Idle issues and Fuel Pressure

[pnishr]

Alright, I've got 2 issues, maybe (probably) they're interrelated...

A: I can NOT get my FP down below 46ish with my AFPR. I can completely unscrew the adjustment bolt, nothing. And that is with or without the vaccum line on the IM.

Background: I had it set perfect. The only thing i've done between now and then is replace the radiator and fans, and remove the A/C and P/S. Nothing else performance wise.

B: I can't seem to get my Idle set either. I've used the ISCpos/LRNDIdleAdj method and had it on 29/144 ish. Now, when I set it using the GrdTiming method, ISCpos is around 15, and I can't seem to get a LrndIdleAdj measure... And it fluctuates a little much.

Background: Same as above only diff. is the A/C, P/S, Radiator, Fans.

As it says in my Profile, I run a 255, NON-rewired, and 450's. DSMLink Idle set for 850. I have it between about 850 and 930 now, but sometimes it drops to 720ish...

Also, I do have all the fittings to the AFPR teflon taped.

Any ideas? Thanks all.

 

[talon96tsi]

I'm pretty sure your not supposed to use teflon tape, but i doubt thats the issue

 

[TSIfreek]

I had a similar problem to this and I found out right away that I over tightened the vacume barb going into the AFPR hitting the spring causing the spring to bind up and not work correctly. I would take it apart and see it anything is hitting the spring inside.

 

[pnishr]

OK, I'll give that a shot. Thanks! But why all of the sudden? It was set just fine before. And why should my idle be off now?

 

[TSIfreek]

Possibly a vacume leak somewere will cause idle problems also may be leaking at the boost gauge itself. AFPR are real basic devises. The only way the FP cannot go down any lower than what you stated is theres somthing internally wrong with it or Gauge is not reading correctly.

 

[larsrya8]

Possibly a vacume leak somewere will cause idle problems also may be leaking at the boost gauge itself. AFPR are real basic devises. The only way the FP cannot go down any lower than what you stated is theres somthing internally wrong with it or Gauge is not reading correctly.

Or if something slipped through and blocked off part of the return line. That's what happened to mine... luckily it was a clog in the FP assembly, so I could use a paper clip to clear it. It was jammed in there really tight.

 

[pnishr]

I guess I'll have to take a look at that this weekend. Might have to delay my dash removal...

I may actually have a vacuum leak at the TB. I keep on having to replace my vacuum caps because they keep on getting hot/drying/cracking. I should have tried replacing those first for the idle issue. Am I the only person that that happens to, or does everybody have to replace their vacuum caps on the TB every 2 months...??

 

[exile]

Pnishr, I recommend you remove and inspect your AFPR once and make sure there aren't any visible cloggs or anything. With the AFPR in your hands, shine a flashlght inside and make sure nothing is stuck in there (I'm thinking maybe a little bit or teflon tape?) You don't HAVE to teflon tape AN fittings, and alot of people don't recommend it *FYI*. If you try this, reinstall the AFPR without the tape and give it a try. If you have any leaks reinstall the tape and let us know which way worked for you best.

Make sure it isn't something stupid like your return line pinched anywhere. You have to think about it logically.. to rule out the solution of replacing the AFPR you have to think: what could be keeping your pressure high? A pinch. A clog.. there's something restricting it there.

Let us know how it works out.

 

[pnishr]

Yeah, I checked for a pinch this last weekend. Thought maybe I put a kink in the line when I was taking the A/C compressor out, but that wasn't it. I only used the teflon b/c I had read on one of these threads to do so. But, even in doing so, I only wrapped it towards the back end of the threads, so as not to have any excess hanging off the ends, but still to be threaded in to seal the fitting... I'm hoping its something simple like the 2nd post said that maybe the barb is screwed in too tight.

 

[TSIfreek]

I guess I'll have to take a look at that this weekend. Might have to delay my dash removal...

I may actually have a vacuum leak at the TB. I keep on having to replace my vacuum caps because they keep on getting hot/drying/cracking. I should have tried replacing those first for the idle issue. Am I the only person that that happens to, or does everybody have to replace their vacuum caps on the TB every 2 months...??

I use caps from ace hardware mine are red. They are a diffrent kind of rubber and dont dry out . I have never had a problem with them.

 

[oldman]

1. Your profile just says AFPR, which is it?

2. A clogged/pinched tank pressure relief hose that runs from the tank to the canister can also reduce fuel return capacity.

 

[pnishr]

The FPR I'm using is the one below, except I got it somewhere else (don't remember where, but... that's the one)

http://www.dsmparts.com/customer/product.php?productid=403&cat=164&page=1

I no longer have the Evap Canister, but that line is not plugged (at least not capped). I used the original one-way pressure relief valve that did feed into the canister. That way my engine bay doesn't smell like gas ALL the time.

And thanks TSIfreek, I'll try some from there.

 

[daren_p]

I have heard of people having issues with that FPR before, though I can't recall the issue exactly. You shouldn't be using teflon tape on the AN fittings, they were designed to be used with tape. Also even if it was a regular NPT thread teflon tape isn't preferred as small pieces can come off & plu small orfices. Is you FP gauge liquid filled? If so have you pulled the plug on the top to vent case pressure? Even if the gauge isn't liquid filled, still pull the plug just to be sure. Have you verified the gauge is reading correctly?

 

[pnishr]

well, I still haven't had a chance to check everything yet (this weekend) but I think it may just be the guage. I went out and looked at it and it said 14psi, and it hasn't been driven in 2 days. Then I drove it tonight and got on it a bit (the first time since trying to adjust it down) and got some "lean" readings on the PLX and had some issues at boost in second. felt fuel-cutty. I'm gonna check it out. If it's just the guage, I'll have to just increase the fuel pressure to the 43.5+ whatever I determine the guage is off by (I think 14psi) at least 'till I get a new guage. I'll let you know what I find.

 

[pnishr]

Well, it was just the gauge. I've got a beer for 'ya daren_p next time you're in Texas. I installed my new 750s, and reset the FP to 43.5 PLUS the 13psi the gauge was off (with the IMvac line off and plugged). Set my DSMLink global to -40% and DT to 315microsec. My idle is now between 820 and 860. I'll have to I'm gonna replace my Vac caps anyway cause they're getting nasty. Thanks all for the input on possible causes.

I don't know how/why my gauge would have gone like that... Bad vibration maybe..? (I do have full prothane from the engine to the ground.) It's not a total cheapo gauge, it's a B&M - not liquid filled (I know, that I did cheap out on)

Thanks again for the positive input and overall friendliness.

Take care all

 

[Auto RS T]

Well, it was just the gauge. I've got a beer for 'ya daren_p next time you're in Texas. I installed my new 750s, and reset the FP to 43.5 PLUS the 13psi the gauge was off (with the IMvac line off and plugged). Set my DSMLink global to -40% and DT to 315microsec. My idle is now between 820 and 860. I'll have to I'm gonna replace my Vac caps anyway cause they're getting nasty. Thanks all for the input on possible causes.

I don't know how/why my gauge would have gone like that... Bad vibration maybe..? (I do have full prothane from the engine to the ground.) It's not a total cheapo gauge, it's a B&M - not liquid filled (I know, that I did cheap out on)

Thanks again for the positive input and overall friendliness.

Take care all

I've been told by a reputable source that the B&M gauge is junk...however I have been running 2 of them for a little over a year, no problems.

 

[daren_p]

^^^ Its not just the B&M gauges that are crap, basically all the gauges they sell as automotive are cheep crap. They just get a huge mark up because they are for "automotive". Those gauges that they sell for $20-30, we sell the same POS gauge, but not "brand named" for like $5. The gauge that Im running on my FPR was $35 our cost so you could imagine how much they would charge you for this gauge if it was brand named for automotive & I still tested a couple gauges before I got one that read dead on from 35-50 psi. I just bought a new Autometer Ultra Lite boost gauge because my old one that was used for 2 summers was sticking in the VAC. I thought the boost readings were still fine but when I swapped it out I tested it, I found it read 4 psi out. It was within 1 psi when new (I also found out the car runs good at 23 psi on pump ) .

 

[pnishr]

Alright daren_p where can I get one of those gauges that works...

I was driving around last night. Decided to launch/do a quick 0-60 test. do it, then coast back to 40. I start smelling gas. BAD. So I drive home (which was thankfully VERY close) open the hood and...

GAS SQUIRTING OUT OF THE FACE OF THE GAUGE! So I shut it off really quick. Holy crap. Has that happened to anybody? suggestions. I guess I could just plug that port and take the gauge, since the FP is set already, and it's inaccurate...

 

[andymoraitis]

Import Evolution has the Marshall liquid filled gauges (you really need the gel in there to deal with vibration - especially with Prothanes) for dirt cheap. You can find them here:

http://www.importevolution.com

Glad it was something stupid,

Andy

 

[pnishr]

Thanks. I'll plug it for now and order one of the Marshalls. Yeah, I'm glad it's an easy fix too. I think maybe the Launch+ No lift to shift was finally enough to put the dying gauge over the edge. Oh well.

Thanks again all. If it's not one thing it's another, right?