So. Changed the injectors and fuel rail (removed and reinstalled fuel regulator) on a 454ci. Now the truck starts and idles like a dream, but when I hit the gas it chokes out and dies. I just ripped the intake manifold off again and checked the vacuum line to the regulator, but I am getting fuel to the rail, and lots of it. But why the heck would it be dying when I hit the gas?

Thanks for any suggestions you have...

 

Make sure everything is plugged in properly (everything you unpluged unplug again and check to make sure there aren't any damged/bent prongs), check fuel pressure, make sure the vacuum line to the regulator is plugged in right and not kinked, and let us know what you find. What was it doing before all this was installed - the reason you replaced everything?

 

I took it to a shop and they told me the injectors were shot. They wanted too much money, so I bought them and did them myself. The symptoms were hard start (especially hot) and crappy mileage. He said the pressure indicated injectors, but now I want to check for myself. So last night I took it for another spin and it idles very nicely.

Only when I put gas to it, it bogs down, sounds like misfiring from under the hood. I'll check that pressure today and hopefully it will be illuminating.

Good news today ! I'm getting a 1999 parts suburban for 200 bucks, with only the one corner smushed a little bit. Most of it will work straight across into my truck, or at least some of it. Hopefully. And if not, I can sit in it and make 'vroom vroom' noises.

 

So. New plan. I asked three mechanics I know today (well, actually 5, but 3 that have done work for me in the past). One of them told me to relearn the distributor, the other one said bring it in and the third said I screwed up.

With friends like these, eh ? So I'm going to buy a fuel pressure gauge and find out if my rail is getting sufficient pressure and, if not, why not. I was tempted to plug off the regulator line and cycle the key to see what my pump is doing, but I can hear it working when I turn the key and it ran reasonably well idling. I am beginning to suspect more and more the regulator; when I lay down the gas the vacuum from the intake should increase, in theory allowing slightly higher fuel pressure. If it drops, I know the diaphragm is shot in the reg, right ?

The new parts truck is sitting very pretty.

 

The vacuum line going to the regulator is easy to kink if it is positioned wrong. I am thinking like you that the regulator is at fault. You can access the vacuum line with the intake on - it isn't easy but if you lay across the motor you can get to it. I would at least give it a peek and make sure #1 it is on right and #2 it's not kinked. Good luck.

 

Solved it. I had not checked the old fuel rail when I took the regulator across. It turns out there are two parts (a screen and an o-ring) that remain behind in the body when you pull the part. So. Having put the regulator together and reinstalled the whole damn thing, I now have 60 psi at the manifold, an even idle and my headlights aren't working properly. lol. So happy right now I couldn't care less.

Right now when I hit the high beam switch the highs come on but not the low beams (they should stay on?) and there is no indicator. Too much to bother with today. Happy it's running, and I'll repost when I get a fuel mileage reading.

 

For a slit second while your pulling back on the turn signal to turn the high beams on, you will have both the high and low beams on. After you let go of the signal arm. The low beam will turn off while the high beam stays on.

There is a trick to keeping the low beams on ALL THE TIME... Not sure how to.. something about putting a diode in the low beam circuit

 

I did a post on how to do the High beam trick. Due a search for High beam Mods. or took under my screenname for the post.

 

Here is the post with a link to making headlights of various comboes work I beleive.
http://www.performancetrucks.net/for...ge=1&pp=10
Read everything before attempting. No need to fry any wires.

 

Thanks, boys ! I drive a Peterbilt in my off-hours (i.e. work hours) and I like the 4-headlight system. I just ripped the rear end apart (full-float rear diff) again yesterday to try and find out why the shoes are still overtightening and dragging. So I found the e-brake cable was too tight, went to loosen it and broke the damned adjuster. Who the heck needs an e-brake anyway ?

Oh yeah, and my mileage is back to 11.5, so I'm pretty happy with that so far.