Fuel/Maf/Or something Issue.

[GU40sx]

Hi guys, just bought a car recently equipped with an SR. I was driving it the other day, everything was fine, and then all of a sudden it started hitting what I think was a fuel cut. Every time I tried to get on it passed maybe 3,000 rpm? it would could out. The next day I took it out & the issue was more frequent, I had a look at my AFR and it was slowly dropping from around 13.5 - 10.0 eventually it was cutting out to the point where getting on the throttle didn't do anything and it died out on me. So I'm pretty sure this was a failed fuel pump issue but when I had the car towed home I checked the fuse (good) and checked if the pump was priming and it was. I was even able to start it! wtf. Is it possible for a fuel pump issue to be intermittent? I also read that a dirty maf could be a problem, and seeing that this guy had his maf tucked away behind the front bumper and me driving it in oregon (constant rain) it's a possibility. I've also read a coolant temp sensor could be the problem, but my gauge seemed to be working fine, temp was staying a little below halfway. I really need advice from someone that had a similar issue that can offer some really quick test solutions to figure out my problem. I just moved here and I have my car parked out in the open with no tools on me. I can borrow tools I need from my roommate but that doesn't change the fact that I have no place to work on it/check things for a long period of time before the people at my apartment complain. Thanks in advance to those that help.

[jedi03]

That's super rich...could be stuck injector...can pull the rail and prime the system (key on engine off) and check...

[cotbu]

Pull codes then do a boost leak test.

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[SoundEfx]

You mentioned afr, so I am assuming that you have a wideband and is boosted.
If that is the case, after you do what Jedi suggested, I would looking into getting it re-tuned the injectors are working good and not leaking.

[GU40sx]

Originally Posted by jedi03

That's super rich...could be stuck injector...can pull the rail and prime the system (key on engine off) and check...

Oh dang. First time reading afr's (never had a gauge on my old car) I was assuming the lower the reading the leaner it is
Thanks, i'll take off the rail and have a look.

[GU40sx]

Originally Posted by SoundEfx

You mentioned afr, so I am assuming that you have a wideband and is boosted.
If that is the case, after you do what Jedi suggested, I would looking into getting it re-tuned the injectors are working good and not leaking.

I'm pretty sure the tune isn't the issue since I drove it two hours with no problems. The issue popped out of nowhere so I'm really hoping it's something as simple as a bad injector. Thanks!

[jedi03]

Mine was leaning out like none other yesterday, I assume bad gas as I have driven on mine for a year...also saw I was grounding out my headlights luckily the fuse popped before my car set on fire...so got new fuel fixed the wire an Wil drive it later!

[zrothpi]

You mentioned afr, so I am assuming that you have a wideband and is boosted.

[jedi03]

Just replaced 02 and put 5 gal good gas with the supposed bad and is back to being great!

[GU40sx]

Originally Posted by zrothpi

You mentioned afr, so I am assuming that you have a wideband and is boosted.

Yes, it's boosted but the previous owner only had an ecu enthalpy tune. The reason why I don't think it has anything to do with the tune is because it was running just fine for a 2 hour drive. Something must have failed. I took off the fuel rail today and none of the injectors shot out fuel. So I think a leaking/stuck open injector is ruled out, fuel pressure gauge was also reading between 45-55 so I don't think the pump is bad. Car is running stupid rich, AFR is at 10 at idle So here's where I think the problem is, since it's the sketchiest part of the car



Yeah I know.. "Duct tape?! wtf dumbass that's your problem!" But just help me out here please. Above that tape section you can see a rubber cap that's obviously covering a hole. So I started my car and took off that cap and absolutely nothing changed, no Idle drop no nothing. Can I assume that my problem lies within that section?? Thanks in advance guys.

[Blk96t]

Most likely a boost leak. You can also check all the ground connections. Especially the ignition harness that grounds to the head on firewall side.
Enthalpy tune should be fine. His tunes are among the best in the business.
Check all connections.
Mine has also ran funny with a failing battery and or alternator.

[Kingtal0n]

I do not like how the intake pipe goes into the corner of the fender area, it makes me think that the filter is going to pick up water. If I had that car one of the things I would do is rationalize the plumbing. For example, get rid of those nasty 90* turns, place the filter in an appropriate spot or design some kind of box to isolate it from water. make it as short and smooth as possible. Make sure the insides are super clean before using. Use a real air filter, a DRY PAPER or similar. Do not use an OIL base filter, like K&N, or a FOAM type of filter. These are high performance filters that flow well at the cost of your engine and turbocharger (they do not filter as well as we would prefer)


You basically need a 150amp tig welder with a machine shop facility for cutting and cleaning plumbing to setup one of these cars.

heres a pic of the hotpipe I just made


Notice it has smooth bends, and the filter is a dry (Apexi). The OEM paper filters are fine also, if you have the time (I will some day) make a special box to contain a large paper filter (pick up a cheap paper filter for a big engine like a vette) and route it so that it can breath from outside the bay (cold air) while also having an elegant way to deal with any water that gets in there (a water trap / drain). Paper filters have a very good filtration capacity. They clog quickly, thus the filter I choose for my special project will be cheap and easy to replace.

[cotbu]

So when i said this

Originally Posted by cotbu

Pull codes then do a boost leak test.

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Your shit was looking like this?!


[emoji41] [emoji15] [emoji12] [emoji31] [emoji24] [emoji19]

[GU40sx]

Originally Posted by Kingtal0n

I do not like how the intake pipe goes into the corner of the fender area, it makes me think that the filter is going to pick up water. If I had that car one of the things I would do is rationalize the plumbing. For example, get rid of those nasty 90* turns, place the filter in an appropriate spot or design some kind of box to isolate it from water. make it as short and smooth as possible. Make sure the insides are super clean before using. Use a real air filter, a DRY PAPER or similar. Do not use an OIL base filter, like K&N, or a FOAM type of filter. These are high performance filters that flow well at the cost of your engine and turbocharger (they do not filter as well as we would prefer)


You basically need a 150amp tig welder with a machine shop facility for cutting and cleaning plumbing to setup one of these cars.

heres a pic of the hotpipe I just made


Notice it has smooth bends, and the filter is a dry (Apexi). The OEM paper filters are fine also, if you have the time (I will some day) make a special box to contain a large paper filter (pick up a cheap paper filter for a big engine like a vette) and route it so that it can breath from outside the bay (cold air) while also having an elegant way to deal with any water that gets in there (a water trap / drain). Paper filters have a very good filtration capacity. They clog quickly, thus the filter I choose for my special project will be cheap and easy to replace.

Nice, thanks for the solid input, I really like your setup! So clean.. Yeah I don't like where the filter and maf are at also. Gonna eliminate that second section, not even sure why the previous owner wanted to route his piping down there. The thing I'm worried about is that if I shorten the piping it might throw off the tune. Oh well, guess it's time to go to a wideband setup and re tune..

[QUOTE=cotbu;6005591]So when i said this

Your shit was looking like this?!

Yup, not my doing though, previous owners setup. Just trying to figure out the problem, but now I'm like 99% percent sure it's a boost leak or a dirty maf.