plz bear with me, I am new to posting. I have an '89 efi 383 chevy, that takes about 3-5 seconds to start, hot or cold. and when it starts it tries to run to the desired idle rpm of 3187[ scanner info] this is not only hard on the engine, its embarrassing, because otherwise this is one good running eng. the idle drops back to normal within 2 seconds. It has almost all the same parts on it as when it was a 350, and i didnt have this problem then. the cam duration was increased 6 degrees, went to 58mm t.b. and a chip from ed wright. I did the checks in the factory service manual for iac motor, it checks good. no fuel pressure problems. haven't check coil yet, has same setup as before. Scanner info : iac counts about 40-50 when warm. fuel press 45 and holds. no vacumm leaks. scanned with old chip[s] no joy. Any help would be appreciated, starting to run out of ideas.

 

What kind of plenum is on the car?......Superrams seem to be notorious for this. Mine, and everyone I know with one..

 

The guy that burned my chip told me about a feature of some TPI chips that actually delays firing the engine until it cranks for a certain amount of time, I think it was something to do with VATS. I don't understand about the scan with old chips. Does that mean you put in the stock chip and it still took time to start? You might want to check with Ed Wright about the chip. I'm betting this is the problem and the injectors don't fire until then. Have you checked them with a Node Light to see if they are firing as soon as you hit the switch? Have you verified you have spark at the plugs as soon as the motor cranks? It has to be one of those since your IAC sounds fine.

 

My 383 SuperRam doesn't rev up like that.....

Sounds like Ed needs to change the cranking pulse width un the chip?

 

mr. brutal form: I have an lingenfelter superram, tpis bigmouth, etc. is there any way i can tune this problem out? It just kills me knowing every time i start her up that I'm hurting it bad.

 

Warbird: Yes I scanned it with the old chips, the stock one and customburned for 350 inch and still did the same thing. I will check with my node light, thanks.

 

Yea mine doesnt rev either, but is does take a few seconds to start. It does it with any prom I use. I cant think of any reason why the plenum would, or could cause this....Alot of S/R owners experience it though, How bout you vernw?

 

Vernw: Ed Wrights tech says they dont mess with stock cranking fuel map. Are there others here who believe this may be the problem?

 

Redjet, what is the base timing set at?

 

Brutalform: Well I'm glad I'm seem to be doing this right. First time to be posting and replying ever. The base timing has been at 6 degrees, which is stock, to 10, as I was trying to tune this problem out. I didnt want to go past this, since the time I tried to advance the timing when it was totally stock and the engine told me it didn't like it, by loud noises and no power.

 

Put it back to the 6* for now. Reason I asked is, when the timing is too advanced, it will rev up on you. There is an initial spark advance constant in your prom, and stock it is 6*. When you set your timing you are disconnecting the one wire connecter to the ECM right? I live with the few seconds it takes my car to start. If I had my timing too advanced, my car will rev too.

 

Brutalform: The timing is at 8 degrees right now. Yes I disconnect the brown wire [ if i remember correctly], before adjusting, checking timing. I'm beginning to think that the ed wright chip may not be the problem since I tried the other chips and have same problem. although the other chips are for a smaller engine.

 

Well if you didnt remember correctly, do it again.
1) start eng. and disconnect it (ECM)
2) set base timing
3) shut eng. down
4) disconnect battery(20 sec. or so)
5) reconnect it (ECM)
Now when you start your engine, the base will be properly set.
I would set it at 6*. TPI engines dont like a lot of advance, or rear gear for that matter.

Give it a try and see what happens. If the only problem is a few extra seconds to start, I would not worry about it....Tom

 

BTW welcome to TGO

 

Brutalform: sorry sent reply to soon, was getting call from g.f. I appreciate your input on the timing, did you mean you have had timing advanced on your engine and experienced uncontrollable rpm's on start-up?

 

YEP. I hope this will help your problem. Just from my own experience. Having problems...Gotta get back to basics.

 

Brutalform: Thanks for the welcome and the step by step instructions. What I meant was I didn't remember what color wire the ecm wire was. Again thanks for the input. Now I need to make some time to apply all my new found knowledge. I work friday thru monday, ten hour days as corporate jet technician. And renovate properties.

 

cool...goodnight.

 

feel lucky I have ligenfelter superram and I crank for 10 seconds,

Mine has to do with fuel pressure, I have a massive fuel pump and for some reason it has always done that It won't start pumping when I turn the key on, only when I crank, my fuel pressure gauge goes 0 10 15 20----45

If I drive it warm the motor up and get out and go back it starts up easy.

 

the fuel pump should pressurize the system for two seconds with the key on engine off. if it doesn't your fuel pump relay is bad. there is a way to jumper the pins on the relay to see if it is. that is in a haynes manual. though i have never had to try it. there is also a connection to the oil pressure sender. when the oil pressure gets to around 4 psi a circuit energizes the fuel pump.you should be able to hear the pump run for two secs when you turn on the key. engine off.

 

Same here, but mine did it with the stock pump, and with the upgraded Aeromotive A1000. Ive just learned to live with it. After warmup, all is good.

It must have somthing to do with the large capacity plenum...

 

The extended cranking is the chips fault, it's not a bad chip just lack of programming. The cranking fuel table needs changed. Buy a programmer and do it yourself since Ed Wright won't.

 

Mine cranks for maybe 4 seconds before it catches when the motor's cold. I think I'm going to up my cranking pulse width a little bit. But I don not see the revving up after it catches that was mentioned in here. If that makes a difference I'll report it back here. Just curious, do you know what your cranking pulse width is set at? FWIW, I'm running $8D speed density. A MAF based system may have entirely different parameters to deal with....

 

Back when I had stock programming, It still did this. Maybe, with the added plenum capacity, the stock cranking p/w would be off? no? vernw, you have been at the prom thing longer than me, what do you think?

 

I'm no prom guru, still way behind on the learning curve (but trying to catch up!)....

But that's what my guess is, and why I'm gonna try pplaying a little bit with the pulse width this weekend and see if mine will shorten up any.

The only other thing I can think off is the cranking timing advance. Since advanced timing can cause the thing to rev up, maybe his cranking advance is set too high.

There's also a chance the really high revving could be caused by too much fuel while cranking (almost flooding it and revving up to burn off the excess).

I'll try and report back my findings the first of next week....

 

Me too. I just learned the basics, with tunercat and all, I also have a programmer. I cant really get into it because my car is off the road for the winter, and Im changing trannys. Should I be lookin at C PW Mult. vs. Ref. pulses (>17), or (1-16)? Sorry to be off topic. If you can answer this here or on the correct board, Ill repost on the correct board, to stay by the rules. Just let me know. I appreciate any help.

 

I agree with John above, the cranking PW needs to be increased.

 

Hey, this is great! seems like I got a few people thinking and wondering about the hard starts with the superram. I'm interested in burning chips myself, thats how I heard about this site. Although haven't started yet, and realize its a challenge, but if all works out, I'm sure it can feel like a real accomplishment.

 

Hello vernw, I'l have to get back to you about the cranking pulsewidth. probably by wednesday.

 

with the stock chip in my car it would take a while, sometimes up to 5 seconds when i would stop cranking and give it a second, but with the chip John burned for me, the car started everytime, the first time, so he knows whats up

 

The cranking pulse width (provided you're showing the right injector constant) is probably your problem. Played a little with this over the weekend, and more pulse starts faster. WIll have to adjust it by trial and error - cam and head specs make a big difference I suspect.

My Formie started cold this morning after about 2 seconds