Crankshaft sensor?

So, I have an Innova scanner and it tells me P0335, but reads the RPM's just fine. The car cranks twice or three times before starting when it is cold, but only once when it is warm. But once it starts the engine never shuts off on me. There is an OL- fuel system fault on idle. However, it clears when I increase the throttle. Once the engine is back in idle, the fuel system fault appears again (no code). I revved up the engine multiple times to 2,000 RPM's (it sounded better) when I did an alternator test, it held up very well. I revved it up to 3,000 RPM's and even 4,500 RPM's four times on different occasions and no problem. But once it goes back to idle (it maintains steady 740-800 RPM's) it reads Fuel system Fault- OL. I ordered a new CKP sensor, but was wondering if that was the real issue. I plan to do fuel pressure testing and see if fuel pressure is okay on idle. I suspect this to be the problem because, somehow, the engine sounds better as soon as the throttle is increased as if it was not able to maintain fuel pressure while in idle but in reality it never shuts off. It just feels very weak and the fuel system fault message confirms that. So, that's where things are at after rebuilding the engine.

Hello,

So, I know this does not sound great- worse than a "sewing machine" (what can I say sister wants it fixed, honestly I am trying). Here is a break down of the video clip:

AT the beginning: combination of idling and throttle
AT 40 seconds: easy start up (engine already warm) but at 53 seconds engine idle grows weak but never shuts off or hesitates and continues at 740-800 RPM's.
AT 142 seconds is a clip of the engine being started on cold. 2 or 4 cranks and it starts but also never shuts off despite being noisy and weird.

Innova scan gives the following:

Fuel system fault OL which clears when the throttle is opened
STFT 25% (It should be lower)
O2 sensor 0.125 V (it should be 0.5 V or so)
RPM's 740-802

ECT on cold 50 F and goes up very slowly to 199 when the thermostat opens up (but now I removed the thermostat to ensure water pump is working- I found it leaking and needs replacement not sure why? I suspect belt too tense since the belt is making a screeching or rather whining. Not sure how to describe it.
Alternator: 14.66 with warning message too overcharging.
And finally P0335 (which is where my question was centered about. How come it reads the RPM if the CKP sensor is not communicating?)

Here is the video clip.

Hi there,

So, I am not done with the endless testing, but here is what I found thus far:
EGR: I could not get definitive conclusion on this valve because I am not sure how the intake manifold or solenoids create vacuum at idle (can you explain how and whether the vacuum is continuous? Because when I apply vacuum (the same as your EGR valve test video instructs, I see the diaphragm contracting, but it goes back where it was after few minutes unless I apply vacuum again. I mean if a vacuum is applied to it on a regular basis as long as the engine is idling, the valve wouldn't return to its original position? Meaning, why should I wait for it to hold vacuum? Does the EGR solenoid create vacuum the same way we test it? Anyway, it does not hold vacuum for more than 6 minutes or so (it kind of gradually relaxes back (it closes the port). As far as the EGR control solenoid and the vent solenoid both passed the tests when voltage is applied and air is passed through the ports.
TPS: It passed the voltage tests but the resistance was less than ideal (instructions 5000 ohms on WOT, I got 4200 ohms)
MAF: 14 g/s
Cylinder Compression: #1 195PSI #2 183PSI #3 195PSI #4 195PSI
CKP sensor was replaced (found ground wire severed under its plastic wrap) but have not done a relearn because it says dtc must be cleared.
Now here is the biggest find: Fuel pressure test: 25 PSI. I used an inline T type fuel adapter becaus the kit I received did not have the schrader valve adapter (I disconnected the fuel filter hose and connected the T hose adapter post filter and pre fuel supply manifold or pre fuel rail and clamped all and ran the test. It holds the pressure but the pressure is very weak. So, am not sure if it is pump, filter, debris and screen blockage in tank or something else (2-way check valve etc). How do I differentiate? Change them all? I have not done injectors or fuel pressure regulator yet (not sure if what I had done was sufficient but I got injector light node test kit? What about the regulator?

Great, thanks for your follow up response. I examined another EGR valve off of a 1995 2-door aspire found at a local pull a part, and I took the vacuum tool with me to test it. It is the same car, but has no boost sensor on its EGR solenoid assembly and its EGR has one vacuum tube on top that goes to the vent solenoid (which I tested and it held pressure while I did other things). The 1996 engine we have here has a boost sensor which has a vacuum line to the side of the EGR. The other vacuum hose (the top one which we are testing) also goes to the vent solenoid). Why the extra vacuum hose and EGR boost sensor on this car? Another thing I found was I had connected the lower hose of the evap purge cansiter to the emission canister and the top hose of the evap purge solenoid to the top of the intake manifold when it was supposed to be the opposite. I must have misplaced them while I was installing the lower intake manifold components. I guess that is all concerning the EGR and Evap. Today, I will replace the fuel pump, filter and screen and clean out the tank if it has any debris and see if the fuel pressure and STFT improve. Do you know if I have to relearn the CKP sensor and whether generic instructions work the same as any other car? (I watched a guy doing a relearn on a Saturn but not sure if the same procedure applies here)

Joe,

After changing the CKP sensor, the P0335 code cleared. But I am still getting the same rough idle or fuel system fault, stft 25% and very low fuel pressure 20-23psi. When I tried to do fuel pressure regulator test by unplugging the vacuum line, nothing happened (the pressure should've surged up a little but it didn't as if the fuel pressure regulator isn't there. The fuel gauge never moves out of its 22 PSI position). The injectors are receiving voltage and are ticking (audible test, never listened to them before but they go tick-tick-tick-tick-tick very fast?), The resistance is amazingly consistent among all 4 (13.8 ohms each). Continuity is excellent. When I unplug the connectors, turn the circuit on (without starting the car-ignition on) and DMM - probe to one terminal and DMM + probe to the other, I get erratic voltage readings (the DMM reads 10+ volts immediately, then it drops to 6 to 5 to 4 to 3 to 2 to 1 until it 0s out. The same happens with subsequent injectors). I can't seem to get 12 volts even after I made sure grounds are all okay and injectors are doing their function when the engine is running. The issue I was facing was low fuel pressure (22 psi as opposed to the specified range 35 to 45 PSI. I mean it is always below 25 and never changes no matter. What is wrong? By the way, after the engine is first started on cold (as I said before 2-4 crankings), the idle RPM is almost 1,100 and the fuel fault clears, the stft constantly changes between 7% to 21% and O2 sensor voltage 0.5V, but as soon as the engine warms up and or if I throttle while idling, the rpm drops to an average of 750 RPM'S, it begins to idle rough, O2 sensor back to low 0.12V and stft 25% fixed causing fuel fault OL. I mean, it sounds like throttle and or fuel pressure have everything to do with what's happening? Or combustion being quenched in one or more cylinders but not all (could that be it?) Any advice on whether this is a fuel pump issue, regulator, filter, injectors. Before I replace them? Voltage? Throttle? Internal invisible leak without compression effects?I could throw parts at it? What do you think?

Exactly Joe, I didn't get any fuel pressure change at all (the gauge is fixated solid on 22 psi (drops to 9 or so over night). I examined its vacuum tube for fuel leakage and none was detectable but the vacuum in the tube is present- meaning there is vacuum on top of the regulator).

I reviewed the car's record, it looks like shops have changed the filter three times in the past 15 years. I can change it again

what about the injectors I described above- any thoughts on why I got such an erratic voltage readings despite successful resistance and wiring tests?

I will go a head and replace fuel pump and screen, run a voltage drop test and report back to you.

Yes okay, I will check the fuel tank out and pull out the pump and replace the entire assembly including the screen. Let me know if you think the injector test I did was sufficient.
Thanks

Thank you for all your help. I just finished up replacing the fuel pump assembly and filter. As it turns out you were right. The strainer, the nozzle and the insulating seal had come unplugged and were laying on the bottom of the fuel compartment while the pump barely bolted to the assembly. The in-line fuel filter had the sole task of filtering the fuel in the past 15 years (no wonder my sister tells me they changed it several times in the past). The fuel pressure is reading 35 PSI up from 22 PSI and many of the numbers are back to normal. Enjoy the Holiday and Happy New Year. Thanks again.

James

I was getting ready to follow a Triple cycle procedure (aka PCM relearn which results in monitoring data for misfire, components and catalyst) after the rebuild, but the Innova 3130 Lat is giving me a couple of things I need answers to. The first is straight forward: P0335 which is CKP sensor malfunction and the second Open Loop- Fuel System 1 Fault with the following associated data: STFT 25% and O2 sensor at B1S1 is 0.13V and TPS of 9.8% while the O2 sensor at B1S2 is 0.06V and STFT at 99.2% the data is at idle (740 to 802 RPM fluctuation). When I throttle the pedal, the fuel system fault clears to CL, then returns to fault. The engine is able to idle at load between 16 and 21%. I let it idle for a long time over the past few days and the results were always the same. I also drove it few times to check alignment after overhauling the steering (I kept the speed to 10 MPH to 35 MPH only), and when I returned, the scanner gave me the same results each time. I inspected the spark plugs which I had cleaned good before installing and they were covered with soot, so I recleaned a different set of spark plugs and installed them with dielectric grease and the engine improved its starting with little to no hesitation- previously on cold I had to crank three times and once on warm). I also inspected the CKP sensor and found metal shavings on its magnet and some silver engine paint (I had done some drilling and figured some got on the sensor). I cleaned it, however the code P0335 returned and the cleaning didn't change the results. This car's CKP sensor is supposed to be pointing at the crankshaft reluctor via a bolt on a bracket. When I cleaned it, it looked like the sensor's round magnet was not pointing accurately at the teeth of the crankshaft; it looked like it was pointing in between the oil pan and the pulley. I could not change the direction. It goes on the bracket in only one way, but also its distance seems to be too far from the crankshaft. I looked at many sensors of different cars and they all seem to "hug" the crankshaft or the flywheel. Should I bend the bracket to get the magnet to point at center of the pulley? Or is the magnet able to pick up the location within its current location? Should I follow the triple cycle procedure (which necessitates driving and stopping and highway speed etc.) And then rescan for CKP sensor? Or should I change the CKP sensor first? Do you advise looking into fuel pressure (fuel filter, rail, regulator, injection or pump or screen problems- the fuel sat in the tank well over a year on 1/4 full which I could not siphon out but treated and filled up to full tank) or look at the distributor/coil plugs voltage weakness (the scanner gave me spark advance in the range of 7 to 13 degrees), the alternator at 14.66 and the battery at 12.8V (brand new battery but I have been cranking the engine a lot and idling a lot as well). It has no problem cranking, nor does it turn off when the fuel fault appears.

So, I am pretty sure the timing belt is right where it should be. Power? Yes, no problem. Last night, I throttled the engine multiple times to 4,500 and 3,500 RPM's four times and to 2,000 RPM's for 20 seconds while I ran an alternator test. No issues. It does sound much better when throttled. It never shuts off no matter how long I let it idle and the idle RPM's never deviates from the 740-800 range. I did an exhaust tail pipe test where a paper is placed at the exhaust tail pipe exit and found that the paper flutters towards and away from the exhaust gases as if being sucked into the exhaust periodically (some kind of vacuum is causing the paper to be drawn back towards the pipe instead of away). Catalytic converter blockage maybe? Stuck open exhaust valve? But what does that have to do with the P0335? I am not sure if a compression test will confirm open exhaust valve? The bottom line is the system has some kind of fuel related issue when at idle. The scanner gives me no other codes besides the P0335 open loop fuel system fault (which clears upon throttle).