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

Please help with engine diaganosis!!

Old Aug 3, 2008 | 10:23 PM
  #1  
RPWS6's Avatar
Thread Starter
Registered User
 
Joined: Apr 2005
Posts: 361
From: Chicago Area
Please help with engine diaganosis!!

Ok here is what I have. A 96 TA LT1 with a full LE2(Lloyd Elliott) package. I has about 1500 miles on the setup(with stock bottom end at 76k). It has a 6 speed trans with a 411 rear(stock) and ALL LE2 necessary suporting mods. I have a ASM 58mm Throttle body. The engine dynoed at 397rwhp/358 rwtq. It is very clean and well taken care of and has run strong and pulled hard thus far.

Today I was getting on it in 1st and 2nd gear when at about 6000 rpm in 2nd gear(I usually run to 6200rpm) the engine felt like all the power got sucked out, the engine died and I coasted to a stop.

After a 2 hour wait for a tow truck and $98 bucks later, here it sits in my garage. The symptoms are below:
It does turn over and sounds like it fires a quick cylinder but almost immediatly the sound of ignition is over and it just turns over then. The sound when it does turn over sounds differnt then usual. It sounds like the timing may not be right. It's not as smooth as usual.
I do not hear any engine restrictions like a piston, conn rod, valvetrain-all in the engine sounds OK. ???? I have not checked yet but it sound like it's getting a bit of spark and fuel as it does fire a tiny bit at first crank.

With this said, here are my thoughts on the issue:
Possible bad opti?? Does anyone know of a good link/method to test all inputs/outputs?
Bad/intermittent coil or heat sync part?

Valvetrain issue? Broken spring, bend pushrod? Colapsed lifter??(would these cause a complete no start/run issue?).

Fuel pump complete issue(but I do smell fuel when I turn it over, and it does fire a tiny bit at first???

CPU issue? Tune issue??

Any thoughts or advise would be a great help.
Thanks
Old Aug 3, 2008 | 10:41 PM
  #2  
shoebox's Avatar
Registered User
 
Joined: Dec 1969
Posts: 27,725
From: Little Rock, AR
Start with basic spark and fuel. I'll throw out a guess that the rotor in the opti went. Do some detective work and come back with results.
Old Aug 3, 2008 | 10:54 PM
  #3  
RPWS6's Avatar
Thread Starter
Registered User
 
Joined: Apr 2005
Posts: 361
From: Chicago Area
Well my wife just got home and I was able to preform a "turn over" test from the engine bay. I did not hear the ign. firing noise that I heard before. I removed the coil wire from the opti and found a both situations when cranking the same. The cranking sound is the same with or without the coil wire on. I stuck a screwdriver in the coil plug(opti side)(comming from the coil)wire and checked for spark, I did not find any spark when held to ground. Does this test work for this type of coil? Could it be a bad coil? How do I test? An impedeance/res test? That would be a prefered low cost easy fix solution.
It deffinetly has fuel, it stunk up the garage. I probably need a new set of plug when this mess is over.

Shobox, is the rotor spinning a common thing? The opti I bought used with 2k miles on it. It looked new. Would you rule out a valve train issue? If it's an opti, that's not so bad and will give me a chance to put a new fluiddamper Harmonic balancer on it(the one thing I do not have yet). Which opti is best the Accell or the MSD?
Thanks again for your help.

Last edited by RPWS6; Aug 3, 2008 at 11:13 PM. Reason: spelling
Old Aug 3, 2008 | 11:49 PM
  #4  
LOW-LIFE's Avatar
Registered User
 
Joined: May 2008
Posts: 99
From: Fort Worthless, Texas
if you had the driver grounded and aint got no spark that is your problem.
Old Aug 4, 2008 | 12:00 AM
  #5  
camaro1fastz28's Avatar
Registered User
 
Joined: Jan 2006
Posts: 251
did you check the fuse for the coil located in the engine comparment fuses block it happon to me same thing it was just the fuse it a 10 amp
Old Aug 4, 2008 | 12:59 AM
  #6  
BCdawg57's Avatar
Registered User
 
Joined: Oct 2007
Posts: 223
From: Carroll, Oh
throwing any codes?
Old Aug 4, 2008 | 05:31 AM
  #7  
Injuneer's Avatar
Administrator
 
Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
The rotors falling off is a problem, if the screws were not checked and some Loc-tite put on them. As far as "Which opti is best the Accell or the MSD?", the answer is neither - factory GM is the best.

Check it for codes.

Did you read the Opti dignosis thread "stickied" at the top of the forum topic listing?
Old Aug 5, 2008 | 12:28 AM
  #8  
RPWS6's Avatar
Thread Starter
Registered User
 
Joined: Apr 2005
Posts: 361
From: Chicago Area
Originally Posted by camaro1fastz28
did you check the fuse for the coil located in the engine comparment fuses block it happon to me same thing it was just the fuse it a 10 amp


You are the man!!!! I can't believe it, so simple!! I have been thinking about it today and the no spark at the coil, I thought if it's a coil it couldn't get much cheaper to fix! . When I got home tonight, I took a look and sure enough, a blow 10 amp ignition fuse. A .20 cent part certainly helps with the $98 tow fee. Not bad, I kept it under $100. So far?? I didn't really rev it or drive it, it was late and the wife was sleeping above the garage. The LE2 rumble is awesome but loud when reved!! Hopefully it doesn't blow again!

Does anyone have any thoughts as to why the ignition fuse blew?

Camaro1fastZ28, did your's ever blow again after that? Did it blow under acceleration? Was the car on? Off?

Thanks to all for the info on the opti, I'll keep it in mind if I ever have it open. How often should the cap and rotor be replaced?

Thanks again for the great tips!
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
willismoons
Parts For Sale
14
Feb 14, 2015 08:42 PM
STR FTR 1
3rd Gen / L98 Engine Tech
5
Feb 10, 2015 10:36 PM
centric
Automotive News / Industry / Future Vehicle Discussion
6
Aug 15, 2002 09:04 PM
Caps94ZODG
Automotive News / Industry / Future Vehicle Discussion
22
Jul 30, 2002 08:45 AM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 08:02 PM.