Truck wont start after engine replacement

[greenday3437]

Well, my friend has a 1998 chevy 4x4 5.0 vortec, and I just replaced the engine for him with a rebuild longblock..

When I first when to start it after putting it back together, I was getting no spark, then I realized I didnt have the crankshaft position wheel on the crankshaft.. So I tore it back apart and put it on.

I now have spark, but the engine still wont start. The plugs are soaked in fuel when I pull them after trying to start it.

Sometimes when I first start to crank it I get a small pop, but other than that nothing just cranking. Does anyone have any ideas? thanks

[bradrhale]

timing alright?? have you made sure that all the sensors got plugged back in?? since it is not hitting but you are getting fuel and spark, i would think that the timing is out.

[FaselZ71]

Yeah I would definalty check timing. Have you checked the compression? Check to make sure you don't have a leak anywhere where you may be losing compression.

[greenday3437]

Originally Posted by bradrhale

timing alright?? have you made sure that all the sensors got plugged back in?? since it is not hitting but you are getting fuel and spark, i would think that the timing is out.

I thought the same thing, I've had the **** distributor out like 10 times now, I'm having a hard time finding TDC thought because I'm doing this alone and cant get the engine to turn whilep being able to be near #1 spark plug hole. So I'm just bumping the starter until I feel the compression stroke coming and get the piston to the top of the cylinder, can you think of a better way?

Also, I was about to make another post on this, I doubt it matters, but there is ONE sensor thats not connected, the oil pressure sensor that goes next to the distributor because I broke the sensor on accident and had to order a new one, but surely that doesnt make a difference?

[Kennyray]

That would keep it from starting since that system is also hooked to the fuel pump. With it broke it may be causing the pump to continue running even if the system is up to pressure.

[bradrhale]

i have always put a large breakover on the crank bolt and spinned it by hand with no plugs in, til i could get it where i wanted it. i sometimes look in the 1 hole with a flashlight or use a screwdriver. of course, dont leave it in there when you are spinning the crank. it might. some autos shutdown when the oil pressure sensor reads low. is this the sending unit there that looks like a cylinder??

[FaselZ71]

See look at that all that time and 2 better answers pop up!!

[greenday3437]

Wow, I never thought that sensor would stop the motor from starting.. I'm going to have to see if I can find that sensor anywhere local tomorrow. I will have to go around to the parts stores tomorrow (or more than likey call them)
I checked oriellys but they had none in stock and said it would take 3-4 weeks. I'll try autozone, I'll check back in tomorow thanks guys for the help.

Oh and yes, it's that black cylinder shaped sensor with the round plug on it, it has a fitting that screws into the motor, then it screws into that fitting, I popped the black cylinder off it's fitting when moving the motor around.

[greenday3437]

Just to give you guys an update, I found a sensor, and got it right before they closed.

Came home and installed it, got ready to fire it up, soon as I started cranking it, BOOM, a backfire that blew the rubber tubes out of both valve covers.

Now I'm thinking its one of two things, either

1) I sprayed a lot of starter fluid in the in the past 2 days trying to get it to start, so some had been left in there and ignited or

2) I have the timing off again and it's igniting while the intake valves are still open, I quickly tried checking TDC and pulled the cap off the distributor and it looked correct, I didnt have much time to look at it though

I didnt get to really try it again however, as I got security forces called out to my house (I live on a military base) because people thought it was a gunshot, I didnt want them called on me two times in the same night so i decided to knock off for the night

Which do you think caused that backfire? thanks

[wradman]

did you spin the oil pump to get the oil up just,checking i would imagine you did. Start over again take your time and make sure you are on compresion stroke if you have to pull the valve cover and check, then double check your firing order didn't get out. If it's still popping pay attention on whether it's comming through the carb or out the exhaust. Let us know