jiggity76 Posted September 25, 2017 Report Share Posted September 25, 2017 So I hooked up a fuel pressure gauge to the Schrader fuel line connection and a little bit of fuel came out so it was pressurized at some point. I suspected a bad fuel pump but not sure. Not hearing the pump come on and the gauge is reading 0 when I crank the engine. Am I correct or do I need to look at something else? I also put a new fuel pump relay on the car. Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted September 26, 2017 Report Share Posted September 26, 2017 Gonna sound stupid, but did you check the fuel pump fuse? Additionally, if the ICM isn’t detecting crank position sensor pulses, the fuel pump isn’t turned on, IIRC. Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 You can't sound anymore stupid than me! What's a ICM? Is the fuel pump fuse under the hood in the fuse area on the right hand side next to the engine coolant tank? Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 I see what you mean now about the ICM, thank you. It might be best to have the car diagnosed at a garage, preferably a GM garage so I'm not chasing ghosts. Quote Link to comment Share on other sites More sharing options...
jman093 Posted September 26, 2017 Report Share Posted September 26, 2017 No, the fuel pump runs regardless of the ICM. It will prime the system before the engine ever begins cranking. 0 psi fuel pressure is obviously a problem. Check the fuse, but in all likelihood the fuel pump is bad. Try banging on the bottom of the fuel tank while someone is cranking the engine over. That will sometimes get a bad fuel pump working again for a time. Galaxie500XL 1 Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 I'm still thinking it's the fuel pump too, thanks for responding guys. I went thru the fuse box under the hood and made sure that no fuses were blown, not sure how to check if the large ones are bad or not. I checked to see if they were in the right spots and were the right amps. If you guys see something out of place, please let me know. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 26, 2017 Report Share Posted September 26, 2017 You would really benefit from owning a small multimeter. Come to think of it USING a multimeter would make a nice FAQ. digitaloutsider and rich_e777 2 Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 A lot of guys at work have them, I should borrow and play around with it. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 26, 2017 Report Share Posted September 26, 2017 You should buy one and have it in your toolbox, a good one will only run you 20 or $30. avoid the cheap China ones like at Harbor Freight. and then there's the high-end ones, I simply can't justify having something like a Fluke meter for things like this and realistically I can't even justify having it for about anything. If you're doing something where you're getting paid to do very precise calibrations then it's worth it but other than that a Craftsman brand or an extech or something would make a fine sidekick. Sometimes chain hardware stores we'll have a good meter that has a built-in DC clamp style ammeter, I got one of those pretty cheap last year and it's a decent little meter. Bear in mind that an AC clamp meter isn't going to be of much use for automotive testing. Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 I've been meaning to get one just never have. The maintenance guys at work will let me know what brands they like and for what reasons. That's some good advice about the clamp, didn't think of that. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 26, 2017 Report Share Posted September 26, 2017 the maintenance guys at work or going to tell you you need a very expensive one. realistically you need a cheap but not terribly cheap one. if it breaks in 5 years you can buy another one and you're still $200 cheaper then a fluke Quote Link to comment Share on other sites More sharing options...
Schurkey Posted September 26, 2017 Report Share Posted September 26, 2017 The '91s must have a different wiring system than my '92 and '93 Luminas. I have a separate fuel pump fuse, and I think my fuel pump relay is where your "3.4 A.I.R. Pump" relay is. I also have a fuel pump bypass wire, touching it to battery + will turn the pump on. It's located near the aux. battery post--a thin red wire with a grey molded-plastic end. The heavier grey wire on the aux. battery post is the fusible link that powers my separate fuel pump fuse. I will not replace a fuel pump until I've verified voltage to the pump, as close to the pump as I can get, voltage on the ground side of the pump (shouldn't be any--but it's common to have a volt or volt and a half because GM used skinny wires) and the amperage draw of the pump while it's running (assuming I can get it to run) If the pump isn't getting voltage, or has bad ground, replacing the pump isn't going to fix anything. Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 If it's under 50 bucks I consider that ok. Hopefully I can just borrow one for now if I have too. Yeah, don't want to spend $200 bucks! Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 The '91s must have a different wiring system than my '92 and '93 Luminas. I have a separate fuel pump fuse, and I think my fuel pump relay is where your "3.4 A.I.R. Pump" relay is. I also have a fuel pump bypass wire, touching it to battery + will turn the pump on. It's located near the aux. battery post--a thin red wire with a grey molded-plastic end. The heavier grey wire on the aux. battery post is the fusible link that powers my separate fuel pump fuse. I will not replace a fuel pump until I've verified voltage to the pump, as close to the pump as I can get, voltage on the ground side of the pump (shouldn't be any--but it's common to have a volt or volt and a half because GM used skinny wires) and the amperage draw of the pump while it's running (assuming I can get it to run) If the pump isn't getting voltage, or has bad ground, replacing the pump isn't going to fix anything. It must be different because this is where my relay is mounted - on the driver's side strut tower. I just found out with the help of another member that this is the fuel pump prime wire. It's the red wire on the right next to the positive battery connection. So can I use this prime wire and touch it to the battery post somehow to see if the pump kicks on? It's got a connector on it as you can see. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 26, 2017 Report Share Posted September 26, 2017 we discussed that fuel pump Prime Wire in another thread like a month ago Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 we discussed that fuel pump Prime Wire in another thread like a month ago Oh yes, sorry I forgot about this. How does that connector work then? What can I plug into it or where to make the connection complete? Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 26, 2017 Report Share Posted September 26, 2017 jump it to power with a hunk of wire Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 26, 2017 Author Report Share Posted September 26, 2017 Alright, I'll give it a try. Thanks Imp! Quote Link to comment Share on other sites More sharing options...
Schurkey Posted September 27, 2017 Report Share Posted September 27, 2017 It must be different because this is where my relay is mounted - on the driver's side strut tower. That's where I'd be looking for the fuel pump fuse, then. Mine is on the passenger-side electrical box. Yes, that's the fuel pump relay jumper wire. As said, touch it to a battery-power source, should run the fuel pump. If it doesn't, the fusible link, the fuse, the fuel pump relay, the wire harness, or the pump is faulty. Remember that the wire you've found only powers the fuel pump relay coil. It's a substitute for the fuel pump relay power that the ECM would provide. It doesn't power the pump directly--it just turns the fuel pump relay "on". For the record, the newer Fluke meters have a lifetime warranty. Consider buying a used Fluke. I have an ancient Mac Tools-branded Fluke 88 "Automotive" multimeter from about 1992 or so. (Too old to qualify for the lifetime warranty.) The current model is 88V (or 88 Series 5) Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 27, 2017 Report Share Posted September 27, 2017 Probably aren't going to see a used fluke worth buying in that $50 specified budget being that those have a $600 new price range. When it's time don't get too hung up on name brand but avoid obvious junk. Be more concerned with features that suit your needs. A lifetime warranty isn't going to be as handy if the little shit next door steals it from your garage or you drive off with it on the roof and lose it on the highway. Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 28, 2017 Author Report Share Posted September 28, 2017 That's where I'd be looking for the fuel pump fuse, then. Mine is on the passenger-side electrical box. Yes, that's the fuel pump relay jumper wire. As said, touch it to a battery-power source, should run the fuel pump. If it doesn't, the fusible link, the fuse, the fuel pump relay, the wire harness, or the pump is faulty. Remember that the wire you've found only powers the fuel pump relay coil. It's a substitute for the fuel pump relay power that the ECM would provide. It doesn't power the pump directly--it just turns the fuel pump relay "on". For the record, the newer Fluke meters have a lifetime warranty. Consider buying a used Fluke. I have an ancient Mac Tools-branded Fluke 88 "Automotive" multimeter from about 1992 or so. (Too old to qualify for the lifetime warranty.) The current model is 88V (or 88 Series 5) Thanks for the response! I had a buddy turn the key on and off and I heard and felt the relay click on and off so it's good to go (it's also brand new). If the relay is working and if I understand what your saying, then I shouldn't have to jump the wire to the battery source since I know the relay is working right? I know that the pump is reading 0 pressure at the Schrader valve so should I start at the pump? I'm going to try that trick of tapping on the tank and seeing if I can get the pump to work too. Another issue is that the digital dash stopped working again. Before it was a blown fuse under the glove box but it's brand new and isn't blown but dash is still dead. Could the cars computer be causing the dead fuel pump and dash at the same time? Forgot to ask the guys at work to borrow a multmeter, I'll ask tomorrow. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted September 28, 2017 Report Share Posted September 28, 2017 Another issue is that the digital dash stopped working again. Before it was a blown fuse under the glove box but it's brand new and isn't blown but dash is still dead. Could the cars computer be causing the dead fuel pump and dash at the same time? Forgot to ask the guys at work to borrow a multmeter, I'll ask tomorrow. The ECM doesn't control the gauges. That's independent of it. Newer cars have a BCM for those kind of features but the Cutlass Supreme never got a BCM. Your issue is wiring. You need to verify that no fuse is blown, no relay is shot. Sometimes one thing not working triggers the fuse to pop. The dimmer or the courtesy light might have a short or false positive causing it to pop a fuse and take out the cluster with it. Look into that. The computer is on a fuse as well so there's that but fuel pumps do die... Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 28, 2017 Author Report Share Posted September 28, 2017 The ECM doesn't control the gauges. That's independent of it. Newer cars have a BCM for those kind of features but the Cutlass Supreme never got a BCM. Your issue is wiring. You need to verify that no fuse is blown, no relay is shot. Sometimes one thing not working triggers the fuse to pop. The dimmer or the courtesy light might have a short or false positive causing it to pop a fuse and take out the cluster with it. Look into that. The computer is on a fuse as well so there's that but fuel pumps do die... Thanks, didn't know about the ECM thing. I've checked all of the underhood and under the glove box fuses and they are all good. I will double check this weekend again. The dash worked for three days and then just quit recently. I haven't replaced the big square fuses or relays or whatever they are under the hood except for the fuel pump relay like I mentioned earlier. Should I replace the big 30 and 60 amp ones in the engine bay area? There's also three big black square ones under the hood for the electric cooling fans and A/C? I wouldn't think this would affect the cluster or pump. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted September 28, 2017 Report Share Posted September 28, 2017 and the dimmer knob isn't rolled all the way down? Quote Link to comment Share on other sites More sharing options...
jiggity76 Posted September 28, 2017 Author Report Share Posted September 28, 2017 and the dimmer knob isn't rolled all the way down? Nope, I just went out and checked. I'm going to go thru all the fuses again, I'll let everyone know. I might even check the connection to the back of the cluster and maybe even switch it out with another cluster to see if it comes on or not. Nas Escobar 1 Quote Link to comment Share on other sites More sharing options...
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