Idle Problem

[STOCK94]

Ok fellahs Ive looked through old posts and cant find an answer besides maybe mass air meter, my car is a little different than the regular 94GT. I have a Factory Five Cobra with the 1994GT running gear including ECU. The engine has TFS top end kit with B-303 cam, BBK 75mm TB, Granatelli mass air with 24lb injectors, also a MSD 6A ignition. Couple a weeks ago I installed a Vortech base kit to start with, the car runs pig rich and surges at idle but off idle it drives descent just rich.
I removed the blower belt and the car cleans its act up and idles, also a little leaner, its as if it were the same as before blower install. I put the belt back on and same old thing rich and Smokey. The Mass air meter is in front of the blower and then the IAT sensor is right behind it then the blower to TB.
The previous owner of the engine and harness has a mass air modifier installed, I cranked the idle knob all the way to the bottom and its a little better but still rich and surging but not as bad. Makes me think TB and its readings have to do with problem. Any suggestions anyone? Is it something a tune can fix?

 

[STOCK94]

Also new 1 step cooler plugs were just installed and gapped to 35

 

[General karthief]

Lets get a couple guys that may be able to help in here.
Although I must warn you granatelli stuff is not a favorite.
@a91what @srtthis

 

[srtthis]

with out really getting my hands on it id say its a combo of that Granatelli mass air... B cam... and the not cam friendly 94-95 computer

 

[a91what]

I have to agree, the issue I am imagining is the turn on the pipe for the intake to the SC.

How does the mass air mount? Is it in the piping or does the filter slam on the end.

 

[RioRed95Cobra]

The IAT needs to be removed and relocated to BEHIND the supercharger.. and directly BEFORE the throttle body.

You are getting false readings off that IAT because the air is metered and such long before the supercharger compresses the air and heats it up/forces it into the intake. Your computer thinks the air is cold and therefore could throw more fuel at it.

Mine did same thing.. this may not be the entire issue but I can promise you it's likely part of it .

And yes you need a tune. Bad. I got mine done by willie at dirty racing. I also got a quarterhorse from em so I can tune it myself later. For the price it's a good buy to know you have it all at your fingertips anytime.

 

[STOCK94]

I have a dyno tune scheduled for next Wednesday, between now and then I will move the IAT sensor and see how that helps. Thanks for the input fellas I will definitely update the results and anything else we find next week.

 

[STOCK94]

The

I have to agree, the issue I am imagining is the turn on the pipe for the intake to the SC.

How does the mass air mount? Is it in the piping or does the filter slam on the end.

The mass air and filter are on the end of the 90deg tube that comes off the blower itself, so probably about 6 to 8 inches from the impeller.

 

[RioRed95Cobra]

The

The mass air and filter are on the end of the 90deg tube that comes off the blower itself, so probably about 6 to 8 inches from the impeller.

Your MAF is only 8" from the impeller?? Do you have any pictures?

 

[STOCK94]

Tried moving IAT between blower and TB, no difference, still surging.
Guess we will have to wait till Wednesday for the tune.

 

[STOCK94]

This is the pic without intake discharge tube installed, mass air is at the end of the 90deg tube under fender.

 

[STOCK94]

RioRed95Cobra the engine sits behind the front wheels in this car so there is plenty of room to turn the tube straight out of the blower.

 

[RioRed95Cobra]

Looks good.. is that enough room for the MAF to actually meter air/work??

 

[STOCK94]

Where it is located there is good air flow and a space of about 2x2 feet with an external duct from brake cooler duct coming in.

 

[RioRed95Cobra]

Where it is located there is good air flow and a space of about 2x2 feet with an external duct from brake cooler duct coming in.

Yes airflow.. too much so i'm thinking.. those MAFs are very delicate.. and so much turbulence from the inlet sucking that much air that close to it could be throwing it waayyyyyyy off. Most people mount their MAF down in the fender away from the inlet so there is less turbulence and the MAF can meter air smoothly..

Just things i've noticed over my own build and all the same questions I went through.. vortech as well. Is your maf a draw thru or blow thru?

 

[STOCK94]

Yes airflow.. too much so i'm thinking.. those MAFs are very delicate.. and so much turbulence from the inlet sucking that much air that close to it could be throwing it waayyyyyyy off. Most people mount their MAF down in the fender away from the inlet so there is less turbulence and the MAF can meter air smoothly..

Just things i've noticed over my own build and all the same questions I went through.. vortech as well. Is your maf a draw thru or blow thru?

That I'm unsure of, I know it is being drawn through right now.

 

[revhead347]

Don't bother wasting money tuning on the dryno with a Chinese MAF. Buy a Pro-M or SCT3000 meter before you go the Dyno.

Kurt

 

[a91what]

Hah I missed the part about it being granatelli..... that stuff is junk.