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

Anyone had an Opti act like this?

Thread Tools
 
Search this Thread
 
Old 06-30-2017, 04:57 PM
  #1  
Registered User
Thread Starter
 
LT1inaMGB's Avatar
 
Join Date: Apr 2002
Location: San Diego, Ca, USA
Posts: 126
Anyone had an Opti act like this?

Driving down the freeway 1800 in top gear and the engine dies like you turned off the key. Tried to immediately restart but wouldn't fire. Car sits for a few minutes and it starts right up. Drove for a couple more miles and it does the same thing. No rain or wet street, high 60's air temp, car running normal water temp. I was alone so couldn't check for spark at the plug.

What's up?

Jim
LT1inaMGB is offline  
Old 06-30-2017, 09:59 PM
  #2  
Registered User
 
shoebox's Avatar
 
Join Date: Dec 1969
Location: Little Rock, AR
Posts: 27,709
Re: Anyone had an Opti act like this?

First thing would be to scan for codes to see if the opti is even involved. Could be a dying fuel pump.
shoebox is offline  
Old 07-02-2017, 01:35 PM
  #3  
Registered User
 
Pullngz's Avatar
 
Join Date: May 1999
Location: St.Louis.Mo,USA
Posts: 215
Re: Anyone had an Opti act like this?

I had an aftermarket ignition box, fail on me and did the same thing. as soon as it cooled down, it would fire back up. Might want to check your coil, if you don't have an MSD or similar box.

My accel 300+ was VERY HOT to the touch, when it would stop working.
Pullngz is offline  
Old 07-07-2017, 06:12 PM
  #4  
LT5
Registered User
 
LT5's Avatar
 
Join Date: Mar 2016
Location: Kentucky
Posts: 207
Re: Anyone had an Opti act like this?

I had a 93 that would turn off and on while driving, but thats the only opti problem i had, although i went through 2-3 of the damn things. The MSD opti is probably your best bet if u want a serious one...
LT5 is offline  
Old 07-07-2017, 06:14 PM
  #5  
LT5
Registered User
 
LT5's Avatar
 
Join Date: Mar 2016
Location: Kentucky
Posts: 207
Re: Anyone had an Opti act like this?

And yes check the resistance of the coil, when cool it will have more conductivity, when hot it will not. But it sounds like an opti problem honestly.
LT5 is offline  
Old 07-07-2017, 07:25 PM
  #6  
Administrator
 
Injuneer's Avatar
 
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,647
Re: Anyone had an Opti act like this?

MSD has been having MASSIVE problems with the optical module for units produced in the last one to two years. Many people have experienced problems with erratic idle, sometimes seeing surges to 2,500 RPM. Additional problems with the engine running rough. By reviewing data logs, I found the problem to be the result of the optical module sending out FALSE RPM spikes as high as 7,000 RPM.

Eventually two of these logs were sent to MSD, and after viewing the data logs, they asked for two defective units to be sent back to them for examination. At this point, one of the units has been sent back with a "new and improved" optical module. The member here has received the MSD Opti, but hasn't had the time to reinstall it in his daily driver. Interestingly, he replaced the poorly peforming MSD with cheap eBay Opti, and it solved all his problems.

The MSD has had one problem after another since they first introduced it. I have never seen any evidence that the MSD was in any way superior to the factory AC Delco unit. Particularly at the elevated price for the MSD. Until I see evidence the MSD has fixed the current rash of problems, I will continue to recommend that anyone NOT buy one.

Plus at this point, the OP has not identified any evidence one way or the other, that his problem is due to the Opti.
Injuneer is offline  
Old 07-08-2017, 02:13 AM
  #7  
LT5
Registered User
 
LT5's Avatar
 
Join Date: Mar 2016
Location: Kentucky
Posts: 207
Re: Anyone had an Opti act like this?

In all honesty from what ive read on hotrod magazines and stuff they say they work fine. But from what you say now, thats ****ed up for 500 bucks LOL.
LT5 is offline  
Old 07-08-2017, 08:27 AM
  #8  
Administrator
 
Injuneer's Avatar
 
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,647
Re: Anyone had an Opti act like this?

Are you saying my info regarding my interaction with MSD are not accurate?
Injuneer is offline  
Old 07-08-2017, 05:00 PM
  #9  
Registered User
Thread Starter
 
LT1inaMGB's Avatar
 
Join Date: Apr 2002
Location: San Diego, Ca, USA
Posts: 126
Re: Anyone had an Opti act like this? - Problem solved

I have found a smoking gun on why the engine shut off and it's not the Opti. When I was building the custom aluminum fuel tank it had a couple pinhole leaks after I had put gas in it so I was reluctant to weld them up. Someone suggested I use a Bill Hirsh gas tank sealer so it would plug the leaks as well as protect the inside of the tank from the alcohol in the gas. BIG MISTAKE! The sealer has been peeling off the walls of the tank in sheets and some of it made its way to the sock filter on the fuel pump. I know it blocked the flow because the material right around the pipe to the pump was sucked down tight against the pipe and filter sock. The rest of the debris was not as firmly attached and so floated away as soon as the pump was shut off allowing the engine to restart.

Anyone had an Opti act like this?-fuel-pump-blockage-2-.jpg

Anyone had an Opti act like this?-fuel-pump-blockage-1-.jpg

I cut the tank open so I could access all the areas of the tank and this is what I pulled out

Anyone had an Opti act like this?-tank-cut-open.jpg

Anyone had an Opti act like this?-tank-sealer.jpg

I called Hirsh and was rudely told that I must have done something wrong and it was my fault even though I followed the kit instructions to the letter. Lesson learned - Don't buy Hirsh products and don't use tank sealers.

Last edited by LT1inaMGB; 07-08-2017 at 05:04 PM.
LT1inaMGB is offline  
Old 07-08-2017, 05:46 PM
  #10  
LT5
Registered User
 
LT5's Avatar
 
Join Date: Mar 2016
Location: Kentucky
Posts: 207
Re: Anyone had an Opti act like this?

No not at all about the opti, im sure everything u said was 100% and accurate, i was just simply saying that the hot rod mag guys said they were decent. Believe me as much as your on here and know your **** quite well i would never question your word lol.
LT5 is offline  
Old 07-08-2017, 05:49 PM
  #11  
LT5
Registered User
 
LT5's Avatar
 
Join Date: Mar 2016
Location: Kentucky
Posts: 207
Re: Anyone had an Opti act like this?

Well as far as the gas tank thing, that blows major *****. Why did u use an aftermarket gas tank anyways? Just wondering maybe to some advantage?
LT5 is offline  
Old 07-08-2017, 07:17 PM
  #12  
Registered User
Thread Starter
 
LT1inaMGB's Avatar
 
Join Date: Apr 2002
Location: San Diego, Ca, USA
Posts: 126
Re: Anyone had an Opti act like this?

Originally Posted by LT5
Well as far as the gas tank thing, that blows major *****. Why did u use an aftermarket gas tank anyways? Just wondering maybe to some advantage?
It's not an aftermarket gas tank, I had to fabricate the tank myself. It is in a widened MGB with a blown LT1.
LT1inaMGB is offline  




All times are GMT -5. The time now is 11:42 PM.