How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask AMEDEE Your Own Question
AMEDEE
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 25062
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
279429
Type Your Chevy Question Here...
AMEDEE is online now
A new question is answered every 9 seconds

I have a no spark condition, cranks OK, fuel pump comes on

Customer Question

I have a no spark condition, cranks OK, fuel pump comes on when the key is turn on, replaced crank shaft sensor, coil, and cam shaft sensor with positive result.
JA: Is the car in "Park" or "Neutral?" Do you know if your car has a "wheel lock" feature?
Customer: I tried starting in both park and neutral, what do you mean "wheel lock" feature?
JA: What is the model/year of your Chevy?
Customer: 1998 chevy astro van 4.3L V6
JA: Are you fixing your Astro yourself? What have you tried so far?
Customer: I have no voltage across the crank fuse under the dash and no voltage across the Illum fuse.
JA: Anything else you want the mechanic to know before I connect you?
Customer: The vehicle died while driving.
Submitted: 3 months ago.
Category: Chevy
Expert:  AMEDEE replied 3 months ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  AMEDEE replied 3 months ago.

Have you checked for codes in the computer?

Does the ignition coil have power while cranking?

Customer: replied 3 months ago.
I do not have any codes, have voltage with key turned on, have not tried to check while cranking. The vehicle died while driving at 35mph.
Customer: replied 3 months ago.
As I've said, there is no voltage across the crank and ILLUM fuses under the dash with or without the key turned on. I do not have wire diagram.
Customer: replied 3 months ago.
No spark from the coil while cranking.
Expert:  AMEDEE replied 3 months ago.

Sorry, I lost connection for a bit.

If there is no spark coming right out of the ignition coil, then lets check for a signal to the coil from the ignition control module. You could simply just have a bad ignition coil.

If there is no spark coming out of the ignition coil at all when cranking and it does in fact have full battery voltage to it, and the ignition module is not sending a signal to the coil, then it is likley the ignition module or crankshaft position sensor is at fault. Just be sure that the computer is "awake" with the key on. You can verify that the check engine light comes on with the key on for a bulb check to ensure the computer is powered up with the key on.

Customer: replied 3 months ago.
I have replaced the coil, ICM, crankshaft sensor and the camshaft sensor. Still no spark from the coil. I do get the check engine to come on with the key on. I also get the security light to come on temp. Then goes off after 2-3 seconds.
Expert:  AMEDEE replied 3 months ago.

Ok, do you have a signal from the ignition module to the ignition coil while cranking?

Customer: replied 3 months ago.
Crank no start, no spark, I do have fuel pressure.
Expert:  AMEDEE replied 3 months ago.

So have you checked for a signal from the ignition module to the ignition coil while cranking?

Customer: replied 3 months ago.
No voltage when cranking.
Expert:  AMEDEE replied 3 months ago.

Sir, the signal sent from the ignition module to the ignition coil is a ground signal trigger. You can use a test light to check this. But only you would hook it up backwards. Hook the alligator clip of the test light and hook it to battery positive, and take the tip of the test light and touch it the signal wire of the coil. (If you need a diagram let me know). The test light should blink when cranking over the engine if its getting a signal.

Customer: replied 3 months ago.
I need a diagram please. Thank you.
Expert:  AMEDEE replied 3 months ago.

It will be the white/black wire.

Customer: replied 3 months ago.
Am I checking at the ICM or at the coil?
Expert:  AMEDEE replied 3 months ago.

I would check it at the coil.

Customer: replied 3 months ago.
I have voltage with the key on, light goes out when cranked, does not blink.
Expert:  AMEDEE replied 3 months ago.

Ok, if not, then the ignition module is not sending a signal to the coil.

Do you have a scanner that can read live data? If so, does it display engine rpm while cranking?

Customer: replied 3 months ago.
I do not have a scanner but I did replace the crankshaft sensor already.
Customer: replied 3 months ago.
I not sure what role the security anti-theft system plays into this. Is there any way to check that?
Expert:  AMEDEE replied 3 months ago.

YES, look for a security light on or flashing on the dash

Customer: replied 3 months ago.
The security light comes on (not flashing) then goes off but the check Gage's light stays on as well as the check engine light as long as the key is on.
Expert:  AMEDEE replied 3 months ago.

Ok, thats normal. I would say the securtiy system is not an issue.

Customer: replied 3 months ago.
I do not have a wire diagram to look at but I've test all my fuses both under the hood and under the dash for voltage and blown fuses. Across the CRANK(10A) fuse and the ILLUM(10A) there is no voltage on either side of these two fuses. Does that help us?
Customer: replied 3 months ago.
This fuse location is under the dash.
Expert:  AMEDEE replied 3 months ago.

No Sir, those fuses only get power power at certain times.

In addition, the fuses you need to be concerned with are on the wiring diagram I have provided.

You need to ensure that the ignition coil has FULL battery voltage going to it while cranking and then check the signals in and out of both the new crank sensor and cam sensor inside the distributor. YES, the pickup inside the distributor could be bad as well.

Customer: replied 3 months ago.
I guess I'll need to get the vehicle to someone with a scanner unless you can come up with some other reason why there is no spark.
Expert:  AMEDEE replied 3 months ago.

Sir, you need to check the signals from the cam and crank sensor. You may not even have voltage to the crank sensor. Have you checked this? This can and will prevent the engine from having spark.

You dont need "another reason" why there is no spark. You need the "main reason" why there is no spark. By running these tests I have provided, it will point you in the "right reason".

Expert:  AMEDEE replied 3 months ago.

Hello! It'sCustomerfrom just answer.

I am just checking in to see if you need any further assistance?

If so, please let me know and I will be happy to help!

Customer: replied 3 months ago.
I have not been able to work on this issue since we last talked. I do have voltage at each of the listed sensors both with key on and while cranking. I have not had time to test the signal wires yet. Thank you.
Expert:  AMEDEE replied 3 months ago.

Sounds good. No problem.

Please dont forget about me.

I will be looking forward to your reply!