402 startup problem
402 startup problem Ok this may be the wrong section to post this but Im not sure. I went to start up the new 402 and it turns over, but it struggles. Its almost a pulsating. It sounds just like a dead battery but the battery is putting out 12 volts. Its connected to the starter and all the grounds are there etc. Is it possible the starter has gone bad? What should I look into? Any help is greatly appreciated!!
If it sounds like it's pulsing either the battery is not charged enough or the starter could be bad. I'd make sure the battery is good before I worry about the starter. If you're sure the battery is good then it has to be the starter.
I learned the hard way of a problem that batteries can have sometimes. They have a dead cell. Your lights will work fine, nice and bright. You check and you have around 12 volts on the battery but the engine barely turns over or not at all. When I experienced this mine just sat there and the starter engaged but never moved the engine an inch.
I was so convinced the battery was good because it powered p the car so well and it had 12 volts but I was wrong.
I was so convinced the battery was good because it powered p the car so well and it had 12 volts but I was wrong.
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TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
Sometimes new motors are so tight that they crank hard until they start and run for 5 minutes. Once you get it started, have a big window fan in front and let it run for 15-20 minutes. It will start a lot easier after that.
ok, the starter was bad, changed it and it still wont start!! Its getting fuel! Its getting spark! The PCM was retuned for the motor, the motor does turn over!! I cant figure this out!!
This cam sensor things.....does anyone have a picture of exactly what this is supposed to look like connected. The timing cover I got from TSP had a black bracket on it with wire that was plugged into the cover and had a connection on the end. With the racetronix adapter I had to take off that wire that came on the cover and plug the racetronix wire directly into the cover. Im sure that sounds confusing.....
any other ideas to try??
This cam sensor things.....does anyone have a picture of exactly what this is supposed to look like connected. The timing cover I got from TSP had a black bracket on it with wire that was plugged into the cover and had a connection on the end. With the racetronix adapter I had to take off that wire that came on the cover and plug the racetronix wire directly into the cover. Im sure that sounds confusing.....
any other ideas to try??
TECH Apprentice
Joined: Jul 2004
Posts: 375
Likes: 0
From: Carolina
You can also check the crank sensor. WHen I put my new motor in thats the only thing I didnt plug back up. As soon as it didnt crank i remember back looking at it and saying 'ill plug it in after I connect the coolant lines and never did, lol.
TECH Apprentice
Joined: Jul 2004
Posts: 375
Likes: 0
From: Carolina
Also. check the fuel pressure. I dont understand what its doing exactly by the post w/o seeing it myself, but i also installed a holly f/p at the same time and the pressur ehose holly sends fell apart insaide the tank and the car would idle but not go anywhere. And dont rule out it being a tuneing issue either but it shouldnt need to be tuned to crank up and drive.
I started my 402 up last night. It back fires a some on start up and then when it is up and running it is ok. It seems like the timming would be off on it. I just extended the cam sensor wire and pluged it in. Does anyone know if the cam sensor plug needs to be wired diff from the ls1 configuration?
ok im pretty sure the problem has been narrowed down to the fuel pump. its a walbro 255 intake. When I turn the ignition on the pump starts and then shuts off. It wont turn back on unless the turn the ign off and back on. something is goin on......
The fuel pump will only stay on a couple of seconds to pressurize the system up to spec.
You need to hook a fuel pressure gauge to the front of the fuel rail and check the pressure. GM spec calls for 55-60 psi with the ignition in the ON position. It should stay at that psi after you turn the ignition OFF for 8-10 minutes with no more than a 2-5 psi drop. Since you have been cranking the motor over and over I would check the plugs for fouling. If there is raw gas on them change right away (also check to see if there is gas in the oil).
I would aslo double check the battery voltage with a digitial multi-meter (DMM) at the battery posts and AUX connector by fuse boxes. There should be no depreciable loss between the two.
Are you getting any codes?
You need to hook a fuel pressure gauge to the front of the fuel rail and check the pressure. GM spec calls for 55-60 psi with the ignition in the ON position. It should stay at that psi after you turn the ignition OFF for 8-10 minutes with no more than a 2-5 psi drop. Since you have been cranking the motor over and over I would check the plugs for fouling. If there is raw gas on them change right away (also check to see if there is gas in the oil).
I would aslo double check the battery voltage with a digitial multi-meter (DMM) at the battery posts and AUX connector by fuse boxes. There should be no depreciable loss between the two.
Are you getting any codes?
Originally Posted by Full-Force
I learned the hard way of a problem that batteries can have sometimes. They have a dead cell. Your lights will work fine, nice and bright. You check and you have around 12 volts on the battery but the engine barely turns over or not at all. When I experienced this mine just sat there and the starter engaged but never moved the engine an inch.
I was so convinced the battery was good because it powered p the car so well and it had 12 volts but I was wrong.
I was so convinced the battery was good because it powered p the car so well and it had 12 volts but I was wrong.
we are gonna try to put some more gas in it......i am gonna borrow a fuel pressure gauge from a friend (i prolly need to buy one) and my gauge cluster is doin funny things so i dont know if its throwin codes.
when i pull the key outta the ignition the rpm and speedo pegs out and comes back down...all the other gauges randomly go up and down......maybe this has something to do with it
when i pull the key outta the ignition the rpm and speedo pegs out and comes back down...all the other gauges randomly go up and down......maybe this has something to do with it
Originally Posted by Mas280
I started my 402 up last night. It back fires a some on start up and then when it is up and running it is ok. It seems like the timming would be off on it. I just extended the cam sensor wire and pluged it in. Does anyone know if the cam sensor plug needs to be wired diff from the ls1 configuration?
I did a quick search
https://ls1tech.com/forums/showthrea...hlight=ls2+cam
Last edited by WhiteRhino; Nov 14, 2005 at 11:14 PM.
IT STARTED!!!!!!!!!!!!! omg I cant believe it, this thing finally started! Now I feel like a complete idiot. The two grounds that are on the back of the head...only one was connected, the other was broken off!!! I feel so stupid but at least its done! now we gotta let it get up to oper. temp and change the oil and start driving!!!!
That 25x/26x .6xx cam sounds NASTY!!
That 25x/26x .6xx cam sounds NASTY!!