Chevrolet Repair: 1995 Chevy Blazer, crankshaft position sensor, sunny south africa


Question
QUESTION: Greetings Tom from sunny South Africa. I have a 1995 Chevy Blazer LT VIN: 1GNDT13W8SK221424. This is the 4 door, 4 wheel drive with a V6 4.3 litre Vortec motor.

A while back I took the vehicle to a mechanic to put in a new pitman arm after which the engine was washed. They did cover the ECM.

The mechanic took the vehicle for a test drive. He says he had driven about 10 kilometers at around 80 Kph, when there was a large backfire and the engine died. The backfire completely ripped open the first baffle box.

When turning on the ignition all panel lights come on normally. The engine cranks but will not start. I do not hear the petrol pump priming the fuel line.

There does not appear to be spark at either the plugs nor the coil. I have replaced both the Ignition Control Module and the Crankshaft Position Sensor.

The vehicle is OBD1 but I am unable to find a compatible scan tool and with our currency being about 9 to the US Dollar purchasing one would be very expensive.

Any help or advice would be greatly appreciated.

Regards

Keith

ANSWER: HI KEITH, THIS IS COMMON AFTER WASHING A ENGINE OFF.I WOULD SUSPECT THAT THE IGNITION COIL IS BAD ALONG WITH THE POSSIBLE DIST-CAP AND ROTOR AS WELL. THE FACT THAT THE ENGINE BACKFIRED LIKE THIS IS 99% OF THE TIME IGNITION FAILURE. THESE COILS ARE MOUNTED ON THE INTAKE MANIFOLD ON THE PASS SIDE OF ENG.THEY DO NOT LIKE WATER!!!I WOULD BE LOOKING AT THESES ITEMS FOR SURE..THERE IS NO FUEL BECAUSE MORE THEN LIKELY THE PCM IS NOT RECIEVING A SIGNAL FOR IT TO KEEP PUMPING. HOWEVER IS WHEN YOU FIRST TURN THE KEY ON AND CRANK FOR 2 TO 3 SECONDS THE FUEL PUMP SHOULD ENGAGE AND THEN TURN OFF. THIS WILL BE VERY FAST HOWEVER.IT WILL NOT KEEP PUMPING IF NO START...LET ME KNOW HOW YOU MAKE OUT..GOOD LUCK,,TOM.

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QUESTION: Hi Tom.

Many thanks for your above answer. It gives me something to go on for now.

Will look at the dist-cap and rotor tomorrow. To your knowledge, is their anything unique about the ignition coil, or should a locally produced one with an equal rating be acceptable.

This could take a while, so will get back to you later.

Regards

Keith

ANSWER: HI KEITH,I WOULD LIKE TO SEE YOU GET A [AC DELCO,IF POSS.IF IT NEEDS TO BE REPLACED THERE IS A BRACKET THEAT YOU WILL NEED TO REMOVE THE RIVETS THAT HOLD IT IN PLACE...I WOULD JUST HOOK THE NEW COIL UP FIRST AND SEE IF IT STARTS,IF SO THEN REMOVE THE BRACKET AND RIVETS TO INSTALL THE NEW COIL..GOOD LUCK TOM..

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QUESTION: Hi Tom. I have removed the ignition coil and carried out the following tests with a digital multimeter. Pos to Neg read 0.7 ohms.  Pos to HE output read 8.3 ohms. Neg to HE output also read 8.3 ohms. I then put an analogue circuit tester across the Pos and Neg connectors. Got a strong continuity reading. Put the same tester across Pos and HE output and got a reading about half that of the previous test. I am unable to interpret this info. From all this, would you be able to indicate whether the coil is ok or should it be replaced? It was made by Delco Remy.

Regarding the dist cap and rotor, I am hoping to get a set of Torx wrenches this weekend. These are not standard here in South Africa. Had a go at it last weekend, but none of my tools would fit. Regards Keith

Answer
HI KEITH,I WILL LOOK UP SOME INFO FOR YOU ON MY SYSTEM AND GET BACK TO YOU ON THIS...CK YOUR EMAIL IT WILL COME AS REVISED QUESTION FROM ME..
LETS START OVER HERE..BEFORE WE GO OFF AND THINKING WE HAVE A BAD IGNITION PROBLEM..YOU SAID SOMTHING ON YOUR FIRST QUESTION THAT I OVER LOOKED...YOU SAID THERE IS NO POWER TO THE FUEL PUMP ???? JSUT BECASUE YOU DO NOT HEAR THE PUMP TURN ON DOES NOT MEAN THAT THERE IS NO POWER TO THE PUMP...CAN YOU CK FOR POWER DOPWN AT THE PUMP WITH A TEST LIGHT..CK THE GREY WIRE AT THE HARNESS GOING INTO THE SENDING UNIT ON TOP OF TANK..HAVE SOMEONE CRANK THE ENGINE OVER,,ALL THE WHILE THE ENG IS CRANKING YOU SHOULD HAVE POWER ON THIS WIRE...12 VOLTS.SO LETS SAY THERE IS NO POWER AT THE PUMP AND ALSO NO SPARK...NOW WE ARE LOKING INTO THE PCM..THIS WOULD BE VERY UNUSUAL TO HAVE A BAD PCM  BUT IT COULD HAPPEN..FIRST THING WOPULD BE TO CK THE PCM AND IGN FUSE..SEE IF THEY ARE OK..NEXT IT WOULD BE NICE IF YOU COULD GET A SCAN TOOL TO CK FOR ANY LIVE DATA WHEN CRANKING THE ENG OVER.IF NO LIVE DATA,PCM PROBLEMS OR HARNESS PROBLEMS..TO CK YOUR COIL, FIRST CK THIS,,TURN IGN ON CK FOR VOLTAGE 12 VOLTS BETWEEN THE B TERMINAL ON THE COIL AND GROUND.SHOULD BE MARKED.IF NO VOLTAGE HERE CK FOR OPEN CIRCUIT,BLOWN IGN FUSE,HARNESS PROBLEMS OR PCM..TO CK SECOND TEST,CIK BOTH A AND D TERMINALS BOTH TERMINALS SHOULD HAVE A READING OF 10 VOLTS OR GREATER,IF VOLTAGE IS LESS ON EITHER TERMINAL COIL IS FAULTY...BUT LETS CK FOR ANY LIVE DATA OR POWER AT THE FUEL PUMP AND LET ME KNOW HOW THIS GOES..GOOD LUCK,,,TOM