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I have been trying fix a problem with the way my C5 starts. When it was new and I turned the key you hear the care prime itself. now my car is 19 years I turn the key and I can't hear it priming. So now, when I started the car it take a few cycles of the engine before it starts up. After it starts us it can have a slightly rough idle, and or when I am accelerating is sometimes back files or stutters.
So, help, where do I start to troubleshoot this item.
Aloha !!
If you have a test light, a jumper wire and a multimeter let's see if we can get you back running...I did a YouTube video on testing the fuel pump relay circuit so I'll enclose it below. For now just swap the horn relay with the fuel pump relay and see what happens...I'm also thinking your crank sensor may be on its way out !!
Super !!!...it just may be your fuel pump is on it's way out also with the rough idle and back firing too !!...and living on "The Rock" doesn't help as far as the salt water environment goes !!....you'll have to look on the bottom of the relay to see where pins 87 and 30 are if you try the jumper wire method...they are caddy corner from each other but 87 will have power on it all the times with the key ON
Just a bad relay if the horn relay worked in it's place...either a bad relay coil not closing the load side contacts...pin 87 to 30 !!...if you watched the video the control side feed was getting power but maybe you have a bad relay coil !!...you can test the old relay with 2 jumper wires to the battery and then check pins 87 to 30 with an ohm meter !!...so if the horn relay was a confirmed fix buy a decent relay !!
thanks, I am not much of an electrician, so this is stuff hard for me, but with your video I will try and verify all connections this weekend. I love a challenge, but I don't fully understand the language of electricians... but I can follow a video. By the way, I will swap out the fuel sending unit and fuel pump this weekend.
So did swapping the relays solve your problem ??...why change the fuel pump if there may be nothing wrong with it ???...I’d be more worried about the power and grounds !!
So did swapping the relays solve your problem ??...why change the fuel pump if there may be nothing wrong with it ???...I’d be more worried about the power and grounds !!
Aloha, Yes the pump is now priming, but I am still getting the misfire and stuttering when i accelerate.
Vette is 2000, C5 now 19 years old with with 148,000 miles on her....
New plugs
New wires,
New air filter
and at 100,000 miles i did the 100,000 check check list
So, I thought, if I replace the fuel sending unit, and fuel pump, which are not too hard, then I can eliminate them from the list. I found a post where someone said that it could be due to a leaky fuel injector, a fuel check valve, and the fuel pump. Not sure how to check this, so I thought I would replace parts, but your advice would be greatly appreciated and your videos are awesome for those of us who don't have a clue about electrical and how it impacts the running of the car.
FIRST can see if you have any codes stored using the DIC !!...that may give you some direction...
A weak fuel pump can give you the stuttering and misfiring due to a lean condition. I would try cleaning your MAF if you haven't done that yet. If you get a hold of one of these amp clamps (pictured and I don't think Harbor Freight Tools has made it to the Islands yet) you can clip it around either the power or ground wire at the pump and read the pumps current flow...easy to do OR use the ammeter setting of your multimeter if you have one and place the leads between pins 87 and 30 of the fuel pump relay with the key ON...most multimeters are limited to 10 amps but if your pump is weak you will see a low current flow...I believe my pump draws around 5-6 amps...you can try cleaning the ground G401 inboard of the left rear tire...it would suck to change a pump and continue to have the same issues !!...check those codes !!
thanks again, let me try this and I will get back to you.
Best Mike
The only codes I have are from my HVAC, and that is for the two actuators which are out of range. I put 2 new in, but still get the codes... I can deal with that later when I get my LS1 running good again.
Maybe there was a bad load side contact in the relay and it took a few times to crank it over before there was enough current flow to get the pump going ??...without actually testing the relay it’s just a guess !!
C5 corvette does not prime before starting.
