Where is the fuel pump relay?

#1

I have a 2000 Chev Blazer V6 with 152000 on it and have been trying to narrow in on the intermittent starting problem. Sounds like I should look at the relay before having the pump replaced. Is the relay something a novice could locate and replace? I can hear the pump when I turn on the ignition. I had the filter replaced and will crank but not start. A few hours or the next day will start like there was never a problem.

#2

What evidence do you have that there is a problem with the fuel pump? Aren’t you going to give it a fair trail, gather evidence and all that, before pronouncing sentence?
The fuel pump relay may be in a plastic cylinder in the driver’s side of the engine compartment, near the strut tower. And, then…?

#3

If you can hear the pump spin up and pressurize the system when you turn the key on, yet the car fails to start, you have pretty much eliminated the fuel pump or the relay as the source of your no-start problem.

You need to collect some more evidence. Are you absolutely certain that you have a good blue spark while cranking?

#4

I would suspect the lack of spark (primary, or, secondary ignition system) as being the cause; though, it could still be a fuel injection problem (energizing thereof).
I suggest you get the repair manual and do the checks, or, turn it over to a mechanic.

#5

I stopped at the shop and mentioned to them that the fuel filter didn’t solve the problem. They mentioned that they would try cleaning the injection next. Is that really something that would work intermittently? I have the same question for the ingition? Is it something that could get condensation when the temp rises, and take some time to dry out? No, I guess I don’t want to pronounce judgement on the fuel pump since it’s a $700 repair. The shot of starting fluid down the throttle body didn’t even give an extra couple of chugs. I’m waiting to have the next time it fails to do more troubleshooting. I don’t want the housecall. CG

#6

Stay away from any shop that wants to sell a injector cleaning to cure this concern,espically since they are not doing the inital diagnostic steps.

#7

It might not be entirely their fault. Last time, I took it in after it was running fine again intead of having the tow truck come to my house. That’s when the fuel filter was changed, and it started fine until it warmed up almost to freezing. No check engine light, and wouldn’t start again until it was cooler outside and sat a day.

#8

You really need another shop on this…not a service toss and parts toss shop. It may be difficult, and diagnostics may seem expensive, but a shop which actually diagnoses the problem will be cheaper than one which, experimentally, replaces expensive parts. Save the experiments for the cheap parts.
To recap, the problem is that it doesn’t start when the weather is cold? Does it matter if the engine is cold? Or, recently run?
An engine won’t start if it has too much fuel. To un-flood an engine (yes, even fuel injected engines). Hold the gas pedal to the floor as you crank the engine. Let up on the gas pedal as (if) it starts.
An engine won’t start if it has too little fuel (of course). To determine if this is the problem, spray Engine Starting Fluid (or, similar brand) into the large black intake tube. If it, now, starts, that could be it.
Get a spark check plug or lamp from the auto parts store. When the engine doesn’t start, check for spark.
All of these check are “troubleshooting”------ just like a real mechanic would perform. Let us know the results of your troubleshooting.

#9

if your hear the energization of the fuel pump, it is not the relay. However several other possiblilities exist…fuel pressure from pump, return pressure from injectors. Possible flooding from one or more injectors, this may eventually show up on a code for convertors if too much gas is being unburned. Any changes in performance or mileage? Before popping for several hundred for a pump a few pressure checks might solve issue. Also may injectors will NOT pump unless they receive 12 volts min. Even though a starter may turn engine at slightly less voltage, so check battery and charging system to make sure you have the juice. I had this problem on an injected water craft and the battery had a slightly bad cell and it just wouldn’t start at 11.8V and replaced battery and it cranked and activated injectors and ran terrifically. Just a thought that it may be electrical.

#10

Thanks for all of the good input, and I’ll let you know when I get it figured out. It doesn’t help that it’s a lightweight plowtruck, with snow making it’s way into the engine compartment. I’ve watched the volt meter dip when too much blowing snow is tossed up by the plow. The voltage could very well be the problem. The plow’s tough on the battery. 20 below this week will be a pain, but at least we get a break from snow. I’m going to have that battery checked right away.