LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Problem wasn't Opti, Now What?

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Old Aug 5, 2003 | 03:37 PM
  #31  
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We're all at different levels here and most of us are here to help

You can get a 9/16" socket and attach it to one of the three bolts holding the balancer onto the crank snout. Turn the crank (balancer) clockwise until the arrow on the balancer is pointing straight up... there will be another notch on the outside of the balancer which should point at 2 o'clock (#1 cylinder).

The valve cover on the driver's side is easy. It can be removed by taking out the four center-bolt hex head cap screws.

Opti and Water Pump are untouched... Let me know if this helps
Old Aug 5, 2003 | 03:38 PM
  #32  
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Although you should check the opti, coil, and definitely ohm the plug wires also do the freebee and bypass your msd box if your running one.. I spent a hella lotta time messing with a car only to find in about 10 minutes that the msd box had fried (weather, vibrations, who knows why) But of course it was the last thing I checked.. Dunno about the timing chain thing.. if that thing is spinning the rotor in there you should be getting zero spark..
Old Aug 5, 2003 | 03:42 PM
  #33  
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Originally posted by 63SSRagtop
Although you should check the opti, coil, and definitely ohm the plug wires also do the freebee and bypass your msd box if your running one.. I spent a hella lotta time messing with a car only to find in about 10 minutes that the msd box had fried (weather, vibrations, who knows why) But of course it was the last thing I checked.. Dunno about the timing chain thing.. if that thing is spinning the rotor in there you should be getting zero spark..
The ignition system has been completely gone through, including bypassing the MSD.
Old Aug 5, 2003 | 05:32 PM
  #34  
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I believe the 1997 had a crankshaft position sensor.... can you confirm? If that goes out, it could affect your ignition too.
Old Aug 5, 2003 | 05:41 PM
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It does, but isn't that in the Opti itself? I'll try the checking that tonight. This test will verify both if the timing chain broke, or if it just slipped. Thanks!
Old Aug 6, 2003 | 01:15 PM
  #36  
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Alright, I removed the driver's side valve cover, and cranked the engine. The rockers appear to be moving as they should. I then set the crank to TDC by hand, and checked the position of the rocker arms on the #1 cylinder, and they looked to be in the position that they're supposed to be when the crank is at TDC (from what I've been told). I posted some pics. Could everybody please look at the pics, and tell me if the rocker arms are in the correct position for the crank being at TDC for the #1 cylinder? Thanks!

CLICK HERE
Old Aug 6, 2003 | 01:44 PM
  #37  
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Looking at the exhaust valve on the #1 cylinder, it appears to be lower than the intake valve. They should be even. If it is truly set at TDC, you're timing chain could have slipped.

When I upgraded to Roller Rockers, #1 was even for both intake and exhaust.

I'm not sure if it is a funny camera angle, but the exhaust valve looks lower (open).
Old Aug 6, 2003 | 02:26 PM
  #38  
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I know the camaera angle can play tricks. I'll start another thread with a poll or something.
Old Aug 6, 2003 | 03:27 PM
  #39  
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Can you verify that one rocker arm is lower than the other on the #1 cylinder?
Old Aug 6, 2003 | 03:33 PM
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I'll have to wait until I get home late tonight to check. I *thought* they were at the same height, though.
Old Jun 6, 2005 | 07:38 PM
  #41  
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Re: Problem wasn't Opti, Now What?

When I measured my brand new wires from Taylor made by me, the measured between 700 ohms to 1000 and some change ohms depending on the wire length.

Z
Old Jun 6, 2005 | 07:58 PM
  #42  
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Re: Problem wasn't Opti, Now What?

Id be checking for continuity in the opti harness wires. Really sounds to me like the harness went bad or the plug-in connector is cracked/corroded badly.
Old Jun 8, 2005 | 09:35 AM
  #43  
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Re: Problem wasn't Opti, Now What?

ZMan, do you have a misfire? Or were you just checking a your wires?

Wires vary in Ohms depending on manufacturer. What you did was good. Mark your Ohms per wire somewhere (data log, Owner's Manual, etc). Later on you can benchmark where your wires are relative to a new set. The more they wear out, the more resistance in the wire. If you eventually have a misfire, you can note which wire is out of spec by the extreme deviance from what was new. (Kind of like a Compression Test with cylinder varience of up to 15-20%).

Accel has even higher Ohm readings.
Old Jun 8, 2005 | 07:37 PM
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Re: Problem wasn't Opti, Now What?

I still have a big miss. I have changed knock sensor, opti, coil, wires twice, plugs twice. Cleaned all of my grounds with sand paper. Checked my injectors with multimeter, and they are all electronically good. I am gonna pull them to see if they spray, because cylinders 6,8,5,7 are not getting very hot. The fron 4 if sprayed with water evaporates instantly. The back 4 take a couple seconds for the water to burn off. So I am starting to think they aren't spraying correctly. They are stock with 107,000 miles on them. I have a friend that is sending me 8 off of a Camaro that has 56k on them. He knows for a fact they work. They will make at the least nice troubleshooting pieces. Oh yeah, my BLM's are at 160 for my whole datamaster logs. That is also swaying me to beleiving I've got some bad spraying injectors even if voltage and resistance checks good. One more detail, I checked compression and within tolerance, so that looks good. This sucks, but I am learning a ton. I will take any advice. Thanks!

ZMAN
Old Jun 8, 2005 | 07:42 PM
  #45  
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Re: Problem wasn't Opti, Now What?

What else do these logs show? That 160 BLM problem is a big one but need more info to see what might be causing it.. things like O2 sensor voltage, MAP and MAF readings. THey may point towards the source of the problem.



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