C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

seeping intake bolts 1985 affect idle?

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Old 11-22-2015, 02:35 AM
  #81  
aklim
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Originally Posted by VikingTrad3r
Thanks and will do today Ak. ive been avoiding timing....back in 1992 i was in grade 11. my first vehicle was a 79 cj5. i messed with the timing on it and had to get it towed! that was before the days of the web and youtube and forums for the dharing of knowledge.

if anybody else is intimidated by timing, here is a grest thread explaining it from 2004! https://www.corvetteforum.com/forums...-88-vette.html


should have it measured today Ak, thanks
Good news. Since the car is running at this level, I suspect that the timing isn't going to be so far you have to pull the distributor.
Old 11-22-2015, 09:09 AM
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Originally Posted by aklim
Good news. Since the car is running at this level, I suspect that the timing isn't going to be so far you have to pull the distributor.
likely right. i did not get the chance to pull timing on it yesterday. We were "chinooking" here yesterday with temps well above freezing so we spent the day getting the yard all christmas lighted up.

will do it this morning.
Old 11-22-2015, 01:49 PM
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Default verified 6deg advance timing

OK guys, I just did the timing on cylinder number one with the EST unplugged and I can confirm that I have 6° of advanced timing at idle in closed loop.

6° on my stock L 98 looks like it is the most passenger side of the timing tab, the top edge. i do not know if my hb is walking but i can certainly compare where its at a fre days from now. so to sum up, my timing line on the harmonic balancer is aligned with the very top of the timing tab I tried to get a picture but my iPhone wouldn't capture it. but it is stock so I'm sure that other people with an L 98 can chime in but if every tooth represents 2° then I'm pretty sure I have six degrees in total from the zero mark to the very top edge of the jagged Toothed timing tab on the block.

so Ak with that verified, should I try advancing the timing? or should i pull plugs and see if any smell like gas to try and uncover an injector thats staying open a bit too long?

I did the ohm test and 2 are 16.5 and the rest are 17. but ive read you saying a thousand times that does not guarantee good injector behavior.



Originally Posted by VikingTrad3r
likely right. i did not get the chance to pull timing on it yesterday. We were "chinooking" here yesterday with temps well above freezing so we spent the day getting the yard all christmas lighted up.

will do it this morning.
Old 11-22-2015, 02:38 PM
  #84  
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Originally Posted by VikingTrad3r
OK guys, I just did the timing on cylinder number one with the EST unplugged and I can confirm that I have 6° of advanced timing at idle in closed loop.

so Ak with that verified, should I try advancing the timing? or should i pull plugs and see if any smell like gas to try and uncover an injector thats staying open a bit too long?

I did the ohm test and 2 are 16.5 and the rest are 17. but ive read you saying a thousand times that does not guarantee good injector behavior.
I'm not there so it does sound like you did it right. As to walking, well, it takes time which is why others have also advised you paint a stripe. It might be great for the next 5 years. OTOH, it might come out tomorrow. You don't know and neither do I. So, anytime you look at it and the line you painted is broken, so is the HB. So simple even a cave man can do it.

I wouldn't advance the timing. Leave it at stock setting UNLESS told otherwise by the tuner. As to the injectors, They are pulsed so either it is on or it is off. Not sure how one can be on and the other off. If you want to see if it is rich or lean, drive it. Hook scanner up. I have done it before. O2 sensor, ASSUME it is in good condition, will tell.

Correct. It is one of the tests that lead you to assume the spray pattern and volume are correct. Exactly why I don't bother and send them out every 3 years.

Have you tested fuel pressure? Engine running with hose off should net about 43, give or take since you are simulating WOT. Take it for a drive and do a WOT blast. See if the pressure drops and gets back or just stays low. Finally, at idle, shut down and see if the pressure drops much in the next few hours.
Old 11-22-2015, 04:40 PM
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been through the fuel tests and pressures are correct for 85. pressure holds for hours.



ive been playing with timing with est off.

the more advanced the timing the worse the rich exhaust. loads of rich fumes out pipes. when i tetard tl like 2 degrees advanced, smell gets better and less white unburned fuel.

does that give you guys any clues?


Originally Posted by aklim
I'm not there so it does sound like you did it right. As to walking, well, it takes time which is why others have also advised you paint a stripe. It might be great for the next 5 years. OTOH, it might come out tomorrow. You don't know and neither do I. So, anytime you look at it and the line you painted is broken, so is the HB. So simple even a cave man can do it.

I wouldn't advance the timing. Leave it at stock setting UNLESS told otherwise by the tuner. As to the injectors, They are pulsed so either it is on or it is off. Not sure how one can be on and the other off. If you want to see if it is rich or lean, drive it. Hook scanner up. I have done it before. O2 sensor, ASSUME it is in good condition, will tell.

Correct. It is one of the tests that lead you to assume the spray pattern and volume are correct. Exactly why I don't bother and send them out every 3 years.

Have you tested fuel pressure? Engine running with hose off should net about 43, give or take since you are simulating WOT. Take it for a drive and do a WOT blast. See if the pressure drops and gets back or just stays low. Finally, at idle, shut down and see if the pressure drops much in the next few hours.
Old 11-22-2015, 06:25 PM
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Default pulled plugs. check what i found.

only got as far as the right/passenger bank and when i was checking plug routing i noticed that cyl 6 had a different style of rubber cap, like not bent, straight, so i went there first, because it looked like it had been mashed onto the plugs so hard it was a bit ripped at the end.

the other thing is that one of the contacts on the underside of the cap had a visible groove in it. the other 7 had white powder on them but this one had a groove.

The other thing is that whenever ive been trying switching between field testing mode or aldl mode or normal mode and i start the car the next time i get a knock from the passenger side. im guessing its cylender 6!

its reversed of what it shojld be in the pic sry.

so left to right, 2,4,6,8.

so my next question, would this cause the stutter/hesitation at idle? according to my shop manual yes, but it doesnt say if allll the plugs need to be fouled or just one.

this car hauls *** once its moving, no power loss other than the hesitation when i stab / smash the pedal.








hard to see but it looks like the plugs bent the metal inside the cap from being pushed too hard. its a straight rubber boot. supposed to be straight?





2,4,6,8





very little build up on any of the other ones. except for 6 where its chunky and black. it does not smell like gas. i assume its oil.








6,8





Old 11-22-2015, 07:11 PM
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OK. Before we go anywhere or any further, lets do a compression test and a leakdown test. If your rings are leaking, NFW we can do anything else for you. I've done a lot of things crazy and/or stupid things in my time but none of it involves growing metal back on an engine. For that, you call Obama.

IF your oil leak is from the valve stem seals, you lucked out. That's an easy fix. Change the seals and you are good to go. After which, change plugs and get a good wire set. Tempting as it might be, if you do one, I'd do all the seals.

Last edited by aklim; 11-22-2015 at 10:43 PM.
Old 11-22-2015, 11:39 PM
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Originally Posted by aklim
OK. Before we go anywhere or any further, lets do a compression test and a leakdown test. If your rings are leaking, NFW we can do anything else for you. I've done a lot of things crazy and/or stupid things in my time but none of it involves growing metal back on an engine. For that, you call Obama.

IF your oil leak is from the valve stem seals, you lucked out. That's an easy fix. Change the seals and you are good to go. After which, change plugs and get a good wire set. Tempting as it might be, if you do one, I'd do all the seals.
Hi again. Ok seeing as i am going to do my compression test over the lunch hour tomorrow, i thought id pull the left bak plugs and get the pictures up for you all to see.

i think i can see why the car is running rich and the blms are pulling back. im thinking the plugs in cyl 7 and 6 are not doing a great job of combusting the fuel.

The bog i have while at idle, shown in my video, i am thinking that maybe the computer is pulling so much fuel back at idle its actualy a lean bog. meaning i instantly jam the throttle wide open and the computer is busy trying to pull back the fuel because the o2 sensor is reading unburned fuel so then there isnt enough fuel for that split second, until the comp thinks "oh, ok i thought i was running rich but now i see im running really lean so i have to swing the other direction".

again, im nooballs so no idea but anyway. we will see what happens on the compression, wet and dry, to help narrow down valves vs rings.

any hi ts as to how u guys are squirting oil in for the wet test? would squirting some penetrating oil in there do it? just thinking something under pressure with a delivery straw to aim in the hole.


pics:


















showed 6 in the prior post, but here is a shot up the bottom. its by far the worst and other than 7 looking like its befinning to foul, the rest look consistent


Old 11-22-2015, 11:51 PM
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just read in my compression tester instruction pamphlet that the car needs to be warmed up for 10 min before doing a test?

does it? i just removed all 8 plugs and would rather not put them all back to run it for 10min.

do i need to?
Old 11-23-2015, 08:45 AM
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Originally Posted by VikingTrad3r
just read in my compression tester instruction pamphlet that the car needs to be warmed up for 10 min before doing a test?

does it? i just removed all 8 plugs and would rather not put them all back to run it for 10min.

do i need to?
My thought is that you need to get the oil all around like it would if it was running. Lifters are filled up, normal amount of lubrication all over the motor and you are not cranking when it is dry.
Old 11-23-2015, 09:38 AM
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Just test and report
Old 11-23-2015, 11:51 AM
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did you put a new knock sensor in with the right torque very important? if not a new one at least the right dope on it. is the 02 still good or did it get crap filled?
Old 11-23-2015, 12:03 PM
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Originally Posted by antfarmer2
did you put a new knock sensor in with the right torque very important? if not a new one at least the right dope on it. is the 02 still good or did it get crap filled?
Not sure I would screw with the KS at this time. If he doesn't have good compression, he can install new sensors on the rebuilt motor.
Old 11-23-2015, 12:11 PM
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Originally Posted by aklim
Not sure I would screw with the KS at this time. If he doesn't have good compression, he can install new sensors on the rebuilt motor.
but you have that covered but might just be a bad wire that he found. and he did play with the knock.
Old 11-23-2015, 12:16 PM
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to oil the cylinder I go to the feed store and get big syringes and the hardware store for some thin tubeing. you can mesure the oil put in the pull the syringe out and blow the rest of the oil in.
I put a bit of dielectrice grease in the plug wires.

Last edited by antfarmer2; 11-23-2015 at 12:27 PM.
Old 11-23-2015, 12:53 PM
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Originally Posted by antfarmer2
to oil the cylinder I go to the feed store and get big syringes and the hardware store for some thin tubeing. you can mesure the oil put in the pull the syringe out and blow the rest of the oil in.
I put a bit of dielectrice grease in the plug wires.
Or buy an oil can and reuse it instead of syringe and tubing you have to rig up. I would just test it dry and then switch to wet and repeat for the next 7 cylinders. I would think that even using WD40 would be fine. Measuring oil us kinda overkill.
Old 11-23-2015, 01:07 PM
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Originally Posted by antfarmer2
did you put a new knock sensor in with the right torque very important? if not a new one at least the right dope on it. is the 02 still good or did it get crap filled?
ks was reinstalled to correct torque. used pipe dope. i realize thats not the "right" stuff however there was zero before and after difference. i suppose i could throw that prt at it but im really trying not to chuck parts at it.

before i realized there was a systematic diagnosis approach to all this, back in the spring, i did chuck a new o2 sensor on it. 02 sensor appears to be crossing nicely. it has the strange behavior of readin dead zero boltage upon decelleration from high speed though. perhaps that is normal but i did notice that it basically flatlined when i decellerated. i thought perhaps that jived with running terribly rich meaning cut oxygen at throttle body, then either a plug or two that is not burning like it should causes extra unburned fuel to go out exhaust until the comp cuts the fuel back which is shown by the perpetually low blm's (no popping out exhaust on decel which i beleive means lean so this supports rich theory).

but at the end of the day, Aklim is right. need to know compression is solid. this is a foundation level measurement and from now on ive realized there are foundation level things that need to be verified first (compression, ignition source and spark quality, and fuel supply). These should be the first thing anybody does.

instead, noobs like me typically start replacing sensors and other "easy things" first. its more like "stuff i dont need to go buy a measuring tool for" first. taking compression is easy. need a 25$ tool. taking fuel pressure is easy. need 25 fuel. pressure testing coolant sustem is easy, need free rental from autozone/autovalue. like that old saying, noobs like me seem to get busy rearranging the deck chairs on a potential titanic instead of going that one extra step of effort and looking to make sure all foundational systems are functioning on the boat first.

so ive dipped my plugs in seafoam, just the tips.

turns out that the chunky bits on the plugs are not burned oil. well, if they are, seafoam and a metal pick cannot get it off. i think they are corrosion of some kind. almost every plug had some oil on the base of the threads of the plug. This comes off with sea foam. i think we have a situation where a recent valve seal compromise has coated the chunky plugs 6 and 7 same as the rest of them, but 6 and 7 are not burning hot enough to burn it off.

im * thinking * what happend here is the quality of spark was crap in cyl 6 especially and not so great in 7. the cap showed some nasty grooving on one post and another one as well. i didnt think to see which one but my bet would be 6 and 7. my guess is that the previous owner, given his display of bubba fixing on this car, likely went and shoved each wite as hard as he could onto each spark plug, and damaged the number 6 even more, which lead to further / accelerated failure of spark quality on that plug. and rotars should be replced, with wires. now in these two cylenders any extraneous substance that was in the chamber, oil, seafoam, gas additives (tacteol) I have read they will leave buildup on plugs that are. cooler, or not as hot, over a long time. Then, add into the fact that the car was running rich anyway, because of the big vac leak i found on the intake manifold. and take into account this leak was at the pcv hose....and from what i read when your pcv is plugged, or, not "flowing" because the intake was just pulling fresh air rather than pulling the pcv fumes in, it caused the pcv hose to dribble some engine oil onto the top of the intake manifold which was the START of this whole process, i noticed dribbles of what i thought was dirty coolant, because the coolant was disgusting. Ive since learned that if it was coolant it would have burned off, so it was oil. A plugged or non flowing pcv valve lead CAN lead to a buildup of crankcase pressure, not a huge buildup in my case because we did have the vac leak, but the full extraction of the pcv was not happening. this can force some oil past the rings and and valve guides and end up getting burned. ON TOP of all this, its recently started to give a little puff of oil smoke for the first couple seconds upon startup after sitting overnight.

So... guaranteed im not right anout the above theory. Im sure there are prts that are right. But, Aks point is that "just do the compression test" and take it from there.

With that said, im off to put the cleaned plugs back in, run the car for 10min, then do the test.

will report back later.

VT.

Last edited by VikingTrad3r; 11-23-2015 at 01:11 PM.

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Old 11-23-2015, 01:49 PM
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pipe dope is not right and no way you put the right torque on it useing it. I agree with the compresson test but hopeing for bad wires and plugs wish you the best luck.
Old 11-23-2015, 02:03 PM
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Originally Posted by aklim
Or buy an oil can and reuse it instead of syringe and tubing you have to rig up. I would just test it dry and then switch to wet and repeat for the next 7 cylinders. I would think that even using WD40 would be fine. Measuring oil us kinda overkill.
maybe overkill but I have big ones around from vetting large critters. they are cheap and you can get them at any feed store. the more consistent the test the more accurate the results are. if you don't believe me leave one dry and test it then fill the same one with oil and see the differants. I would not use wd40 to thin. :chee4rs:

Last edited by antfarmer2; 11-23-2015 at 02:19 PM.
Old 11-23-2015, 03:34 PM
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Originally Posted by antfarmer2
pipe dope is not right and no way you put the right torque on it useing it. I agree with the compresson test but hopeing for bad wires and plugs wish you the best luck.

fair enough ant. i assume i have OVER torqued it? like the pipe dope would have over lubbed the threads?

i do want to do this right and i am taking the time to do it. what is the right dope for the ks? i will do it right.

Last edited by VikingTrad3r; 11-23-2015 at 03:35 PM.


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