I am stumped. I replaced my MAF with a granatelli adjustable one for two reasons, to hopefully get their claimed "10-15 hp", and to hopefully resolve some idle issues i was having. I watched my grams/sec and felt that it was lower than it should be. Well, now I am trying to dial in this new MAF, but I'm getting nowhere with it, and I feel its because of engine load/MAP. I have a 350 TPI that uses just the MAF, there is no MAP. My engine load is constantly reading entirely too high. On a cold start up, it reads somewhere around 110+. Fully warmed up, it was down to 80, and if I revved it up it would reach maybe 150. I could really use some help in figuring out what I need to check to find out why this number is so high. I really don't think its a vacuum line, but say I had an exhaust leak at the headers, or a leaking intake gasket, could that be causing this?

After I eat lunch, I'm going to head back out and hook up a vacuum gauge and see where my vacuum is at.

 

I would go get a stock maf and throw that granatelli away

 

Ok, vacuum tested... im pulling 14 in. hg at an idle of 800 rpms. Usually the car idles about 700, which i think it somewhat dipped down to while idling and I saw the needle creep to 13 when it would do that. I revved the car up and it would raise the vacuum up to 21. I noticed when i let go of the throttle, it jumped up a couple for a second. So i held the throttle open longer and it slowly climbs up to 23ish. So now im wondering if I might have a restricted exhaust? But still, I feel like my vacuum at idle should be higher than what it is. I don't know what cam is in the car, as I've not modded it from how I purchased it... but among the papers the previous owner left for me was a card for a zz-9 cam grind from TPIS. So i've always assumed thats what he put in it. Not sure if thats a big enough cam to lower my vacuum that much?

Edit: Ok, so I read things over and maybe its not a restricted exhaust since the vacuum does go up when i hold it at higher rpms, and it does not drop at all from there. Holding it at 3,000 rpms it gives me about 22 in. hg. Its not exactly steady, the needle does kind of vibrate there. Not very fast, and it only moves like .5 in either direction. When I snap the throttle open, it does drop straight to 0, and goes up to 25, then returns right to the idle vacuum. So, maybe my timing is off a little... and I have been questioning the valve timing since the timing mark appears to be 180 degrees off. I dont have a pointer on it for the timing mark to line up with, so I dont know if it is exactly 180 degrees. I had someone rebuild the engine for me, so its quite possible they messed up that part. Either way, I know I need to pull that cover off and make sure its right.

So the question now is, can this low vacuum at idle be causing me this issue where the ECM is seeing a really high load?

 

Ok, so I went back out and did a little more work. Replaced the coolant temp sensor, since my gauge showed a little different reading than what my scan tool showed. Had both of those side by side and tested them in hot water. The old one did have higher resistance. Doubt that really makes much of a difference, but what I did after that was turned the distributor and watched my vacuum gauge. By doing that I got the car to idle with 18 in. hg. vacuum. So that's where I left it. Seems to run fine and all, but the issue is still kind of the same. I have about 40-50% engine load at idle, and when I start driving down the street it still about falls on its face and picks itself back up when the CEL comes on. It stalled when sitting at a stop sign, restarted it and it idled fine. Started to drive it again and it did it all over again. So out of frustration I tried putting my old MAF sensor back on and car would not start and stay running. It would just stall immediately.
So does anyone agree with this: My old MAF is junk, and the granatelli MAF is faulty?

 

Granatelli MAFs are junk in my opinion. They certainly won't give you 10 - 15 HP. There was one on my Corvette when I bought it, all sorts of tuning issues. I replaced it with the stock MAF and tuned the MAF table, it was a different beast.

 

If you can adjust it to 8-11 gps with the feedback of tunerpro or a scanner, or get a used bosch !

 

It was showing 8 gps on my scan tool at idle and fully warmed up. I bought a remanufactured one from Advance Auto, just waiting for it to get here. Will send the granatelli back once I get that one.

 

Ok, finally got the remanufactured Bosch MAF from advance, hooked it up and all is good. For the most part.. I still have 40% engine load at idle, and the idle was hunting a little bit but I'm assuming its just relearning. It stops hunting once I give it some gas, and there was a couple times it stumbled on take off. None of that bothers me because I'm sure I can fine tune it from here. No longer falls on its face like i was describing, so I guess I just needed to get a new OEM mass air flow from the start.