Crank Sensor

[captainrags]

I have my Opti out for the third time trying to solve a random misfire issue I have two questions I think I will replace the distributor as replacing the cap and rotor did not cure the problem. So I now have two issues. Should I purchase a MSD unit or ACCEL ? Also one other issue that has been bothering me is the CKPS the crankshaft sensor I have not had any codes for that, but have received the 300 code. Any advice wouldbe appreciated as I’ve had the car off the road for weeks trying to get around these problems. My Corvette runs, but erratic and needs starting fluid to get it going, fuel is good spark is good.
Ray

96 Manual LT4 100,000 miles

 

[boomdriver]

can;t help with your engine issues but I can offer some FREE advice...to prevent more engine issues.

save the starting fluid for the diesel. The cast aluminum pistons in a GM V8 gas motor won;t stand for the huge KNOCK as that crap ignites from being hi-flash no or low octane.

 

[Hib Halverson]

DO NOT use "starting fluid".

The active ingredient is ether which is a very low octane fuel and causes massive detonation when it "starts" the engine. It can crack pistons and break rings in gasoline engines. On an engine with that many miles on it, you're asking for trouble.

If the engine won't start normally, diagnose the problem which prevents starting.

I would add that, if the engine runs erratic and is hard to start, then fuel and spark are probably NOT good.

As to the question of MSD or Accel, based on my long experience with MSD products, I'd go that route.

 

[captainrags]

Boomdriver and Hib
Thank you for the feedback will not do that again.
I purchased a crank sensor from rock auto and a MSD distributor from JEGS seeingthey will honor the best price, I found a new MSD for $486 from Geek parts Jegs honoredthat price. I think it’s a good deal.
Lets hope all will be ok when its back together as I’ve replaced the coil andplugs tested everything several times.
As an old 60,s hot shot mechanic, this new stuff sort of leaves mebehind, but I still seem ok on brakes and suspensions so far.
Thanks again

Ray

:thanks: :thanks:

 

[boomdriver]

no worries...
the starting fluid is a common mistake that people often learn about thru a blown engine...

Unlike the internals of 40-50 yrs ago, pistons are now made with minimal "meat" on the bone to reduce weight and to add thermal cooling by heat transfer. They are almost all aluminum which is known to be strong but brittle compared to mild steel. beat one of these pistons straight down with a uniform explosion of sufficient force and they do well. With a less powerful explosion the piston suffers unequal pressures on the dome and then "rattles" as it travels down the cylinder where it simply cannot tolerate the side stress of lateral movement due to its lightweight design.

AKA as "knock"...this is when a piston is literally rattling in the hole and we all know how tight pistons fit.

Then its easy to understand that for something that snug to actually rattle, it must be under tremendous force. Enough to break it.
Problem with starting fluids is they offer an easy ignition but a low yeild result. Easy to light but not much of an explosion. For a piston to travel safely down the stroke it needs a bigger explosion with enough force to keep pressure thru the stroke. Thats what hi-oct gasoline does...simply makes a longer explosion and keeps more pressure, longer on the pistons as they travel.

Starting fluid is a fraction of what gasoline would do. Because diesel engines are designed to knock and rattle with pistons designed to do this, they tolerate starting fluid much better but most mfg advise against the liberal use of the sprays in winter like truckers have done for decades....Block heaters and other aids help create a normal enviroment so starting is easier.

 

[captainrags]

Still no fix

Here’s my problem still . Any help would be good. I blew a radiator hose several weeks ago engine stopped, I changed the hose and drove home no problem. Four days later engine stopped would not start I presumed it was the Opti I replaced the cap and rotor newplugs, engine ran but missing and coughing back firing so presumed the opti was out of timing, so removed opti checked my work and reinstalled everything. So for the third time no improvement I did it again, this time I replaced the distributor with MDS iinstalled new coil and crank shaft sensor and still no start, used easy start and engine fired for shorttime dst were P0100 and pins connection under wheel were showing H64 and H65 replaced MAF, checked fuel pressure again and now have no,fuel pressure but had it before, so replaced fuel pump and filter (now have good fuel pres) but still missing, and showing still P0100 ran car around the block it appeared to have some oil sprayed from area of cyl 6-8 now could not identify where from, changed oil and filter when I removed oil cap there was water impregnated oil on cap sopresumed it was possibly a head gasket today removed all spark plugs and did compressiontest all cylinders were 150 psi removed valve cover on passenger side and waterin oil impregnated that had been there for some time also drops of clear water on valve rockers ??also some clear water in breather pipe.
Is this water condensation or possibly left over from theoriginal hose burst? Seem strange that it was clear clean water droplets andthe yellow oil gunk seems to be rather old. The oil drained was completely normal no water. There appears to be no oil in the water system. Is it possible that water has got into the MAP causing the miss, due to it be sticking? Checking the PCM circuits fromthe MAF what color is the wire location connection.

 

[boomdriver]

Here’s my problem still . Any help would be good. I blew a radiator hose several weeks ago engine stopped, I changed the hose and drove home no problem. Four days later engine stopped would not start I presumed it was the Opti I replaced the cap and rotor newplugs, engine ran but missing and coughing back firing so presumed the opti was out of timing, so removed opti checked my work and reinstalled everything. So for the third time no improvement I did it again, this time I replaced the distributor with MDS iinstalled new coil and crank shaft sensor and still no start, used easy start and engine fired for shorttime dst were P0100 and pins connection under wheel were showing H64 and H65 replaced MAF, checked fuel pressure again and now have no,fuel pressure but had it before, so replaced fuel pump and filter (now have good fuel pres) but still missing, and showing still P0100 ran car around the block it appeared to have some oil sprayed from area of cyl 6-8 now could not identify where from, changed oil and filter when I removed oil cap there was water impregnated oil on cap sopresumed it was possibly a head gasket today removed all spark plugs and did compressiontest all cylinders were 150 psi removed valve cover on passenger side and waterin oil impregnated that had been there for some time also drops of clear water on valve rockers ??also some clear water in breather pipe.
Is this water condensation or possibly left over from theoriginal hose burst? Seem strange that it was clear clean water droplets andthe yellow oil gunk seems to be rather old. The oil drained was completely normal no water. There appears to be no oil in the water system. Is it possible that water has got into the MAP causing the miss, due to it be sticking? Checking the PCM circuits fromthe MAF what color is the wire location connection.

I can't help because I think you've gone way past the original problem and I have no idea where you';re at now....but I wanted to recap so maybe someone else could step in if they had some clear info.

1st.....do you have a FSM ?

2nd just about everytime a LT motor gets soaked and starts to misfire or act up its going to be a wet Opti. They cannot be dried out and caps and wires do not help. Its internal and its junk. Its also expensive. Call or write your congressman @ GM... The upgraded 'vented' Opti is supposed to be the better unit. People build shields and splash gaurds to protect the unit from water pump leaks and hose leaks. Hoses can be wrapped and water pumps can tap a drain into the weep hole and a drain line connected.

3rd The MSD...was this a complete replacement of the dist that totally replaced the stock Opti? were all the connections made/done properly? I ask because the inj circuit gets reference signals from the dist. No reference signal...no fuel pump.

4th "so replaced fuel pump & filter" ? How did this come about? Was the pump bad before all this started or was the alleged bad pump the result of false evidence from d/c wiring around the dist?

5th "all cylinders were 150 psi removed " well within normal. Minimum pressure is 100 psi.
did pressures come up quickly or did it take 3-4 cycles to get 150 psi? Balance is just as important as pressure. Having all cyl at the same press is equally as important as the pressure itself. Looks ok if all were stable at 150 and tried to hold.

6. Water in oil...
if there is/was oil/foam in the cap and pcv or lines, there is at least a lot of condensation. If your area is extremely wet or rainy, thats not unusual. To prevent damage the car needs to be run long enough each trip to reach normal op temps and stay there long enough to boil off the moisture in the oil and eliminate it.
IF there is water entering from an outside source, it needs to be identified and fixed. The cap, and pcv should all seal well enough to prevent ANY water from entering. If there is no water loss from the radiator, no steam from the exhaust, and no more foam/sludge on the dipstick or cap then I'd guess that its condensation from high humidity and short run times.


Water 'sprayed' from #6-8? from where? around the head gasket area? or a loose spark plug?
There are few ways that oil or water can spray from anything on the outside of the head. Will be interesting to see what that is or where it came from...

 

[captainrags]

crank sensor

Boomdriver I real appreciate your experience and comments thankyou.
1 yes I do have FSM and read it to death looking for problem.
2 Spark wires are MSD but old except for coil wire its a prestolight.
3 The MSD was a complete new unit, checked and check allspark and coil wires, unit came with its own wire from opti to connector near purgesolenoid.
4 fuel pressure in the past had trouble holding after 2minutes. Ignition on, pressure would go to 47ish and then slowly fade back, butnoted before it held around 30 while running. After pump was removed I suppliedit with direct 12 volt on bench and it did not work.
5 comp test first revolution was 100ish second and third and4[SUP]th[/SUP] pressure was 130 after 5 compressions it was 150 -155lb sq inch
6 last week In FLA we had lots of rain and humidity thereforeI do suspect condensation but not as much but clean water that seem right, the foam oil was rather thick andonly in valve cover only clear water in breather making me think it was therefor a little time there has never been any discoloring on dip stick . I diddrive through a puddle months ago and witnessed the missing and spluttering butit cleared itself up then.
The oil sprayed couldhave been from spark plug as 8 did not seem real tight on removal but I didtoque them to the correct tension when installing them but 8 is real tight working space and possibleI did not get it right.
About the only thing I can now think of is the MAP
I wanted to check the wiring to the MAF for a possible shortI do have a good ground and 5.1 volts to the unit but didn’t know what terminalthe wire comes off the pcm “red” “black” ect.
Spark plugs appear to be all firing, reading them, some seem alittle sooty considering they are new.
Other possibilities are I’ve had a open purge DTC for sometime. But did not think it would cause a miss.
And I have not yet checked the MAP voltage.