car wont shut off

sometimes when i shut her down she likes to keep running or diesel as i have been told...it's like a spit and sputter and it is really embarassing...some times it might last as long as a minute...its an 86 carbed z28...it starts fine and runs good.. but i think it might idle a little high and there is an engine light on...the guy who i bought it off of said that the ecm may be bad or something to do with the timing...but im told if it runs ok the ecm should be good....im so confused...does ne body have a clue to what this could be???

sounds like timing.

does the car flood while trying to start?

run the codes to find out why the engine light is on But it sounds like your timing is off..

does the car flood while trying to start?

I had a little nissan pick up that did that , the little Z4 bastard needed a card rebuild kit.

sounds like timing to me.

it has a new timing chain....so if i get a new carb. put in should it go away after that ?

it has a new timing chain....so if i get a new carb. put in should it go away after that ?
just cause it has a new timing chain doesn't mean the timing is right i would really check that out cause it does sound like thats what it is

timing

so when i get the new carb and intake put on in april....this problem should be cured ?

Dude...no. That's not what we're saying. YOU NEED to time if properly. ie: Timing light and a professional.

i mean wont he do that when he puts the carb on tho ?

not unless you ask him to.. engine timing has nothin to do with installing a new carb..

crap

crap? its quicker, easier and cheaper to do. somebody, prior to you , may have adjusted the distributer to possibly compensate for the worn out timing gear that was replaced. i use to always try to set the timing without a timing light, until i got it checked once. i was only out 17 degrees...lol

haha...so after he puts the carb on and i have told him to check the timing he could prolly do it easily without too much extra $$$ ???

Ok...... Ill be patient, and use small words to clear this up for everyone, cuz we dont seem to understand.

First off, i agree with post 15 that as the timing gear got old and stretched, they changed the timing to account for it, this is what i had to do with my IROC and have still done because i havent had a chance to replace the timing chain. The high idle, and diseling of the engine at shutoff, are all symptoms of advanced timing, which is the remidy to a stretched timing chain, as the chain wears out, the timing is physicly retarded, and you have to advance the distributor to account for it. Now that your cam is physicly timed correctly, the electronic timing is far to advanced, and needs to be brought back to proper specs.

Now, In reference to the carb. Why are you looking to replace it? You say the car runs fine, other than this single problem. Putting a new carb on will have no effect, this is not being caused by the carb. So are you looking to do it as a performance modification? because that would be viable.

For instance, if you are swapping to a performance carb and intake, any mechanic worth his salt is going to tune it to run best with the new setup, which would involve setting the timing according to vacume, and recording the setting in degrees for future tuneups. Because my chain is so bad ive had to set my own timing by vacume instead of with a timing light. i think its 16 degrees advanced at idle right now according to crank position. (its supposed to be 0)

Now in any case, you should have the car running properly before you start doing mods, because if the problems persist, you dont know if its because of the new parts, or the old ones. So i would strongly suggest you take the car to the shop, and have them set the timing properly, and go from there.

3 degrees off of gm engines is usually safe but 17 could end up causing a large amount of damage.

Plus a new timing set - gears and chain.- aren't that expensive..replace them now before they blow and really f*** something up.

lol, believe me i know, the car isnt being driven, i just start her from time to time so she dosnt feel neglected. But for now im living 10 hours away from home, and its winter, so ill wait till summer to worry about the timing chain, also, i still have to put the dash, stereo system, and interior back in the car, so methinks that comes first lol.

don't feel bad. everything i ever owned was pretty much wore out. old engines sometimes aren't worth putting a lot of parts into, without rebuilding. ie: ya change your timing gear, but yer cam is prolly wore. ya change that, ya might want new bottom end parts, and on and on, and you'd still have an old engine w/some old internals. a lot of times your almost better to just rebuild.

the top end was rebuilt and a new cam was put in and the engine runs fine besides the dieseling... iwas just looking to put the intake and new carb on for better perfomance..

i'm no mechanic but was always told never to rebuild the top end of an engine w/o at least putting new crank bearings in. rebuilt top end puts more strain on the bottom.

i really doubt that a new intake and carb will put enought stress on the lower end to make a rebuild worth while. If you are putting the intake on the shop should set the timing to make it run right. but you could have the timing set until then so the desiling stops. it shouldnt cost all that much to have that done.

thanks...

(quote)i really doubt that a new intake and carb will put enought stress on the lower end to make a rebuild worth while.(quote)
i believe he also said the top end was rebuilt and it has a new cam, which would undoubtedly put more strain on a likely already tired bottom end. i wasn't trying to imply that a new carb/intake would be the end-all of this engine.

to be fair, we would have to know what exacty the rebuild entails, i think you are seeing it as a performance rebuild, whereas i am seeing it as a "freshening up" to factory specs. it would depend on which one it was. Obviously if he was running an additional 200hp from a set of high performance heads, massive bumpy cam, and tunnel ram intake, it would be a very good idea to rebuild the bottom end with a fresh set of bearings and such. but if he just had the seals freshened, some mild port work, stock valves and some Z28 springs, and a mild say, .450 lift cam, a rebuild wouldnt be nessesary.

idk what lift u are talking about but...but the spec sheet that came with it says the gross valve lift for intake and exhaust are .44 and .454 for respectively...

the lobe lifts are .2980 and .3030 for intake and exhaust respectively...i imagine these are pretty close to stock numbers...what would probably be a good size to buy if i decide to go bigger ?? and what is the range for installation $$ ??

i was just throwing out random specs. id say with that cam, youre fine. I wont be running much bigger in my engine because its a daily driver. If yours is too, i dont suggest doin the whole .500+ in cam lift thing. as far as cost, depends on where ya go.