I just got my engine and trans in the car. Before i get started i want to mention that the factory 350 tpi ran perfect with no ses light or trouble codes. Well, i built a pretty wild 350 and used a converted LT1, 58mm bbk, and some 36lb accel injectors that were said to be as new. I had the prom burned by alvin at pcmforless. I deleted egr and smog. Well i got everything together and turned the key. Could not get it started for the life of me. I might as well mention now that i used the accell afpr and left it at the stock setting. I haven't changed the pump yet, its still sitting here on my bench. Anyway we got it started by dumping a coke cap full of gas in the plenum. It wouldnt idle and ran really crappy from around 1500rpm-3000rpm. I had to hold my foot on the gas quite a bit to keep it going. Once it was going, it wouldn't run out of fuel. It seemd to run fine above 4,000rpm but anything below was super rich and rough. When i'd turn it off you could see all of the raw gas vapor coming from the TB if you opened it. If i put my foot on the gas and turned the key it would start right back up but still not running properly. Anyway, since then it seems like i've been going backwards. I tried the factory (LT1) injectors that the manifold came with and it did the same thing only it would lean out and backfire out of the tb above 4k rpm. So, i decided to change the prom with the one that came with the car (hypertech). Same problem! Since then i've tried several things, checked timing again, cleaned plugs, and used vacuum pump to pump up map sensor to see if it would hold an idle. Same problem. Fuel pressure seemed fine as the rails would hold pressure and it would fire back up with foot on pedal. Now, i can't seem to get the rails to hold pressure. If i pull the supply line off before it would spray everywhere, now it doesnt. If i put a gauge on it it goes up to about 28psi while the pump is priming then immidiately goes back down when the pump shuts off if it isnt cranked. If i crank on it with the gauge attached it goes up to about 33-34psi. Seems to me like it should hold that pressure even when the pump stops priming.

Now, for the real trouble. I got a noid light to see if injectors are pulsing which i assumed they were since it would run after i dumped a little gas in to get it going initially. Well, i get no pulse. So, i check grounds and they all test good. I run the ignition module to autozone, it checks out good. So i grab a new pcm and it does the same thing. With the key off i would get 12v on both pink and dark green or dark blue injector wires while the testlight was grounded. When the key was turned on the dark wire would no longer have 12v with the key OFF?!?!?! I've read this is supposed to be normal. I assumed it wasnt which is why i bought a new pcm. So i disconnect all injectors and take the rails off and use my vacuum pump to see if rails or injector seals are leaking. It holds about 20" vacuum fine. I put the rails back on and break out the test light again while ALL injectors are unpluged. If i ground the test light and probe the two leads, the pink wire will show 12v with key off and the dark wire will show nothing. With the key on the dark wire will light the test light (still grounded) now. And stays lit while cranking. Now here is the part i cant figure out, if i move the clip on the test light to the positive post on the battery, the dark wire shows the exact same results. OFF with key off, lit with key on and while cranking. Just on hour before both leads would light the test light (12v). Either way the noid light does nothing when hooked to any injector harness while cranking. I am completely stumped. Someone please throw some ideas at me. All grounds check out ok, all fuses check out ok, and module checked out ok. What else is left?

 

You try your stock prom?

It's kinda hard to read your post, sorry.

 

Yes i tried it.

 

VATS
Did that get disabled in the bin?

You're post is rought to get the details from but I think I can clarify some things for you here.
You must have power to the injectors with the key on.
The outgoing side of the injector (dark wire) goes to the driver in the ECM and is grounded to fire the injector. (D6 & D7 if its a 730)
By the ECM grounding the secondary side the current will flow and cause the noid light to come on.

When you check with your "test light probe" connected to ground you should have power on both sides of the injector.

When you put your test light probe on the battery (+12V) the ECM "firing" should turn the light on by connecting the pointed end to ground through the ECM. (dark wire only)
This is not really a good test and could possibly draw too much current through the ECM so I wouldn't advise doing it too much.
would depend on the test light resistance.

The noid light should turn on if current flows when the ECM fires the injectors.
Is your noid light burned out ?
Check the injector resistance with an ohm meter and verify they all are above 12 ohms (14-16 is ideal IIRC) Any less and they may be dragging the system down and causing the whole problem.
HTH,
Jp

 

Sorry about being unclear. Noid light is brand new and works. I forgot to mention that injectors all read 14.2-14.4 ohms.

 

Ground strap from motor to firewall/chassis.
Throw a jumper cable on it and give that a try.

Noid should be flashing. Double check the grounds at the ECM (wiggle connectors)

FP should be higher and stay for a while when the pump stops.
Might look at that regulator and then possibly the injectors leaking.

 

I did a wtf is my post......
This post is on two boards with same title.

Do what Rbob said and get back to us.

You also need to set the minimum air on your new TB.
You actually want it to mostly idle on the TB not the IAC.
Since you need to give it throttle to get it to start. It is rich at idle.
Since you need to give it a lot of throttle to run, it sounds very rich, or you have a vac leak.
Go back and verify the basics again. Timing, FP etc.
If you didn't do much with the throttle to start, you might try giving it 1/2 open and see how it does.
Once you get it to operating temp & idling you can go back and set the minimum air.

Normally a high speed idle requirement is a vac leak.
The chip would need to be real rich I'd think to cause it.

 

Here is what i have done. I drilled a 1/4" hole in what used to be the iac passage on the intake. I bled the system again and started it up with the fuel pressure gauge on it. I played with the screw on the regulator and the best i got was 33 psi at about 1200-1500 rpm by turning the screw out. I turned back in and got lower pressure (24psi) Now i cant get it back up to 33psi or more by turning the screw either way. Do these accel afprs ever come defective? When i had it at 33psi i could get it to start everytime. Now i cant. OTOH it is still running super rich at low rpms. I did confirm that the injectors are pulsing to. Just as i suspected these noid lights are too slow to pick up a pulse while cranking. The duration of the pulse is way too short in the custom chip to light up that light. I knew this was the case. Now i need to workout fuel pressure problems so i can get back to the idle issue.

 

I pinched the return line and the pressure went back up to about 42psi. It seems to be fine now. Still runs rich and wont idle though. Why would pinching the return line for one second bring the pressure back up? I'm going to go ahead an order the ALDL cable so i can see whats going on with the ecm now.

 

I've been working with him lately and we have found a few things pretty far off.. slowly but surely its getting there.

First the IAT or MAT was left unplugged.


I got a datalog and we found the TPS was bad (reading 4.6 volts the entire time). I also noticed the IAC counts where at 160 at a 800rpm idle so I had him open up the blades a bit to get them back in check around 25-35 at fully warmed idle.

The final thing we are having a problem with is setting the base timing.. He says it won't run anywhere but way off the timing marker. Sounds like hes reading a ATDC or the pointer is a bit off... or a mixture of the two.


Just thought I would share.. you see post like this alot of times but hardly ever see the solutions.. Might help someone later down the road you know.

 

One tooth off on the dist stab will make the timing go up around 11-12 o'clock.

Easy way is to line up the timing mark with the tdc mark and check the rotor position. Is it pointing at #1 wire or #8.
Pointed at #2 really f's with you.

 

Yeah that makes more since also seeing how I remeber him saying that he phsycially couldn't turn the distributor anymore.. I told him it sounded like it was out a tooth but it didn't go any further than that.

 

yeah,

The whole off a toof really sucks it lol

Oh I'm almost there! Dohhh I cant turn it anymore!

I dont even pull them out until I point it to number one, on intake lol

Line it up and check the balancer

later
Jeremy