Hello everyone maybe somebody can give me some ideas on what type of problem I am looking at. I have a 97 Chevy Tahoe with 5.7 vortec that runs decent sometimes and other times it won't even start. When it does start and run it smells like fuel for the first few minutes. Checked all relays and fuses. The crank fuse was blown so replaced it and still same problems. Wondering if it could be a fuel issue or electrical. I have had to replace several fuses that keep blowing as well. Not sure if I have one issue or two.

 

Which fuses keep blowing? Will it start and run when these fuses are blown? Does it only start and run when these fuses are good?

 

I have had the instrument panel fuse blow and the crank fuse. Even after replacing them it still wouldn't start. But the next day it started right up but was bogging down pretty bad.

 

Might be time to replace the starter.

 

Keep running like that any your catalytic converter will go bad. That is not cheap. Check everything. Run a scanner on it and post the results here.

 

So, when it does not start, does it crank and not start or does not crank at all? If it does crank you have to start with the basics and see what is not there. Lost spark? Lost fuel pressure? May have moisture problem inside the distributor cap, corroded rotor, small crack on cap? The crank sensor is known to have problems that are explained in this statement made by another person I know: " Another strong possibility is the crankshaft position (CKP) sensor being too close or even contacting the reluctor on the crankshaft. This was a common issue with the composite timing covers introducing comparatively poor manufacturing tolerances where extreme accuracy was paramount. GM released a shim kit to space the sensor away from the crankshaft .010"-.020" (two .010" shims in the kit). It was hardly a problem on lower-mileage engines. But, worn high-mileage crankshaft bearings coupled with a flexing crank at high loads and RPM, the reluctor can get too close or even scrape the sensing tip of the CKP sensor. Take five minutes to grab a 10mm (or was it 8mm?) socket to remove the bolt, pop out the sensor and check the tip for tiny scratches in it. If they're there, add a shim and see if the problem is resolved. If it still happens but less frequently or at an even higher RPM or load, add the second shim and retest. When you're done, have a shop perform a crank relearn procedure. Note that even though the reluctor wheel may not actually be contacting the sensor, the extra movement in the crank may be enough to throw off the readings, resulting in misfires. I would say to replace the sensor if it has scratches, but I've never had a problem with NOT replacing it and just shimming it. Also, being where it's located, the wire harness is in danger of getting hot oil on it from the likely leaking seals. Something else to keep in mind."

What is the fuel pressure at cranking? After running? Lots of basic tests are needed to pinpoint.