Cranks will not start?

Tiny
MCGUIRE70
  • MEMBER
  • 1995 BUICK PARK AVENUE
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 110,000 MILES
I checked fuel pressure to rail it's good, checked spark at plug it's got spark, changed camshaft position sensor, new mass airflow sensor, replaced starter, battery is working fine. Please give me some expert advise!
Sunday, July 30th, 2023 AT 2:21 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,268 POSTS
Hi,

If you have spark and fuel, it should run unless the compression is low, or the timing is off. Will it start briefly if you use starting fluid? If it does, then we have a fuel-related issue. Although you are getting good fuel pressure, it may not be getting into the engine.

We need to make sure there is power to the fuel injectors. First, check fuse 7. See attached pic for location. Make sure the fuse is good and has power to and from it when the key is in the run position.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If that tests good, then we need to test for power at the injectors. If you look at the wiring schematic below, note that each injector has two wires. A pink wire at each injector is the power supply. Check that for power with the key in the run position. If there is power, we need to check for a ground path from the PCM.

The second wire, which can be a few different colors, is what needs to be checked. Disconnect the connector at an injector. Take a test light and attach the alligator clip to the battery positive. Probe the opposite color wire. Have a helper crank the engine. The test light should strobe on and off while the engine cranks.

Now, if the engine refuses to start with starting fluid, disregard the tests I provided. We will need to move on. Keep in mind, I am basing this on having an ignition spark at the spark plugs.

Take care and let me know what you find.

Joe

See pic below.
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Monday, July 31st, 2023 AT 12:27 AM
Tiny
MCGUIRE70
  • MEMBER
  • 3 POSTS
Well, I listened to your advice, I just went straight to spraying carb cleaner in the intake because I remember when I first started working on getting it to start, I took the plugs out cleaned and re-gapped and went ahead and swapped coils to see if that made a difference and on the second try starting it it made the loudest backfire I had ever heard! So back to trying to start with carb cleaner in air intake and when removing tub to the carb I had bright green fluid pouring out of the tube that's right radiator fluid! So, I commenced to replacing the upper and lower air intake gaskets, upon removing intake and carb in one piece and below the intake body was a puddle a green and black mixture of antifreeze and oil so that backfire was the cause. Question after finding this in a car you were working on what all would you replace when putting it back together because of course I need to narrow down what's causing it to backfire. Thanks Joe for pointing me in the right direction. Let me know your thoughts.
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Thursday, August 3rd, 2023 AT 9:04 AM
Tiny
MCGUIRE70
  • MEMBER
  • 3 POSTS
Oh, and it's important to tell you I've never had this car running, it was given to me for a dollar. I had a bad car wreck in my other Buick when walking 15 miles went by my car salesman's place told him what happened with my wreck and that my daughter was a newly quadriplegic and we needed a car so he said his son was driving this Park Avenue 110,000 miles made a wired noise and parked it in the driveway and it had sat there for a year. So, I got it for nothing and they had no idea what was wrong with it hopefully this will give you some insight into the car's condition and help with any other problems you might think I might encounter. Thanks for your time. Sorry about the novel yall!
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Thursday, August 3rd, 2023 AT 9:16 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,268 POSTS
Hi,

First, I am very sorry to hear about your daughter. That is horrible. That was really nice they gave you the car. Now, we need to get it running.

The backfire could be a few things. My biggest concern is if it is an ignition timing issue due to a timing chain issue. The prior owner indicated it was making a strange noise. Did he describe what it was doing? Also, take a few pics of what you found so I can see it. Also, confirm there is no evidence of coolant in the engine oil.

We may want to check engine compression to see if could be timing. Let me see some pics before we jump to that.

Let me know.

Joe
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Thursday, August 3rd, 2023 AT 8:28 PM

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