newbie help

[jroymcd]

just got me a 75 blazer.im kinda green when it comes to engines. had a re-built th350 installed, had a compresion check done and the motor is very strong (150 and even on all) it has Hei.

anyway, it ran good when i got it except a weak tranny which i already replaced. its starting to run bad. power loss and hesitation. its taking longer to start as time goes by. is it a timing issue?

 

[down4thakrown]

did you try doin a tuneup? oil,air filter, plugs and wires,.......

 

[jroymcd]

air filter is clean. wires are not to old. plugs look good. so i have Hei and it says delco on top. how do i know what rotor i need?

 

[Mad-Dog]

sounds more like a ignition issue (no fire in the hole)
It's 1:49am here in indianapolis and i'm really tired after fixing my brokedown kenworth, but i will find time tomorrow to explain how to check the individual components......goodnight

 

[jroymcd]

sounds good i need any help i can get

thanks

 

[tRustyK5]

I would guess you have a carb issue personally, but ignition parts aren't hard to change/diagnose either.

Rene

 

[R72K5]

yeh its either module or coil related or the carb is crappy dirty gummy

and 150 psi cylinder pressure is normal minimum, its not real strong, its average normal nothing special at all by any means

alot of the 80s and up 305s are way more than 150 psi even(the 190hp ones and etc L69 RPO etc)

truck engines hi torque were usually always lower CR than car turbo fire engines, trucks got screwed but did get lots more low end low rpm torque than the cars got

normally


is your dizzy not clamped tight at the base on the intake manifold ?

see if you can turn it by hand real easy, but if it takes some effort to turn it then its ok

hard to start ? whats it do when you crank it, does it crank over unevenly like hesitantly ? when hot ? or all the time no matter temp ?

may be too far advanced, but it depends on what its doing wrong when youre cranking it

 

[jroymcd]

it used to start right up, less than a second after turning the key. now it turns for a bit (5 seconds) than fires up. it cranks evenly and the same hot or cold. could it be a week fuel pump? it idles decent but when i give it gas it just does not have the power it had before a wants to chug a little.

i picked up new wires, a rotor, and fuel pump today to see if any of them help. i will install them tonite and try to check the timing. what should the timing be?

 

[jroymcd]

just put in the new fuel pump in. it helped but, something is still not right. going to do wires, plugs, rotor and timing tommorow.