D1SC 383 LT1 Trouble! Need help!!!!

Hey guys,

Some thing got messed up and I have no Idea what! Well here's whats done so far:

1995 Z28
4L60E trans
383- 9.79 compression
Forged everything
custom cam
4bolt main
heads ported and polished with matching intake
75lbs injectors
accelleronics injector driver
D1SC -FMIC
headers/catback


Fuel system is in the works, right now I just cruise the car to the local store and such. No hard running. Well until today! My brother in law wanted to take it for a spin and I figured why not, just be easy with it!

Well 10min. goes by and I get a phone call, he says it died on him. I get over their, than he tell me when he turned around to come back he got on it comming out of 1st and into 2nd and it just cut out on him, so he let off and it was barely idleing. If you gave it gas it wanted to shut off.

So I try to start it and just doesnt want to stay running. If I give it gas it would shut off. I figure it had something to do with the injector driver. tested it and all was OK. Fuel pump is kicking on, the car just doesnt want to run. No funny engine noises of nothing like that. I get it to start and it idles very low. Finally I diconect the intake for the blower and it runs. Not great but enough to get home. I change the MAF and still the same thing. I changed the stock Fuel pressure regulator and still the same thing??? I still hear the fuel pump kicking on when I turn on the key... I dont know what it can be. I even pulled a couple plugs and they looked ok?????? I'm LOST!!!:confused:

Sounds like a boost leak after the MAF check all of your couplers you will probably find one has come loose and blowing air out. The maf is measuring a bunch more air than the engine is seeing dumping fuel for it and killing the engine.

Thats one thing I will have to check, along with the fuel filter and the fuel pump. Dont know what else it can be....

Thats one thing I will have to check, along with the fuel filter and the fuel pump. Dont know what else it can be....

I have a 383/D1 '1997'. I had the fuel line tube come off the pump. I was OK cauz I run two pumps. You can test the pump by connecting the small red wire to pos. side of the batt. Disconnect the fuel line and run it to a gas can. Look for good flow. I assume you have replaced the pump with a 255lph or similar.
Also, I had alot of opti rotor failures. I broke 3 of them. I was running a MSD 6A with 8202 coil, and, the rotors were not surviving. Some times it would run very strange as you have said. The plastic rivet on the brass rotor contact can melt under large engine acceleration and large spark energy. Something to check. I replace all my gm opti's with my own rivet (I've had good luck so far.)
Also, it is easy to flood a blown car with large injectors under high wheel spin (reduced load). The LT1 PCM will go into closed loop WOT and use PE mode. It can dump alot of fuel in there and flood.
A third thing is the fuel regulator. I had one go partially bad. The diaphram was leaking pressure to the intake manifold. I would get enough pressure to fire @ low throttle, but this would not support the engine under load. I had to replace the Aeromotive regulator. (I don't like them much).
Just some ideas.
Hope this helps.

it def sounds like a problem after the maf...hoses always blow off on FI cars.

Thanks guys, I need all the help I can get. I will get after it tommarro after work!

check all your plugs.....make sure all of em are still intact...probably went lean and melted a plug or two :eek:

9.79 compression and "fuel system in the works", you may want to check the head gaskets. Even a small amount of coolant will make it barely run. This happened to me last year in my Nova.
Steve

"Note to self": Kick brother in law's ass!

A blown off hose/vacuum leak sounds like the most likely candidate. If you have a Diagnostic labtop, or know someone who can plug into your car and read it on a program such as LT1 Edit, it would make finding the problem easier.

I have a dual intank system myself, and I personally had lots of problems with the fuel lines poping off from the pumps in the tank! I wasn't even getting on it, I just noticed while drving it normally on the highway and it started to loose power. Fortunatly I have a fuel pressure gage, and I new what had happened instantly. I also fortunatly had some tools handy so I could open up the top of the fuel tank and put the hoses back on. This happened at least a dozen times to me in about a month. I have since changed the rubber hoses with braded lines, and they haven't came off since.

I will check all the plugs. Hopefully I can figure it out...

what are your plugs gapped at? maybe spark is getting blown out? i also had the fuel line blow off and i just clamped it to the metal line and have not had any problems for a year now.

fuel line blowing off..what in the world are you guys talkin about?! anyone have pics of a hose that supposobly blow off :eek:

rubber hose that connects to the top of the tank,i think mine might have been just for the evac,i don;t remember and i think the added fuel pressure would cause fuel to squirt up into the metal line and with the rubber one off it leaked in my garage on me..

I knew a guy with a boss 429 (not original) that had his fuel line pop off after installing a bigger fuel pump. He was running methanol in the car and it caught fire, burned his garage down along with the car:(

Moral of this story....fire is bad:cry:

I am referring to the actual rubber hose I attached to the fuel pump in the tank. All the hoses were meant for fuel systems, but they kept coming off while the car wasn't even making any boost! After overtightening them a few times, the rubber actually started to fall apart! Again, after I swapped out the rubber with the braded lines, there have been no further problems.

I had the same damn problem with the EFI rubber hose on the walbro pumps. They would slip off and leave me stranded. After a while the rubber fell apart and lost pressure to the rails. =(

-B

that sounds like exactly what happened when i blew my intake elbow off my piping, it was sucking less air than it was measuring. Try unplugging the maf and see if itll run, then you know youve got a leak

Well guys here is everything I checked and what I have come up with:

Fuel pump- good
fuel pressure regulator-good
coil-good
optispark-good
No boost leaks
MAF-good
No codes on the scanner
Compression-good

The only thing I can see it being is the spark plugs are beat. I pulled all the ones I can get to easily and they were all really black and wet. My guess is they are fouled out. I will change out the plugs tomarrow and let you guys know how I make out!

Thanks for all the help guys!

well either plugs are a step to cold or you are running to rich..

I know you say you checked but it REALLY sounds like you have popped a clamp and are leaking boost somewhere between the MAF and the TB. The syptoms are there. Car will car JUST be able to stumble then die. Pull plug and soaking wet. the maf is reading a lot of ai caus e the blower is sucking it throught the MAF but the TB is only getting a "natural" vacuum. The PCM is sending a ton of fuel for the air its reading.

Originally the D1 had the maf down by the air filter before the blower. I think there new instructions are to move it up to the TB Elbow.

Not to be repetitive, but you popped a hose between the MAF and Throttle body.

Happened to me twice last week. Car absolutely dies a horrible death. Difficult to start, spits blue smoke (fuel dumping), idles irregularly, won't accelerate without dying....and makes a funny hissing sound?

My problem was I had just changed my blower belt and the added pressure that spooled up (slipping belt), in combo with a little silicone spray on the inside of my bellows to help it slip on, caused it to eject itself from my throttle body. It only takes a little leak to cause problems. I also use to have the blow-off bypass hose come off, until I got better clamps.

All my connections are good. Me and my buddy went over them, no leaks. I wont be able to get to it today, but tomarrow I will swap out those plugs and see where we are at.

Check your IAT sensor and coolant sensor(in water pump). If
either of these go bad your PCM will dump excess fuel and your
car will barely run.

If you have a scanner or datalogger you can find out really
quick if either is bad. If the IAT sensor is bad your IA temp
will read -36 degrees. If your coolant sensor is bad your A\C
temp will read -130 degrees. If you see these negative temps
you might try cleaning the connections before buying
new sensors.

Hope this helps.

Emil:93Z,383,Vortech,NOS,water/methanol

I had a scanner on it and no codes showed. I will be swapping out the plugs Saturday, thats all I can see it being. If that isn't it I'm going to be mad as hell! It's frusterating when things happen and you have a hard time finding the problem! :mad:

i rarely drive my car and i was running autolite 103's and they kept fouling out on me from normal driving cause they are not made for easy driving,they are more of a track item. my car run like crap and had starting issues,replaced the plugs and bingo. now i only run 104's

Hey,

The plugs were a no go! Fired it up and tons of black smoke came out! It started flodding out again! Its the stupid injector driver! My injectors are stuck wide open! I disconected it and stuck smaller injectors in it and its running much better! I just have to change the injector size on my PCM.

How the hell do I do that... i just recently got the Tuner Cat software, but I never used it... Anyone with experience using this, I would greatly appreciate some pointers!!!

injector size is in the ecm constants table.