Just got the car back together after a head gasket change. During the process, I changed out my busted 60psi BBK fuel pressure gauge with a 100 psi Summit gauge. No other fuel system changes were made.

Upon firing it back up, I'm only getting 32 psi max while running. I have tried adjusting the AFPR, and get no pressure change whether I'm at the highest or lowest pressure setting. When the engine is reved, I get no increase in pressure either.

Just priming the system, initial pressure is at 27 psi, and drops immediately to 5psi. On shutting off the engine after running, pressure drops immediately to 0psi.

I've crimped the return line at the tank, and I get the same result.

I have not ohm'd the injectors yet.

 

If the pressure still dropped with the return line pinched, you need to take a good, hard look at your injectors.

 

Just wondering, How long were the old injectors sitting open while you did the gasket? I don't think you will find a bad injector coil on a Bosch, only the multecs have bad coils by design. My question is because if you let the old pintle type bosch injector sit dry for a couple of weeks in the high humidity of Jupiter, the injectors actually rust inside and become very empermental.
The best thing to do with them while they are out is keep them submerged in fuel.

 

didn't see the blower.. same question what injectors are you using?

 

Fms 42#

 

green top ford/bosch.. steel pintle, not stainless.. they rust also.. how long did they sit?

 

Oh...they were probably down about 4 weeks or so.

 

you might have a leaker.. a 42 doesn't have to leak much to reduce pressure very quickly.

 

Fan-freakin'-tastic. Just got her all back together. Anything I can do at the homefront to cure the problem if I find the leaker?

 

if a injector has accumulated rust inside it might wear off just from the pintle beating it off. Your blower can help by increased map. You can try a heavy dose of fuel injector cleaner plus a good seafoam treatment in the tank and through the intake, Those injectors can take any chemical. I would try it.

 

1 more thing.. turn up your fuel pressure as high as you can when you run the cleaner.. If that don't work try an on the car BG fuel injector cleaner. Its done at a shop and is run directly into the fuel rail. Last resort pull it apart.

 

Thanks for all the good info. I really didn't want to pull her apart again.

I pulled plug number 1 last night, and it was a little white (about miles on it since the reassemble), but not overly concerning. I have the AFPR set at maximum pressure just as a precaution.

I'll pick up some Seafoam or injector cleaner this afternoon and see what happens (I have about 4 gallons in the tank). If nothing changes in a few days, I'll take her down and have the system cleaned at a shop.

I'm a little nervous putting it under too much boost, even though I think the FMU (6:1) would shore up any leaning out condition.

 

Wow...this get stranger. Last night, after dumping a can of Seafoam into the tank, I went to prime the system. Now, I'm getting 0psi rail pressure from priming. I tried 4 times. However, when I kick the car over, she fires up and pressure is 31psi, but with a quick drop to 0psi on shutdown.

I'm going to check the in-tank pump (I can hear the in-line pump working), going to pull the injector harness off to see if I have a grounded wire somewhere (I actually had an injector driver go bad in my old pcm and the injectors would dump all of the fuel the pumps would provide), and then I'm sure I'll have to pull the rail and physically check for leaking injectors. Just eliminating things in order of difficulty.

 

you probably got some crap stuck in the pintle.. they only open about 18 to 20 thou.. so crud can keep 1 or 2 open. does it run ok or is it feel like its loading up?

 

It seems to run ok...slightly rough. If I pull the EST, she dies right away (initial advance is set at 8*). But, I did reset the valve lash as well the other night, so I'm going to do a compression check this evening as well to make sure everything on that front is ok.

 

When you turn the key to "ON" but don't crank the engine, can you hear the FP energize for 2-3 seconds?

If not it's probably the FP relay not allowing the priming. If you hear the pump but still NO pressure, you probably have a leak. Injector?

Jake

 

Yesterday, the pumps would prime and I would get 0psi at the rail.

Today, the first time I primed it, it came up to 25psi and held. I tested the injector wiring - good, I tested both pumps - good, and she fired right up. But, I'm still only getting 32psi rail pressure with the AFPR on the full pressure setting while running. Also, tonight, when I shut it down, pressure dropped instantly to 22psi. It slowly came down over about 35-40 minutes as oposed to going directly to 0psi yesterday.

 

pinch the return line and take the AFPR out of the loop. See if the pressure goes up to 50 or more. If not, punt. It sound like the injectors are freeing up but again, 42 lb injectors can dump pressure rather quickly with a little leak. keep trying to free them up, also sounds like you are making some progress. I would still try the on car service to really clean those out.

 

Yeah...it's coming along. I'm in no big hurry. I've got to put a helicoil in the plenum (found that tonight), and I still need to do a compression test to make sure the lash isn't too tight.

Thanks, guys, for all the good info and tips. I'll try pinching off the return line again tomorrow. Too many beers already tonight for messin' with flamables!

 

Alright...had a little time this weekend, and this is what I found.

I initially pulled the afpr off before pulling the fuel rail. I found the spring washer had a slight "concavity" (is this a word?) to it. I use the Holley 512-501 afpr, and the housing/spring is quite a bit shorter than the stock unit...I'm not for sure if other afpr's are as short. What I'm thinking is that the additional FMU presure under boost as pushed the diaphragm spring with enough force to bend the spring washer. Now, is this possible without really tearing the diaphragm first? Or, perhaps the actual spring has been permanently compressed by the additional pressure. Not sure, just what I observed.

I installed an additional washer under the original spring washer, and reinstalled the afpr. I primed the system, and immediate I got 65psi and it held steady. I made the adjustment for 42psi, and it held.

I also pulled the fuel rail to check for injector leaks...I couldn't find any. I had primed the system last night after reassembling the upper intake, and this morning, the pressure was still at 8psi. So I think I'm good there.

Now........upon start-up, I'm getting a very rapid surge. I haven't performed the compression test yet (this evening), but I'm thinking the 9th injector isn't sitting correctly since I had to make an odd bend in the line this weekend. Either that, or I've got the lash down too tight, or my O2 sensor is on the fritz.

Isn't this fun?!