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Don't overlook the simple... or obvious
Posted to Technical Discussion Forum on 10/13/2012 34 Replies

So a customer shows p with a barely running 1996 Chevrolet Blazer with a 4.3"W" code motor. When I say barely running... I really mean it dies when pulling into the parking lot. He stated he had been to three other shops, spent a lot of money and still it runs like crap or just doesn't run.

We checked for spark... it was weak, but at least present. Initialization fuel pressure was 58psi.... and timing while cranking thru our Solus Ultra was reading 10 degrees advance with CKP/CMP good. I looked at the distributor cap... some corrosion, but I have seen much worse. The wires ranged from 7 ohms to 19 ohms. The spark plugs were an Autolite copper... not a platinum. But they were also wet with fuel. We replaced the plugs and wires. After about 30 revolutions, she finally started. It ran rough, but I assumed that the cylinders wold have fuel saturation. After about 15 minutes of running, she was sounding and idling much better. On the Engine Data Screen MAP and MAF looked pretty good, but the O2 Sensors were showing a lot of unspent fuels. WAIT A MINUTE... its been running for over twenty minutes.... and the engine temperature is only 144 degrees!! We replaced the thermostat with an OE Temp and bingo!! His truck runs fine. Starts fine. And O2 reading are back to normal. The customer told us after the fact that he had asked the other shops to please check to see why he didn't have any heat either.

Somebody missed the obvious.

Arthur Tousignant
Harder Automotive
Raeford, North Carolina, USA

34 Replies Received (View Replies)


car Vehicle Data

1996 Chevrolet Blazer LS 4.3L

Engine4.3 L
Trans4-speed Automatic (Electronic)