CMPFI "W" Engine Leak Diagnosis Documented- Video and Photos

[brcidd]

I had a neighbor bring me his '92 "W" engine van last night. He said it gets really hard to start- he has been told by another mechanic that he needs to replace the regulator.

Symptoms: Van will crank for 10 seconds or more until it starts- Van will restart immediately when warm- but wait ten minutes and you must crank it awhile- it also runs rough for a little while after it does finally start- runs fine otherwise.

There has been so much talk about fuel pressure measurement and leaking into the top of the engine- I could not help but document some things- for future reference

So I do the first test- the fuel pressure and pressure decay measurement. In the video below- I simply turn on the ignition for 1 second and shut it off- notice the pressure rise and fall- the pressure decays about 1 psi per second- which is a sure indicator of a leak--The pressure should rise to about 61 psi and hold above 50 for 5-10 minutes to pass this test.

Fuel Pressure Gage Reading

Now that I know this- and the fact it is hard to start, I know there is a leak under the upper plenum- so I remove it and see the actual leak location and leak evidence...



Now - Here is a labeled photo- to explain a little better.



And Lastly- you can see the leak spraying in this video....

Plastic Line Leak Spraying and Cleaning the Plenum

I hope this helps explain to those who have these symptoms and are not sure what to do.

The plastic pipes are available separately for around $50- it is commonly referred to as the "Nut Kit" - this is what I will replace. The "Spider Assembly" or regulator assembly is the high dollar item- usually $300+, and can be replaced at the same time-- I consider it optional- based on the owner's consent....

I hope this helps some of you- I sure would have liked to have seen something like this on my first time doing this repair......

[CD Smalley]

Awesome post!

[tony4jesus33]

Thanks for posting this, I fixed my van and she is running great. I changed the Fuel Return Lines "Nut Kit" and put New AC-Delco Platinum Spark plugs. I appreciate this site very much and I will refer other Astro-Safari Owners to deal with their Van issues.