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Oil in opti, replaced cap, now won't start

5K views 23 replies 7 participants last post by  aroberson77 
#1 ·
I recently replaced the cap and rotor that cost $157 on Amazon. Now the car won't start (it tries but won't turn over). The Opti was soaked with oil inside, so I cleaned it and thought it would be good. The reason I replaced was because cylinder 8 was misfiring w/ code. There are no codes now.

AC Delco D8301 GM Original Equipment Ignition Distributor Cap and Rotor Kit with Housing, Seals, and Bolts is what I bought.
Any help would be much appreciated.
 
#3 ·
Quick test to see if low resolution pulse is occuring is to crank engine and see if rpm is indicated on tach. Should read about 200 rpm while cranking. If no, you have no low res pulse and car won't run.

Opti low res pulse missing code does not light the service engine soon light. You have to use an obd 2 scanner to scan for codes.

If your going to live with a lt1 equipped car, better buy a pc based oscilloscope from Ebay, Amazon, etc. They cost about $70 Use it to test opti low & high res signals. Also good for testing fuel enable signal that's part of security system.

If you need a new opti, don't cheap out and buy a store brand or Ebay special. Get a GM, Delphi, or Msd. They are the best of a sorry group of available parts. With your cheap opti, you will have a 50-50 chance of it being bad right out of box.

If lucky enough to get one that works, you have a 50-50 chance of it failing within a few thousand miles.
 
#4 ·
I'm not sure about having spark at the plugs as I am alone. While cranking the RPMs flutter so quickly it's hard to tell if it makes it to 200. It lasts about a second before it gives up. The cap was not beige like the OEM it replaced even though it says it is GM. Hopefully I didn't get screwed. While diagnosing the original Opti, I slid a paper towel into the crevice of the optical sensor and a little oil was on there. Do you think I ruined the sensor? Low res is optical right? I wonder if it is too late to send the cap back and get the $500 MSD Opti-spark.
I will invest in the PC based oscilloscope as I am never getting rid of this car.
 
#6 · (Edited)
From what I have read on this site as well as CamaroZ28, is that there have been numerous problems with the MSD Opti-Spark. Some guys have lucked out, and others have had problems from right out of the box to shortly afterwards. Maybe you will luck out.

Maybe disassembly and close inspection of the current one will reveal something you missed.
 
#5 ·
are you sure you got the opti lined up to the cam pin right?

did it sit dead nuts flush against block by just holding it on with hand.....or did you draw it in when you tightened the bolts?

the answer to the later better be no.

I have had oil get inside opti and gently & carefully cleaned it out and all was/still is fine

the metal disc with the 360 small slots in it goes "in" the optical sensor. If you smeared that sensor with oil and didn't get it all out, this would cause a no start issue.

paper towel, can of air or compressor on low to clean, blow out anything that may be in the optical sensor
 
#7 ·
Go ahead and buy you a opti and get it over with.If you have oil in the cap its over for that opti.Also change out the seal behind it.Why your in there just change all 3 seals in the timing cover.You can get the whole kit with water pump gaskets for $12.Its cheaper that way.Ive been threw this tooooooo many times.Change the opti!!!
 
#8 ·
I am sure I lined up the opti and didn't force the screws. When cleaning I wasn't sure about the discs relation to which was up and down. Didn't think it mattered. I installed it with the words/numbers up. Was that correct? Also I didn't follow torque specs when bolting the cap back on the distributor. I wonder if I didn't go tight enough. I used blue lock tight on all screws. I should not have half assed that part. I did replace all the gaskets and O-rings when I installed a new cam (CC-503-8) a few months ago. At that time I should have opened the opti as it was missing before the cam swap-Another stupid thing I have done.
I will tear apart the car again this weekend and examine what I have done. If I can't find anything , I guess I will buy the remanufactured AC Delco opti on Summit.
 
#9 ·
Well I replaced the Opti with the AC Delco from summit w/ the new pigtail and Nothing! Same thing. I'm getting tired of tearing this car apart. I'm at a loss. This time I did have to force the screws a little (1/8''), but I think that it felt normal (maybe new O-rings?) I'm sure that the pin drive was lined up also. Should I start replacing the icm and wires or take the Opti off and try to line it up again?
 
#11 ·
This time I did have to force the screws a little (1/8''), but I think that it felt normal (maybe new O-rings?) I'm sure that the pin drive was lined up also. Should I start replacing the icm and wires or take the Opti off and try to line it up again?
you should always be able to have the Opti flush with block by pushing with hand. New Opti with new O ring does have a slight "snug" feel when putting on but by hand it should sit dead nuts flush with TC. If you had to pull it in last 1/8" with the 3 Opti bolts....it is not lined up on dowel pin and will never start this way

your action stating you "force the screws a little (1/8") contradicts your next statement "I'm sure that the pin drive was lined up.."
 
#10 ·
Did you get a pc based oscilloscope like I suggested in post #3? It's the only 100% reliable way of seeing if low & high res pulses are there and the correct voltage and wave form.

Have you checked the opti pigtail harness which runs from passenger side of intake to opti? It's connectors, pin, and wires can go bad.
 
#12 ·
I did not purchase the oscilloscope, but will now. Is there a recommended one? The opti's pigtail is brand new and heat-shrinked on there. I guess the dowel wasn't lined up. I messed with that thing for 20 minutes before it would even get to that 1/8'' gap, so I thought maybe I was there. Is there a trick to this? I had no trouble with the original.
I guess I will be buying a set of water-pump gaskets for the 4th time.
 
#14 ·
I just removed the distributor again and the dowel pin was in the correct slot of the coupling. I did however notice that I didn't hammer in the the new seal in the timing cover all the way (maybe a 1/16'' left to hammer on the bottom) I think that was why I had to force the bolts.
I am looking on Ebay for the scope and see a lot of them. I was wondering which one you have? While I am ordering things, do you think I should get a new coil?
 
#18 ·
So after re installing the new opti after hammering the seal in better the LT1 is back to running the way it did before I replaced it . The Oscilloscope shows Low & High res pulses are good and the correct voltage/wave form.
The scanner shows I have a misfire on cylinder 8. So I replaced the coil with a MSD blaster, AC Delco ICM, new plugs, and new Taylor 8.25 mm wires. Same issue. I just swapped the fuel injector on cylinder 8 with another. Still no fix.
I just realized that I'm idling at 1000 instead of 800 like the tune specifies.
Should I reset valve lash? Valve seal gone? Is there a major vacuum leak that I'm not catching? The is the best to drive this car. I'm wishing I never installed this cam.
 
#20 ·
Agree with BALLSS. Get a noid light or a mech. stethoscope and see if that injector circuit is firing. If it is, and you've confirmed spark at that cylinder - it's time to look at the air-side of the combustion triangle. Put a vac gauge on it and see what its pulling and how the needle is acting. If you have a vac leak at the intake gaskets (not unheard-of), then it'll show up on the gauge. Then a compression test.
 
#21 ·
Thanks for the guidance. I just ordered a fog machine to do a vacuum leak test. I sure hope it's not the intake because that was a PITA, but it wouldn't surprise me due to the fact that I replaced all vacuum lines a year ago to dress up the engine bay.
The code stayed with cylinder #8 and they all tick while listening with my stethoscope.
I really hope I'm not tearing the whole car apart again.
 
#22 ·
some cheap hand tools like a vacuum gage, noid light, IR temp gun, stethoscope (even Harbor Freight cheapo ones) are very helpful in diagnosing engine.

Injectors still "clicking" with stethoscope. Confirm with noid light

Temp gun on cyl 8 exhaust manifold near head if low would indicate not firing because of ignition (no spark) so yo would look into Opti, plug wire and spark plug on that cyl

vacuum gage will tell a great deal about engine. You can google and easily find results on what the gauge is showing

smoke machine will find vac leaks
 
#23 ·
So while waiting on being able to afford the suggested tools,I figured I would start all over on setting valve lash/pre-load. As soon as I remove the cover I see that cylinder 8 intake rocker was very loose. I'm not sure how I didn't hear that. So I went ahead and re-did all of them at 1/2 past zero lash. There is no longer a SES light but cylinder 3 has misfired once and cylinder 2 as well after idling for about 15 minutes. It seems like its a lot better but the idle is still at 950. The fog machine showed no leaks. Is it possible that the valve train wasn't adjusted properly to affect the idle making it 150 higher? Should the CC-503-8 cam be 1/4 turn or 3/4 instead? Seems like it's not very choppy like I hoped.
I want to drive the car but I'm scared I'm going to mess something up.
 
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