Ok guys. I just started my engine for the first time and it ran pretty good. I didn't have the maf hooked up, nor the mat sensor or the o2. Then I hooked up the maf and it would not idle anymore. It kept trying to die. Why is this. I just don't understand.

 

Your maf is bad. It ran because it was in limp home mode. When you plugged the maf back in it tried to read it and it can't.

Get a new maf.

 

Is it ok to drive it in limp home mode until i can afford a maf. that damn thing is $300.

 

Yes, the ECM will adjust for no Maf readings. No matter what people say you can run the car without the Maf senor.
Ran mine for six months before I found a bad connector to the Maf.

 

Someone told me that not having a o2 sensor hooked up would cause it to not idle. They also told me that I need to let the car run for a while and the ecm will adjust to all the sensors. I just built this car. the motor is a 355. I have a 305 tpi setup on it. is it anything that needs to be changed on the tpi setup to make this work properly.

 

Itll just stay in open loop not reading the o2 sensor and rely on the CTS, MAF And IAT i believe, Youll be fine Until you get it hooked up

myn has been "inactive" for months will no ill effects

 

I bought my MAF at advanced auto for 170.00 that was 3yrs ago still working.

 

I got a couple of spares from this board. Tested them both on my car and both are operable. I thought my MAF had failed and it turned out to be the IAC sensor.

 

maybe i should check the iac out then. is it a way to test it?

 

In my experience when the IAC fails, you will get a really really choppy idle or it will be erratic. The easiest way to check it is to use a shop manual and run through the tests. You can also remove the throttle body and you are going to need a 1 1/4" big mother wrench to loosen it from the throttle body. You will need throttle body cleaner and some new gaskets to reinstall everything. When you unscrew the IAC, notice to see if the pintle is still connected to the shaft that turns. If it broke then most likely when you take it apart it will be in pieces. Not a bad idea to use that TB cleaner and spray the hell out of everything, but dont get any on the electronic parts of the IAC. If you have never cleaned the TB before it will be all gummed up with black soot and gunk.

I would start with the MAF and the MAF relay if i were you.

 

I would watch E-bay like a hawk!

 

When the MAF died on my 86, I hit the wrecking yards and picked up one for $50.00; that was over three years ago and it's still going strong.

Even though I have a Vette, many of the 'F' bodies use the same MAF; the one I bought came off a Trans Am.

BTW, you might be surprised how many parts are interchangable; take cruise control servos for example. I picked up one off a Tempest for five bucks; same yard.

Jake

 

are you running the 305 chip/injectors? if you are, that could be a big part of your problem.

 

mine did the same thing about 4 months ago. bought a new maf sensor havent had a problem since.

 

There is now way that the 305 setup can run the 355 properly.

 

Except in this:



355. 19 PPH injectors. Full street trim (spare tire, all four doors, etc.). 14.48 on rather skinny tires.

Granted, with a stock program and 19# injectors, it's going to have real problems feeding the 355.

 

As long as the injectors match the cal. itll run fine at part throttle. You risk going static at higher RPMs, though, not to mention the hard 255 g/sec limit thats in the 8 bit ECMs.

BTW, thats an awsome setup, Vader. I like,
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Incedentally, with 19 PPH injectors, youll be able to fuel up to 230 gms/sec of air at 12:1 AFR, so with the stock injectors its alreay close to maxing out the MAF before it goes static.

 

I also agree that its probably a bad MAF, but it might be worthwhile to hack out the rear screen and clean the wires before tossing it. Sometimes they can get REAL dirty and itll block heat transfer, which causes the engine to go real lean.

 

thanks for all the replys. I am running 305 setup injectors and ecm. It runs fine when i unplug the maf. It only acts up when i plug it in. I do however plan to change the injectors soon. I'll be installing 26# injectors in the near future. I'll try removing the rear screen and cleaning it. The front screen is already removed, so i guess i'll just descreen the thing and clean it good. What should I use to clean it?
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By the way, it actually runs really rich with the maf. When i kill it smoke rolls out the tail pipe.

 

I beg to differ. Mine ran with all the stuff in my sig ( minus turbo ) perfectly . It was a 305 ( APYS .bin) but I had 22 lb injectors in ... I have an autometer C2 A/F guage( not perfect I know) but I had a lean idle and rich topend ( wierd I know) . It actually ran better with that chip than the current vette prom I am running now ( APYP) . The only reason I changed was to get rid of the speed limiter so I could see how well she got up to topend .
Just wanted to toss in my experience with that

 

Yup watch ebay for mafs. I just sold 2 of them on there for 50 a piece.

 

It's funny, after about a dozen of these cars and working on a few here and there, I've only come across 1 bad MAF vs. over a dozen bad relays. No idea why everyone is always so gung-ho on changing the expensive stuff first...