98 tahoe backfire

[caw333]

To add to the large number of electrical problems I've already got. My motor backfired out the exhaust real hard and now the engine will not crank. It acts like it wants to start for a sec but just won't. The motor was already running rough but it would crank. I was slowly replacing everything that was showing to bad like three sensors. That didn't solve my running rough problem so I got a new computer for it today but I can't tell if that solved my problem cause of the backfire and not cranking thing. What are some of the things I can look at.

[16th hippy]

assuming you have the 5.7L in it, right? now, i am also confused about your problem, so a little more info will help. will it crank but not start, or will it not even crank now? If it does crank, but not start, does it have good fuel pressure and spark? if it will not crank, can the motor be turned over by hand?(put a socket on the harmonic balancer center bolt and try). if not, take belt off and try again, could be a locked up pulley. let us know, and post the other relevant info too so we can try and help you out!

[j cAT]

[quote=caw333]To add to the large number of electrical problems I've already got. My motor backfired out the exhaust real hard and now the engine will not crank. quote]


in addition to other info requested . exactly what electrical problems are there ??

[caw333]

The engine is a 1998 5.7. Ok I hooked a scanner up to the truck cause the engine started running rough like it was out of time. It showed a crankshaft position fault, a camshaft position fault and a maf circuit high and low. I changed out all the sensors and it still ran rough. The scanner is still showing a camshaft position fault even after changing it out twice. So I unpluged all the plugs on the computer under the hood and I found two wires on the white side that looked like they got hot. I'm thinking the two wires that look like they got hot go to the camshaft position sensor. While waiting on the computer to get here I cranked the truck after checking out some other stuff and thats when it backfired and will not start. I put the new computer on but need to figure out that problem now. The motor will turn over easy and will start to crank but just won't. Before the backfire it would fire up with just a slight touch of the key.

[777stickman]

Please post the DTC numbers so we have an idea of what the codes are.

"The motor will turn over easy and will start to crank but just won't."

Your terminology here is a bit confusing. "Cranking the motor" usually means turning it over with the starter. So do you mean the motor turns easily with the starter and then tries to start?

[caw333]

When I turn the key the starter spins the motor over and it acts like it wants to start running but just won't. It will lightly spit and sputter for a split second. These are the original codes and the only one that still comes up is the PO341
PO102 MAF or VAF circuit low input.
PO103 MAF or VAF circuit high input.
PO339 Crankshaft position sensor A CKT Intermittent.
PO341 Camshaft position sensor A Bank 1 CKT range / Perf.
The codes 339 & 341 show to be pending codes.