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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Volvo
Satisfied Customers: 1516
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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No spark to plugs. New coil, voltage to coil good

Customer Question

No spark to plugs. New coil, voltage to coil good
Submitted: 1 year ago.
Category: Volvo
Customer: replied 1 year ago.
is someone going to answer my question?
Customer: replied 1 year ago.
What would cause an ignition coil to go bad other than plugs and/or wires?
Expert:  Chris (aka-Moose) replied 1 year ago.

I am sorry for the delay in getting a response to you. Sometimes we get alot of customers and just can not keep up. Sometimes you just have to wait for the correct tech to login.

Do you even still need help. Sometimes customers seek help elsewhere or figure it out on their own before we get to each and everyone.

I am sure I can help a lot or a little at least something if you give me a chance and work with me. I am going to get an answer to you regardless if you reply or not sooner or later.

If your concern is urgent reply and let me know and if you have anything more you think will help me, to help you, let me know. I work on here normally 3pm-3am central.

Thanks Chris

Customer: replied 1 year ago.
I do still need some help
Expert:  Chris (aka-Moose) replied 1 year ago.

An ignition coil can premature fail from grounded spark plug wires or from poor power or ground to the coil. The spark plugs would not be to blame unless the end is smashed or the porcelain is cracked, using up all the power the coil is making.

You want a excellent 5 star answer & I would like to be rated the same for providing it. Consider I don't know your skill level & I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies. Try your best to respond with good detail so I can do the same. I normally log in at 3pm and work late. A rating is required. Your rating me, what I type. I am not an employee of this website, nor have control over the fees or the time it took to get a response. If you rate negative or not at all you still paid, but I get nothing. I want you pleased with me and my efforts, so let me know if your experience here has come up short.

Thanks Chris

Customer: replied 1 year ago.
I will rate you good Moose! This all started with the vehicle just shutting off while driving. I tested the in tank fuel pump and it tested bad. I went ahead and replaced it as well as put in new spark plugs and wires. Also new distributor and rotor. Wires marked and in correct position on distributor. After I changed the fuel pump it still didn't start so I tested to see if I was getting a spark at the plugs and found nothing. That is how I found out the new coil tested bad
Expert:  Chris (aka-Moose) replied 1 year ago.

Do you want to hold off till you get a new coil to try?

Customer: replied 1 year ago.
That may be best. I am getting the new one on weds afternoon.
Customer: replied 1 year ago.
Hey Moose, before I go I wanted to let you know that I performed a test on the ecu jumping pins 5 and 6 as the manual stated and I got an opposite reading than the book described. It said that I should have no voltage with key off and around 12 volts when key is in the II position. I was reading 12 volts when the key is off and 0 when the key is in the II position.
Expert:  Chris (aka-Moose) replied 1 year ago.

That is odd, that reading was backwards. My diagrams for the year model are not great but it makes me lean towards the ECU.

Customer: replied 1 year ago.
I feel like I am chasing my tail with this car! I know it's old and it's time for things to fail but damn!! The ecu wouldn't have a back flow of voltage causing the coil to fry would it? I am good with mechanics but electrical issues throw me for a loop.
Expert:  Chris (aka-Moose) replied 1 year ago.

I think its best I let another try, I am just not as certain as I would like to be.

Expert:  Juan Crespo replied 1 year ago.

Hi there. Different expert here.

Do you still need help with this issue?

Customer: replied 1 year ago.
I may Juan! I was cleaning grounds on the battery to the shock tower and back of compressor as well as the grounds on the back of the fuel rail today and found the ground from the corner of the valve cover to the firewall was about to fall off. I am hoping after I put in the new coil things will work but I am going to test pins 5 and 6 on the ecu again to see if I get the correct result before I try and start the car. Does that make sense and do you think I am heading in the right direction? Thanks for your help Moose and Juan!!
Expert:  Juan Crespo replied 1 year ago.

I'm pretty sure together we can diagnose this no-spark issue, but first, can you tell me what series Volvo are you working on (240, 740, 760, 780), engine type and size (4 or 6 cyl, turbo or not), auto or manual transmission?

Customer: replied 1 year ago.
It's a 1989 240DL 4 cyl no turbo, auto trans
Customer: replied 1 year ago.
Juan. I put the new coil in and still no spark to the plugs
Customer: replied 1 year ago.
You there Juan?
Expert:  Juan Crespo replied 1 year ago.

Sorry for the delay.

The usual suspects for a no-spark condition on the 240s are the radio interference relay, the power stage, or the crank position sensor. Please give me a few minutes more to finish digging up my notes. I'll be back in a bit.

Best Regards.

Customer: replied 1 year ago.
Answer this, the coil pri and sec resistance test should reflect what it says in the book right? I have had two different coils that the pri resistance reads 0.00. what should it read?
Expert:  Juan Crespo replied 1 year ago.

Sorry about that.

Let's start by doing the easiest check first, which is the 25A fuse located in its own holder about a foot behind the battery on the driver’s side inner fender, next to the coil. This fuse holder tends to corrode and cause all kinds of problems. Check it not only visually, but by ensuring current is flowing through it.

If the fuse is not the problem, then we need to check the power stage:

  1. Remove air cleaner assembly. Ensure ignition is off and disconnect power stage connector. Remove connector dust cover. See attachment Fig. 3.
  2. Clip multimeter negative (-) lead to ground and positive (+) lead to connector pin No. 4. Turn ignition on and note voltage reading. Voltage should be approximately 12 volts.
  3. Leave multimeter attached and crank starter motor. Voltage should be approximately 12 volts. If voltage is too low, check battery and charging system. If voltage is not present, check Blue wire from ignition ECU to ignition coil and power stage. Repair or replace as necessary.
  4. Check power stage ground resistance with multimeter attached between power stage connector pin No. 2 and ground. Multimeter should show continuity.
  5. Check ignition coil resistance with multimeter attached between power stage connector pin No. 1 and No. 4. Resistance should be 0.6-1.0 ohm. If resistance is below 0.6 ohm, check wires for short circuit.
  6. If wires are okay but resistance is still below 0.6 or above 1.0 ohm, attach multimeter between ignition coil terminal No. 1 and No. 15. See attachment Fig. 4. If resistance is below 0.6 or above 1.0 ohm install a new ignition coil. If resistance is 0.6-1.0 ohm, check continuity of wires between ignition coil and power stage connector pin No. 1 and No. 4. Repair or replace as necessary.
  7. Check shield wire (ground) between ignition ECU and power stage. Shield wire should be connected to power stage connector pin No. 3. Repair if necessary.
  8. Check that power stage receives ignition ECU signal by disconnecting wires from ignition coil terminal No. 1. Attach positive (+) lead of multimeter to power stage connector pin No. 5 and negative (-) lead to ground. Crank starter motor and monitor voltage reading. Voltage should be pulsating between 0-12 volts. If voltage is within specifications, install a new power stage and recheck circuit.
  9. If a very low voltage is present and/or is irregular, check wiring between ignition ECU and crankshaft position sensor. Repair or replace as necessary.

Please let me know what you find and we'll take it from there.

Best Regards.

Expert:  Juan Crespo replied 1 year ago.

Here are the attachments.

Best regards.

Customer: replied 1 year ago.
Thanks Juan! It may take a little bit but I will get through the list!!
Expert:  Juan Crespo replied 1 year ago.

Great. Looking forward to hearing from you.

Customer: replied 1 year ago.
Ok here we go
1 and 2 checked good read battery voltage
3. Checked good read 12 volts
4. Showed 0.00 good continuity
5. Test showed same as coil 0.00
6. Tested coil prior to install (3rd coil which tested the same during primary resistance test of 0.00) yes all 3 brand new coils tested 0.00
7. Ground looks good
8. Voltage was between 1.2 and 1.4
When I put the latest coil in it did start and run for about 5 seconds then shut off. Back to where I was before!
Customer: replied 1 year ago.
How do you test the ecu?
Customer: replied 1 year ago.
Just tried to perform the ignition diagnostic test via pin 6 with ignition in II position and didn't get any lights, it never came on. Tested fuel system diagnostic via pin 2 with ignition on and the test passed
Expert:  Juan Crespo replied 1 year ago.

Let's not get ahead of ourselves and do this in a systematic way.

Regarding the coil resistance tests resulting in 0.00 Ohms, try another ohmmeter. Primary winding resistance must be between 0.6 and 1.0 Ohms, if not the increased amperage will burn something (resistance is inversely proportional to amperage - sort of like a see-saw, if one goes down, the other one comes up).

The fact that the engine momentarily started leads me to believe there is a bad connection somewhere in the circuit.

On test 8, you say you're getting between 1 and 2 volts which is too low. It should fluctuate between 0-12 volts. By-pass the 25A fuse and holder temporarily while you test the circuit. If OK, check the wiring to the crank position sensor. If it looks dirty or frayed, replace the sensor.

Please let me know what you find.

Customer: replied 1 year ago.
Well I don't think it is the meter cause all three coils tested good with the secondary positions. Now all three coils I got tested 0.00 on the primary positions.
Customer: replied 1 year ago.
Where is the crank position sensor?
Expert:  Juan Crespo replied 1 year ago.

The reason I said try another Ohmmeter is because if yours is not calibrated, it might not be able to read down to 0.6 Ohms or so. If I were you, and just to be sure, I would check the coil at the parts store with one of their Ohmmeters.

Also, and since it is the most common cause for this type of failure, don't forget to by-pass the 25A fuse holder.

The crank sensor is on the bellhousing, above the starter - it's not easy to replace. last time I did one of those, I had to do it by feel alone with a stubby 10mm wrench.

Customer: replied 1 year ago.
I think I found the sensor on the top of the bell housing behind the engine. Wires look fine
Customer: replied 1 year ago.
Disregard the failed test on the ignition system. It worked. Had the ecu unplugged
Customer: replied 1 year ago.
Since the 3rd coil failed the primary but passed the secondary test I am getting the 4th coil in the morning. I just can't believe that I have gotten 3 bad coils in a row
Expert:  Juan Crespo replied 1 year ago.

Actually, it's not uncommon for a whole batch to be defective from the factory - try using a reputable name brand such as Bosch.

Expert:  Juan Crespo replied 1 year ago.

Just in case, here is the crank sensor test:

  1. Attach multimeter positive (+) lead to ignition ECU connector pin No. 6 and negative (-) lead to ground. Turn ignition on. Voltage should be approximately 12 volts.
  2. Check resistance of engine RPM position sensor by attaching multimeter leads between ignition ECU connector pin No. 10 and No. 23 See attached Fig. 5 . Resistance should be 500-600 ohms.
  3. Check and ensure shield wire (ground) is connected to ECU connector pin No. 11.

Best Regards.

Expert:  Juan Crespo replied 1 year ago.

Sorry for me being a "worry wart", but did you by-pass the 25A fuse and holder? As I said previously, this is the most common cause for those low voltage readings.

Customer: replied 1 year ago.
Do I just take out the fuse and connect the wires from the voltmeter to each side of the holder?
Customer: replied 1 year ago.
Hey is there a good aftermarket coil that I could put in rather than the one that is stock for it?
Customer: replied 1 year ago.
I put the red wire (tester) on each lead and the black on the battery ground. Read voltage from each side. Tried to show my son and one of the leads will not read voltage anymore. Did I screw something up or is the a bad wire
Expert:  Juan Crespo replied 1 year ago.

NO, you didn't screw up. As I've been trying to tell you, that fuse holder is the most common cause of the no-spark. Go to the parts store and get a replacement inline fuse holder (click here for example from Advance Auto)

Customer: replied 1 year ago.
Will the 30 amp be good.or make sure it's a 25 amp
Expert:  Juan Crespo replied 1 year ago.

That was just an example. Make sure to put in a 25A fuse. And please, no crimp-on/butt connectors. Make sure the new fuse holder is soldered in and protected from the elements with heat shrink tubing (also available at the parts store)

Customer: replied 1 year ago.
Got it thanks I will let you know what happens!!
Expert:  Juan Crespo replied 1 year ago.

Great. I'll log back in tonight to check on you.

Best Regards.

Customer: replied 1 year ago.
The wire coming from the battery still shows 12 volts. The other one is testing 0. Where does that one connect at after the fuse?
Expert:  Juan Crespo replied 1 year ago.

The complete circuit that includes the 25A fuse is attached.

As a preventative measure, you might also want to replace (or at least have spares on hand) the EFI/FP relay and the crank sensor.

Best Regards.

Customer: replied 1 year ago.
what do I need to do?
Expert:  Juan Crespo replied 1 year ago.

What do you mean? Did you replace the 25A fuse and holder? Did the engine start afterwards?

Customer: replied 1 year ago.
I replaced it and it didn't start. It doesn't have power going to the other wire still that's why I asked where the other wire went to
Expert:  Juan Crespo replied 1 year ago.

Do you mean there is voltage from the battery to the 25A fuse, but there is no voltage past it? If so, either the fuse is blown or the connection is bad.

I always recommend this free basic Auto Electricity tutorial (click here). You might already know all the stuff in it, but I thought you might use it as a quick refresher.

Customer: replied 1 year ago.
Where does that wire go?
Customer: replied 1 year ago.
Where is the connection?
Customer: replied 1 year ago.
The 25 amp fuse test good but car still will not start. Still no spark
Customer: replied 1 year ago.
I tested the resistance on the rpm position sensor and got 183.9. Not 500-600 as stated above. What is my next step
Customer: replied 1 year ago.
Sorry Juan I never saw the crank position sensor test above. Got caught up on the fuse
Expert:  Juan Crespo replied 1 year ago.

Not to worry. Replace the crank sensor and let me know when the engine starts.

Best regardds.

Customer: replied 1 year ago.
I installed the sensor. Performed the test you gave me and I am getting 12 volts from pin 6 and ground. I go to pins 10 and 23 and getting less ohms 168.8. Still no start. Could it be the ecu?
Expert:  Juan Crespo replied 1 year ago.

If you're getting only 168 Ohms resistance, then either the sensor is partially shorted internally or you have the Red/Yellow and Blue/Yellow wires shorting together. Since the test is done at the ECU connector with the ECU disconnected, I don't think it is the problem.

Expert:  Juan Crespo replied 1 year ago.

To further determine the ECU is not the culprit, let's pull the any codes that might be stored in the system:

ENTERING SELF-DIAGNOSTICS (IGNITION SYSTEM) CONTROL FUNCTIONS

The system monitors the operation of certain components by operating the item(s) in question. When the component or switch is operated according to a set procedure, the LED will display a 3-digit code. Failure to display a code indicates the control unit has failed to detect operation of the component/switch. In this case, the fault lies with the component/switch, connectors and/or wiring.

The functional check system can also test whether components/switches are correctly wired. As an example, it can be used to check whether the permanent/magnet generator (engine speed sensor) and wiring are intact if the engine fails to start.

CONTROL FUNCTION NO. 1 (ACCESSING CODES)

This function displays any codes stored in ignition system ECU memory during engine operation. The system can store 7 different ignition system faults.

Please let me know what you find.

Customer: replied 1 year ago.
No codes. 1 1 1. Hey do you know what test this is? I can't find it anymore. Something told me to jump pins 5&6 on the ecu connector and that I should have 0 volts when ignition is off and 12 when the key is on. Mine is opposite 12 volts when key is off and 0 volts when the key is on. Is that testing the power stage?
Expert:  Juan Crespo replied 1 year ago.

I don't know about jumping pins on the ECU. See the attachment for a test to check the crank sensor lead. Let me know what you find.

Expert:  Juan Crespo replied 1 year ago.

All this time we've been chasing a no-spark condition, but do you know if the ECU is pulsing the injectors? If not, disconnect any one of the four injectors and plug in a Noid light (available at most auto parts stores) in its place. Noid light should flash upon cranking the engine. Please let me know what you find?

Customer: replied 1 year ago.
I performed the diagnostic test on the fuel system and could hear the valves moving. If that is the test you r referring to. The test I was talking about test the power from the fuse to the ecu. It is backwards. I have voltage with ignition off and no voltage when the key is on. I also am testing bad on the speed sensor test. I can't see the part I just changed being bad and the backwards reading on the circuit test going to the ecu. does the power stage have influence on both the ecu and the cps?
Expert:  Juan Crespo replied 1 year ago.

I don't think I'm communicating effectively with you - I thought I had given you specific instructions on using a Noid light to check for injector pulse, yet you're talking about a fuel test and valves moving.

Also, if you replaced the 25A fuse and its holder as I indicated, you wouldn't have to test the power from the fuse to the ECU - you would know if it was there or not.

At this point I feel I'm not the best person to guide you through the tests required to diagnose your Volvo's issue. I'll opt out and re-open the question to the field so other experts may have the opportunity to chime in. Please don't reply to this response or the site will revert the question back to me.

Best Regards