Hi, everyone, this newbie sure could use some advice.
2000 malibu,145.000 mi. Replaced fuel pump and filter. Can hear it run when I turn the key on. Cranks but won't start. When I depress the schrader valve on the fuel rail I get a squirt of fuel and then nothing. Computer shows no codes.
I'm baffled any help will be appreciated.

Let's back up here a minute. Did the car start before you put the fuel pump in it? The fuel pump was diagnosed as being bad or just a guess? Do you have spark to at least 2 cylinders? Do you have access to a fuel pressure gauge? If so, check fuel pressure, you should have 52-59 psi Key On Engine Off or KOEO. When you cycle the key from OFF to RUN the ECM commands a 2 second prime of the fuel pump. You may have to cycle key a few times to get a good reading, wait 10-15 seconds when you turm the key off before you go back to run. You could also crank the engine for a few seconds until the fuel pressure gauge stabilizes. If you get a pressure reading, it may drop slightly when the pump shuts off but should hold, not dropping more than 5 psi in 10 minutes. Come on back with a little more info and we'll go from there.

thank you, rodents, for your speedy response.
The " bad " fuel pump was a guess on my neighbors part. His daughters car. He assumed fuel pump when it wouldn't start, towed the car to my garage (I volunteered to help). I got no sound from the pump when I turned the key on, also no fuel at rail. We replaced the pump, now there's sound when key is on but no fuel at the rail. Cranked engine over and over, still no fuel at rail. Will get a fuel pressure tester today. Have not checked spark as yet. I thought maybe anti-theft or map sensor some other system was causing no-start. I really don't know what the next step should be.
thanks again, so nice of you to respond

I got no sound from the pump when I turned the key on, also no fuel at rail. We replaced the pump, now there's sound when key is on but no fuel at the rail. Cranked engine over and over, still no fuel at rail. Will get a fuel pressure tester today.

Okay, now with some more information, we can move on. In the original post, you said you got a squirt of fuel, then nothing. Now your last post seems to say after the fuel pump was replaced, there wasn't fuel at any time. For now, I'll assume there never was fuel. Does the instrument cluster light up normally? A lot of telltales should light up, not worried about the gauges right now. Is the check engine light illuminated with the key in the run postion? Check the F/P Injr fuse in the underhood fuse block with both a test light and a meter if you can and check in the run and crank positions, the test light should light up bright and the meter should show whatever your battery voltage is, nominally 12 volts. In the left junction block, side of dash there's a panel that just pulls out, you'll see it with the door open. Check the PCM ACC fuse in all positions except OFF and you should have the same results as above.

At this point in time I'm not concerned with the theft system as the PCM should still give a 2 second prime to the fuel pump, we need to address that first. If you find anything other than full battery voltage to either of the fuses I mentioned, usually 4 or 5 volts is what you'll see or a dim test light, the issue is frequently the ignition switch itself. See where this gets you and we'll keep at it.

Instrument panel all illuminated in RUN. Check engine light on in CRANK.
F/P Injr fuse...RUN-dim light.6 volts CRANK-dim light, 6 volts(slowly creeps up to 10 or 11 volts)

PCM ACC fuse...RUN-dim light.12 volts CRANK-dim light, 12 volts (creeps down to 10 or 11 volts)

Fully charged battery (12 volts) at beginning of tests. Triple checked tests..pretty sure I got it right. Thanks again for your help, it means a lot.

F/P Injr fuse...RUN-dim light.6 volts CRANK-dim light, 6 volts(slowly creeps up to 10 or 11 volts)

PCM ACC fuse...RUN-dim light.12 volts CRANK-dim light, 12 volts (creeps down to 10 or 11 volts)

Fully charged battery (12 volts) at beginning of tests. Triple checked tests..pretty sure I got it right. Thanks again for your help, it means a lot.

Works for me! Put an ignition switch in it and you should be set. Now you need an ignition switch. For clarification purposes, this is an electrical device mounted behind the ignition lock cylinder which is where the key goes. Some people get the two confused. If you have any more questions or problems, come on back. Good luck.

I finally got the ignition switch out and checked for continuity across the various terminals in the switch in run and crank positions (according to the diagrams in the haynes manual). Everything checked out OK. Do you have any suggestions as to what I should try next?
Although I'm a little frustrated, it's a learning experience and Im very grateful for your help.

I finally got the ignition switch out and checked for continuity across the various terminals in the switch in run and crank positions (according to the diagrams in the haynes manual). Everything checked out OK. Do you have any suggestions as to what I should try next?
Although I'm a little frustrated, it's a learning experience and Im very grateful for your help.

Let me explain why you got continuity. When you do a continuity test, you're supplying a very small current to the circuit. Let's forget this is a switch for a minute, let's say you have a lamp that doesn't work but when you measure the voltage circuit and the ground circuit, you get continuity and the socket and bulb are good. If you have a break in one of the wires so that most but not all of the strands of the wire are broken, you have enough of a connection to pass a continuity test but not enough to supply enough current to the bulb to light the bulb. The break in the wires is a point where only so much current can pass or a point of high resistance to current flow. Same thing as a pipe, If you have a 4" pipe and then at some point you put a 1" pipe in place of a 4" section, the 1" pipe now becomes the restriction to flow and only so much water can pass through the 1" section.
Now, back to the switch. You pass a continuity test for the same reason, there's a high resistance connection in the switch that you don't 'see' in a continuity test but under normal circuit loads it shows up. That's why when you checked voltage you got 6 volts that rose to 10-11 volts. The ignition switch is fed battery voltage, nominally 12 volts straight from the battery, no switches in line before the ignition switch. Now it's extremely unlikely you have an issue prior to the ignition switch, possible but let's say better than 9 out of 10 times, the ignition switch is to blame for an issue like you have. I would put one in and see what you have then. If you know someone with a PowerProbe, you could use that to supply battery voltage to the fuse that has only 6 volts and the car would probably start then. Nice tool but you have to know what you're doing with it.
You're doing a good thing, trying to understand why it doesn't work, that's great, and this kind of stuff can be frustrating, it gets a lot worse than this too! I'd recommend a GM switch but if you go aftermarket, it should be okay it just might not last as long as a GM one. I hope I answered your questions and you understand where I'm coming from with my descriptions. Understand, I'm counting on your diagnosis as far as measurements and all but it sounds as if you've done a good job so far. Put a new switch in and get back to us then.

I believe I checked continuity incorrectly, and rechecked according to the diagram I've attached. The red Xs are the only connections that had continuity. I really was happy with your explanation. Happy that maybe it is a bad switch after all. I sure would like to get this thing fixed. I'm now convinced that it is a bad switch, especially after reading your last post. Let me know what you think of this last test, illustrated inhttp://www.newmexicoartists.net/ignitionswitchdiagram.jpg the attachment.

http://www.newmexicoartists.net/closeup.JPG
http://www.newmexicoartists.net/ignitionswitch.JPG

C1-A to C2-B is the combination that would power the Fpmp/inj fuse. What you did is a great learning experience, I give you a lot of credit for digging in like you did. However once I see anything less than B+ at an ignition switch fed fuse, almost without fail my next step is an ignition switch. I look at the wiring diagram first but the feeds to the ignition switch are less numerous than the feeds out of the switch. If I see multiple 'legs' of the switch are below B+, then I'll see if they share a common feed to the switch and then verify that feed is good prior to putting a switch in. In this case you have one leg out that's of concern to me so I'd go for the switch first. It's something that comes with going down the same diagnostic path numerous times, you adjust your strategy to make the diagnosis quicker without losing accuracy. Nothing is ever guaranteed except death so I don't try for absolute proof most of the time. Once I've ruled out all but the most off the wall possibility, I go for it. Good luck.

thank you so much for your comprehensive and thoughtful explanation. I think I understand now that even if a new ignition switch and a defective switch display identical continuity readings the defective switch cannot supply appropriate voltage for some downstream requirements and if the F/P injr fuse reads less than 12 volts ( B+) then it's the switch. I Just purchased the new switch (Gm $225) and got the same continuity readings. Your explanation dispelled my doubts. I'm going to hook it up and try it. I'll let you know how it works.

I installed the new switch still won't start. Didn't put the dash back together.
would that make a difference? Rechecked the F/P injr fuse, same readings as before. Same with the PCM/Acc fuse. Now I'm stumped.
Did I install the new fuel pump incorrectly? Do I keep trying to start it until the computer catches up? Faulty new switch? I've sprung a leak in my pot of patience.

With only 6 volts going to the F/P/Inj fuse, the fuel pump will never work right. That has to be addressed first. Okay, well now we need to dig a little deeper. In the underhood fuse block, check each of these fuses with the ignition in the run position. IGN/MOD, B/U LAMP, PCM IGN, F/P INJ ( which we know is 6 volts already) , A/C BFC AUTO TRANS and last, ABS IGN. Then since you have it apart yet go to the ignition switch C2 pin B a pink wire and if you can back probe the terminal, what do you have there? Nothing you've done will make that F/P INJ fuse have 6 volts potential. If you shorted something, you'd blow a fuse. Faulty new switch? Well, you're going to tell me that after you do the checks I just gave you. First, new doesn't mean good and that unfortunately does apply to factory parts, just they back them up better. First time in years that I've had one not be an ignition switch. I feel bad now that you got that new switch but honestly sometimes that happens with the vehicle right in front of you much less over the internet. I understand the frustration, been there many times, this is relatively mild really. Well, let's see where this gets you and we'll go from there.

ok, here goes:

ign/mod - 11 volts
b/u lamp - 11 volts
pcm ign - 11 volts
f/p inj - 6 volts
ac bfc - 11 volts
auto trans - 11 volts
abs ign - 11 volts

Back Probe c2 pin b - 11 volts

ok, here goes:

What's the voltage across the battery ??

I don't know what all those points you are checking ARE, mind you, but all those 11's sure look suspicious to me.

(and now back to the real analysis being conducted by Rodents!!)

What's the voltage across the battery ??

I don't know what all those points you are checking ARE, mind you, but all those 11's sure look suspicious to me.

(and now back to the real analysis being conducted by Rodents!!)

I'm not concerned about the 11 volts as the battery state of charge may be low due to a lot of cranking and no running. What was checked was power to the underhood junction block which is good, all of those fuses are fed by the same leg of the ignition switch and share a common feed path internal to the junction block. Only one fuse is having a problem so you've narrowed it down to a junction block. Now, what we need to do is determine if we need connector work or just a junction block.

There's going to be sliver colored bolts in the junction block, 10mm most likely though some are 8mm. Disconnect the battery and anything connected to the junction block and completely loosen the silver bolts but they won't come out. lift up on the junction block and there is about 6 or 7 connectors that unplug from the block. Some are the ones held in by the silver bolts, others have a retaining finger,look at it, you'll see how it works I think. What you're looking for is obvious burn marks in the body of the connector or any terminals that look overheated and may have spread. If you don't see anything, get a junction block, used is a gamble but new might surprise you, some are big bucks, some not so bad. If there is connector damage, you have some work ahead of you so I hope you're lucky. I would tend to think it's going to be just a block but we'll see what you come up with. I haven't seen this in that era Malibu for a while but it does happen. If you have a good sense of smell, smell the junction block and it may smell burnt. Okay, hang in there, we'll get it running.

I have a brand new battery, fully charged, tested 12V across the terminals.

The underhood fuse relay box has no bolts in the threaded holes (see picture), and I've taken everything that I can find loose. How do I lift the box? I assume I should be able to look under it to see the connectors? I don't smell anything. I'm assuming I should be able to see the connector for the FP/INJ fuse from underneath. I hope I'm understanding this. http://www.newmexicoartists.net/FuseRelayBox.jpg

Hmmm, okay so my photgrahic memory isn't so photographic. The junction block snaps into the bracket under it. Might be a 10mm nut holding it somewhere. The bracket will hold the junction block with a 'three fingered fork' ( best way I can describe it) The middle prong of the fork will latch on to the block unless the photographic memory failed again. Show me some side views of the block if you can't figure it out. The connectors are underneath and you don't get a lot of room to work with to lift the block up too far until the connectors are off. You won't be able to see the ignition switch side of the fuse where the problem is but by chance if the fuel pump was drawing too much current at some point though not enough to blow the fuse, due to maybe a clogged fuel filter or just a bad pump, the pump side of the fuse is connector C1 pin A7, a pink wire. C1 is gray 68 cavity connector. C1 has a gray wire in A6, no wire in A5 or A8 through A10. Look real good for spread terminals or overheating, not hard to see most of the time. Hopefully it's just a block. There will be a bolt holding the three large connectors in the block, just from the bottom, not the top. Could be 7mm, 8mm or 10mm. Those large connectors come out hard sometimes. Once the bolt is completely loose but remember it doesn't come out, sometimes a small screwdriver to GENTLY pry the connector out is needed. DO NOT damage that connector, you WILL hate life if you do. Take your time, if you get annoyed, take a break, cool heads prevail. Stick with it, you got a not so common failure and I stopped my diagnosis too early but we're here now so we'll see it to the end. The pictures help as even service information has lousy pictures.

I've had some interruptions (family visiting). Please don't give up on me. The chevy dealership here will allow us ro return the new ignition switch, quite a relief. Haven't figured out how to remove the fuse relay center. Will try again and send pictures if necessary.

I was wondering where you went. I am sorry about the incorrect diagnosis there, just got too sure of myself and well, we see how that went. If they let you return the switch, great, on electrical stuff sometimes they do and sometimes they don't. When you get back to the car, look for metal tabs around the side of the junction block. I don't have one here to look at. If you still can't see how it works, put some pitures up showing side of the junction block. I'll be in New York for school for 2 days Monday and Tuesday so my time to check here will be later in the evening and not at all during the day.

Very glad you're still there. Got the fuse/relay center box out, slid on the rails toward the front of the vehicle. I have no idea how to take it apart,fearful of damaging something or pulling loose all the connectors and not able to get them reconnected. I've taken pictures...here they are:http://www.newmexicoartists.net/topviewfromdriverside1.jpg

Pic #1: Don't know if these are really release points. When you look down the holes there's a little brass-looking tab down there. There are 3 of these.

http://www.newmexicoartists.net/viewfromfront1.jpg

Pic #2: View from front of vehicle.

http://www.newmexicoartists.net/viewfromdriverside1.jpg

Pic #3 View from the driver's side.

http://www.newmexicoartists.net/viewfromfrontlookingupattop1.jpg

Pic #4 From the front looking up.

http://www.newmexicoartists.net/viewofbackfirewalltotheright1.jpg

Pic #5 View of the back with the firewall to the right. I hope this helps.

http://www.newmexicoartists.net/viewoffrontpassengerside1.jpg

#6 View of front - passenger's side

Almost forgot that one.

Head down to the junkyard and find one (hopefully) and monkey with it a little. Try not to break it for the next guy, but you'll be less stressed on that one than on yours.

On the Gen7 (2008 +) the three bolts in the center simply ensure a tight connection underneath. The sides are just snapped in place.

Pic #1: Don't know if these are really release points. When you look down the holes there's a little brass-looking tab down there. There are 3 of these.


I know for sure those brass things aren't release tabs. Probably what you see is an unused fuse location in your application. To get the bottom cover off it unsnaps. I saw the junction block, and it does just slide out but without seeing it, I didn't remember that. Getting old. The connectors should be on the other side of the lower block cover when you get it apart. Where the harness goes in it should come apart with a little gentle prying. The other side probably has a tab going into the upper part of the block holding the two halves together. Might be held together in three or four spots around the block. Just gently pry along the block halves and you should see where it's held together. I think I saw one of the tabs in the last picture ( #6)on the right side of the picture closest to the camera angle. Got a new block or getting one from a yard?

I finally did get the box apart. 2 plastic snaps in corners toward the firewall. I've turned it bottom up and folded back the bottom cover to expose 3 junction blocks (I assume that's what they're called) In the center of each, as you've previously described, is a silver bolt. So far I cannot see or smell any damage. I also understand I should exercise extreme caution in loosening this bolt and lifting the block to look under it for damage. Sorry to be soooo tentative but I'm wary of causing more damage The dash looks as though the DEA has been looking for contraband and under the hood a display of multi-colored spaghetti. Intimidating to say the least. Here's a photo. Can't wait to hear back from you...hope school's going great!http://www.newmexicoartists.net/junctionblocks.JPG

Great, it's apart! You have a picture now to reference when you go back together. Just completely loosen the silver bolts, they won't come all the way out probably, there's usually a washer that stops them from falling out. When those bolts are loose you may need to take a small screwdriver between the connector body and the junction block and kind of GENTLY pry the connector a little. Those 3 big connectors will not just come right out most of the time but once you get the first one, the other two will come right out. Just take your time. The four two wire connectors are held in by the tab on the right side ( in your picture)of each connector. Just depress the tab and pull the connector out. Check the connectors like I said before, if it all looks good ,put the new junction block in, put it all back together and let's see what happens next. We should be good to go.
Intimidating would be an understandable feeling but you're doing great, stick with it, we'll get it running and back together. I'll check back and see how you're doing. School was good, lots of detours due to the tropical storm last weekend. The Volt is a lot different than the average car. That's what I went to school for.

I'd like to have a Volt if it was the size of the 'Bu, but someday I still might buy one or a competitor.

I'd like to have a Volt if it was the size of the 'Bu, but someday I still might buy one or a competitor.

Great while they're under warranty. Out of warranty you need some deep pockets for repairs. Had an '08 Tahoe Hybrid in yesterday with 114K on it. It needs a battery pack for the hybrid system. Battery alone, not including installation, 2500 bucks. Not on my wallet.