Now it wont even start

[stang_racer20]

How important are mass air flow voltage settings for a car to RUN period?
I'm having big issues.

After spending $10K and over a year of time now I cant get my car
running again. Right after the engine install it ran, but idled bad
and ran lean(as far as i could tell). Now ever since ive started to
try different settings on the twecer it doesnt even run anymore. Ive
tried to use the stock eec-iv again to see if it'll run and it wont.
What the hell? The only thing i've changed since is i went from 87
octane to 89 octane un-reformulated gas for my cam setup. Any
thoughts?

[Mendari]

Sounds like you're having electrical problems.
When you put the key in the ignition, do all of the lights on the dash turn on? Or is the car completely dead? Do your accessory lights, headlights, and radio turn on? Does the engine turn over?
Sorry for presenting you with more questions than answers. But don't worry, we will solve your problem.

[stang_racer20]

the engine turns over just fine and it wants to start, but the split second its ready to kick over it cuts out and backfires. all the accessories work fine(lights, etc.) although i have no radio or dome light right now cause the interior is not put back together yet. im gonna go out and check for spark at the plugs when i can get somone to help me later.

[GTStang]

The description of almost firing then cuttin out and backfiring sure sounds like timing is F-ed up somewhere.

[Mendari]

O.K., so far so good. We know that your electrical system is doing its job. If the engine feels like it's backfiring, then we have narrowed the problem down to either cam degree timing, ignition timing, spark plug firing sequence, or fuel pressure. Start diagnosing the easy problems first, the spark plug firing sequence. Make sure no one messed with your cables. I had a "friend" that would play jokes on people by switching spark plug cables around. He could make flames come out of the carbuerator.

[stang_racer20]

the timing is fine cause i havent touched it since it was running. its set at 15 degrees btdc. i havent touched the wires but ill recheck. i'll increase fuel pressure a little too, and give it a try

[HiFlow5 0]

So the motor ran before you started messing with the Tweecer right? Or did you buy the Tweecer cause you were having engine troubles? Now I'm not to sure how the Tweecer system works, but doesn't it plug inline of the stock computer or does it totally bypass the EEC-IV unit?

OK before we go any farther on the whole Tweecer thing. How long have you had this engine combo together, and has it been tuned and broken in correctly? You say after the engine went it, the motor ran bad and lean? Have you set the correct timing, and fuel pressure with and adjustable regulator? Also did you take the proper steps to break in the cam? I know when I started up my motor for the first time, it ran like shit. The timing was also way off and the stock computer needed to adjust to the changes that were made.

Sorry for the 20 questions, but just trying to narrow things down a bit.

[GTStang]

I don't know cause I have no first had expirence but I think the tweecer works inline with the factory computer. What is your cam degreed in at? Also bump the intial timing down to 10-12 degrees BTDC until you get it running.

[stang_racer20]

the tweecer works as an add-on with the computer. you plug it in to the j3 port and your pcm takes calibrations through the tweecer to use. if you disconnect the tweecer from the port, its a stock computer again.

heres what i just tried and results:

checked firing order- just fine

reset fuel pressure one full turn clockwise(increases i believe) - ran for about two seconds then killed again.

replaced battery with one i knew was good - no change

adjusting timing little by little each way - no change(considering the car wont run, i cant tell what the actual degrees are though)

"Before the Tweecer, upon first startup" - the motor ran before i bought the tweecer to the point where it would barely stay running. it had a really low and lumpy idle and sounded like it wanted to kill. in fact in order to start it i would have to press on the gas to get it to start. i set the timing at 10 degrees btdc and it idled bad. then i set if to 15-16 degrees btdc(like my teacher suggested) and ran a lot smoother, but still pretty bad u know. i broke in the cam the exact way my college teacher(who knows everything in the world about engines!) told me to. "once its running, increase rpm's to 2,000ish for 15 - 20 minutes, then slowly let off to idle and turn off." the rest of what he said about cam and engine break in involves driving it. i havent had that liberty yet since it didnt drive then and it wont start now. after talking with 3 or 4 friends of mine they ALL agreed it was most likely my stock computer that was making it run so bad. so that is the reason i bought the tweecer. to recalibrate the stock settings so it would run good and i could drive it. some good that did!

if you need any more info or if you didnt understand that book i just wrote let me know.

[atssystemsusa]

what is your mass air set up for, blow through, or draw through, that may have something to do with it. that and how its compatible with your engine setup.

[Mendari]

So far so good. You got it to turn over and run for a few seconds. Now try adding a little more fuel pressure. Also, check your throttle body for smooth operation and your intake for vacuum and your exhaust for smell and pressure. Make sure the intake and exhaust are flowing properly. Last but not least, try to reset the computer settings to factory stock. The last step will be most important.
If this doesn't work, start at the top of the electrical list and re-check your alternator.

[stang_racer20]

Originally Posted by atssystemsusa

what is your mass air set up for, blow through, or draw through, that may have something to do with it. that and how its compatible with your engine setup.

blow through/draw through?

its an 80mm vortech maxflow for 42# injectors. the only odd thing i thought of is the mass air meter didnt come with a new box on it. i called the place i ordered it from and he said u use your old one cause the way it works is it fools your computer with the tube inside for 42# injectors.

[stang_racer20]

Originally Posted by Mendari

So far so good. You got it to turn over and run for a few seconds. Now try adding a little more fuel pressure. Also, check your throttle body for smooth operation and your intake for vacuum and your exhaust for smell and pressure. Make sure the intake and exhaust are flowing properly. Last but not least, try to reset the computer settings to factory stock. The last step will be most important.
If this doesn't work, start at the top of the electrical list and re-check your alternator.

higher fuel pressure shouldn't be an issue since ive already added 42# injectors and a 255lph pump. in fact im supposed to run like only 35 psi with my combo. how am i supposed to check my vacuum when my car does run, all the lines are new and most are even clamped on so they wont come off. like i said before i havent changed or touched a thing since it was running besides my gas and hooking up the tweecer(which i have temp. taken off). check the t-body for what? what does the alternator have to do with starting?

[GTStang]

What cam are you using? what are the specs on your cam card? It sounds like all the issues you are having are, MAF system inability to handle your cam within the stock parameters. So the Tweecer might be what you need, you just need to get a good baseline set-up before you can fiddle with it.
Oh and please make sure to include Cam Lobe Seperation. If you give me this info I will try to call the boys at Anderson Ford through my work. They will give me some good ideas to help you out. I wish I could help more but I have no real world expirence about the Tweecer. Because AEM is taking forever to come out with there unit for the Mustang. I may go Tweecer to so I'd like to learn about it also.

[stang_racer20]

that would be awesome man, i'll find the cam card and post back in a bit. im using the trick flow stage 2 cam