'05 Limited Convertible, when I went to start my car this morning the engine turned over for 5 seconds or so but would not fire and crank. I normally wait for the fuel pump noise to stop before I start cranking, on my first try I thought I just didn't hear it start up. But after the failure to crank I tried again and it was definitely missing.

I pulled the RCM and looked at the solder joints thinking this was a mystery no start. However, they look pretty good, have a negligible resistance from the backside to the front side. I then plugged the RCM back in and had someone turn the key to the on position. The relays snapped closed to complete the circuit, but there was no noise for the fuel pump (there was a fan noise that started up). I had them then try to crank and once again it just turned over for a few seconds before shutting down.

I've read on here that the fuel system needs input from the crank shaft position sensor and cam shaft position sensor. If either of those were bad I would not expect the relay to snap into the closed position. Is that the correct way to think about it? Right now I'm thinking I've got a bad fuel pump. How can I verify before purchasing and replacing?

Prior replacements as follows:
Camshaft PS - October '18
Crankshaft PS - August '15
SKREEM - October '18

 

My notes are in red.

 

Measure pin 3 for 12 volts ( or better ) when the fuel pump relay is energized :

 

Thank you very much for the feedback.I was writing the post this morning from memory and my trouble shooting was a little rushed because I had to get to work. I've got some more detail to clarify now.

I said the resistance is negligible because it's not a very good multimeter. It is just a free one from Harbor Freight. When I measured the resistance of the fuses it bounced around between 0.6 and 1 ohms. The solder joints did the same so I assumed they were likely good to go, but maybe not.

The fan that was kicking on was not the radiator/engine cooling fan but rather just the small one that is in the housing the RCM resides within. However, when I unplugged the RCM connector to measure the voltage at the pins, the engine cooling fan did ramp up to high speed when the key was turned to the on position. The voltage across the pin 3 to pin 5 was about 5 volts when I manually closed the fuel pump relay. (The battery terminals are measuring 12.07 V across them.) This makes me think the solder joints have gone bad after all and it's cutting the voltage before it can get to the fuel pump. Am I on the right track this time?

 

So I pulled the connector, and measured the voltage between pins 3 and 5 on the RCM and got 0 V. I then turned the key to the on position and manually closed the gate and that measured with a voltage about 5 volts. My battery is showing just over 12.0 V so if I'm understanding things correctly, this point to the solder joints? There is a bad connection in there somewhere that's acting like a resistor and eating up the voltage supply before it can reach the pump?

 

You should measure voltage between pin 3 and 5 with the harness connected.
For about the first 4 seconds after you turn the key to start there should be battery voltage present.

 

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This may be a stupid question but how do I measure the pins for that connector with the harness sitting on top of the pins? I don't have the rcm in from of me right now, are there contact points on the opposite side of the PCB or something like that?

 

I'll throw in my one time experience with my no start. Blown fuel pump fuse (the yellow 20 amp I think at the end of RCM). After changing it twice in a short few minutes, I decided to check the connections to my new fuel pump. Sure enough, it was a loose connection on one of the terminals. I was afraid of breaking the post and didn't cinch it down well enough. I think it was a very small 7mm wrench for that. And don't forget the little lock washer like I did (probably why it backed off like it did).

 

Pizzaguy you seem very knowledgable. I have a 2004 coupe w/28000 miles. today I got into my car turned on the key....and nothing ( no cranking )
I thought...dead battery but I heard a fan running and I turned on my lights and they were well lit. I remember when I parked it last night I saw a red lit warning light
near the check engine light. Before I start tinkering ( RCM ?) or?? please help

as always your input is always appreciated. Also anybody else with ideas please weigh in.

 

Turn key, nothing but dash lights and engine cooling fan running is most surely the RCM.
Solder it, or send it to DJ ( tighed1 )

 

can I screw this up??
what if the solder melts into the other 2 pins ( next to them)
can solder be too high??

 

I don't know about you, but I can screw anything up
However, the resolder is something I have done many times for myself and others and have not managed to screw it up.

 

ala_xfire, I took a look back at those harness connectors and noticed the hinge so I was able to pop the top and measure the voltage. When the key is first turned to the on/run position the voltage between the 3rd and 5th pin jumps to 10-11 volts and then drops off. The same is happening at the positive and negative terminals of the pump itself. The battery is reading just under 12 volts on my meter.

The car is still turning over very strongly when I try to crank it but it isn't firing. Also there is still no noise from the fuel pump when at turned to the on/run position. Is it time to order a new pump or is the slight voltage drop relative to the battery a red herring I should look into?

 

"A fan running" does not tell me what I want to know, if it is the engine fan (which, after 30 seconds, if it is so loud you can hear it 250 feet from the car, it's the engine fan), this is a sign the RCM's engine control output is bad.
This is almost 100% certainly the relay itself or the connections on the RCM board. THis is VERY common. Order a new RCM ($130 or so) or just contact DJ and send it to him for reworking.

The warning light bothers me, ya gotta identify which light it was. IT may or may not tell us something.

 

Sounds like a bad pump to me. Of course, the pump does cut out in a few seconds, if the ECM detects that the engine has not started. TO verify there is no fuel presure, you can always put a gauge on it.

I bought one of these at Summit Racing. It comes with small and large Schrader valve fittings for the Crossfire and Ford Ranger - so any car with a "Schrader valve" on the fuel rail is easy to measure. My Crossfire runs around 56psi and the Ranger runs around 60psi. If I ever had a problem with them, at least I know what "baseline" is. It is no harder to measure fuel pressure than it is tire pressure with one of these (tho smoking while using this will set you and the car on fire, you bleed a little gas using it - so don't do this with a hot engine).

 

I think I'm going to just have to pony up and order a new pump and filter. I was hoping it was just going to be a some re-soldering to the rescue but it would seem my board must have been one of the good ones to sneak out of the factory. I think I'll probably order a fuel pressure tester too for future diagnostics, I'm pretty confident it's going to read zero right now. Considering I can't get it to crank, testing on a hot engine doesn't sound a problem for me but it's good advice for the future thank you.

I'm going to be out of town for a few days so hopefully the pump will have shipped by the time I get back and I can get under there. I'll let y'all know how it turns out. Thank you again for all the advice!

 

Generally if a car turns over then it is cranking. I believe this comes from the times when cars were or could be cranked by hand to start them.

 

I was going to suggest disconnecting the fuel pump connections at the pump, and clip on 12volts w/ alligator clips, and see if it sounds off for you. But it sounds like you've already ordered another pump.

 

Open the RCM. Have someone turn the key to the ON position.
For 2 seconds the 3 middle relays should close. After 2 seconds the fuel relay will open, leaving the other 2 closed.
If other than this happens, send your RCM to me for repair.

Email tighed1@hotmail.com for details.

 

New pump came in while I was out of town but I haven't had a chance to get up under there and replace it yet. One additional bit of information is the old pump has a resistance from the positive terminal to the negative (with the power cables disconnected) of 3.0 ohms while the new pump has a resistance of 9 ohms. Based on this I'm guessing something shorted out. So now the current is flowing through the short and the voltage isn't making it to the electric motor in the pump.

Tighed1,

I check the relays and they were operating just as you described (middle three close, fuel relay clicks open after 2 seconds). So that gives me a little more confidence it's just the pump that has gone bad. Once I can get under there and put the new one in I'll check back in and provide an update.