Ok helping someone with a 88 blazer with a new rebuilt tbi 350 just dropped in. This is his first engine and he did it by a good book I recommended. Alright fuel is getting to the tbi and he goes to start and it backfires. So I know fuel is being injected. He setup the timing by a online guide set it to btdc on cylinder 1 pointed the oil shaft towards cylinder 5 and dropped the distributor in and the rotor was alitte before or on number one fire. So whats going on? It just backfires and doesn't even start. Maybe its out 180? I've always hating timing. Thanks
CK5
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New Engine Start
- Thread starter danny7139
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westcoastblazin
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danny7139 said:
sounds a tooth out.. turn it back a notch, you'll have to turn the top of the oil pump with a long screwdriver... dont drop it in :P
Definitnly sounds like a timing issue of some sort (distributor set wrong, plug wires in correct order, timing chain lined up correctly). Getting a distributor in correctly always seems to be the ass-kicker for anyone doing an engine R&R for the first time.
180 out. TDC by finger/plug method or valves.. lace #1 from where the rotor ends up pointing....
Ok it was 180 out got that fixed and it started right up. Not sure about the idle as we only did it for a second and went right to 1600 rpm for cam break-in. Held it there for maybe 3 mins then I noticed the exhaust manifolds were cherry red on both sides but only on the back 4 cylinders. The y pipe was cherry also. Not sure about the cat I didn't look. Its a single 3 inch back exhaust. I looked around and found it can be either lean or the timing is off. My friend thinks its the collant system. I don't think so but the temp gauge was in the red area. Not sure its accurate either. So what should we do? When it cools off I'm going to pull the plugs and check. But how can I know its the timing when I can't idle it because its not broken in? It wasn't stumbling at 1600 at all and run smooth.
remember once that thermostat opens, you'll be down gallons of fluid.... need to top em off....
hows it turn over? retarded timing will lead to overheat, but your ecm should take care of that. if you ran it for a bit you could quickly unplug the wire and check timing.. just be quick and bring it back up for the rest of the break in.. i like to vary rpm for break-in from 1500 to 2000 evry 30 seconds or so..
... and yeah, pull the plugs to check for a lean condition...
hows it turn over? retarded timing will lead to overheat, but your ecm should take care of that. if you ran it for a bit you could quickly unplug the wire and check timing.. just be quick and bring it back up for the rest of the break in.. i like to vary rpm for break-in from 1500 to 2000 evry 30 seconds or so..
... and yeah, pull the plugs to check for a lean condition...
It turned right over first crank. We did what the haynes manual said and disconnected the EST wire. Should we not have done that? After letting it sit we took off the radiator cap and the fuild is full like it was before. So maybe the thermostat isn't working? Its a new one. But would the collant problem also cause the manifold's to heat cherry red that fast?
the manifolds will be a combustion issue...
not sure if i understand correctly, your running it with the est disconnected?
iirc, your supposed to disconnect to time. fire up, time. shut down.. reconnect... disconnect battery to reset ecm.. fire up..
not sure if i understand correctly, your running it with the est disconnected?
iirc, your supposed to disconnect to time. fire up, time. shut down.. reconnect... disconnect battery to reset ecm.. fire up..
the manifolds will be a combustion issue...
not sure if i understand correctly, your running it with the est disconnected?
iirc, your supposed to disconnect to time. fire up, time. shut down.. reconnect... disconnect battery to reset ecm.. fire up..
not sure if i understand correctly, your running it with the est disconnected?
iirc, your supposed to disconnect to time. fire up, time. shut down.. reconnect... disconnect battery to reset ecm.. fire up..
Yes the haynes manual said to disconnect the est wire and start it to time. Then reconnect the wire and clear the ecm. So I guess we need to have the est wire hooked up before going into break in? Because we started it up with the est disconnected and went right it doing the break in on the cam. Is it possible the est wire being disconnected is causing the manifold issue?
yup.. thats your issue i'd bet... timing isn't advancing when the rpm's are going up...
nope.... unrelated... your system may be full.. if it was filled slowly initially, its prolly purged.. but like i said, run it with the cap off and once it gets to temp, just make sure your level is ok and hasn't dropped...
JpEater
1/2 ton status
danny7139 said:
Best way to prevent an air lock is to drill a 1/4 inch hole in the thermostat before you put it in. That small hole will let all of the air through to bleed the system without a chance of an air lock and/or overheating. I do this now even on a regular ol' t-stat/coolant flush job. Whenever I install a rebuilt engine I idle it up to about 1000 rpm's, set the timing, wait till the t-stat opens top off coolant with it still running(cap has not been intalled yet) put the radiator cap on and then take it up to break in speed. I have done this many times and never had one problem with overheating.That will give the motor time to expand with the pistons and avoid premature cyl scuffing. Starting it up and going to 1500 to 2000 thousand is not good and especially hard on an unglazed cyl wall. Thats the same reason why you always warm up a diesel before driving off.
