Low fuel pressure with autotech internals and stock

[nofear72784]

Need some help. I used to hold 1650psi 24/7 with my stock pump. I installed a new downpipe and intercooler so I figured I needed the better internals. I replaced the stockers with autotech's. Been driving easy for the past few days and today when I got on it it was surging. Pulled out the AP and did some logs. Holy crap my fp drops to like 500 randomly at WOT. I removed the internals and they look perfect. I reinstalled the stock internals and logged again.... same shit... also flashed back to an older tune where I know I had 1650 just for a try and also the same, any ideas?

[bmylez]

Hrrmm...you could have blown out your relief valve, but I think you would have other problems...maybe just post up a cruising/idle log.

[nofear72784]

I was just thinking about that valve. I do have significantly higher pressures with the internals but they drop out randomly. I looked super close at the inside of the sleeve and there are deep swirls in it almost like rifling. The piston is 100% perfect though. Installed with oil, I know it was clean, don't know how it got that unless it was manufacturing defect. What would I notice if the valve was bad? I'm thinking the stock internals are just low because it can't keep up with demand anymore. Here is a log I made last night slow roll in 4th when I noticed it was cutting at WOT.

[Chimmike]

what are your fp targets in the AP tune? Did you up them based on the new internals? Let's see the log

[nofear72784]

Upped the commanded FP to 1780psi

[Chimmike]

Let's see the log though. I'm assuming you saved the map, put it on AP, then flashed the map onto the ecu right. If you can show on the log commanded fp as well as actual

[Enki]

This might be the same issue I've been seeing off and on. My fuel pump internals are sticking, causing it to not physically pump occasionally.

When you installed the internals into the retainer nut, did they go in super easy or did you have to work at it?

[nofear72784]

Yeah I didn't log commanded since I know what it's commanded to. I could do that laer though. I just removed the internals to take pictures of what I was seeing. God damn it's hard to take a picture of such a small thing! I did my best. The lines inside the bore are what I was saying looks like rifling. The piston is completely spotless though. That is dust on the piston btw not scratches. Sorry for the large files but I needed a good camera to catch the scoring.

[nofear72784]

Originally Posted by Enki This might be the same issue I've been seeing off and on. My fuel pump internals are sticking, causing it to not physically pump occasionally. When you installed the internals into the retainer nut, did they go in super easy or did you have to work at it?

They slid in easily. I was actually surprised because the stock internals felt much tighter.

[nofear72784]

Originally Posted by bmylez Hrrmm...you could have blown out your relief valve, but I think you would have other problems...maybe just post up a cruising/idle log.

You get 10 points! After a crap load of swapping around parts I got a junkyard rail with the relief valve for 100. Replaced the valve a that fixed it! You can actually blow into it and hear the air leak through it. As far as the scoring of the internals Autotech is honoring their warranty. Thanks to JP for the help.

Question for everyone though, is this a pressure release that is supposed to reseal after a high pressure spike? What is the pressure it it supposed to open at?

If anyone needs a rail or the crows feet PM me.

[bmylez]

The RV opens up at ~1900psi. You need to verify in your WOT logs that you are not exceeding 1850psi or else you will eventually blow it out. I had forgotten about this while I was tuning over the last couple months then someone reminded me. Sure enough, I had several spots of over 1850psi, so I toned it down. With FP internals, if you set pressure to 1787 (or whatever the max is), it will actually exceed that value, so you have to go through your log and make it lower than 1787 to get it below 1850 in reality.

[nofear72784]

I was noticing that the other day. Even when it was set at 1650 I would run 1750-1800. So that confirms my suspicions. Thanks! you probably saved me from ruining another one of these stupid expensive pieces of brass.

[travis9935]

So what happens if you replace your internals and this happens and you don't have the ap? I have a ht instead.

Sent from AT&T Inspire 4G using Tapatalk.

[nofear72784]

Originally Posted by travis9935 So what happens if you replace your internals and this happens and you don't have the ap? I have a ht instead. Sent from AT&T Inspire 4G using Tapatalk.

I'm assuming you mean you have high pressures. I started the thread due to low pressures. From what I understand the higher pressures would make the relief valve open more often than stock and possibly cause premature failure of it.
When I had a hypertech they did not allow any changes to any of the tables. Unless they changed this your not capable of changing it. You could get a higher pressure valve at PTP but they are expensive. PT-Performance.com
I would sell the Hypertech and get an AP. I wish I got the AP from day 1.

[travis9935]

Originally Posted by nofear72784 I'm assuming you mean you have high pressures. I started the thread due to low pressures. From what I understand the higher pressures would make the relief valve open more often than stock and possibly cause premature failure of it. When I had a hypertech they did not allow any changes to any of the tables. Unless they changed this your not capable of changing it. You could get a higher pressure valve at PTP but they are expensive. PT-Performance.com I would sell the Hypertech and get an AP. I wish I got the AP from day 1.

I don't want a frickin ap or zoom zoom boom for that matter! I like my safe tune, I'm not goin bt so what's the point? Geez half you people on here getting kick backs from cobb?

Sent from AT&T Inspire 4G using Tapatalk.

[Dizzy Turbo]

The ap is invaluable even without plans for big mods. It allows you to monitor everything and you can still run a safe tune

Sent from my Desire HD using Tapatalk

[09Speed3Z]

Because like what he said, you can't log and monitor anything with a HyperShit.

The only proven reliable tuning software for this market is an AP.

[08cosmic3]

Hypertech fanboys------------> 247.

Try monitoring with your Hypertech.

If you don't want an AP then you have to buy a HT and then a Dashawk to monitor. Once you've done this you have spent enough to buy an AP. Many people who buy HT end up with an AP, there is a reason for this. Questions concerning monitoring engine perameters with HT should be posted in 247.

[anavrinIV]

The AP also has OTS maps that run perfectly safe tunes out of the box, and still allow for monitoring and further tuning capabilities. I have no plans of going bt, but I do plan to be fully bolted and my next purchase will be an AP so I'll know what's going on each time I change a part.

[travis9935]

I didn't buy my ht for logging, I have torque with extra pids for that. What the hell is it to anyone what way I tune my car?

[Dizzy Turbo]

You asked a question, and the answer was you need an ap. Nobody cares what you do, just giving you the answer that you asked for

Sent from my Desire HD using Tapatalk

[travis9935]

Originally Posted by Dizzy Turbo You asked a question, and the answer was you need an ap. Nobody cares what you do, just giving you the answer that you asked for Sent from my Desire HD using Tapatalk

If nobody cares what I do then why all the ht shots then?

Sent from AT&T Inspire 4G using Tapatalk.

[Dizzy Turbo]

I didn't mention ht. But they do not allow logging so they just aren't enough for these cars

Sent from my Desire HD using Tapatalk

[bmylez]

Originally Posted by travis9935 If nobody cares what I do then why all the ht shots then? Sent from AT&T Inspire 4G using Tapatalk.

First off, you're getting way too defensive about a programmer, and secondly, people are making HT shots because it fugging sucks. Sure it's "safe" but it's also slow.

Anyway, don't come into someone else's thread asking a question different than what the original post was and THEN get butt-hurt about people making reasonable replies.

You need to do a lot of reading if you think AP = zoom zoom boom. You're a good 2 years in the past if you think that.

[travis9935]

Wtf I asked how you can lower fp if your new internals run high, then the whole ht sucks thing started by someone else. Wow I can see why other forums call this one a group of assholes.


Sent from AT&T Inspire 4G using Tapatalk.

[Dizzy Turbo]

Thick skin goes a long way.

Sent from my Desire HD using Tapatalk

[nofear72784]

Holy shit, I haven't been monitoring this since I thought it was a closed issue. Dude, I wasn't taking shots at your Hypertech! I HAD ONE... You asked a question and I answered it. Either get a PTP high pressure relief valve or an AP.
BTW the AP is perfectly safe if you know what your doing. There are too many people that just think they know what their doing, don't read any of the good guides from abilor or dano or the other guys and blow their shit up! Then they blame the AP for their stupidity and never own up to it.
I was simply answering your question sorry if you didn't like the answer. If the other forums think were assholes why did you look here for the answer...... DONATE

[Dooby]

What is the easiest way to tell if your relief valve is shot? I thought someone mentioned watching the HPFP pressures just after the car is turned off. Would this be the pressures visible on the AP or is there something else needed?

Thanks!

[travis9935]

I dont have any issues, i was just curious.

Sent from my YP-G70 using Tapatalk

[bmylez]

Originally Posted by Dooby What is the easiest way to tell if your relief valve is shot? I thought someone mentioned watching the HPFP pressures just after the car is turned off. Would this be the pressures visible on the AP or is there something else needed? Thanks!

You could try that. Residual pressure should be in the 200s, I believe. The AP will see it, yes. If you really want to verify (assuming you have pump internals), go out and do a WOT pull in 3rd while watching pressure on the AP like a hawk. If it drops a bunch, most likely your problem.

[Dooby]

I noticed on the AP that the pressure slowly builds after the car is first turned off (like up to 1800 psi or so), after about 20 min, I rechecked it and it was at like 50. Are you saying that at that 20 min mark, it should be at 200? Should it always settle at around 200 even if the car has been sitting for even longer?

I do have KMD internals just installed and the pressure was dropping pretty quick after the 2.0 load mark. (fine up to that point though). So, thinking it may be the relief valve unless something is wrong with the KMD internals (wrong sizing or something). The piston seems tighter in the 18mm nut housing and requires about double the amount of force as the stock piston to get pushed through... so not sure if that would causing the pressures to drop at full load or more likely the RV here... Obviously that piston can't be "Duggar's loose" since it needs to hold pressure and not leak around it but not sure it should be too much tighter than the stocker.

[nofear72784]

Dooby, can you post a log of your commanded and actual fuel pressures? If you remove the connector on the top of the pump you should see 60psi ie tank pressure if you want to rule out your in tank pump. Also I don't know the spec for bleed down rate but if its that slow it's not going to affect you that much... leak down will happen overtime. Mine wouldn't hold shit and it was barely stuck open.

Heres what I did:
Removed the front return line- yellow connector I think line from the pump
clamped a rubber line with a bolt in it on same nipple you just removed
start the car IDLE ONLY and look at the end of the line you removed from the pump, other end is connected to relief valve
there will be residual fuel because its Y'd to the tank line when on the pump but if you see fuel flowing out of it when idling then it is leaking from the valve

Yes I suck at ms paint drawings

FYI mine was shitting out on the top end periodically before getting slightly stuck and I thought I needed the internals. I didn't have issues at low pressures constantly till this thread.

[Dooby]

One of my logs attached of starting at partial throttle and going to WOT briefly (stopped when saw the fuel pressures dropping hardcore). This is with KMD internals v2.1 in there so perhaps my relief valve is going to crap.

When you say to watch for fuel leakin out with that bolted and plugged yellow line, are you saying the fuel would be coming out of the pump itself (the part that is now open to the air)? I would assume so since nothing else would be open to the world but just confirming I am not misunderstanding your artwork and description

Thanks!

[Enki]

It's possible the in tank pump cant keep up (Btw, you're missing the HPFP Commanded Pressure PID in your log); if this is the case, swapping pumps with someone whom has no issues will tell you for certain. What kind of pressure do you see at the rail just before a cold start? It should be in the 50-60 psi range, and anything lower could indicate a problem.

Do you smell fuel in the engine bay when the car has just been started?

[Dooby]

Originally Posted by Enki It's possible the in tank pump cant keep up (Btw, you're missing the HPFP Commanded Pressure PID in your log); if this is the case, swapping pumps with someone whom has no issues will tell you for certain. What kind of pressure do you see at the rail just before a cold start? It should be in the 50-60 psi range, and anything lower could indicate a problem.

Ah - right, I'll get another log with the commanded. Pre-cold start pressure I saw last was around 50psi. I need to find some more local folks that are willing to let me borrow parts I guess Guess, I could order a CPE pump as well.. but kind of an expensive test there.

Do you smell fuel in the engine bay when the car has just been started?

Nope

[Enki]

The only other thing I can think of to try is to drop your boost to 16 psi across the board and see if pressure still drops. If it does, swap KMD out with stock and see if it still does it. If so, probably bad ITFP. If not, probably bad KMD internals.

[Enki]

Hmm, thinking about it more, your internals could be binding due to offset (incorrectly installed pump). You should try loosening all three pump bolts until the pump slides out a bit, then evenly bring them back down, making sure to torque the bottom one *first.*

[nofear72784]

Originally Posted by Dooby One of my logs attached of starting at partial throttle and going to WOT briefly (stopped when saw the fuel pressures dropping hardcore). This is with KMD internals v2.1 in there so perhaps my relief valve is going to crap. When you say to watch for fuel leakin out with that bolted and plugged yellow line, are you saying the fuel would be coming out of the pump itself (the part that is now open to the air)? I would assume so since nothing else would be open to the world but just confirming I am not misunderstanding your artwork and description Thanks!

That yellow line is connected at the pump and the other side to the relief valve. Your removing the end off the pump and just plugging the barb so it doesn't spray tank pressure when you idle it. If any fuel comes out of that yellow line which is now ONLY connected to the relief valve you will know it's leaking. Can't read logs on this computer I'll check them out later. Hope that helps.

[nofear72784]

Just took a look at that log... well I don't see any spikes that could have opened it and it seems consistently low at most points. If it is leaking it would be always stuck so you should be able to see it at idle. My money is going to be on the internals though.. took a total dive when boost jumped like it can't keep up with the required volume. Keep us posted.