'99 Volvo 5.0 GL turns over doesn't start

[larson24]

My 5.0 GL ran a fews days ago, today it turns over but doesn't start. Battery is fully charged and 800 amps, have not load tested it. Meter shows 7.78 volts at coil on pos and neg connections with key on. Not seeing spark with a spark tester at lead from coil to distb, but did see slight spark when grounding lead to block. Not seeing spark at plugs with tester. Nothing has been changed since engine last ran. Thanks for any input.

 

[Maclin]

Re: '99 Volvo 5.0 GL turns over doesn't start

Sometimes the tachometer can cause problems, it is connected to the coil negative wire and can confuse the coil signal on when to fire. If the coil has 2 leads on the negative terminal then one of them is for the Tach (the other goes to the distributor), I would unhook that Tach wire and see if the spark test results change. It is a pretty simple thing to do and can save a lot of headaches troubleshooting if the Tach decided to go south for the winter already.

Sometimes the signal wire junction to the Tach is made at the harness so there may not be 2 wires at the coil. In that case to isolate the Tach you would need to go to the Tach and disconnect the signal wire there, be sure the open connector does not touch anything.

Best to refer to the wiring diagram for your engine, those are avaiable by following the stickies topics at the top of this forum.

 

[Don S]

Re: '99 Volvo 5.0 GL turns over doesn't start

Charge the batteries, 7..8 may be to low a voltage to fire the ignition system.
What is the full model number of your engine, need all the letters after the 5.0GL

 

[larson24]

Re: '99 Volvo 5.0 GL turns over doesn't start

On a harness cover, stbd riser, 5.0GL PBYC, also a production # 3868844. I find I have 9.68 volts if I ground to block rather than neg coil terminal. Battery shows 12.35 volts with meter but only showing 11 at amp gage on dash. Also, coil is aprox a year old. Not sure what specs are needed to test.

 

[Maclin]

Re: '99 Volvo 5.0 GL turns over doesn't start

Just fyi for next time, the negative terminal on the coil is not grounded. It is used to ground and unground to build up the spark, the grounding and ungrounding is contolled by the dwell of whatever the signalling mechanism is (points or electronic). Any voltage reading using that as a gound is really useless info, just sayin'.

 

[Don S]

Re: '99 Volvo 5.0 GL turns over doesn't start

Here is the troubleshooting info from the service manual for your ignition system.

 

[larson24]

Re: '99 Volvo 5.0 GL turns over doesn't start

Thanks Don, you came through again! This should be a big help.