Won't start without Starting Fluid

[EdJordan]

Dodge Wizards: I am a Dodge guy but have what I consider a strange issue.. I have a second generation 1500 with a 5.9, going down the road and it suddenly shifted down to "limp in" mode, then in a couple miles the battery meter went all the way down and the engine light came on. The truck was still running ok at this point. Pulled over and **** it off then it would not start back up. Would crank but not hit. Found a loose ground from the battery to the frame and fixed it. Still wouldn't start up. Had it towed home. Ran code check and nothing came up. Checked spark and fuel and both are present. Checked timing and it is good. Reset ECM, replaced cap, rotor, Cam sensor, coil. Still wouldn't start. Tried spraying starting fluid into it and it started right up and runs fine. Shut it off and it won't start again unless starting fluid is sprayed into the intake. After it starts it will run good and drive good until the next time it is shut off. Will crank but not even hit unless I spray starting fluid. Any ideas?

 

[HolyRamBatman]

Welcome to RF.

Have you actually checked the fuel pressure? It sounds like you don't have pressure pre startup and do after startup.

 

[EdJordan]

Checked fuel pressure.

Yes, I checked the fuel pressure, it is running about 49 pounds while cranking or running. Discovered today that the battery is not charging and it has a stored error code of P1389. This points me toward the ASD relay or the CPS. I replaced both of these which made no difference. Once you get it started using starting fluid it will run ok, but won't even hit without a spray.

 

[hemihustlin]

I think the fuel pressure should be higher than 49, more like 60-70, when starting. But i dont know the actual spec for this motor.

 

[dodge dude94]

Nope, OBDI trucks were lower pressure. 49 sounds about right.

 

[hemihustlin]

Then idealy you would need to get access to a scope to check your injecter PW at start up or swap your pcm with a known good one.
All signs point to a fuel delivery problem. What are we missing?

 

[dodge dude94]

Should be able to feel the click of the injectors when they fire. I'd be wondering if the fuel pump is being a problem.

 

[hemihustlin]

Hea but what if there not firing at the right time?

 

[dodge dude94]

Fuel sync or PCM.

 

[EdJordan]

Please tell me if I'm wrong, but my understanding is that the PCM takes input from the Cam Position Sensor, Crank Position Sensor, ASD, and the Oxygen Sensors to properly control the injectors. Three of these four I have already verified. The only one I didn't try is the Crank Sensor. I also have not replaced the PCM at this point. Would anyone think the Crank Sensor could cause this problem, or should I go straight to the PCM? Since the truck runs fine once started with a squirt of starting fluid, what other sub-systems or components would cause it not fire the injectors while cranking then fire them properly once the engine starts?

 

[dodge dude94]

Unless I'm totally wrong, you've got the roles of the cam sensor and the crank sensor backwards. The cam sensor controls fuel sync, crank sensor contributes to the ignition timing.

 

[EdJordan]

Thanks for the info Dude. Should I check and adjust fuel sync? If it's out, could that cause it to not start without starting fluid then run fine?

 

[dodge dude94]

You'd need a rather nice scanner that can read real time data. Not saying it's your issue, but it's possible.

 

[wingnut]

Just spent 10 minutes typing an explanation, just to get bumped-off by the site, and lose everything. Wearing thin guys!

I know this one, but trying to remember the cause! Ed, Does the fuel-pump "spin-up", and go off when you turn the key to ignition "ON"? The computer has logic written to it that ENABLES the fuel-pump ONLY when receiving a signal from the ckps. This is for safety in the event of an accident. BUT, there is a by-pass line of logic in there that turns-on the fuel-pump for a timed period at the time of "ignition-on", even though there is no ckps signal yet. This enables the system to be pressurized before cranking, even though the computer is NOT receiving the ckps signal. The fact that you can start it using fluid is helpful. I think there may be an RPM threshold from the ckps that the computer looks for before it enables the fuel-pump again. With starting fluid, you attain this RPM threshold, and the pump comes on, and the engine acts normally. If this is the case, then the fix is small. I just cant remember what it was.

 

[EdJordan]

Thanks for the information Wingnut. I checked for fuel pressure during engine crank and it has full pressure at the valve. Fuel pump is on during crank. It seems that the injectors are not firing during crank.

 

[Merc225hp]

From the 95 fsm

CAMSHAFT POSITION SENSOR TEST—3.9L V-6 OR 5.2/5.9L V-8 ENGINES

The camshaft position sensor (Fig. 1) is located in the distributor on all 3.9L V-6 or 5.2L/5.9L V-8 engines.

To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual.

To test the sensor only, refer to the following: For this test, an analog (non-digital) voltmeter is needed. Do not remove the distributor connector from the distributor. Using small paper clips, insert them into the backside of the distributor wire harness connector to make contact with the terminals. Be sure that the connector is not damaged when inserting the paper clips. Attach voltmeter leads to these paper clips.

(1) Connect the positive (+) voltmeter lead into the sensor output wire. This is at done the distributor wire harness connector. For wire identification, refer to Group 8W, Wiring Diagrams.

(2) Connect the negative (-) voltmeter lead into the ground wire. For wire identification, refer to Group 8W, Wiring Diagrams.

(3) Set the voltmeter to the 15 Volt DC scale.

(4) Remove distributor cap from distributor (two screws). Rotate (crank) the engine until the distributor rotor is pointed towards the rear of vehicle. The movable pulse ring should now be within the sensor pickup.

(5) Turn ignition key to ON position. Voltmeter should read approximately 5.0 volts.

(6) If voltage is not present, check the voltmeter leads for a good connection.

(7) If voltage is still not present, check for voltage at the supply wire. For wire identification, refer to Group 8W, Wiring Diagrams.

(8) If voltage is not present at supply wire, check for voltage at pin-7 of powertrain control module

(PCM) 60-way connector. Leave the PCM connector connected for this test.

(9) If voltage is still not present, perform vehicle test using the DRB scan tool.

(10) If voltage is present at pin-7, but not at the supply wire;

(a) Check continuity between the supply wire. This is checked between the distributor connector and pin-7 at the PCM. If continuity is not present, repair the harness as necessary.

(b) Check for continuity between the camshaft position sensor output wire and pin-44 at the PCM.

If continuity is not present, repair the harness as necessary.

(c) Check for continuity between the ground circuit wire at the distributor connector and ground.

If continuity is not present, repair the harness as necessary.

(11) While observing the voltmeter, crank the engine with ignition switch. The voltmeter needle should fluctuate between 0 and 5 volts while the engine is cranking. This verifies that the camshaft position sensor in the distributor is operating properly and a sync pulse signal is being generated.

If sync pulse signal is not present, replacement of the camshaft position sensor is necessary.

For removal or installation of ignition system components, refer to the Component Removal/Installation section of this group.

For system operation and component identification, refer to the Component Identification/System Operation section of this group.

 

[Saltillo Express]

I wonder if he got it going? I miss my 2nd generation Ram. The best ever.

 

[EdJordan]

Still no luck. I replaced the crank sensor and still have the same symptoms. I do have another symptom that I just discovered.. I got the truck started using starting fluid and took it for a short drive, it stays in second gear all the time. I assume this is "limp in" mode.

 

[Saltillo Express]

Hey Ed. No limp mode won't hang it in second. Or, "when mine went into limp mode it didn't stay in one gear." Even being OBD1 - that thing should be slinging codes all over the place. Have you scanned it for codes?

 

[EdJordan]

Had it scanned and got code P1389. I believe that is an ASD code, but have already replaced the ASD relay. Today I'm going to check for voltage at the ASD relay socket.