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A little hiccup last week. My post was accidentally deleted. I replied in the MIA thread. It's all good! I've adjusted the post to reflect the excellent tips you guys gave me last week.
I have a 1999 Nissan Altima GXE that will crank, but not start. However, it will start for a couple seconds with starting fluid. Checks performed through Friday, 3/31:
* Fuses checked with multimeter in car and under hood
* Compression checked and have spark per above
* Fuel pump, fuel relay, fuel filter, fuel pressure all good
* Fuel injectors ohm out to expected value
* Fuel injector feed wires have expected +12v with ignition on
* Noid light does not come on when engine is cranked
There were some voltage issues present last week. I fully charged the battery over the weekend. Thank you to the forum members that pointed to that as a possible issue. Previously, I indicated that it appeared as though the computer was sending the ground control signal to the fuel injectors. I performed a resistance and volt check this morning, along with a noid light (incandescent) test. The noid light did NOT light. I am now doubting my prior assessment of the ECU ground signal to the fuel injectors.
The results of this morning’s, post battery charge, resistance and volt checks are as follows:
DC volts between battery NEG and FI connector+12V feed
IGN OFF = 0V
IGN ACC = 0V
IGN ON =12.5V
IGN Crank = 11V
DC volts between battery POS and FI connector +12V feed
IGN OFF = 12.8V
IGN ACC = 12.8V
IGN ON = 0.4V during the time fuel pump is primed, then drops to 0V
IGN Crank = 0.5V
Resistance between battery NEG and FI connector +12V feed
IGN OFF = 45Ω
IGN ACC = 165Ω
IGN ON = 0Ω/13MΩ (0Ω during fuel pump prime then approx. ½ seconds on each value, repeats)
IGN Crank = 0Ω/13MΩ (0Ω during fuel pump prime then approx. ½ seconds on each value, repeats)
Resistance between battery POS and FI connector +12V feed
IGN OFF = 105Ω
IGN ACC = 105Ω
IGN ON = 270Ω during prime, then 315Ω
IGN Crank = 200-230Ω
DC volts between battery NEG and FI connector ground control
IGN OFF = 0V
IGN ACC = 0V
IGN ON = 0
IGN Crank = 0V
DC volts between battery POS and FI connector ground control
IGN OFF = 0V
IGN ACC = 0V
IGN ON = 0V
IGN Crank = 0.3V
Resistance between battery NEG and FI connector ground control
IGN OFF = 0Ω
IGN ACC = 0Ω
IGN ON = 0Ω
IGN Crank = 4MΩ avg. fluctuates first couple seconds, then 0Ω
Resistance between battery POS and FI connector ground control
IGN OFF = 0Ω
IGN ACC = 0Ω
IGN ON = 0Ω
IGN Crank = 4MΩ avg. fluctuates first couple seconds, then 0Ω
The above readings were taken with the FI wiring disconnected from the FI's.
I believe I should get intermittent continuity to ground, during crank, when testing resistance between battery NEG and FI connector ground control. I'm not sure what to make of the readings at this point.
I'm still a little concerned that I get 12V between battery POS and FI connector +12V feed. With the harness connected to FI, won't that give me a slow battery drain over time. The battery does seem to discharge over time.
Possibly a bad ECU? Ignition switch? Perhaps wiring short? Just not sure.
Glad you got your post back up!
It looks like you need to start looking at the cam sensor. This is the input responsible for injector timing.
It's an optical type, mounted in the distributer.
If you have a scope, that's great, if not you can use your meter to at least know SOMETHING is happening.
The pins on the distributor connector are laid out as follows:
[6 5 4 3 2 1]
4 and 3 are going to be 5v square waves while cranking. With your meter set to VDC, the black lead at Battery Negative, backprobe pin 3.
With the engine running, you should read about 2.5v. I would expect cranking readings to be lower, but measuring something here would be a good thing.
Pin 4 produces a more intricate waveform, so anticipating cranking voltage would be little more than guess work. Running voltage would be 0.1v to 0.5v on a meter.
Forgive me if you posted in the last thread, but are there any engine codes?
Theft light solid on or blinking during cranking?
does the check engine light come on for a couple seconds when you first turn on the ignition?
