The vehicle is a 1999 Dodge Ram Van 3500 with a 5.9L engine. Last time the van broke down (2 years ago), the owner was driving down the road when the van started to sputter and died. It has been parked ever since. I can not get the van to fire unless I spray starting fluid into the TB.

The Van has no codes at this time.
Van will fire with starting fluid and immediately die unless starter fluid is continually sprayed. This leads me to a fuel or Security issue.
I have 50 PSI to the fuel rail at key on and when activating the ASD with the scan tool (Good Fuel pump and FPR)
I have battery power to the injector plug while cranking, at initial key on, and when activating individual injectors with the scan tool.
I can audibly hear the injectors clicking when activated with the scan tool (Pulse from ECM)
I get a fast blink (on the ECU ground pulse) from the injector plug with a test light when activating the circuit with a scan tool.
For whatever reason, the circuit will not illuminate the noid light under these same conditions. However, I did confirm operation via two other methods, and I also tested the noid lights, and they are operational. So, this one baffles me.
Battery to Firewall, Battery to block, Battery to various locations on the block (including the back of the heads), all tests good.
The previous owner replaced the crank position sensor, cap, rotor, and coil.
I replaced the cam sensor after the sensor tested for high resistance (New cam sensor)
The crank and cam sensors display counts within the scan tool; however, I have not checked the waveforms.
I verified that MAP and TPS are operational via the scan tool.

There is a security light on the dash that does not illuminate when the initial key is turned. It never lights up, and the scan tool will not connect to the SKIM module.

It seems that the wiring is good, considering I can fire everything with the scan tool; it's just not getting an injector pulse while cranking.
Does this model van have a security module I could check for power? Does this module just inhibit the injector pulse, or am I barking up the wrong tree here?
Is it just the Cam and Crank sensors that the ECU uses to fire the injectors?
Any ideas are welcome.

Robert

 

I don't think security uses a separate module...... but, not 100% on that... I *think* it's just programming in the PCM. But, if the light isn't on while cranking, but tests good.... I don't think that is the problem.

If the PCM is seeing both cam, and crank sensor signals, the engine *should* run..... But, if you aren't getting injector pulse while cranking..... That's purely PCM.

Does it maintain fuel pressure while cranking??? Or does it bleed off slowly? (basically is the pump running while cranking?)

 

The rail maintains pressure on a gauge hooked to the fuel rail Shrader.

So the security light on the dash is there but it never lights up. I can't seem to connect to that part of the ECM/SKIM (if its even there.

The injector pulse does test good when commanded with the scan tool however I have not been able to get it when just turning the key over. It seems like something is stopping the ECM from sending the signal, but I know it's capable of doing so because the scan tool test proved that.

I just want to make sure I cover my bases before blindly ordering an ECU. I hate throwing parts at vehicles.

Robert

 

Run you VIN here. (case sensitive, so, all caps please.) That should tell you if it came equipped with any variety of security features.

 

Have you tried starting the van in neutral?

 

I ran the VIN through that site and nothing about security or SKIM is listed under any tab of the equipment. I also check both fuse boxes and there is no relay or fuse labeled security or skim. I’m going to assume this vehicle does not have that system.

I am going to double check fuel pressure and spark while cranking. If those both test good I have to assume it’s the PCM unless there are any other ideas I am missing.

Robert

 

Actually I have not, I’ll give it a whirl just for fun. I did check the selector position using the scan tool and it recognized the gear based on selector position.

Robert

 

Just confirmed the following:

Has constant 48ish lbs of fuel pressure at key on and while cranking
Has spark while cranking
Has voltage to the injector plug at initial key on and while cranking
Has Spark while cranking
Vehicle does not start in Neutral

It has everything but the negative pulse from the ECU. However, I know the ECU and injector drivers are capable of activating the injectors because I can command it through the scan tool and it does. I can confirm that I have RPM (Good crank sensor) and I also have "counts" that display for the cam sensor when trying to start the engine. The "sync" value in the tool displays "in sync" so I assume the ECU is seeing what its supposed too unless that value should be changing. The vehicle has no codes.

Any idea as to why the ECM wouldn't be firing the injectors is greatly appreciated. It feels like since it can activate them, it's not getting an input it's looking for but everything I have read says it just needs the cam and crank signal. Any additional test I can do to the sensors short of back probing and looking at the signal outputs? I did not do that because I was getting a reading through the tool.

Robert

 

That's a bizarre one. It appears everything works as it is supposed to, but, the PCM still doesn't want to pulse the injectors......

As your van doesn't have anything in the way of factory security..... Bad PCM is the only thing I can think of...... Is there a local yard you can get one from, and see if that one will actually run the engine?

 

IIRC the PCM takes over injector pulse after 3-5 seconds after start up...it need to see either the CPS or distributor information on the bus to continue to operate...
I think