Most car owners with classic cars will agree that visiting your local mechanic for repairs is quite expensive (however simple the task). Working on a decades-old vehicle isn’t a walk in the park either. For starters, sourcing old parts isn’t easy. Also, diagnosing problems on these vehicles will take you back to the old ages – a simple OBD II scanner won’t do.
If you’ve been following our stories, we recently did a piece on a saltwater-flooded 1991 C4 Corvette that got a new lease on life.
The classic ripper belongs to Sam of Samcrac YouTube channel. Like most of his car purchases, he sought an easy way to get the grounded 1991 ZR1 back on the road.
Most straight-thinking classic car buyers wouldn’t touch a water damaged 1991 Chevy Corvette with a ten-foot pole. But Sam isn’t what you’d describe as your average car enthusiast. He lives on the edge and thrives on getting his hands dirty. Nine out of ten times, his DIY hacks come to fruition – but not without a few hurdles.
On a previous upload, he managed to do the impossible and got a flood-water damaged 1991 Chevy Corvette ZR1 running without breaking the bank.
It involved bypassing a three-decade General Motors anti-theft system, draining and cleaning the vehicle’s oil pan and windage tray, and replacing the oil pan gasket, starter, fuel filter, and a set of ignition coils.
That alone was good to get the 32-year-old King of the Hill to run right, but only for about 3 miles (5 kilometers) before hitting a snug.
Before we get into the details of what could have been the perfect happy ending, Sam had another 30-year-old GM security feature to bypass - ZR1 power key switch.
Stock, the 1991 Corvette ZR1 comes with a 350 cubic-inch 5.7-liter configurable to several inputs. The LT5 V8 in the C4 ZR1 was capable of 375 hp (380 ps). To unlock its full power potential, this ZR1 came with a full power key.
After repairs, Sam was only getting about 200 hp (203 ps) from his newly acquired C4 ZR1.
“That drive we just did. We were probably just making about 200 horsepower. Remember, we need this power key to unlock all of the 385 horsepower our ZR1 is capable of,” Sam explained the classic Chevy ripper’s power deficiency problem.
To remind you, Sam's 1991 ZR1 did not come with any keys, but fortunately, Sam found an alternative solution: a ZR1 power switch (bypass switch) ideal for the 1991 model C4 ZR1.
It worked perfectly, unlocking the full power of the classic ripper for a couple of miles before everything went bust. It started overheating and, at first, he suspected it was a blown head gasket. A quick head test proved otherwise.
The 1991 C4 ZR1 is still not in the clear. Sam still needs to diagnose a new check engine code 43 (knock sensors).
Also, there was a lot of smoke billowing from the engine (upper RPMs), which he suspected could have been caused by residual fluids stuck in the exhaust.
This 1991 ZR1 Chevy Corvette seems to have a long way to go before it's back to 100% health.
“ Not everything’s been resolved. We still have that smoke billowing out the tailpipes, especially when we get the engine really warm. The thing idles so good it kind of negates the idea that maybe we’ve got a fuel injector issue,” Sam revealed.
In my opinion, the residual fluids stuck in the exhaust could be the root cause of the billowing smoke. It would take more than 3 miles (5 kilometers) to burn out and stop the tailpipe from smoking altogether.
What do you think? Share your thoughts in the comments section below, we’d love to hear your opinion.
Humphrey is a car enthusiast whose love and passion for automobiles extended into collecting, writing, driving, and working on cars. He got his passion for cars from his Dad, who spent thousands of hours working on his old junky 1970 E20 Toyota Corolla. Years later, he would end up doing the same with a series of lemons he’s owned throughout his adult life. Full profile
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