needed: engine vacuum tips for dummies

[ebbtide176]

i came back to post this quickly, and spent 1.5hrs catching up on the other topics <br /><br />i'm trying to get the old 77 cj7 304 going. its not running right, and i really suspect a vacuum problem. it didn't run right when i got it, running very rich, cold natured. anyway, i want to get back to basics. it appears to have new carb, distributor, cap, rotor, wires, water pump, steering gearbox, etc. also valve covers have been off, and now a new coil. i think the guy i got it from (diesel shop trailer repair & otr driver) at one time had the engine out and possibly rebuilt or minor overhaul.<br /><br />looking at chilton & haynes, i'm bogging down with the vacuum stuff. can someone give me some lowdown on starting with nothing? can i plug off everything but pwr brake booster, pcv off intake, and distr adv? if i did, i need to verify(since its not hooked up per diagrams, and has TCS & CTO,plus the air pump & exh connctns)<br /><br />-pcv off intake should go where? (generalized)<br />-distr adv should come from where? (..)<br />-can i block off egr with hvyaluminumfoil?<br /><br />i just want to get the thing idling/running dependably, and then will go for adding the complex vacuum circuits...the latest symptom is: its almost impossible to get running, very rich, then warms up with a decent idle, although it has to be alittle fast to maintain running. but running under load it will run for @ 10mins then just suddenly goes haywire, and will barely make it back at idle, anything above this and it seems to choke out.<br /><br />when i first got it, it had to be pedal-pumped alot to crank, but i got it home. i found the breather vacuum needed to be unhooked, as it was closing the flapper. also, the anti-diesel solenoid was on fast idle speed...<br /><br />any help would be greatly apprec. i will be out playing with it, but will ck in from time to time. maybe at least skinny & schem will see this

 

[DJ]

Re: needed: engine vacuum tips for dummies

ebb,<br /><br />First off, do you have a vacuum guage? If not, get one, they're about $20.00.<br /><br />The engine should have a STEADY vacuum reading of at least 16 inches. Fluctuations mean problems.<br /><br />Yes, you can plug every line for diagnosis. That includes the brake booster. Brake boosters can cause all kinds of running problems.<br /><br />As you are working, plug them in one at a time and see if your running condition changes.

 

[ebbtide176]

Re: needed: engine vacuum tips for dummies

thanx DJ. nope, i guess i really should get a handheld pump. mine was borrowed & lost yrs ago.

 

[SeaMasterZ@aol.com]

Re: needed: engine vacuum tips for dummies

better yet, get a pump/gauge combo for about 30 bucks<br /><br />that way you can test EGR and dashpots and the like for leakdown<br /><br />if ya get bored, you can always get a new piece of hose with an adapter to bring it up to 3/8 inch, and creatively apply vaccum to your gf, hehehe<br /><br />make sure shes tied down good and tight tho, blindfolds so she cant see what you are up too might be a good idea too<br /><br />

 

[ebbtide176]

Re: needed: engine vacuum tips for dummies

thanx LMAO<br />i needed that

 

[ebbtide176]

Re: needed: engine vacuum tips for dummies

i didn't think of pluggin off the brakes, but i've dang near done everything imaginable- if you know what i mean. i guess you could say that i reached a plateau- next step is to call in SBN with a bomb...<br /><br />i've verified timing, plugs, wires, rotor, coil, cap, ign module, adjst carb idle screws per specs, gas dryer fluid in tank, started pluggin vacuum hoses. my wife is already making fun of it <br /><br />what she doesn't know is, instead of selling it for an instantantly drivable POS, i'd find someway to buy a rebuilt motor... its my baby now, i'm hooked

 

[SeaMasterZ@aol.com]

Re: needed: engine vacuum tips for dummies

hmmmmmmm<br /><br />yanno, if memory serves those 304 AMC motors were a biotch to get the intake manifold on, I wonder if he buggered a gasket - also, spray some WD 40 along the base of the carb, make sure the carb gasket isnt leaking or a hairline crack, the WD will temporarily "seal" it and it will smooth out<br /><br />Toys are toys, Im already schemeing on getting a 4.3 vortec blazer with too many miles to use as a play toy - or a 4 wheel S 10, lol, something I wouldnt mind getting scraped up<br /><br />I KNOW I would freak out hearing that SCCCRAPPPPEEEEEE down the sides of the brand new truck, lol, but not on a ten year old beater

 

[SeaMasterZ@aol.com]

Re: needed: engine vacuum tips for dummies

dist adv comes off the base of the carb, vaccum signal is maximally responsive right by the throttle plate<br /><br />brake booster taps into the intake manifold<br /><br />should be a "tree" of tees, bunch o vaccum hoses<br /><br />diagrams are your friend, I always make a diagram of unfamiliar motors, soon it will be WAY too familiar, lol, as reflexive as tying your shoes<br /><br />the 304, once sorted out, is a bulletproof, slow reving, torque monster that in low low, will rip a house off its foundation if yer running lockers front and rear

 

[ebbtide176]

Re: needed: engine vacuum tips for dummies

thanx senyor Ray<br />vac adv= near base, throttle plates<br />booster= intake<br /><br />that's more kosher, 10-4, si senyor, i can understand that<br /><br />just for kicks i'll give you one. we've been overtaken (on the job) by a nationwide co called WebMD. they use this term LMK "let me know".<br /><br />we(techies) use those terms quite often, and you should too. lol <br />except our version is "lick my keister"<br />LMK <br /><br />(if enough surfers get into this, we can stop these mind numbing niceties ya know )

 

[SeaMasterZ@aol.com]

Re: needed: engine vacuum tips for dummies

lolol, well LMK how eet work ouuut, don need no steenking nicetees !!!!<br /><br />

 

[Skinnywater]

Re: needed: engine vacuum tips for dummies

Hmmmm. Sounds like a real abortion. With the way it's running you'll have vacuum fluctuations without vacuum leaks.<br /><br />ebb, fifty bucks cash and a few longneck Buds with your local shadetree might be worth your while. I'm not sure how confident you feel under that bonnet.<br />Depending on your answer, check for restrictions in the exaust and pay dang close attention to your point gap/condition. If I was tossing dice from 3,000 miles.....commmm....oooonnnnn.....CONDENSOR!!!<br />Even if it's new.

 

[ebbtide176]

Re: needed: engine vacuum tips for dummies

the condensor on it had a broken lead. when i replaced the coil, they said it didn't list a condensor. so i checked the manual, and it didn't list one. soooooo - it has not got a condensor. <br /><br />i'm not feeling too dam confident right now. i've been there with computers before, it usually takes another point of view, then turns out to be staring me in the face.

 

[NOSLEEP]

Re: needed: engine vacuum tips for dummies

77 is electronic ignition. No condenser<br />It has a stator reluctor in distributor.<br />pcv hose at throttle base below carb usually at<br />the back of carb base.<br />Vacuum advance off of throttle body, before base.<br />Brake booster off intake manifold, full vacuum.<br />EGR can be blocked at valve use heavy metal plate.<br />Dont forget to remove thermactor pump belt .

 

[NOSLEEP]

Re: needed: engine vacuum tips for dummies

The condenser on the coil is a ignition suppressor<br />for the radio.

 

[Skinnywater]

Re: needed: engine vacuum tips for dummies

ebb vacuum leaks cause lean running, not rich and choking out. There isn't a collapsed exaust on that Jeep is there? <br /><br />Weak spark as the problem occurs? Is the voltage to positive/primary side of the coil less then 9volt as the problem occurs?<br /><br />An hour with a pro can get a lot of questions answered ebb.

 

[ebbtide176]

Re: needed: engine vacuum tips for dummies

well, i spent the weekend working on the jeep as much as possible. me & pop (the pro maint man) went over all the things i'd done plus more. the women made fun of us & shopped, which was fine, as long as they kept a healthy distance from our personal space. which i'm still figuring out, since when mom came into garage to admire my latest construction, pop told her to find somewhere else to be... i was ready to be distracted but he was all into making the jeep a running vehicle.<br /><br />anyway, to update the situation- i still suspect this jeep engine has previously had distributor, cap, wires, waterpump, timing chain, and a couple of Ujoints replaced before i got it. it ran, although rich, and was hell to crank.(these are my thoughts) <br /><br />vacuum line was closing breather, so that was undone to get it running a little better, in the beginning. the new plugs made it run smoother.<br /><br />it for sure is a 77 304ci that belongs with this particular cj7. and it has compr at 130 on 5cyls, plus 135 x2 + 140 on #3cyl, so that seems ok. the book lists 140<br /><br />once i'd killed the coil, but replaced it with another hi-perf unit that requires step down, which is what manual suggests.<br /><br />but the weekend work was very intense.<br />weak spark was for breakfast. 4 courses of timing, new rotor,cap,plugs & wires were had. once the new ign module was served it fired up like a prom date. but decided not to run under load, which led to much weeping & gnashing of teeth. <br /><br />then for dessert, we had dist removal & new orders for bbq duty. late night snack was for visual vacuum line checks and a some electrical connection checks.<br /><br />for breakfast it was a new pickup coil. several base adjustments + additional idle screw tweaking were lunch. grand opening of the (shiny new looking) carb top with label "reman" were seen later, prior to parking back in the garage for a late lunch. i saw the box this carb came in when i got the jeep. it looked new. <br /><br />now its all back to normal, cranks like a champ when cold, warms up, tapping throttle drops it down to a healthy altho somewhat fast idle, and once in gear it strains properly for a short while, won't handle putting in gear, dies as if choked out. idle screws have been tried at 1/2 to 4 turns open. and it still won't crank when warm. if it does, it flooded. <br /><br />my next idea is to put this new motorcraft 2100/2150 carb kit thats sittin on the bench in that puppy, for a clincher....i'm having thoughts of a junkyard with an available car crusher.