Okay where do I start. Been having problems with my 93 running bad. Pulled codes and getting code 26. Didnt really know where to go from there. Asked a few questions on here and found out could be many problems. Went ahead and did all that was suggested to me like changing wires and plugs and fuel filter. Still runs the same. Almost seems like it has a small back fire in it or a popping noise out of the exhaust. Any more suggestions on what to check next or where to go from here. Then to make matters worse, get home today from work and notice antifreeze in my drive way. Popped the hood and sure enough water pump went out. Working on one thing and now another problem has arrived. Any suggestions would be appreciated thanks

Also when I started having these problems, my gas mileage went from about 18 mpg in town down to about 9 or 10 mpg

 

Might be Optispark going.

 

Fuel or spark is the question! Do you feel like its power is way down? Do you have a fuel pressure tester? If your fuel pressure is good and you ohmed out your injectors and thats good then its time for a opti. With LT1 its the opti 99% of the time, as told to me from Tom at D&M Corvette. Its good and bad news because your car will run awesome after a new opti goes in. Bad news its not cheap.( Get the vented opti) that came standard on the later LT motors.

 

no i dont have a fuel pressure tester, but plan on getting one this weekend to test that. as for the power, yeah i would say its pretty way down compared to what it use to run like. all my injectors tested at 13.6 couple were 13.4 or 13.5 From what i have read this may be a little low, but not for sure. As far as the opti goes, you say get a vented one from a later model. Where would you or anyone recommend getting one. I've done a little search but nothing serious just yet. And what brand to get also. thanks

 

Try MSD pro Billet
http://www.msdignition.com/2006/06-4.htm

 

Yeah it could be many problems. The code 26 refers to the QDM. The quad driver module is used by the ecm and controls several different functions. I suggest getting a manual or the t/s chart from a manual and start from there. "shotgunning" parts gets expensive, its ok if you arent paying for them, but if you are.......$$$$$$$.

But the absolute first thing I would do is fix what is broke. If the water pump is leaking, you better fix that one right away. As you probably know by now the opti spark unit is directly below the wp. When it leaks, it takes out the bearings on the opti. The only way to access the opti is by removing the wp. #1. remove the wp. #2 remove and inspect the opti spark unit. You may find it full of corrosion and damaged beyond repair. I have seen pictures of opti's that were working, kind of, and they were so corroded from a leaking wp that it was amazing the car ran at all. If so buy the complete MSD unit. From what I have read, its far better than the original equipt unit. I replaced just the cap and rotor with upgraded msd parts. It included a vent hose kit that uses engine vacuum to draw dry air from the air intake duct through the opti effectively removing moisture.

After reassembling those items, no doubt the battery would have been the first thing you disconnected. Hint hint. That will clear any codes. Run the car and see whats returned. If the code 26 is still there, well you have more work to do.

 

Thanks for all the help. Like you say first things first. Will pull water pump this weekend for sure and get to the opti. Will check it. Was wondering if there was a way to do that and you answered that for me. May seem wierd but hoping its bad so i will know why my car is running so bad. lol But if not, will keep checking till I figure it out. Will reply when i get the opti off and tell ya what i found Thanks again everyone