Fuel pressure regulator question

karld · July 20, 2004

I've been having a hot start problem with my truck and tonight for kicks I pulled the vacuum line off the fuel pressure regulator and fuel poured out of the vacuum line. I am not an expert on this system,but I don't think this is good. If the regulator is in fact bad, can I pop the old one out of the fuel rail and replace? My truck is a 99 2wd 4.8L. Thanks!!

99-2door · July 21, 2004

You are correct. If there is fuel in the vacuum line the regulator is bad. Just replace with a new one and you should be good to go.

karld · July 21, 2004

Replaced the pressure regulator today and the truck now runs absolutely perfect!

SteveCZ · July 22, 2004

Well, after cleaning my K&N Drop in Filter and re-oiling it, cleaning the throttle body with some GM Top Engine Cleaner, and cleaning the MAF Sensor off the air box with some good Electrical cleaner spray, I started having the same problem.

I since pulled the filter and replaced it with a regular paper one, thinking some oil got on the MAF sensor and cleaned it up again with the Elec. Cleaner.

I'm still having the same problem. Since I still have a warranty on this beast, I'm taking her down to the stealer to have them work on it... no sense in me paying for the part if they will fix it for free....

The more and more I read about it, it has to be the regulator....

My one question is, when your's went bad, did you hear any noises when you turned the key to "on" but didn't start it when it was cold?

When I did it this morning, after the usual fuel pump HUMM, I heard something like slipping gears up in front of me coming from the engine bay (driver side).

I know the regulator is up there, on the driver side valve cover.... but would that make that kind of noise?

sxmax · July 22, 2004

Another way to check if you fuel pressure regulator is going bad is that if your truck does not start on the first try, hold the accelator to the floor. If the fuel pressure regulator is indeed bad, it should start with the pedal to the floor!

SteveCZ · July 22, 2004

Thats what its doing, once she gets going its fine..

Now... the million dollar question.... I have to haul some wood up to the camp this weekend, about 60 miles away

Will I be able to do this, or should I not take a chance with it.......

Its been doing this for about a week or so....

What are the next stages after the "hard hot start"... or does it just stop sending fuel all together (not good)....

karld · July 22, 2004

SteveCZ, no I didn't have any strange noises,but when trying to start hot, the truck would struggle to start then run but almost stall and then hunt until it found idle. My truck as well would run fine out on the road. The sure fire test is to pull the vacuum line off the regulator and was my case,fuel poured out of the vacuum line which is a dead giveaway that the regulator is bad. It's a pricey little part,I payed $67 for mine GM p/n 17113678. Hope this helps