Leaking injector(s)?

[Talesin]

This has been driving me nuts for the last few months... currently has blue-cap 450cc injectors, though my mechanic suggested that they might have just had the caps swapped, if they had larger injectors put on.


Symptoms:
Car's been getting low gas mileage for a while now (17-20mpg), hard start when cold or sitting for more than a few seconds (7-12 seconds of cranking to turn over), unburnt gasoline stink (but no black smoke) in the exhaust at WOT (with a sweetish odor at idle... friend described it as 'like tea'), throttle delay, bogging at takeoff. Large dip in fuel psi from AFPR-tapped gauge when letting off throttle. Near-immediate loss of fuel pressure when car is turned off. Running just barely above the 'cool' line on the thermostat, never getting over a third of the way up, even on blazingly hot days.


Possible causes:
Running for 1+ year (prior owner) on an upgraded Walbro 255 HP pump with no AFPR. Measured 35psi with the stock FPR.


Attempted fixes:
Aeromotive AFPR purchased and installed, with an AutoGage pressure gauge. Adjusted to 28psi on the return line gauge with vac on.



I plan to head to my mechanic on Monday and have him test the fuel pressure at the fuel filter... he'd set the Aeromotive to 38psi with vac off, from that metering point. Car was running terribly badly... stuttering, bogging, trying to die when the slightest throttle was added. Raised fuel pressure until it was less pronounced. After installing the AFPR-tapped gauge, it read 20psi with vac on at idle. Raised it to 28psi, seems to be running... moderately. Low-end torque is kinda there, still hesitates on takeoff unless revved to 3Krpm and the clutch is slipped. But much better idle, with occasional 'hiccoughs'.
Originally I'd thought the hard-start problem was a torn o-ring on the fuel pump fitting... would a leaking injector cause the same problem? Could the injector apertures have been 'stretched' by running at +30% pressure for god knows how long, leading to streaming, instead of misting the fuel (as well as eating more of it) at stock PSI? I won't know how much of a PSI drop there is between the filter and the return line for a couple of days.. is there something stupidly obvious that I might be missing? I already ran a bottle of fuel injector cleaner through, in hopes that they might just be clogged. No dice.

Unfortunately I don't have access to a wideband O2, but if it's bad enough for bystanders on the sidewalk to smell gas...

 

[gurrmanator]

where do I start....you have a major vac or air leak,the ecu is upside down with the air/ fuel ratio.Fuel injection requires alot of fuel pressure(40psi).use a liquid filled gauage,the other ones are junk.low f/p will cause the injector to stream,your tps could be bad,check all your hoses,check your turbo system,mass air flow sensor could be going.to sum it up,you are sucking air somewhere.

 

[Talesin]

Uh, dude... the stock fuel pressure on a 1G Eclipse is 27-28psi with the vac on, 37-38 with the vac off. It was running at 36psi with the vac on, 46psi with the vac off for I'm guessing a year and a half, at least. And I *highly* doubt that a going-bad MAS would let air into the fuel line. When I pulled open one of the taps to put the gauge on, it just had non-pressurized air inside the AFPR.


DSM Wisemen... does it seem like I've got a decent idea what might be wrong, or am I off in left field?

 

[Talesin]

Was reading through a Haynes earlier, and it recommended checking the injectors with a stethoscope to listen for the click of actuation... thankfully I'd picked an inductive probe one up last month, to listen to silly stuff like the sound of the air in the UICP, and to hear lifter tick better (without making it worse).

CAS to timing gear cover being 1-4, 3 and 4 were clicking loud and crisp. 2 is a little muddled, but around 80-90% the loudness of the other two. 1 is about 50% as loud as 2.
So I'm figuring at this point that 1 was mostly hosed as it got the full brunt of the raised PSI, and 2 was slightly damaged, but the pressure dropped enough to keep 3 and 4 okay.

I've gone through and checked the fuel feed and AFPR lines, as well as fuel filter and AFPR for leaks, and have come up with nothing. Meaning it could be a leak in either the feed or return lines under the car, at the tank (improperly seated o-ring on the new fuel pump... but the pressure drops INCREDIBLY fast, and there's no gasoline-stink in there), or at the filler neck.


Anyone else have thoughts? I'd rather not shell out $300 for new 450cc injectors at RRE, but that may be the only way to go.. people getting rid of used ones could have damaged them as well. Never know. :b Going to get my mechanic's opinion once he opens shop, but he usually deals with Porsche, rather than DSM.

 

[Gigaah]

I have most of the same symptoms, cuddy milage, hard cold start(wich starts ok if I don't let it sit longer than a few minutes). Not sure about the exhaust smell.

I've personally suspected a leaky injector but I've not replaced them yet. I will probably swap them with the one in my other dsm and see if it help. I'll post results when I do it.

 

[clapbak]

u can get evo pink top injectors for 100 USD.. Shipped.. like i did..

i got a fuel problem too.. Runs very rough.. Thought putting on my AFPR would help / along with new plugs / wires.. didnt do much.. Im gonna get a new fuel filter / new injectors.. and do a boost leak test.. See if that helps.. If not.. rebuild time!

 

[Talesin]

Well, my mechanic confirmed my suspicions/diagnosis. One injector completely DOA, another in the midst of dying, and the last two starting to lean that way. Ran down to RRE and picked up a new set of blue-tops for $99 plus core. Gonna swap 'em out tomorrow morning (too dark now) and see how the car reacts.

Mental note, hook up a fuel press gauge to the filter and set it on THAT *before* replacing the injectors... I don't want to damage the new ones. :b

Also.. aren't pink tops 240cc, and only for low-end E/T/L? Evos have red and yellow tops, 510cc and 560cc respectively. Stock 4g63t (manual) come with 450cc blue-cap.
Sounds like your new injectors are probably the cause of your fuel problem.

http://www.robietherobot.com/storm/fuelinjectorguide.htm <- Reference Table

 

[steve]

Also.. aren't pink tops 240cc, and only for low-end E/T/L? Evos have red and yellow tops, 510cc and 560cc respectively.

Yellows are the 510cc. The EVO VIII 560cc injectors look like this.

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Steve

 

[Talesin]

Ahhh. Thanks. Well, picked up a cleaned and balanced set of stock 450s from RRE (for $99... I misread the listing) and tossed them on... throttle hesitation was reduced a LOT. Also, the AFPR is holding the stock fuel pressure quite nicely now.. while the car is running. As soon as it shuts off, all my pressure is gone. IIRC, aren't they supposed to hold 21psi for a few hours at least (if not indefinitely)?

I'll have to take the AFPR off and all the fittings, get that piece of teflon tape OUT from the aperture, and reattach everything. If it still doesn't hold, I'll be checking the fuel pump fitting o-ring, and then the feed line attachment points. Past that... no idea.

As for boost leak, I'm pretty sure I have a minor one at the TB elbow, that I can hear at idle and when revving. I'm also only pulling 15 in/Hg at idle most of the time, sometimes dropping to 13, other times happily going up to 22. Just gotta pull the elbow off, lay a bead of RTV and smooth it properly. That or get the right gasket. And build a boost leak tester, when I feel like getting into a suicidal mood tracking down every little hiss and squeak.


Mental note, new plugs. Or at least check the old ones for carbon fouling... still getting an uneven (occasional 'coughing') idle, and sometimes an abrupt momentary power drop in the middle of a pull.

 

[steve]

My AFPR looses fuel pressure in about 10 mins after you shut the pump down. From what I've read the aeromotive and SX regulators will bleed down quickly as well. As long as the fuel system comes up to pressure right away and regulates correctly I'd say the regulator is fine.
If it doesn't come up to pressure as soon as the pump starts I'd check the pump o-ring.

Steve

 

[Talesin]

Mine loses all pressure within seconds... Aeromotive. I'm pretty sure it's that bit of loose teflon tape though, letting the fuel leak into the return line. It was doing that before the AFPR though, so yeah... gotta check the o-ring anyway. And my return/feed line fittings, as I'm still getting the stink of fuel near the back end, with the car running and the liftback closed. Takes about 8 seconds to get it to start once it's been sitting for a while, but only about 3-5 if it's been sitting for about five minutes. 2-3 seconds if I've just turned it off.

On a side note, don't try to lean the car out with the AFPR. :b Results in a bad distribution pattern that results in less power. Looks like the MAF-T setup is becoming more of a necessity, as it'll still serve some purpose after going up to DSMLink, as opposed to a VPC.. which I'd have to try to sell off to someone else. :b