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ok. trucks overheating,dieseling,starting hard....what gives??

01maroonz71

01maroonz71

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well, i put this motor in my truck about 2 months ago, and it has about 1k miles on it. at idle, it overheats like a mofo but cruising is fine. the ENTIRE cooling system is new, thremostat,radiator,waterpump,hoses, and a direct drive fan.

also, in the morning when it's cold, it fires right up no problem...but kinda backfires every once and a while on me. once it heats up, it runs like a bat out of hell, but if i shut it off when it's hot, it takes it cranking over for like 6 seconds for it to fire up.

sometimes she will diesel also, not always, but maybe every 10th time i drive it or something like that


i initially thought timing, so i hit it with my gun again, and it seems fine....BTDC with the vac advance unplugged is at 8degrees...and it maxes out (w/ vac advance hooked up) at about 32degrees.

now, could the mechanical springs in my dizzy be worn out and causing it to come in too fast/tooslow???? or could there be something wrong with my idle mixture on my edelbrock 1406??? i haven't messed with it since the swap, and think that may be it...but that wouldn't cause dieseling would it???




oh yeah, there really isnt' any "heat soak" in the fuel line....it doesn't really heat up, so i don't think that could be it.
 
well, i just tried retarding the timing(clockwise) about 2 degrees and it ran like ass, so i bumped it forward(counter-clockwise) about 2 degrees and it seems to run better....still got hot at idle(got up to about 210) but definatley not as fast at all. so maybe i should bump it a bit more. would 12 BTDC be bad on a brand new 290HP goodwrench 350???? is that too much???? thanks guys
~Dave
 
My first thought was timing. But to me it sounded like you were a little too advanced. Mine was dieseling a little when hot, and I just retarded a couple of degrees, and it stopped.
I don't have a working timing light, so i just played it by ear. tweaked it a little at a time until I got it to a point where it wasnt pinging too much, and was easy to start, but no dieseling.
 
well, i think the dieseling is attributed to it running so hot, so if i fix the overheating, maybe it will get rid of the dieseling, hopefully. i do know that im about to go tak ethe truck somwhere, so we'll see how she does...im taking my 9/16 wrench with me, so i can adjust it as needed while im driving
 
Yeah, I thought that advancing the timing would generally make it run cooler. (assuming all the cooling system components are working correctly)
Good luck.
 
well, i just got back from where i had to go(about 30 minutes away) and it's actually running WAY hotter....it got up to about 220 a few times and i could watch it climb. it seems way more responsive...but it does still diesel, i believe a bit worse. i don't get it, when i retarded the timing, it wouldn't really run at all....then i tried advancing it, and it gets hotter way faster. what the hell is going on here
 
well i would say its some sort of a timing issue...i have no idea what....if you want to stop the dieseling till you get it fixed then just leave the truck in gear when you turn it off then put it in park...always worked for me at least...
 
i just read that improper/inferior spark plugs could cause the dieseling that im experiencing...but could that cause the overheating???? the search continues.
 
how can i tell if it's running lean??? i can only adjust the idle air/mixture screws......would that make a difference??? if so, i just set the timing to 12degrees BTDC and im gonna see what that does. how can i adjust the idle mixture screws....i believe i just turn them right one at a time until it starts to kill the motor, then back it out 1/2 of a turn. is that right???? would that cause the dieseling????
 
I'm not sure about adjusting edlbrock carbs I have never owned one. I'm using the thought process that the dieseling is being caused by the motor running hot. A friends truck was having very similar symptoms to yours and it was the carb running lean, this was on a holley and we rejetted it to fix the problem.

I'm throwing the lean condition out there since you have messed with the timing several times and it doesn't seem to help. the idea may get shot down but I wanted to see if anyone else agrees. I would wait for some more feedback from others before you start turning screws on the carb.
 
ok....i may have just found something new.....i hooked my vac. advance to ported vac. on my carb(that's what ya'll told me to do) and now whether or not i have the vac line hooked up or not, plugged or not...it doesn't change the BTDC timing. would that cause my issues???? does it need to be hooked to ported or full manifold???? i've heard both. but, what would be the point of unhooking it while checking the timing if ported doesn't have any vac. when it's at idle???? im gonna try full manifold vac. and see how she runs.

anybody know what the timing should be at idle with the vac advance hooked up????
 
When you set the initial, you have to plug it off, not just unhook it.
I have mine connected to ported vacuum on the carb, because thats how I got it, and it works, so I left it. I have read pages and pages about which to use, and i still don't have clue. I have heard arguments for both ways. I think the most convincing that I heard was for manifold vacuum, but it wasnt convincing enough to get me out there to change it! (not yet anyway...)
 
well, i just hooked it to full manifold vac and it idles WAY WAY better, sounded way smoother, it also bumped my idle way up about 400degrees or so. so i turned it down. it didn't heat up past 190 as i let it idle for like 20 min or so, and it didn't diesel. now, the problem is that it's pulling 30degrees of advance at idle with the vac line hooked up. when i bloop the throttle, it drops down to the 10 i have it set at(mechanical advance) and it bogs and almost dies. can i adjust my vac advance down in my mallory dist.???? would droping that down help this, or maybe turning my idle up to like 12 or 14(BTDC)??? im not sure, but im getting closer to where i need to be i know. thanks guys
~Dave
 
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