cranks but won't start?

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slicknapier

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Alright guys, I got the 2000 5.2 magnum in my 63 Crewcab this week! I used the Durango wiring harness, ecm, pdc, guages etc..I can get the truck to crank, but it won't start? I have spark and I have fuel to the rails. My voltmeter busted , so just testing with a test light the injectors are firing. I can get it to run by spraying ether in the throttle body then it runs fine, but will not start again on it's own. I just have the Durango tank in the bed of my truck for now with the original pump/sending unit. Also, when it is running the alternator is not charging, any relation to not starting? Everything worked fine in the donor, what has changed or what do I need to look at? I will be going back over all my grounds tomorrow. Amost forgot, i don't have the exhaust hooked up, just the manifolds. Thanks, Andrew
 
slicknapier said:
I can get it to run by spraying ether in the throttle body then it runs fine, but will not start again on it's own. Thanks, Andrew
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So, it runs OK once you get it started, but won't fire up when cranking?
 
When you first turn the key on, the fuel pump should run about 2 seconds to pressure up the system. Maybe you could go to one of the parts stores and rent a fuel pressure gauge that attaches to the fuel rail through the shrader valve. It would tell you if you have sufficient fuel pressure to start.

If it was electrical, the engine wouldn't start at all. Starting with the aid of the starting fluid tells me it's a fuel problem during initial start. That's all I could think of.
 
Thats kind of where im at. Fuel pump does come on and i have fuel at the schrader valve at the rail. Is it enough pressure? I don't know.
 
Not sure on a 2000 but my 94 318 Magnum has a vacuum operated fuel pressure regulator left side fuel rail area. A Lower vacuum reading allows more fuel pressure (as in start and high engine load). You can check that with a fuel pressure gauge and hand pump vacuum attached.
 
I'm a few days behind you, Slicknapier! I just put a Mighty-Vac on my fuel line to draw gas through the pump and filters, didn't want to start the pump totally dry. I put a pressure gauge in the fuel line before it connects with the original line on the fuel rail. Mine is a 2001 Ram 5.2.

Quote:
"Not sure on a 2000 but my 94 318 Magnum has a vacuum operated fuel pressure regulator left side fuel rail area."

Ours doesn't have the regulator on the fuel rail. At some point, don't remember which year, the federal gov't mandated the pressure return be inside the fuel tank. I think your year also runs at a somewhat lower fuel pressure. I had a fuel rail from a 92 Dakota, but it wouldn't work without switching out the fuel injectors so I used the 2001 setup.
 
can you buypass and keep running spraying gas into the motor ? or iwould look at a ballast resistor sounds electrical ,Make sure your regulator is good 1 live grounding wil lkill them. on an older style set-up
 
it runs fine after its started. Just drove it to the end of the driveway and back no problem. Just wont start on its own.
 
Pretty crude for, but this is where Im at right now. Maybe something obvious will jump out for someone smarter than me!
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This is just a suggestion. Can you turn the key on and off three or four times to get the fuel pressure up, and then try starting? If it's not the fuel pressure, it may be that the injectors are not pulsing during the cranking period. Seems there was a wire that I had to connect to the start terminal on the ignition switch. The start terminal supplies power until the engine starts, then power is supplied through the on terminal of the ignition switch. The start terminal may be what is supplying power to pulse the injectors.
 
I've cycled the.key and it doesn't help. Ignition switch is out of the Durango so it just plugs in. With just a test light i have power to the injectors while its cranking. Doesn't seem to pulse? Just constant power.
 
I would get a scan tool on it check for codes and check the data ,ECM relies on sensor inputs and you could catch a bad reading on scan tool data (IAT and CTS temperatures and MAP are the big 3 I believe for fuel control) , Incorrect inputs could cause a lean no start .

Of course good grounds and battery volts to the ECM need to be good and checked first . ( weak battery can cause lots of problems too)

Sounds like its lean, low fuel pressure/volume or bad input from a sensor ,or sensor connections .

Usually you find in engine swaps grounds left off /loose or pinched wires are common things .
 
The cheapest scan tool you can get is the Torque app from the Google play store. The basic version is free and the advanced is $4.99. It will allow you to read the codes and reset the check engine light. Works for most brands of cars. You will need to buy a ELM327 bluetooth dongle from Amazon about $8.00. Good Luck
 
You can also remove the fuel rail and injector assembly and watch the injectors to make sure the injectors have a good spray pattern while cranking engine over, I use paper towels laid down to soak up the gas . Make sure you unhook the primary side of the coil so you won't have a source of ignition during this test.
 
you really need to check fuel pump pressure. Inside the tank there is a short rubber hose from the pump output to the fuel pressure regulator inlet. I've seen these split and leak fuel internally inside the tank.
 
Fuel pressure is good while it's cranking. 48-49 psi. Kind of stumped and tired of going over the same things. I have added extra grounds and double checked all the grounds and fittings. Does the alternator not charging have anything to do with it? I charged the battery last night so it's good. I just ordered the elm scan tool and i will get the torque app. Just don't want to wait 2 weeks for it.
 
Another thing i just realized is the pcm is screwed directly to the steel inner fender. The body of the pcm itself is grounded. Is this an issue? Should it just be grounded through the ground wire and the body of the pcm itself isolated from ground. I tried unbolting it and didn't make a difference, but could this have fried some portion of the pcm?
 
Most of the internal grounds for the PCM go to the PDC. They're considered isolated or noiseless grounds. The data link connector also has one of those grounds. I think they are mainly for the digital signals going to the microprocessor for the dash and gauges and the DLC.

Do you have both connectors going to the alternator? There is also a battery temp sensor. I'm not sure whether that is absolutely necessary or not but it does deal with the function of the alternator.
 
When you swapped the engine in, did you have to remove or loosen the distributor at all? There is a cam-crank sync that has to be done if you do, and it won't start or in some cases may start after a really long crank. Also the asd relay will kick on only after the PCM sees cranking rpm, so it wouldn't fire injectors if it is cranking slow or another sensor issue.
 
I just remembered you said you had power to the injectors while cranking so shouldn't be an asd issue.
 
ralphie361 said:
When you swapped the engine in, did you have to remove or loosen the distributor at all? There is a cam-crank sync that has to be done if you do, and it won't start or in some cases may start after a really long crank.
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How do you sync it up, or does it do it automatically?
 
No didn't touch the distributor. I do not have a battery temp sender in it. Did not have one when i took it apart and i'm 99% sure it was charging before the swap.
 
68coupe said:
How do you sync it up, or does it do it automatically?
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The easy way is with the drb, but you can do it without it. The cam sensor switches from 0 to 5 volts, so backprobe the signal wire and watch it with your meter. Then manually put the engine at top dead center on the timing mark. Loosen the distributor and you should be able to twist it and watch the meter go back and forth between 0 and 5. Right at the moment it switches tighten the distibutor, it should be almost flickering between 0and 5. That is from memory, but it does work, I had to do it this spring on my cousins truck and we didn't have a drb. His magnum swap wouldn't start until we did this, but it would start with fuel down the intake.
 
slicknapier said:
No didn't touch the distributor. I do not have a battery temp sender in it. Did not have one when i took it apart and i'm 99% sure it was charging before the swap.
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Ok, there is a tool called a noid light that you plug in instead of an injector, and it flashes when the injector would pulse. They are cheap and it would tell you if the injectors are firing while cranking.
 
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