loss of fuel pressure and Q about a N/T FPR

[DSMatMSU]

recently my car has been running very lean under heavy throttle and WOT... Im thinking i might have a bad FPR, since ive tried just about everything else, including two sets of injectors., new o2 sensor (it cycles fine at low throttle, per the logger), and a new fuel filter

I found out I had an automatic motor in my manual, thus having smaller injectors... i picked up some used 450s, and i still have the same problem...

all the junkyards around here have 1.8L or 2.0 n/t.... i read a few threads about raising the FPR with the N/T regulator.... so im considering giving one of these FPR a try... i have a EVO 3 16g turbo... i dont have an AFC or injectors YET (note only running 13 psi at the moment)
but i do have the walbro 190 (re-wired)

i have a little fuel pressure gauge i was going to install.... can i just put it in-line btw the fuel filter and the rail?? with a NTP T-fitting... basicly just for diagnosis purposes at the time...

which one should i pick up the 1.8 or the 2.0???
is the fuel rail for an automatic different??
is the FPR for an automatic different??
or could something else be causing a loss of fuel pressure?? im going to pull the pump to see whats going on down there as well...

 

[BoostedTalonTS]

Having gone through this myself, this was the results of my search:
2.0L DOHC:
1G MT Turbo FPR - 37.5psi
1G AT Turbo FPR - 43.5psi
1.5L SOHC:
NA FPR - 48.5psi

... I'm still in the process of getting a new EPROM that will handle my current set of injectors, with the raised BFP of the 1.5L NA FPR, but for now, I rely on my SAFC. -You should REALLY start thinking about getting one, if you are planning to fully reap the benefits of your E16G... Heck, I'm on 560cc injectors, and I still haven't reached the full potential of that turbo yet.

As for the FR's, the 2.0L DOHC 4g63 FR are all the same.

When you installed the 190, did you have any issues with that O-Ring in the factory fuel line's reciever on the OE FP? -If that's leaking fuel back into the tank, that would explain the loss of FP topside.

 

[DSMatMSU]

Oh dont worry, the AFC and injectors is in the works.... but i KNOW this car should run better than what it is right now.... im just trying to fix it before i install more stuff.... OH, and that little money issue...

on that o-ring, as far as i know i didnt have any problems when i installed the pump.... the only problem i did have was that hard line broke, but it still had about 1" - 2" sticking out of it, so i was able to fix that up pretty easily.... it worked for the first couple months after install.... then i tore the whole motor down for a rebuild... and ive just now got around to having it running again.... Ill definately be pulling the pump to see what going on in there....

so having that a/t FPR on the rail with the 450s shouldnt cause too much of a problem??

 

[BoostedTalonTS]

"so having that a/t FPR on the rail with the 450s shouldnt cause too much of a problem??"


If anything, you will be running more fuel, as those 450s are rated at 450cc @ 43.5psi. -In the 1G MT Turbo cars, the same set will run only 417cc @ 37.5psi.

-If you are getting a lot of knock, check your O2 sensor's output via a logger for a general idea of how lean or rich it is running at WOT... My guess is that you are still running too lean with those 450s, even at 13psi.

 

[DSMatMSU]

oh it completely ZERO's out!!! it will cycle normally under idle and light throttle, thats what led me to this whole fuel pressure problem... under light throttle it usually sits at .75.... im NOT driving it hard either.... i dont even try to go to WOT, because before i get there the volts start dropping... so its redundent to even try to push it that far... dont want to blow anything up....

 

[BoostedTalonTS]

Hmm... Just a thought, how did you wire that 190lph pump? are you still using the OE ground wire & location? -I found mine had a lot of built up corrostion on it, and when metered had a bit of resistance (don't remember how much) between the FP's ground wire and the battery NEG post. -Since I was relocating the battery at that time anyways, that action presented me with an alternative of running a direct ground to the battery, as it's about 2' away. -That won't help you any, but you might want to verify your ground wire's resistance to your battery post prior to pulling the pump.

Are you using MMCD (or any other logging software) that offers built-in diagnostics, specifically the activation of the FP while the engine's not running? -If the problem is in fact electrical, then this feature could aid in tracking it down.

 

[DSMatMSU]

i did take the time the other day to go over all my wiring for it again.... i cleaned up the ground wire in the hatch, it had gotten a little corroded down there... but now everything should have a good connection....
I do have MMCD, but something appears to act funny about it... when you go in diagnosis mode, for some reason there is no option to start logging like the picture has on their site... but I can just read and it will pick up CELs... the only other test that works is the injector test, where you can turn each one off.... none of the others do anything....

 

[BoostedTalonTS]

Huh? -That's odd... What version of MMCD are you using? -The latest that I've been able to find is 1.5d. -I would try reinstalling your current version just to be sure, but just so you know... The rest of the other diagnostic test buttons will ONLY work when the car IS NOT running, and the key is in the ON position (NOT Accessory). -Try that first.

 

[thegreatms]

MMCD might have trouble with his car because its a 90. I know on my 90 MMCD won't let me clear engine codes, and its a little weird with other diagnostic stuff.

 

[DSMatMSU]

ok, i got another FPR and installed my little fuel pressure gauge.... i have 43 psi at idle with the vac hose off.... anyway it pulls much smoother now.... up untill i hit about 5000 rpm, then it hits this brack wall and stops pulling.... i have a re-wired walbro 190....

i picked up some magnacor wires, they were on the car at the junkyard, so i figure what the hell... anyway, im going to try my old wires out again and see what happens....

it appears that my problem did lie in the FPR, but since i have this crazy low RPM phantom knock (that comes whenever it feels like it) i really cant tell if ive fully fixed it yet.....

 

[Mike000]

Try the new version of MMCd 1.6n

http://www.3si.org/forum/showthread.php?t=203226&page=1&pp=10

You might check for boost leaks

 

[BoostedTalonTS]

Try the new version of MMCd 1.6n

http://www.3si.org/forum/showthread.php?t=203226&page=1&pp=10

You might check for boost leaks

Mike,
Any chance that you could post a functional URL for those of us that are not members of the 3Si group? -I tried your link, and is says that you must be a member of 3Si in order to download it.

 

[Mike000]

The file is hosted on the site. You have to sign up, it shouldnt take long.

 

[DSMatMSU]

tonight I installed an EGT gauge, put it on the #1 runner about 6" out... anyway... go out and drive, and of course my car is knocking horribly bad right now, at the point where every time you give it gas it falls on its ass.... the EGTs were really high almost 1600 at very light throttle, low RPM acceleration...

so i go home and disconnect the battery. hook up the timing stuff and ground out that wire.... hook everything up and set the timing at about 4~5*... I also decided to try and get some better grounding, i ran a piece of wire from the battery to the throttlebody, and from the throttle body to the bolt on the CAS.... and grounded the head to the body on the other side...

when i was setting the timing, sometimes the light would just go blank, like it was missing a spark or something.... and the timing was jumping all over the place on the pulley(car was allready warm).... so i finally get it to calm down and set good.... checking it multiple times, I even let it sit for about 15 min. and tested it again... still set at about 4~5*

I go out for a ride and DAMN... it pulls hard as hell... running much better with very little knock... the EGTs are MUCH lower at just about 1500 under full throttle... something like 900~1000 at idle...
now the bad part, i think these magncors i picked up at the junkyard could be causing my problem.... it will be pulling GREAT untill about 5000 rpms, when it misses horrbily bad, backfires a little and all that good stuff.... so ive ordered some NGKs to see how they work out... sounds kinda like an igntion issue to me??? my plugs are brand new NGKs and are gapped...

 

[DSMatMSU]

well i picked up some NGK plug wires... and I still have the same issue.... pulls hard as hell till about 5000 where it fuel cuts.... at least ive finally fixed the majority of my problems that i incountered during the rebuild, so now its definately time for an AFC (only reason i waited was to make sure everything was running properly, oh and money )

im running 15 psi with an evo3 16g, i have a dejon tool short intake pipe, dejon tool UICP, greddy BOV, full 3" exhaust (no cat), with my only fuel mod being a re-wired walbro 190. and then ive got the 2g pistons...

 

[chris90gsx]

Have the caps in the ecu been replaced? My friend bought a talon a couple years ago and had a very similar problem to what you have (although that car was completely stock). Once the car hit 5000rpm it did a nose dive and lost all power. The ecu had gone bad and the caps leaked onto the board causing all sorts of weird problems. Just another possibility for you to check out, plus since you have a 90 it would be a good idea to get those replaced anyways. A set of new capacitors costs around $5 and the job is simple enough for the novice to do even if you've never messed with a computer board before. Desolder two connections for each of the 3 caps, pull it out, insert the new one and solder it in place.

While checking out the ecu, this will let you find out if you have an eprom ecu or not. If you do, I would look into one of keydivers chips (www.dsmchips.com) so that your ecu is programmed for the whatever you decide to upgrade (i.e fuel pump, injectors, MAS, etc.).

On another note, did you check the gap on the spark plugs? You might want to close the gap. I believe factory recommendation is like .030". I gap my plugs to .028"