Tip & How-To about Chevrolet Impala

Engine miss,stumble,check engine light

Newer vehicles have very high voltage ignition systems.
Often faulty plug wires are the culprit.
To avoid a costly diagnosis,try this,
After dark raise the hood ,vehicle running ,disconnect the underhood light,must be very dark.After your eyes become accustomed to the dark,any voltage leaks will be very obvious.Spraying glass cleaner on the ignition wires will enhance the effect.(not pure water)
Obviously,be very cafeful to stay away from the belts and fans,since it's dark.

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where is fuel pump harness on a 2000 escalade


DTC P1351 Ignition Coil Control Circuit High Voltage
The enhanced ignition system uses the crankshaft position (CKP) sensor in order to provide a timing input to the control module. Ignition control (IC) spark timing for each cylinder is based on this input. The control module provides the ignition timing signal to the ignition control module (ICM) to control the ignition coil. Each timing pulse detected by the ICM allows it to energize the ignition coil. A large secondary ignition voltage is induced in the secondary coil by the primary coil. This high voltage is switched to the correct spark plug by the distributor.
This diagnostic trouble code (DTC) will set if the VCM- (vehicle control module ) detects an unusually high voltage on the ignition timing signal circuit.
Diagnostic Aids
Intermittent test -- If the connections and the harness check OK, monitor a digital voltmeter connected between VCM terminal C3 pin 9 and C4 pin 18 while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change. This may help to isolate the location of the malfunction.
An intermittent may be caused by any of the following conditions:
?€¢
A poor connection

?€¢
Rubbed through wire insulation

?€¢
A broken wire inside the insulation
Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Check out this guy's video on GM fuel pump electrical circuit diagnosis !

GM Fuel Pump Relay Testing

Apr 21, 2016 | Cars & Trucks

2 Answers

not getting spark


need more info (need to know what type of ignition system your vehicle has: (1) traditional ignition coil /distributor system, or (2) electronic ignition, but lack of spark problems are usually a faulty coil
on traditional vehicles, and on the newer electronic ignition cars, total lack of spark would be
a faulty ECM (electronic control module) - partial lack of spark (diagnosed with a HEI (high energy ignition) spark tester kit), would be caused by a faulty coil pack (in the waste spark system), where
there's 1 coil pack for every 2 spark plugs.
I bought my HEI igntion testere kit for $20, but Harbor Freight sells a similar unit for $10.
Hope this helps.

Dec 27, 2010 | Ford F-250 Cars & Trucks

2 Answers

My 2003 honda accord v6 refuses to start. It cranks but no spark on the plug. What should i do?


Either the spark plug is faulty or the coil pack is faulty.The spark plugs get power to spark from coil packs.

If the engine has no spark, check for voltage at the coil positive terminal when the ignition key is on. If NO voltage, then problem is on the trigger side of the coil (pickup, crank sensor, ignition module or primary wiring circuit).

But If there is NO voltage at the coil itself, then in that case the problem is on the supply side (the ignition switch or ignition wiring circuit).

But if the coil has voltage, then problem may be a bad high voltage output wire from the coil to spark plugs or hairline cracks in the coil output tower.------Getting this all possibilities checked will point towards the exact faulty part which is to be replaced.----------This should help.Thanks.Helpmech.

Dec 24, 2010 | Honda Accord Cars & Trucks

1 Answer

2002 chrysler 300 M 3.5 liter immediatly quits after starting.


The ECM is most likey the culprit but I would check ground wires and wiring harness to be sure they aren't faulty. With you telling me the voltage is too high, it pretty much points to wiring but the ECM may have gone bad and its just sending blind signals hence the high voltage. The engine light isn't coming maybe because of the ECM isn't working. Pray it isnt the ECM, its costly but exhaust your options by checking wiring and ground beforing fingering the ECM

Dec 06, 2008 | 2001 Chrysler 300M

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