Turn off key, fuel drops to ZERO psi instantly. HELP!

[chickendreamer]

May not be recommended, but it's worked for 5+ years and a LOT of juice ran through it for 2 of those years. Ran 2 bottles a w/e for longer than I care to admit (threw away a lot of money).

My stock rev limiter is way too low to get the full potential out of my car. As a matter of fact I don't think I could spray the car with the juice on. I'll hit the limiter in each gear which is MUCH more dangerous.

The car doesn't detonate with the timing dropped down as long as the plug gap is closer and the fuel pressure is up.

As far as building a new engine... that's been the plan all along anyway. The stock engine is close to 200,000 miles and I've never had the valve covers off.

I need to figure out the idling issue as putting a new engine in will most likely have the same results. I would rather find the problem BEFORE I have to swap engines.

yeah I guess if you've been running it for that long it's ok to keep the chip in. Not much it could do now...

But yes, swap the maf/injectors and see how that affects your idle.

btw, i switched my signature just for you.

 

[gcomfx.com]

yeah I guess if you've been running it for that long it's ok to keep the chip in. Not much it could do now...

But yes, swap the maf/injectors and see how that affects your idle.

btw, i switched my signature just for you.

I noticed the sig change.... I signed up on turbostangs just to see your pics. My username there is 100mphclub.com. Nice thread/write up. I learned a lot! I learned I'm not going to get a turbo kit unless I can afford someone ELSE to install it for me.

I'm hoping this w/e the weather will hold. Kinda sucks to change the injectors only to pull them back out again.... but my club has a track rental day coming up and I need to the juice just to keep up with most of the guys.

So I better get to it. If I end up getting different injectors and M/A what does everyone recommend? I plan to do a mild H/C/I car and keep the juice. So nothing too major. I've toyed with a 331 setup, but doubt it'll actually happen.

 

[chickendreamer]

I noticed the sig change.... I signed up on turbostangs just to see your pics. My username there is 100mphclub.com. Nice thread/write up. I learned a lot! I learned I'm not going to get a turbo kit unless I can afford someone ELSE to install it for me.

I'm hoping this w/e the weather will hold. Kinda sucks to change the injectors only to pull them back out again.... but my club has a track rental day coming up and I need to the juice just to keep up with most of the guys.

So I better get to it. If I end up getting different injectors and M/A what does everyone recommend? I plan to do a mild H/C/I car and keep the juice. So nothing too major. I've toyed with a 331 setup, but doubt it'll actually happen.

Thanks for the words on the turbo kit, it's really not as hard as it looks... it's actually quite easy. If you can change injectors and a maf you shouldn't have any problems with a turbo kit. I am in the process of building up a stronger block for my car, I have the 331 rotating assembly and most of the other parts for a short block minus the block, just waiting for the new boss block to come out. I'm hoping it will be a bit more cost effective than an R block or a Dart block.

The With the Pro-M you could probably get it recalibrated or if you don't want to get that done you can get a C & L. I've mixed reports about the C & L, so it's really your choice but for myself I wouldn't hesitate in buying a C & L since they have sampling tubes which you can swap out if you ever step up to larger injectors. I myself have a Pro-M univer and really like it but it's an expensive unit and not really needed for your application.

 

[gcomfx.com]

Okay, I've been driving the car this entire week. It's hard to start and hard to keep idling. Runs pretty good other than that. LOL

I noticed the CEL light coming on occassionally. In the past that usually meant I was running too rich, due to being setup for the juice.

I ran the codes with engine off... and here were the results.

179 - System at lean adaptive limit at part throttle, system rich (right)
188 - System at lean adaptive limit at part throttle, system rich (left)
334 - EGR (which has been deleted)
556 - Fuel pump primary circuit failure
511 - EEC ROM test failed. Always get because of the chip

I plan to pull the plugs while cycling the fuel pump, to see if any of them get wet with fuel from a leaky injector (mechanic friend recommended this before trading injectors with stock ones).

What is a fuel pump primary circuit failure???

 

[Yobi1Kanobi]

I am willing to bet you have a partially stuck injector. I just found this thread and it took a while to get through the whole thing

Anyways pulling the plugs will give you a good indication of where your problem is but if you have encountered a lean condition.... becuz remember the injector may be stuck only half way therefore bleeding out when off and leaning out at full throttle. Anyways just food for thought .

If you are using a dry kit it puts alot of strain on the injectors running at high presures I know mine ran at about 80-90 psi with a 125 shot Hang in there

 

[gcomfx.com]

I'm with you on the injectors most like being the problem now. Heck I've changed everything else, there isn't much else to blame. My only problem now is why I have a code "556 - Fuel pump primary circuit failure"

 

[final5-0]

I read the whole thread

PRESSURE ... PRESSURE ... PRESSURE

Lets set aside the pressure dropping or not holding for a while and think about the idle issue.

The pcm is at its complete lean maximum adjustment which is telling us things are way too rich.

At first thought, it kinda does sound like one inj is not closing completely. If that was the case, why do you get the lean codes on both banks.

How about a pcm reset and then see what the first code it throws turns out to be?

I have never had any dealings with afpr or gauges and the like so let me ask this. What is the pressure at idle of a normal combo with no known issues and does yours mimic that pressure when you are at idle?

You say this issue has been a long time sore spot. Maybe the maf cal and inj's just don't work together all that well for the cheat method to be all that effective.

The fuel pump code does make you wanna think something is up there.

If you still got all your stock stuff you can use it to trouble shoot.

Good thread to think about and it will be interesting to see what the prob turns out to be.

Sorry Paul ...I know those are only thoughts and not proven fixes but it could be one or more of several things causing the prob as I see it.

Grady

 

[gcomfx.com]

My fuel pressure adjustments with the same M/A and injectors has worked fine for 3+ years. This past year is when things started going down hill. It just seems to be getting worse and worse. I've listened to all kinds of ideas and have thrown about every part at the car I can afford.

"At first thought, it kinda does sound like one inj is not closing completely. If that was the case, why do you get the lean codes on both banks."

Do you mean RICH? Seems to make sense to me that a stuck injector would make it rich as it would spray all the time. What doesn't really make sense is that BOTH banks would do that. I don't know much about how the system works, but wouldn't that mean at least one stuck injector on each rail?

Thinking back when I can remember this whole thing starting, I really thought I got some bad gas. The fuel filter was pretty dirty too.... Perhaps a bunch of the injectors got clogged all at once. :?

 

[final5-0]

My fuel pressure adjustments with the same M/A and injectors has worked fine for 3+ years. This past year is when things started going down hill. It just seems to be getting worse and worse. I've listened to all kinds of ideas and have thrown about every part at the car I can afford.

"At first thought, it kinda does sound like one inj is not closing completely. If that was the case, why do you get the lean codes on both banks."

Do you mean RICH? Seems to make sense to me that a stuck injector would make it rich as it would spray all the time. What doesn't really make sense is that BOTH banks would do that. I don't know much about how the system works, but wouldn't that mean at least one stuck injector on each rail?

Thinking back when I can remember this whole thing starting, I really thought I got some bad gas. The fuel filter was pretty dirty too.... Perhaps a bunch of the injectors got clogged all at once. :?

Yes Paul

We are talking about the same thing here.

The pcm has reached its lean adaptive limits and can not dial back any more pulse width. It is doing this to try and compensate for a fat condition.

Yes again Paul

I does indeed seem to me that you would have to have one or more bad inj's on each side of the motor. That was why I thought about the idea of a pcm reset to clear out all the old codes and see what fresh codes popped up.

Lots of trouble I know ... but ... you could put back your stock maf/inj and see what happens if you still got em.

Like you, I wonder about the fuel pump code. Maybe some other member can shed some light on this code.

Grady

 

[final5-0]

I did think of one more thing that may be causing your both bank lean codes.

If you have been jacking up your pressure a good bit, that could cause your adaptive to go to its extreme lean limit.

Grady

 

[HISSIN50]

The FP code comes if the fuel pump monitor notices that the pump did not get power at some point when it was being given the signal that it should (kinda' like an IDM code).

Sometimes this is a ghost code, but given your issues, it might not be.

Good luck.

 

[gcomfx.com]

The FP code comes if the fuel pump monitor notices that the pump did not get power at some point when it was being given the signal that it should (kinda' like an IDM code).

Sometimes this is a ghost code, but given your issues, it might not be.

Good luck.

I wonder if the extra key cycling could be causing it. I've been priming the pump once extra before trying to start the car.

Tonight I'm going to swap out to my stock parts and drive the car next week with those on it. See how it does after I clear the codes. I'll post back.

 

[Yobi1Kanobi]

the extreme presure is being cause by the nitrous dry kit most likely.

 

[HISSIN50]

Paul, extra priming should not cause the code. WHen you prime the pump, the computer is grounding the FP relay control side to energize the pump. Now if you are priming it but the FP relay is not energizing for some reason at some point, that could cause the code.

I have heard of an inertia switch on the outs causing it - sometimes the switch degrades and will only pass 6-9 volts, which is enough to energize the FP relay coil, but it is on the border. If the voltage drops (due to IR, etc) in the wire through the inertia switch, the FP relay can burp of and then right back on (the inertia switch isnt tripping, it's just resistive). The diagnostics monitor should pick this up.

That was just a random example of how the circuit can fail and 'fix' itself with no input from you.

Good luck.

 

[gcomfx.com]

I have the stock injectors back on... but didn't continue putting it back together yet as the red vacuum line finally gave up on the abuse of being moved around over the years. Wow, that thing is brittle now.

I did test the fuel system with the stock injectors. After filling the fuel rails back up and getting pressure. I let the car sit for a bit. Then watched the pressure guage and cycled the pump again. First cycle aprox. 10psi - second cycle aprox 25psi - third will jump up to aprox the 40psi range. Stop cycling.... the fuel pressure will drop dramatically to 15psi then a little slower drop to 5psi and then hang there for a minute and go on down to 0psi.

Again as Grady has mentioned, I'm not 100% the new regulator is suppose to hold the pressure anyway. But first observation is that the stock injectors are behaving the same way as the 24lbers.

I should have it back up and running this w/e. We'll see how it does.

Where is our fuel pressure relay? If that code comes back I guess I'll swap that out too.

 

[final5-0]

It sucks this stuff is going on for you Paul

however

The rest of us are learning from it

Hope you find the prob quickly

Grady

 

[gcomfx.com]

I kinda slacked on fixing the car this winter based on being frustrated with it and getting clear of some debt. Now I'm in "hurry" mode as my club has some great events coming up this spring and summer.

 

[HISSIN50]

I have the stock injectors back on... but didn't continue putting it back together yet as the red vacuum line finally gave up on the abuse of being moved around over the years. Wow, that thing is brittle now........................


Where is our fuel pressure relay? If that code comes back I guess I'll swap that out too.

Paul, if not mentioned before (I aint about to re-read this thing. ) if you use fuel line crimpers (sold at parts stores) on the return line, you can try to rule out the FPR bleed.


I still kinda think an injector that is leaking might show up in a CBT. And since I think you have swapped them, you can test them yourself or have a shop flow test and clean them. The gist of testing them yourself is to rig the air compressor line (air tool compressor) to your injector. Put the injector in a cup of water with just a little soap. Open the regulator on the compressor outlet to around 40 PSI and see if air bubbles come out of the pintle area of the injector. If so, it is leaking.


Oh, the FP relay is in the CCRM AFAIK.

One can get runs of that crappy plastic vac line at the parts store. I broke the line on my EGR right at the top where it connects to the EGR. I back-cut the plastic line (to a clean spot) and ran a piece of vac line as a splice. I left the nub of vac line that was still in the rubber boot (it broke right below the boot) in place so I could connect my rubber line to the nub - in order to retain the stock 90* connection (that's how it is as I recall atleast).

Good luck.

 

[gcomfx.com]

I had my daughter this w/e and didn't work on the car. I should be able to finish it up Tuesday night after I fix the vaccum line and make a nice plug for the EGR bung. I FINALLY got that freakin' nut off!

I plan to drive the car the rest of the week and see how it does with the stock injectors. My club has a road rally on Saturday, I hope I can take it there. :worship: I finally have an air compressor (christmas gift this year) and have yet to take it out of the box. Guess now I have a reason to.

 

[chickendreamer]

If you have your stock fuel pressure regulator throw that back on too.. see if you still have the fuel pressure drop.

I wouldn't be suprised if that chip is part of the problem too, you're timming is retarted a bit too much for my liking.