No start and no power to the fuel pump, help!

[Tbars4]

...just my thinking but i believe your fuel pump relay is your problem...if all else fails replace it...the battery issue is a sign of the relay going bad...:scratch:

 

[budwich]

I think if he said he changed it in the first post.

 

[Tbars4]

...doh', i read all the post and missed that......then i would be looking for a grounded connection..

 

[mikesparky]

Update - low current is the prob?

Haha, yep that was the first thing I did. Thanks for the input though. How would I look for a grounded connection? I'm pretty much a novice on electrical issues.

I've checked for a current at the inertia switch and I'm getting what I think is a very low current (the light comes on but not enough to beep) from the main wire (green/yellow) and the line going out (pink/black) which I'm pretty sure means the switch is ok.
Soooo what would limit the amount of current I'm getting? The only other place I can think to check is at the relay. I'll look for a way to check the current when it stops raining, which may be tomorrow. Still I feel like I've made some progress. I may try to go pickup a voltmeter tonight since it may come in handy before this is through.

 

[mikesparky]

Update - measurements and more observations

And I'm back. Sorry for the delay, I've been working all weekend. I now have a multimeter and have checked the voltages at the inertia switch and the pump.

At the inertia switch I found:
11.62 V - lt blue/orange [coming from the fuse]
0 - pink (fine since the switch is unplugged) [goes to the pump]
9.7 V - green/yellow [from the relay]

At the pump:
9.2 V - pink (inertia switch plugged in)
1.3 V - yellow/white
two other wires read 0

I have read in other threads that the pump needs 12V to run...so I'm guessing this is a problem. Just to check, I stuck the probe in the cigarette outlet to get an idea of the voltage and got a little over 6V. I also checked for obvious grounding points in the engine compartment and I found one that looked tight and nothing obviously loose.

I've also noticed that my pump relay is clicking open, but clicks shut again after a second or so. I don't think this is supposed to happen, but really don't know. I noticed the other 2 relays doing the same. Does the PCM relay affect the Fuel pump relay? I'm pretty confused at this point. Has anyone else had all these symptoms?

Thanks.

 

[mikesparky]

I think I've narrowed the problem down to the fuse box and whatever supplies power (pcm). The voltage is the same at the pump, inertia switch and the relay.

The problem now seems to be the relay which is fairly new (although I did blow out a 20A fuse after I got it). When I turn the key to on the relay clicks on and within half a second clicks off. I checked for readings at the inertia switch and relay and they both jump up to nearly 12 for a fraction of a second and then back to 9.7 which cooresponds with the relays.

I'm thinking it could be the PCM relay because I hear it clicking off at about the same time the Fuel Pump Relay is... what do you guys think?

 

[budwich]

well, I think you need to start "back at the beginning". First, you need to check you voltage at your battery then at your fuse block. They should be "roughly" the same... if not then you have a connection problem along the way. Nothing controls your PCM relay other than your key so if it is "clicking", you have poor voltage going to it (so it can operate completely) or your key / ignition has a loose connection.... but don't go there til you check the other stuff.

 

[CDW6212R]

Ditto, and don't go jumping power to any wires, it sounds like you might put full power to the wrong item if you do(The PCM is a 5V max device, and don't ever probe or apply voltage to a PCM wire).

First, does the fuel pump function for a short moment when the key is turned on(not start)? I ask because it must, that's the first thing to look at. The fuel pump primes the system for a second or so, then it shuts off. It should do that every time the key is turned on. That one test alone verifies the functioning of the fuel pump relay and inertia switch.

Next check the voltages that you haven't. Start at the battery, then the power distribution box(main terminal), then the fuel pump relay terminal inside the PDB. The voltages should be full, near 12v.

If you have the interior lights coming on with the battery troubles, turn them off with the master dial. Charge the battery, check and replace the battery cables if the terminals have been cut off. Bolt on battery terminals are very bad, they are temporary because they corrode internally.

If the voltages and pump function seem okay, which you can check in two minutes, then check the fuel pressure. That's how to verify that the regulator is working properly. Good luck,

 

[mikesparky]

Thanks for the info, I'll check the battery and block first thing. When I check for voltage at the fuse block, should I just probe where the battery feeds into it?

 

[CDW6212R]

Yes, that is just as straight cable from the battery. The engine should start/run if the voltage is high enough to crank, and the alternator is good. When you do get it running, check the alternator then. The battery trouble may be the starting issue, or the cables or alternator. Regards,

 

[mikesparky]

I didnt notice Don's post. To answer your questions the fuel pump is not priming and there's literally a split second voltage jump to near 12v when I turn the key to the on position. Then the relays all click off again. I have a really old bolt on terminal on my positive battery cable from the previous owner. I'll change that out tomorrow. It will be pretty sad if all of this trouble was from a bad battery cable!

 

[CDW6212R]

Fix the fuel pump connector also if you have not already, those never really fail. Get the pump to run to begin with for a second, before starting the engine. Once you have that working, then you can look at say the fuel pressure(35psi or more). Regards,

 

[mikesparky]

Thanks Don. I'll definitely fix the connectors before I finish up.

 

[mikesparky]

update

I replaced the bad positive terminal (the rest of the wire looks sound) and while I was at it I changed the fuel filter which I was planning to do anyway. There seemed to be some fuel pressure but I don't ever hear the pump prime. Still no go. Starts and dies.

I checked the voltage at the battery (a little over 12v) and the fuse block (same, bit over 12v) and at the relay (same). So power at the block doesn't seem to be the issue.

Just to be thorough I tested for current at the inertia switch and pump. Both read a split second jump up to nearly 12v but immediately go down to 9.7.

This leads me to conclude that there is either a problem with the relays or a problem with the pcm. Agree? Ideas?

 

[blorbic]

If the pump needs 12v to run, and it only runs for 5 seconds mabey the battery is bad. I would try and test the voltage on the battery with a load on it. If it is the battery i think you could get a new one sense it's only a month old. But if the battery is bad it would explain why it will not start but not why the battery it dead.

Just my two cents

 

[mikesparky]

Thanks blorbic, I was thinking of trying to start with a jump and see what happens. The car turns over strongly, but who knows at this point. The engine literally starts and fails within a second. It sounds like it gets a sip of gas and then runs out.

 

[CDW6212R]

The end of your last sentence hits it, the pump is not running long enough to prime it well, or the pump is not working when cranking or engine running.

The PCM runs the pump with the one relay trigger wire. It is supposed to be powered for a second or so when the key is turned on, and during all cranking, and when the engine runs.

Try this first, turn the key to on(not crank/start), then off, then on again and start it. That will raise the pressure more to begin with. If it runs then it points to lack of pressure.

If that doesn't make a big improvement, then you need to get a real fuel pressure checking tool, confirm the pressures. You will need to know the pressure first when primed, turn the key on and off until you get decent pressure, and stop, to see how long the pressure holds. If the pressure falls off immediately or doesn't even reach say 25psi, there is too much leakage, or the pump isn't working right.

This is a step by step process to verify what does work and what doesn't.

 

[blorbic]

Thanks blorbic, I was thinking of trying to start with a jump and see what happens. The car turns over strongly, but who knows at this point. The engine literally starts and fails within a second. It sounds like it gets a sip of gas and then runs out.

Forgot that it starts, so it's probably not the battery. Have you tried giving it gas to try and keep it running?

I just had my fuel pump replaced (my dad wouldn't let me do it in the driveway) worked fine until i was 30 miles from home and it would barley keep running. I had to give it a lot of gas in order to keep it from stalling at red lights. I got it on the freeway, but I noticed it went threw a quarter tank of gas in like 5 miles. I pulled off the freeway and had to towed back. Anyways, turned out it was the fuel regulator. It was stuck open and dumped the fuel into the engine.

So it might be the fuel regulator. I doubt it, but it's an option.

P.S. make sure you have gas in the tank. :

edit: Just read post above mine. Listen to him.

P.P.S. I think there is a redneck way of checking fuel pressure/flow by haveing the pump on and running it into a jar to measure it.

 

[mikesparky]

It seems like I get a little pressure from the split second voltage jump but that's it. If possible I'd like to figure out why the fuel pump relay shuts off prematurely causing the fuel pump not to operate. I'd also like to know a good way to temporarily wire the pump until I can fix the problem since I'm tired of borrowing my girlfriend's car (she may kill me if I need to much longer).

 

[mikesparky]

Oh yeah, I did try flooring it, no difference.