Car won't idle after supercharger install!
 

I installed a Novi 1000 over the winter and now I'm having some problems with the idle. The car will idle for a few seconds (~20) and then the idle gets really rough and the car stalls out. The same thing happens while driving...it'll stall when coming to a stop. I've checked the vacuum system (pulls 19-20 at idle) and there are no leaks, changed the O2 sensors, new plugs, wires, etc. My plugs are Autolite 23's gapped at .035. Any suggestions on what is causing this problem? I've tried all kinds of fuel pressure settings, from 35 psi to 45 psi and it doens't change the idle/driving characteristics. What else could be causing this erratic idle?

Here's something weird...

I was messing around tonight and took off the vacuum line for the bypass. It was hooked directly to the tree on the firewall and when I removed it, I didn't cap the end on the firewall. I started the car and it idled decent. It was surging but not stalling out. I went around to the vacuum tree and plugged the end with my finger. When I did this, the car almost instantly stalled. When I removed my finger, the idle rose and began to surge again.

When my finger wasn't plugging the vacuum, my gauge showed 16-17. When it was plugged the gauge showed 19-20. Wouldn't the car run BETTER when the vacuum wasn't leaking?

Also, there was alot of water/condensation coming out of the tailpipes when I revved it. Could this cause a problem? The condensation is from the car being stored for the last 7 months.

ok while testing vacum was the charges belt disconected ?

Im not ure about your set up but with my turbo's it changes all the readings.

do a search on vacum problems or just look through PKWRDS post he explained it better than i could .

was the car running good after the install ?

your talking about the blow off valve right ? why would you have it conected to the vacum tree and not the manifold ?

also if the cars an auto it could be something weird like the converter staying locked and causing the car to stall.

To answer your questions:

The chargers belt wasn't disconnected because the Novi 1k isn't a seperate drive blower (well, not mine). It runs off the same belt as the other accessories.

The car never ran good after the install. It's always stalled out after a few minutes of idling or when coming to a stop while driving.

My bypass valve isn't a blow off valve. It's connected to the vacuum tree because there was an empty slot that I could use. It doesn't matter where the bypass's vacuum line is tee'd into, just as long as there is vacuum.

My car is a T-5 so that rules out any problems associated with a converter.

When you unplug the vacuum source and it is venting to the atmosphere that part sounds correct because that is what your IAC does also to allow the car to idle. Now when it comes to no idle with everything plugged in the first thing I would check is make sure no leaks from the supercharger outlet to the throttle body or a leak from the MAS to the blower inlet. You can not have any un-metered air into the system. Have you adjusted the throttle screw on the throttle body if not unplug the IAC connector and adjust your idle to 900 rpm then plug the IAC back in. If you try that and it does not idle let us know and I will go to the next step when I hear the results.

where did you get you're MAF meter. Tell you a story- When we installed my supercharger (procharger) my car would stall when coming off boost and would idle very irratic// also the CEL was on// checked the CEL and it had code 66 low ground inside the meter// i had to unhook my O2's to get my car to run right/ sent the meter back to Pro- M ( Univer Meter) and i havent got my car back together to try it. One of my (friends) dropped a screw down my lower intake when it was being put back together hence the 306 on the way// Blew a head gasket was why it was apart. Choke pull off stuck- $14.00 dollar part- &*^%ing peice.

Couple of things here...

From other posts:
1. Check for air leaks in between the blower and the MAF and the MAF to the T\B.

2. Check your IAC

3. VERIFY that your meter is calibrated correctly. (It took Pro-M 2 tries to get my Univer right)

Since the car never did idle correctly after install, I'm suspecting either a leak somewhere, an MAF sensor problem (this includes possible bad readings if there is a bend right before the MAF), or possibly a need for a dyno tuned chip.

I haven't bumped the IAC up yet...it idles around 700-750 rpm. If I bump it up to 900, that may solve some of my problem. I went over the discharge, bypass, and inlet to make sure the clamps were tight and secure. My MAF is calibrated correctly for the 36# injectors.

The car seems to idle better with around 37-38 psi of fuel pressure. My timing is at 11*. I really just want to get it running for now. I'm not concerned with performance because I plan on getting a custom dyno tune/chip in the next 3 weeks.

I'll bump the IAC tonight or tomorrow morning and report back. When I had my foot slightly on the gas (idling at 1000 rpm) there were no problems and it could idle all day. I also have a spare sample tube for my MAF(also calibrated for the 36's). I might try swapping that in to see if I maybe had a bad sample tube.

probably not conected but have you checked your fuel filter ?

what about the tfi moduale ?

just a couple of parts I've overlooked in the past .

The plot thickens...
 

Sorry for the late update but working 13 hour days doesn't leave much time for the Stang.

I was fiddling around tonight when my dad stopped over to see how things were going. He never heard the Novi at idle so I told him I'd fire it up. Before I did, I warned him that the car would probably die in 30-45 seconds like it always had. I started the car and as it idled, we chit-chatted. A few minutes went by and the darn thing was still idling! And it was smooth too! We kept talking and at one point, I got in and revved it up a few times. When the rpm's came back down, the thing idled just like it had been. It was strange. After about 8 minutes, I shut the car off and we went to dinner.

Now the only thing that was different was my fuel pressure gauge. When I installed it, I never put a fuse between the lead wire and the battery, I just had the lead wire directly connected to the solenoid. I had removed the lead wire from the solenoid so it wouldn't be draining my battery day after day. Could my idle problems be related to this? I think they have to be because it's the only thing that I had changed. I never got a chance to mess with the IAC. I just unhooked the FP gauge's wire. I knew what my fuel pressure was because I never changed it from teh last time. FP was 38 psi and timing 11*.

So here it is in a nutshell:

Fuel pressure gauge connected = bad idle. Car dies after 30-45 seconds.
Fuel pressure gauge dis -connected = great idle. Car idled very very smoothly for 8-9 minutes.

I'll be taking it for a test drive on Sunday to see what the driveability is like. What do ya guys think? Think she finally got tired of fighting with me and decided to run correctly? :D

who cares its running how is the fuel pressure gauge hooked up at the fuel rail ?

just glad it's running good for you.

It was the gauge all along. The idle was fine today with the gauge unhooked. I connected the lead wire for teh gauge and the car almost instantly died. I'm so happy that I've finally figured this car out. I checked everything but I never thought to check the gauges. All that's left is to call up Autometer and find out why I'm having problems with their FP gauge.

On a side note, since the car was running good today I took her out for a drive and OMG this thing feels great. 11* timing and FP at 39 psi. Not a hint of detonation but it was running a tad rich at idle (check engine light would come on and engine would stall every once in a while). I saw 5 psi in third gear. My DR's were spinning through first and half of second!

After hating my car for the last month, I love it again!!


For the gauge, I removed my schrader valve and installed an adapter for the sender. The sender goes in the adapter and the wiring harness plugs into the sender. It's a real simple gauge and hook up but there is something in the wiring that's causing the problems...