I bought a used FMU, and I dont know crap about FMUs. So I had my buddy install it for me and when I started the car there is this hole where air sucks in thats on the left side of the adjuster. Is this supposed to be there? The hole doesnt have any threads so IDK. BTW Im buying a Vortech 12:1 FMU eventuall, so no worries about me keep this crap. The car will just have to sit for a while. I just want to know if that hole serves a purpose?

Crappy cell phone pic cause my digital camera took a shit.



Thanks
Luis.

That hole should only be sucking in air if the diaphragm in the unit is ruptured. if such is the case, it's broken and won't do what you need.

Whoa thats good to know, THANKS. Im going to take it apart and see whats up. Since Im getting rid of it maybe I can learn some more about it.

Luis.

Hey DarkOne, I took apart the POS FMU, and theirs a little piece of tin in there that had a pin sized hole in it. SO I replaced it with tin from a coke can to see if that was the problem, and It didnt help any. That little hole beside the FMU was still sucking inward. I tried to fix it but Im really stumped, what else do you think it could be? Im getting a Vortech, but I still want to know why I got sold a POS.

Luis

Originally posted by hnda8r
Hey DarkOne, I took apart the POS FMU, and theirs a little piece of tin in there that had a pin sized hole in it. SO I replaced it with tin from a coke can to see if that was the problem, and It didnt help any. That little hole beside the FMU was still sucking inward. I tried to fix it but Im really stumped, what else do you think it could be? Im getting a Vortech, but I still want to know why I got sold a POS. Luis

Can you show me pictures?

Yes I can provide you pics, but Im at work right now. I get them to you via PM, tonight.

Luis

Originally posted by hnda8r
Yes I can provide you pics, but Im at work right now. I get them to you via PM, tonight. Luis

Or just post them up here so you can get more experienced responses.

Well I remembered that I did take one with my phone last night but I dont know if this is going to help at all. If not what exactly do you need me to take a pic of??



**EDIT** I just wanted to add that when I took this apart, everything including the diaphrams were dry.

LMK thanks
Luis.

If you take off that bottom portion or whatever, doesn't that mean it's not calibrated anymore?

What do you mean? And how would you go about recalibrating it?
The reason Im persuing with this thread is soo others could benifit and learn something, like I am.

Luis

Originally posted by totaleclipse_05
If you take off that bottom portion or whatever, doesn't that mean it's not calibrated anymore?

Typically the calibration is a function of the disc and spring rate.

I'm going to assume the black disk with the square of metal on it is the rubber diaphram, correct? Make sure there are *no* tears in the rubber.

Aight man, Ill def check that tonight. Is there anything else that you think might be the problem? Do you have any specific part that you want a pic of?

Luis

Alright can someone please tell me the way an FMU works. Is there fuel supposed to go through the FMU. Is it supposed to be a return? I have pics of how the guy installed the FMU and my Walbro FP. Im host them in the morning. Lets just say Im really confused and really pissed.

I finally got the FMU to work I think. The problem was that tin wasnt allowing the diaphram to flex. I started the car and it ran really good, but when Im driving and come to a stop and push the clutch the car dies. Is fires right up, but I drive again and it happens every time I push the clutch in. WTF??

Can someone just please tell me step by step how the FMU is supposed to work? ANd how the lines are run, cause im pretty sure the person that installed my stuff did it wrong.

Thanks
Luis.

Here are some pics of the Fuel pump, is this right? Is there supposed to be filter attached to it? It looks ghetto rigged to me. Also about the FMU could some one tell me exactly how its supposed to work, and also what lines go to it. Right now the left line of the FMU runs all the way to the fuel pump for return(OUT?), and the right line goes to the fuel rail (IN?). Is this right? lmk asap

Thanks
Luis.

Both my stock and walbro fuel pumps had filters on them, if I remember correctly. As for the FMU, 1 line should be connect to the fuel rail and the other connects to the fuel pump or stock return line if you're a 95'. But since I've never seen your type of FMU before, I couldn't tell u which is which.

Well I kinda figured that. I bought the pump off the guy who installed my turbo kit. He had a turbo neon and he put in the fuel pump from that. I tried putting on the filter from the stock pump, but it looks like the part where the filter conects got grinded off. Talk about installing things half assed. So now I have to purchase a Walbro 255 on top of everything else.

As for the FMU, he does have the "IN" side hooked up to the fuel rail (where it screws on the left side), and the "OUT" side hooked up to the return which he ran a tube to the fuel pump (its not hooked up to the stock return line.) So I guess he did something right. lol

So how would you explain the stalling when I push in the clutch? Could it be not enough power to the pump? Or the gas inside the tank is swishing around and the pump isnt picking it up? This is what happened: I drove around the block at about 30mph and when I come to a light I push the clutch to down shift and the car shuts off.

Luis

Originally posted by hnda8r
This is what happened: I drove around the block at about 30mph and when I come to a light I push the clutch to down shift and the car shuts off. Luis

Could be running rich. What's your idle fuel pressure like? Could also be a vacuum leak, or a malfunctioning EGR, IAC, many things. They'll all affect idle quality.

Ok I do have the EGR tube disconnected cause I was using that for a vaccume source for the boost gauge. Im going to T in it so that I can run both. I'll keep a look out for vaccume leaks. As for the IAC not sure how to check that. Im going to work on it tonight again and see what I can do. Ill keep yall updated

Luis

Alright I T'd off the EGR, so no I have the EGR hooked back up and also the boost line. I spent a good hour trying to look for vaccume leaks. I couldnt find any. I dont know how to check the IAC so....

The only thing I can think of is that there may not be enough power to the fuel pump?? I mean what else could it be?? I filled the tank to the top and it still does it. I need to get another check list of things to check, if someone could provide me one that would be fantastic.

Anyone with a "missing link" is there supposed to be a hole in the one side of it? I tryed covering it with my finger, but that made the car shut off.

Luis.

What is your idle fuel pressure?

I ordered a FP gauge it hasnt come in yet so I dont know the answer to that question. Sorry. I hope it comes in soon tho. When it does come in and I install it, would I be able to adjust the Fuel pressure with the FMU?

Luis

Originally posted by hnda8r
would I be able to adjust the Fuel pressure with the FMU? Luis

Nope. You'll need a SFMU for that. You can only change the rising rate when in boost with the disc inside the FMU (12:1, 10:1 etc... )But you shouldn't have to adjust your idle fuel pressure if you still have stock injectors. When not in boost, your car should run exactly as it did before. Maybe you should try to bypass your FMU then drive the car *BUT DO NOT BOOST* and see if it still shuts off...if it doesn't, then it's your FMU, and if it shuts off , it's mostly something else.

How would you "bypass" the FMU? I want to try that.

Luis

first remove and plug up the vacuum line running to the FMU.
Then disconnect the fuel lines. I'm not sure if you can just connect the 2 line together(someone else can chime in), but if you're a 95' then all you have to do is connent the return line on the fire wall to the return end of the fuel rail.

Can someone verify as to, this is what needs to be done to bypass the FMU?

Luis.

Originally posted by Rondan97
first remove and plug up the vacuum line running to the FMU. Then disconnect the fuel lines. I'm not sure if you can just connect the 2 line together(someone else can chime in), but if you're a 95' then all you have to do is connent the return line on the fire wall to the return end of the fuel rail.

Can someone tell me if this is true? I really want to know if my fuel pump, or FMU is messed up or its something else.

thanks
Luis.

Im still waiting for someone to chime in.

Luis.

as long as you still have the stock regulator in place yes that'll work. I have a '95, where the stock fpr was on the fuel rail, and if you do like he says it'll just make the return line off the rail a little longer, and your system will run like stock.

Sweet, thanks for chiming in. lol. Im going to get started on this right away. Ill keep yall updated..

Luis.

Well I installed the fuel pressure gauge and it says 52 when Im @ idle. Is this right?? Also I installed the FCD from Eclipse982nrRST, and now my car seems to be idling very well and Im not getting fuel cut at all. I can finally start driving my car everyday. Thanks. The only thing I really want to get is a SFMU.

If I run into any more trouble, I will def be making another thread. lol

Luis. (thumbs up)

Originally posted by hnda8r
Well I installed the fuel pressure gauge and it says 52 when Im @ idle. Is this right?? Also I installed the FCD from Eclipse982nrRST, and now my car seems to be idling very well and Im not getting fuel cut at all. I can finally start driving my car everyday. Thanks. The only thing I really want to get is a SFMU. If I run into any more trouble, I will def be making another thread. lol Luis. (thumbs up)

glad to hear another success story with one of my FCD's!