MPI stage 1 troubles on first ride

[Apex Man]

I just got it together with the following:

Vortech bypass valve, MSD fuel pump, Ulmer clutching, 26/24 pulleys and 3 head gaskets.

problem #1

surges badly when trying to accelerate slowly during Transition from vac to boost. Bypass valve need adjusted?

problem #2

Air to fuel ratio goes to 16 to 1 for no apprent reason during accerleration.
It will stumble and sputter big time. This occurs at about 6000-7000 rpm. Loss of fuel?

problem #3

Runs extremely rich 12.0 to 10.0 to 1 most of the time even when creeping, except for the 16 to 1 lean condition under medium acceleration.

note: I have the two 1/2" IAC elbows turned down with no plastic "collector' attached.

I'm running at about 1000'

The lean condition really worried me and it was bucking wildly like a bronc so I borrowed my friends spare sled and parked mine.

Happy New Year Everybody!

 

[badluck]

#1 Sounds like a manifold boot is off between the throttle body and head, had the same problem with mine the other day.
#2 Because of #1 I had problem #2
#3 Because of #1
Again this is what I found with mine after retuning after the bypass valve install. Hope this helps

 

[badluck]

Sorry apexman,
Problem #3 just needs more fuel adjustment because of the bypass valve

 

[gsxr]

My apex is perfect running 5 lbs,
using Ulmers, clutching,and fuel numbers off their web site,with a vortex bov.
I had a lag , at transition from vacuum to boost before Ulmers clutching.

 

[rxrider]

To rule out the Vortech as the cause to your problem you could take off the vacuum signal hose from the Vortech and block it.

 

[Ted Jannetty]

The IAC hoses Might need to be connected to the intercooler.

There is some debate about this with supercharger because of high pressure in intercooler at Idle without bypass, but with it I would connect them to the intercooler.

Ted.

 

[srs8288]

I am having the exact same problem. My fuel/air ration is all over the place and sled surges badly during transition from pressure to boost. Throttle body boots have blown off twice. I am going to permanently fix that issue tonight. So Ted, you think we need to attache the IAL directly to the Intercooler and that will solve the surging problem? I also, installed your BOV, can't compare without it because I installed when I put the supercharger on.[/list][/code]

 

[Ted Jannetty]

I am having the exact same problem. My fuel/air ration is all over the place and sled surges badly during transition from pressure to boost. Throttle body boots have blown off twice. I am going to permanently fix that issue tonight. So Ted, you think we need to attache the IAL directly to the Intercooler and that will solve the surging problem? I also, installed your BOV, can't compare without it because I installed when I put the supercharger on.[/list][/code]

Yes directly to the intercooler plenum.
I believe this will help alot.

 

[lakercr]

I am having the exact same problem. My fuel/air ration is all over the place and sled surges badly during transition from pressure to boost. Throttle body boots have blown off twice. I am going to permanently fix that issue tonight. So Ted, you think we need to attache the IAL directly to the Intercooler and that will solve the surging problem? I also, installed your BOV, can't compare without it because I installed when I put the supercharger on.[/list][/code]

Yes directly to the intercooler plenum.
I believe this will help alot.

Ted - have you measured what vacuumn the IAC sees? also, is it smart enough to care about mass air?

If it is just looking at vacuumn, you should be able to show the circuit what it wants with a bypass and possibly a small restrictor in the IAC lines?

Just thinking out loud, that may not make sense...

 

[Apex Man]

Sputter, surging, lean spots

I did not see where the boots came loose but I will check deeper to see if a vacuum hose came loose. I only got 10 pounds once and stayed under 3 pounds until I got back to the trailer. I only pulled the shroud off and have not removed the head light assembly yet. Does the little black collector need to be on the end of the 2 IAC hoses or can they be just turned down and left seperate? I took it to Quebec right after I got it together and I was lucky my buddy brought his spare sled (660 Turbo). I need to get it in order before my next Quebec trip on the 21st of this month, if I can. I was thinking of setting the BOV to dump under a higher vacuum like 8-10 inches.

Thanks eveyone and keep them coming so I can get to the bottom of this. Testing and tuning is hard to do here in Ohio because of the lack of snow.

Ralph

 

[Apex Man]

MPI troubles

I'm thinking maybe a fuel pump issue as I got the MSD pump from ebay for $65 and it had no MSD sticker on it or in the box, only the pump. Maybe I got a factory second because they normal are $100. I have a 1/4" ID aluminum fuel line in the tank, 3/8" ID Goodyear hose supplying the pump, 5/16" ID Goodyear hose from the pump to an automotive fuel injection filter and then to the fuel rail. The pump is triggered off the stock fuel pump connector. I use the stock pump power supply to turn on a relay which powers the new MSD pump. I'm using #14 AWG wire for the pump. Maybe I should try the stock pump setup and see what happens. I 'm full up on gauges so a fuel pressure gauge is a no-go. I still have not checked anything closely yet because of my work schedule right now. I'm looking for directions to go.

Keep them coming guys!

 

[Apex Man]

MPI troubles

So far I did not find the throttle bodies loose or and vacuum leaks. I do believe I had the MPI fuel controller modes out of whack though. When using a BOV shouldn't you tie the MPI fuel controller boost port after the throttle bodies instead of at the intercooler like MPI says? I notice the MPI blue boost present indicator LED on when I actually have vacuum after the throttle bodies. I was playing with the bypass valve adjustment and set it so the blue light is off at idle but on when applying throttle but I still think the module should see what the motor actually does.

Thanks guys,

Ralph

 

[Ted Jannetty]

Take the filter off the bypass valve it is restricting flow.

Do not hook the fuel controller to vacuum it will blow the internal map sensor of the fuel controller.

Ted.

 

[srs8288]

valve?

Ted, the vortech valve that I bought from you for the supercharger, is it a Vortech Bypass Valve with 4"-5" vacuum or a Vortech Blow off Valve that is set at 10"-11" inches of vacuum? Just need to make sure! Thank you. By the way, my name is Scott Shelp if you look in your computer.

 

[Ted Jannetty]

Re: valve?

Ted, the vortech valve that I bought from you for the supercharger, is it a Vortech Bypass Valve with 4"-5" vacuum or a Vortech Blow off Valve that is set at 10"-11" inches of vacuum? Just need to make sure! Thank you. By the way, my name is Scott Shelp if you look in your computer.

They are all preset for 1.5 inHg.