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And you thought the procedure was a long post.... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Tue, 16 Oct 2007 18:04:36
In Reply to: Used Ari's No Start procedure and found this:(long), Todd98CSE, Tue, 16 Oct 2007 14:23:05 Members do not see ads below this line. - Help Keep This Site Online - Signup |
You got pins 6 and 10 right. Pin 6 has the fat black wire right across from the blank. Pin 10 has the fat grey with red stripe on the same side at the end.
You don't need to complete all the steps - it's a troubleshooting tree, and not all branches need to be followed.
The fuel pump may not be bad - there are more things to try (see below).
I'd try cleaning the fuel pump relay contacts - it's cheap and easy to do. I like cheap and easy.
I wouldn't worry about the anti-theft - the relay pulled in (test 2) so the anti-theft isn't the issue.
Here's some more things to try:
Replace fuse 14. I've seen fuses that look good but make a poor connection. It probably won't work, but See Cheap and Easy.
The three volt reading on test 2 is somewhat disturbing - it could still be fuel pump or wiring, or poor contacts. The procedure covers most typical faults, but not all possible ones.
Pull fuse 14 out. Pick one side of the fuse box socket for fuse 14, and measure to ground. Do Test 2 (pull fuse 23, etc.). Repeat for the other side. One side will go to 12 volts, then drop down. The other won't budge. The side that doesn't budge connects to the fuel pump. Set your meter to ohms, and measure fuel pump side of the fuse to ground. If it's more than two or three ohms, the fuel pump is bad or the wiring from the fuse box to the fuel pump is bad (or the fuel pump has a bad ground). See Checking the pump wiring, below. Put fuse 14 back in.
Put a voltmeter on fuse 22 (any side will do) to ground, car OFF. The voltage should be around 12 volts or so. Turn the car to ON (don't try to start). The voltage should drop, but should still be at least 9 or 10 volts. If not, the problem is a poor connection at the battery. Honest.
Assuming the voltage doesn't drop much, turn the car Off. Measure the voltage between fuse 22 and fuse 14. It should read 12 volts. If not (like a few millivolts or an open circuit) then the problem is the wiring to the fuel pump, the fuel pump, or the fuel pump ground. Why? Fuse 22 is pretty much connected to the battery. Fuse 14 ties to the fuel pump with a wire (no relay, etc) in the way. Between 22 and 14 is the fuel pump relay, which is open. So the fuel pump provides a ground return, or should. No 12 volts, no ground return and something wrong on the fuel pump side. See more below.
Assume it's 12 volts - do test 2 (pull fuse 23 for five seconds, reinsert). The voltage should drop from 12 volts for a couple of seconds and come back up. If it drops low - below a volt - the fuel pump relay is OK. If it doesn't drop much - say goes to 3 or 4 volts - suspect the fuel pump relay contacts. Why? This measures across the fuel pump relay contacts under a current load (fuel pump). A good set of contacts should have minimal voltage drop - only a few millivolts. But that's hard to see because most digital voltmeters don't update fast and you've only got a couple of seconds. A poor set of contacts will drop a lot of voltage - too much to get the fuel pump to run.
Checking the fuel pump wiring-
OK, say the fuel pump relay seems OK, now what? Go to the fuel pump - you'll need to get there anyway. Open the hatch, fold forward the rear seats. Pull the cover on the trunk floor. Look just forward of the hinge on the trunk floor (padded board covering the spare tire). You'll see two small screw heads - torx I think - undo them. Pull the cover back and out. On the driver's side up by the seatbacks you'll see a metal cover over the fuel pump. Remove the cover and you'll see the fuel pump and the wiring to it. There is a four pin connector. Pins 1 and 2 (fat grey wire with red stripe, fat black wire, respectively) are the power to the fuel pump, and the fuel pump ground, respectively. (The thin black wire is for the gas gauge).
Disconnect the connector. Measure the RESISTANCE from the black wire (pin 2) to ground (clean metal of the chassis). Less that 1 or 2 ohms is reasonable. It should be much lower, but most home ohmmeters don't read low resistance accurately. If you get a higher resistance, you've got a bad ground. Measure the VOLTAGE between pins 1 and 2 while doing the famous Test 2 - the voltage should be 12 volts - if not, there is a wiring problem between the connector and fuse 14.
next test - reconnect the connector. This one will take an assistant for sure. Poke the meter leads into the back of the connector, so you're measuring the voltage on pin 2 (Black wire) to ground while they're connected to the pump. Have someone crank the engine. If you see more than a couple of volts, you've got a bad ground. This is a more accurate test than the resistance test. If the voltage is low (hopefully less than 0.1 volts), you've got a good ground. Now, repeat the test measuring the voltage between pin 1 (Grey w/ red) and ground. If you see 12 volts or so, the fuel pump is finally, definitely bad. If the voltage is much less than 12 volts (like 6 or so), it is likely wiring between the pump and the fusebox.
The usual failure mode of the fuel pump is an open circuit - easy to find. It would show up waaaay at the top where you measured from the fuse 14 socket to ground. But it is possible that there could be an internal short in the pump, or it is jammed, in which case it would pull lots of current but not spin. This would cause large voltage drops on the fuel pump relay contacts but not pop the fuse. So if you see a big voltage drop - not much voltage right at the pump, like 4 or 5 volts, and you've ruled out bad relay contacts, etc, then you could have a jammed pump.
The ideal test would be to connect 12 volts and ground right to the pump. It's just a little trick because getting voltage back there can be problematic. And you don't want to be waving 12 volts around all that metal (and a fuel tank, which should be sealed). If you do, by all means, use 12 volts from a fused source.
Yes it's a lot - sorry - I've tried to pack a lot of things in. Try a few tests and report back - I'll try and help.
posted by 76.219.88...
, Tue, 16 Oct 2007 18:04:36 <-- Viewing This Message, Thu, 18 Oct 2007 14:23:37
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