FMU trouble.

[jessica2112]

Well I thought I had my FMU under control. I ran to about 3-4 pounds of boost today, and my FMU either came on and is sick, or it's not coming on at all. I had 46 lbs F/P. I still show rich on the A/F gauge. Is my computer retarding the timing alot? I have another FMU to swap out. SHould I? All the lines are correct. I'm baffled.

[1DangerousV6]

if its a norrow band A/F gauge i wouldnt go by what it says AT ALL..they're pretty useless..i have one..but it just sits there and looks pretty..if it were me..id try disconnecting the FMU completely..the stock injectors can handle 6 psi just fine..put 93 octane in there and set your boost timing retard to 0*

[Mighty Thor]

I'm going to go and take a shot in the dark and say it's the vacuum line of the FMU. Is the Boost line and BOV line connected to it as well?

If so, it can cause it to flutter when you nail it but ok in normal driving. Check the connection and make sure it is OK. I don't see your car so I'm just going to say is that.

[grayman]

get the fmu working. better safe than sorry.

fmu lines should not be kinked.

with engine relatively cold:
open gas cap, bleed fuel rail shcreader valve or at least the evap port. (little green cap on drivers side)
Disconect the FMU end that has the strange plastice thing stuck in it. (i can see it in those pics you sent viper) Rettach the FMU lines. close the gas cap. Turn the car to RUN...get out and look at fuel lines for leaks. If no leaks then start the car.
Double check your VAC lines as MT suggested.

This stuff (fmu) is really straight forward. The FMU should kick in with just 1/2 pound of boost...everytime. It does sound more like a failure in the VAC line.

Have you tested the one way check valve by removing it? They do break...they are only a cheap little plastic part.

[ June 09, 2005, 02:47 AM: Message edited by: grayman ]

[jessica2112]

The bov and the vac/boost gauge and the fmu are all run off the same tap. As far as I know, that is the only one I can use. The strange plastic thing is a quick disconnect, I found out. I will check the lines today at lunch. I have the old fmu in the car, I may hook it back in and see what happens. Check the one way valve then too. I need to tighten the belt anyway. It is running very bad off the line when it is cold. Stalling a little and then it goes. I don't know if that is connected to any other problems. I used the schrader valve for the F/P sender. Also, I have no timing retard, did not come with kit.

Also, if any one has suggestions for my header install coming up, please chime in OK?

[ June 09, 2005, 11:21 AM: Message edited by: jessica2112 ]

[Mighty Thor]

Jessica, if there's still no improvement. Take it to a performance novelty shop and have them deal with it.

I'm sure you have a kink somewhere. Keep us posted.

[phoenix64]

Originally posted by jessica2112:
The bov and the vac/boost gauge and the fmu are all run off the same tap. As far as I know, that is the only one I can use. The strange plastic thing is a quick disconnect, I found out. I will check the lines today at lunch. I have the old fmu in the car, I may hook it back in and see what happens. Check the one way valve then too. I need to tighten the belt anyway. It is running very bad off the line when it is cold. Stalling a little and then it goes. I don't know if that is connected to any other problems. I used the schrader valve for the F/P sender. Also, I have no timing retard, did not come with kit.

Also, if any one has suggestions for my header install coming up, please chime in OK?

You should really autotap your car or check it with HPtuners.

I'd lay money the reason the car stalls when cold is your MAF readings are screwed up, so when the car is in open loop it runs rich.

It is also retardng your timing. Which is where your getting the bad part throttle power.

Like I said I had the exact same problem.

[jessica2112]

Well, I put the old FMU in and it brought the F/P to 55 tops under 5 lbs boost. Didn't get there till I was almost ready to shut down. Vac line is OK, so is 1 way. Finding alot of belt residue on the alt, and the top bolt to the SC. (With the real long sleeve.) It's OK underneath where I filed for the wrap, the tensioner pully has a spacer and all the other pullies look lined up and good. Can't see where it's getting rubbed up agaist anything. Still stumbling at idle to about 1,500. Pheonix, I have no tuner or access to one. Do I really have to chuck up 4-500 bucks for a dyno? If I did, what can they do there? Can they tune it like the HP would? Or just tell me what needs to be done?

[grayman]

it sorta sounds like you are not getting enough air to the engine at low rpms. Does the car haul *** when you are hitting 5 psi? what happens when you are going about 20 miles per hour in "DRIVE" and you punch it? When I do that in my car it is hard to see over the hood. does your car ROCKET when you do that?

[grayman]

Have you figured out the misfire yet? I forget if you are using ngk tr6 plugs or not.

[phoenix64]

I would suggest an MAFT or mini AFC or HPtuners.

You could post on some local boards or in the lounge here, and see if anyone could loan you a scanner, or just an MAFT.

There is no need for a dyno, Its a very simple procedure.

[jessica2112]

I am using tr6 plugs. It boggs off the line, the last bit of first gear is ok, (auto)nothing like raising the front end. Second gear I loose all my torque, so it seems about as fast as it used to be. Third is ok, but i'm pushing 80 so I shut down. I'm using a little strip of Dixie Highway, but there is always the possibility of cops... but my car never rockets.
I haven't replaced the coil pak for cylinder #1 yet. Not sure if that is the problem with the misfire. It seems the misfire is when it's cold at 2 grand or less. I thought of doing all three at once but that's expensive. It has 43,500 on odo. I would hate to put those in and have it run the same.

[ June 10, 2005, 02:15 PM: Message edited by: jessica2112 ]

[Mighty Thor]

Jessica, perhaps you do have a defective FMU and all. I think it would good idea now to meet up with one of the members here that has a SC. Wasn't there a guy with in Florida close to you?

Take a ride in his car and have him drive yours. Get a feel what a SC V6 feels like. Compare setups and all. I think that's the best thing to do before spending money on something else and finding out it might not be it.

That's just me.

[jessica2112]

OK, thanks! I appriciate all the help [img]smile.gif[/img]

[grayman]

concerning coil packs. Deffinatly do as John suggested and just swap them around. then go up and get is scanned at autozone for free. see if the missfire has moved to the other cylinder. (followed the bad coil pack.)

Regardless of the FMU working or not....your car did not take to the supercharger at all. (you know that...not rubbing it in) Have you tried contacting Bill? He had either a 1999 or a 2000. I never heard him complaining that his car suffered from these symptoms when he was running the SC. He might be able to give you some heads up info.

I don't think you are hitting 'reduced power mode.' You would know that for SURE.

Two questions: Are you running Premium Fuel? (92 octane or higher...never mixing it with anything else? Never getting cheap Am/Pm style gas?

And: Who put the spark plugs in? did you see them gapped to .035?