, etc. And....

The car would not start. Same symptoms. So, I went straight to the store, picked up a new coil and ignition module, and a real spark tester. The old coil could not jump the huge gap on the tester. The new one could. New coil R&R and the car runs like new.

Curses. At least the next owner will get a freshly tuned up Z28 with new opti.

The moral of the story is: Don't cheap out on a real spark tester.

Anybody want a slightly used (178K miles) opti covered in oil ?

One bright side to all this, besides being DONE. This vehicle has always had a SES light associated with the AIR pump system, since I bought it in 2000. After putting everything back together, that code is gone and gone. I did not pay close attention to how it came apart, and went by shoebox's diagram here http://shbox.com/1/air_pump_recall.jpg to reassemble, and now the computer is happy.

Thanks for everyone's input, and please pray for my sanity as I reflect on what awful diagnostics capability I have in my brain.
drago