Still struggling with car at idle after 8 years

[jalexquijano]

Well i can open the engine and see what needs to be rebuilt. I posted the specs in previous post. Compression was good! Why another engine???

[Yarb]

I’ve mentioned this three times now on the forum about doing a leak down test. Not sure why thats out of the question of truly giving you a confidence level of each cylinder. At least do it on cyl #4 and go from there. Does anyone agree? Been at this along time….

 

 

 

[jonbill]

If you get another engine, it'll probably work and you can drive your car. and used engines are cheap.  get it with the inlet manifold too in case that's where the problem is.

Then you or someone else can leisurely work out whats wrong with this engine.

 

[Barefootdan]

1 hour ago, Yarb said:

I’ve mentioned this three times now on the forum about doing a leak down test. Not sure why thats out of the question of truly giving you a confidence level of each cylinder. At least do it on cyl #4 and go from there. Does anyone agree? Been at this along time….

 

 

 

Definitely. Its an easy test to do and would help diagnose the issue.

[dutchzcarguy]

22 hours ago, jalexquijano said:

Sorry im not taking the distributor and pertronix ignitor from the engine

Oh well that's your good right but tell me have you ever then tested another ignition system on your engine?  (sorry if you have i didn't read the whole text as i'm tired.. and to lazy haha) Now you don't/can't know if it's any good...

Do i need to tell the story of the guy with the Mercedes block allover again, he was also convinced it was a good block.... NEVER EVER go out that some parts are okay because you bought them new.. they can't be a piece of S**T.. 

The most important thing in finding a mall function is to check everything. And never asume something shoud be good because it was a new part.

(Lesson i learned not long ago..

Few years ago i installed a new clutch slave cylinder.. on my 280zx.. And a week later i tried to use it as i needed to switch the direction of the car on my lift.. the clutch worked no longer! (There was a puddle of oil under the car! There was a crack in the slavecylinder!!  Then i took the old box out of the "round archive" (wastebin  😉 )  and saw on the box: made in Italy..  I already had a giant dislike to italy parts and stuff but now i really hated them..  Makers of JUNK! )

[Mark Maras]

There's something that ZedHead mentioned a while back as a possibility and that's a bad oil ring in #4. We've covered most, if not all, of the easy things. How does one check to see if an oil ring is bad without pulling a piston? The only thing I can think of is a borescope?

[jalexquijano]

2 minutes ago, Mark Maras said:

There's something that ZedHead mentioned a while back as a possibility and that's a bad oil ring in #4. We've covered most, if not all, of the easy things. How does one check to see if an oil ring is bad without pulling a piston? The only thing I can think of is a borescope?

Should i do a leak down test now before tearing the engine apart? 

[emccallum]

After knowing you have good compression, I would be looking at ignition. I know you dont want to go there, but this simple tool may give some insight as to the offending cylinder.

 

https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6?th=1

 

[Mark Maras]

58 minutes ago, emccallum said:

After knowing you have good compression, I would be looking at ignition. I know you dont want to go there, but this simple tool may give some insight as to the offending cylinder.

 

https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6?th=1

 

 @jalexquijano A spark tester is an excellent idea and cheap too.

[gundee]

May be something as simple as a torn valve guide seal. Has that been mentioned and pulled apart to check?

If in fact oil fouled. Can be done with head on. 

[gundee]

25 minutes ago, gundee said:

May be something as simple as a torn valve guide seal. Has that been mentioned and pulled apart to check?

If in fact oil fouled. Can be done with head on. 

Now that I am looking at a blown up photo of that no. 4 plug, It for sure looks to be carbon fouled.

I would like to see a photo of no. 4 with the valve cover removed. Cam, springs, retainers, lash pads, etc, just of no. 4. Cropped.

[Patcon]

On 3/8/2023 at 9:05 AM, Mark Maras said:

There's something that ZedHead mentioned a while back as a possibility and that's a bad oil ring in #4. We've covered most, if not all, of the easy things. How does one check to see if an oil ring is bad without pulling a piston? The only thing I can think of is a borescope?

I don't know of any way to definitively determine the health of the oil rings without disassembly