Hi...I'm new to this forum..I've got a 98 4x4 LS that wont run, I've replaced the fuel pump. and I'm now replacing the spider injectors...and I've got a question..when I removed the unit, what I believe to be the pressure regulator on the back of the unit doesn't have a vacuum line going to it. it looks like it has a nipple for one..I've checked Haynes but can't find any thing on it...If it does, where does it hook up??? Thanks for any info anybody has..... Bud

 

It's inside the plenum, right? See the inside of the throttle body on bottom side. It's IN the vacuum.

 

The fuel pressure regulator is inside the plenum and is exposed to manifold absolute pressure at all times so it doesn't need a vacuum line.

Unless you need help with an oil change, toss your Haynes manual in the trash
GM factory shop manual is the ONLY way to go.

 

Thanks Capt Hook, I was stumped, but I didn't think about there being a vacuum in there at all times......appreciate your help..I'll go ahead and put it back together then.. .Bud

 

Make sure you put oil on the O ring where the injector housing fits through the plenum

 

Hi...It's me again, still stumped, I put the new fuel pump in, put a new injector spider assembly in...fired right up and ran like a charm...drove it about 2 miles and put it in the garage...this morning it won't start..turns over fast and has almost 60 lbs pressure on the rail..it doesn't even act like it wants to start. put a timing light on plug wire and it's getting spark..anybody have any suggestions on what to try next???? Thanks..Bud

 

See it if starts when you put a shot of carb cleaner in the air intake. Fuel pressure must be 60psi to 66psi with the key ON, engine OFF, fuel pump running, and must remain above 55psi for 3 to 5 minutes after the pump shuts off. Post your results.

 

Thanks Hook...I put just plain gas into the intake. and nothing happened.. I'll get some starting fluid tomorrow after church and let you know what it does....Bud

 

Starting fluid can cause serious damage to a gasoline engine, and to you! One backfire can blow the rocker arm covers clean off the engine.... seen it happen.... and it's not pretty. You're better off using carb cleaner.

If it won't start with the carb cleaner, check for a hot, blue, not orange, rhythmic spark at each plug while cranking. Using a timing light can be deceiving. Spark should easily jump a half inch gap.

 

Capt Hook....I had already bought some starting fluid, before I read your post. and used it. didn't seem to hurt anything..but It started right up and ran until the fluid ran out. what do you suggest??? Bud