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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Chevy
Satisfied Customers: 43862
Experience:  16 years of experience
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1ve got a 96 z28 water pump and optispark were replaced 5

Customer Question

1ve got a 96 z28 water pump and optispark were replaced 5 yrs ago ran great .parked it for awhile cuz pwr windows were bad and ac went out at same time id start from time to time then one day it wouldnt .just changed out fuel pump and filter and coil power going to coil but not coming out power to distributor but no spark ive had the vats bypass gimmick done pretty much stumped i can build a small block ole school chevy blind fold but this one with all these electrical gimmicks and sensors got me in a bad way
JA: Does the engine turn over? How old is the battery?
Customer: turns over great , battery 650 crankin amp yr old
JA: Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: fuel pump replaced coil replaced fuel filter cvopuld not get a decent reading on fuel pressue but when crankin hit shrader valve and gas shooting everywhere
JA: Is there anything else the Chevy Mechanic should be aware of about your Chevy?
Customer: vats has been by passed have power to coil but not coming out
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Chevy Mechanic about your situation and then connect you two.
Submitted: 4 months ago.
Category: Chevy
Expert:  Chris (aka-Moose) replied 4 months ago.

Welcome, I'm Chris (aka Moose). I normally log in after 3 pm central everyday. Please let me know exactly what you need from this conversation so I can provide EXCELLENT 5 STAR service.

  1. Disconnect the distributor 4-wire connector, then turn the ignition on. On the PCM side, check for a 5-volt reference on both the low resolution (Red/Black) and high resolution (Purple/White) signal wires.
  2. Verify that there is battery voltage on the Red wire and a ground on the Pink/Black.
  3. Plug the connector back in. Check for good square patterns from both the low and high resolution circuits while cranking the engine. If a lab scope is not available, check for about 1 volt DC during cranking on the low resolution signal and about 2.5 volts DC during cranking on the high resolution signal.
  4. If the signals are erratic or 0 or 5 volts, check for bad, chafed wiring to the distributor.
  5. If all OK, replace the distributor.


At the top of your screen you will see 1-5 stars and a green submit button. When your ready please make sure to pick a rating. Rating is the only way I get compensated for helping. Don't worry about a follow up later if needed, they are free and I welcome them. Ask me about a phone call if you prefer that service.

Thanks Chris

Expert:  Chris (aka-Moose) replied 4 months ago.

Hello again Chris here,

I am contacting you because the post has not been closed or rated. We have 7 days to get a post rated before it times out. When a post times out, that means its no longer on my active list (if you reply I never know it.) You have already paid the fees to get this question answered, but it appears your not pleased, or need more help.

Let me help some more. Is there anything else you feel I could offer so you would be pleased with my help. I have the option to call you if that would be better.

Thanks Chris