Fuel pump, crank no start

Thanks. That be it. I will get another one and well see what happens.

Okay, well I will try it and let you know.

CARADIODOC is one of our best! Please let us know what you find. We are interested to see what it is.

It is out for delivery this morning. I sure hope it works but guaranteed I will be asking what to do next if it's not. Lol. I will be honest i am thinking crankshaft sensor.

Or ECM. I do not know. I'm no mechanic. Does the BCM control the fuel pump and spark? I guess I'll find out today.

Okay got bad news and good news, sorta. Well i put in BCM and car still didn't start. So i was pretty bummed out. Check all fuses again and same issue. No 12v going to ECM fuses. Hmm. So put old BCM back in and car started. Ran rough as hell but then i got out and looked at engine and gas was squirting out from test valve. Button was stuck in so i shut it down. Now letting gas dry up before i try starting again. So. What the heck happened? Why did it start? I know it's not fixed yet but hoping if i get it to start i can get codes off it and maybe something new will show up.

And i know it's not because i unplugged BCM because i did that before.

It sounds like it could be the ignition switch. Can you please shoot a quick video with your phone so we can see what's going on? that would be great. You can upload it here with your response.

We've been concentrating on the Main Relay not turning on. That is turned on by the Engine Computer, but where the problem usually comes in is it's the Body Computer that is turned on when you turn on the ignition switch, then, if the programmed-in VIN matches, it is what tells all the other computers to turn on. The assumption has been the Body Computer hasn't been sending messages onto the data buss to the other computers. From what I've been reading, this appears to be a common problem that is solved by replacing the Body Computer. Some people have reported it only took disconnecting a battery cable to let the computer initialize and reset when powered back up, but you tried that already.

It's possible there's a poor connection between a pair of mating terminals in the connector, or even a broken wire right next to a terminal. Don't ask me how a wire that never gets flexed can break, but I've seen that more than once.

If the problem acts up again, the only course of action left is to connect a scanner so you can see what the computers are doing. You'll be able to see, for example, the state of the ignition switch as seen by the two computers in question, and whether that agrees with the position of that switch. You can watch if commands are being sent and received between the computers.

Also be aware that data buss runs between all of the computers, and a short anywhere will kill it and stop the messages from being sent. At one of the Chrysler schools I attended, the instructor used a paper clip at the load-leveling computer at the rear of a Jeep to short the two data buss wires together. That resulted in a crank / no-start. Her contention was that any computer on the vehicle could short internally and cause that. There would also be no communication with the scanner at that point, so the only solution would be to unplug every individual computer until the engine would start.

Later she qualified that to say she did that to make the point that the data buss could be shorted anywhere, but as for the computers, there was too much circuitry inside them that isolated any internal short from the data buss. To say that a different way, a computer could fail but it wouldn't take down the entire data buss. Because the wires are so well-protected inside the bundle they're in, there is a better chance of finding corrosion on the connector terminals. The data signals on older Chrysler products were only 0.2 volt digital signals, so they weren't affected too much by corrosion, but it is the type of thing we have to look for.

Related to that corrosion, it seems computers under the hood are designed pretty well to be immune from the effects of water and heat. It's the computers under dashes and seats that get less attention even though there's a lot of moisture in those areas. Ford has had a real big problem with their "Generic Electronic Modules", (GEM) doing weird things. That's their version of the Body Computer. A lot of problems have been caused by leaking windshields and water dripping onto the connectors, but corrosion forms there even when there is no leak. Anything that sits close to the driver's feet is prone to moisture problems. Watch out for connectors with wires that go straight in and you can see the back side of the terminals. Being exposed like that is a perfect place to find corrosion. Wires that run through rubber weather-pack seals are less troublesome. Those are what you'll find under the hood.

I will do that. I have to say that i'm a service tech for arcade like games and slots. so when i opened the BCM i notice that some pins looked like they got hot and could use re-solder. I didn't but when i put the BCM back instead of sitting on top of glove box i twisted it up above a little higher. so i'm thinking maybe now those pins are making a connection for now anyways. I might pull it out and touch them up a little bit and see what happens. I will go now and shoot a video.

This is now as i'm texting this but next ones are minutes before that it didn't start then it did start, but rough as heck. Right now it smooth up and regained power.

Minutes before. At first it didn't want to start then this original BCM still.

And now when i shift into drive it clucks pretty hard.

I restarted it and it stopped clucking into gear.

Clunking.

Those pins with bad solder connections were real common in TV's years ago. I was a TV repairman for over 35 years, and I re-soldered a lot of them. This has also been a problem in the 1990's with GM HVAC controllers.

Now it started. Running rough now.

Running.

What have you done between not running and now?

Just unhook negative to battery last night and kept trying to restart it and it started up. I let it warm up drove it 10 miles and let it run at idle at a buddy's and it just quit running and now I have to go and tow it back home. I stop there because i notice i didn't have turn signals but had everything else. And it was idling 10 minutes and just shut off.

Put the new used BCM and relearned the pass-lock but still no start and no fuel gauge no tachometer movement also. And scanner wont connect. Crankshaft position sensor? It was changed in 2012.

I'm going to have it towed home soon. Ugh. Frustrating. And it shifted hard out of park and kinda funny while driving and it was all highway 55 mph.

Could both BCM's have broken solder connections? Did you re-solder them on either computer? It sure sounds like everything else is working in those circuits, other than the BCM.

No i should of and going to now when i get her back here. I will keep posting my so call progress. Thanks

I'm at a total loss. Even change crankshaft sensor so i can scratch that off the list. Forgot to grab the BCM to solder it. Car still not at home. Going to get it towed home or thinking maybe to dealership and bite it. Hate to do that though.

I'm going to start over and check grounds. Something's just not right.

Thanks guys you did help a lot. it was my fault. after I took a couple days off from it I went back started over . It end up being that I purchased a faulty main relay from the store after finding the same relay. I swap it out and I got power to my ECM am I fuel gauge came on. I did a relearn on a BCM car started right up. thanks guys you were a great help. I owe you big time but tell you what I learned a lot and I'm going to save this information that you posted. The 2004 Saturn L300 crank but no start problem is solved thanks to 2CarPros. If I knew where you were I'd buy you a drink.

Dandy. I'm happy it was so inexpensive even though it took us a while. In the end, you figured it out so give yourself a pat om the back.

Yes sir, thanks again. though what was the odds of getting a bad relay new? the whole job was frustrating for something so simple but I knew I had to start over something wasn't right. thanks a lot guys.

CARADIODOC is one of our best! Use 2CarPros anytime, we are here to help. Please tell a friend.