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Unable to Idle, runs ruff

pomai

pomai

1/2 ton status
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First start up of my 383, its unable to idle, and runs real ruff. I adjusted the new IAC, and it ran real nice for approx 20 seconds and then back to real ruff again and unable to idle. when I release the throttle linkage, it just dies.

Removed each spark plug and all are identical, (Black). What does this condition mean?

Any help is really appreciated.

Thanks, Ed
 
no oil, kind of a dry black film.
454 injectors, 15 psi fuel pressure.
Could it be flooding?
 
pomai said:
no oil, kind of a dry black film.
454 injectors, 15 psi fuel pressure.
Could it be flooding?
Click to expand...


So you smelled the plug and it smelled like fuel? unless the injerctors were stuck wide open i dont see an efi system flooding without a computer error.
 
Thats what I was thinking, would a vacuum leak make the plugs black like that?
 
Vacuum leak to the MAP sensor or no vac to the MAP at all would certainly do that. Makes the computer think it's under load, and adds fuel.
 
I have the map sensor vacuum line connected to the rear port on the TBI. Is this correct? Or is it supposed to go the manifold?

Thank you for all your help, Ed
 
Off hand it sounds very rich. Try backing the fuel pressure off to 12psi.
What Cam and Heads are you running?
How's your ignition timing?
 
Unless you had a chip burned the 454 injectors are waaaay too much fuel for the stock chip. The black sooty plugs tell you it is running rich.
 
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1988 Chevy Full Size 4x4 Blazer​


Engine is a late model factory roller 4 blt main block, 383 rotating assembly, scat crank, 6” rods, JE forged 40 over pistons, World S/R torquer heads. JBA shorty headers

Cam is a Roller Comp Cam 08-304-8, .500/.510, Duration 266/276, Lobe Separation 114,.1.6 roller rockers.

Throttle body bores are 2” by Xtreme-FI from eBay along with there intake manifold bored the same.
MSD Distributor and Coil.
3” Cat Back Exhaust system
Delta Flow- Muffler

www.tbichips.com
Computer chip
High Pressure fuel pump
Regulator spring

www.Bowtieoverdrives.com
700r4
Xtream Package

www.cfm-tech.com
CFM GM TBI Power Plate (bored 2”)
Hypertech Power Charger
TBI Injector Spacer
Adjustable Fuel Psi Regulator
3 wire (heated) Oxygen Sensor
15 psi Fuel Gauge

www.TBIPARTS.COM
New 454 Flow Matched Injectors

1 Ton Drive Train
Rear end is a14 blt, 4.56 gears (Eaton Limited Slip)
Front is a Dana 60 with 4.56 gears
33” tires, will go with 35 soon
 
So did you make positively certain that Brian at TBIchips knows you're running a 454 TBI? There is still the chance that even if you did tell him he did not get the chip tune done properly. Also when i had him do a chip for my initial set-up he made a chip based on ALL the engine specs i gave him then i had to datalog and send him the file and he made an adjustment and sent me another chip, this went on for several (5 times to be exact) before i was happy with the results based on driveability and datalogging. Sounds like it might be time to call and talk with him and then do some datalogging if you can get it to run long enough to do so then send him the file and let him decide what he needs to do.
 
The TBI is a 5.7 bored to 50mm from Xtreme I bought from eBay, the injectors are 454

I have the map sensor vacuum hose connected to the port on the rear of theTBI. Is This correct?

When I come home from work, it started right up but wouldn't idle, ran real ruff. When I let go the throttle it just dies, tried to start it up again and it just floods, plugs are all wet with gas and black.

Going to remove the regulator spring that I got from you and put the original one back in.

The first motor I put in was a 383, one size smaller cam, with Brains chip. That engine did the same thing, wet black plugs but with a real bad knock, removed the engine with 0 miles and went back to the machine shop. Installed again with the same problem (Knock)

With still 0 miles, removed it again and went to another machine shop, had to go to 40 over, went one size up on the cam and decided to go with the windjammer. But I'm having the same problem with the wet black plugs and the gas just poring in, on the second rebuild.

The first engine I couldn't get it to idle below 1,000 rpm’s this time around I can't get it to idle at all.

Could the MAP sensor be bad with out throwing a code?
Should I replace it?
 
Yes the MAP sensor vacuum gets hooked to the port on the rear of the TBI.

Once again, it sounds like your issue is with improper dwell time for the injectors which is a chip issue that you need to talk to Brian about. Sounds like maybe he has the chip set for a stock injector and NOT for the 454 injectors. When you ordered the chip from Brian what exact info did you give him? Does he know you're running 454 injectors in a bored 5.7 TBI? Does he know what fuel pressure you're trying to run? All of this is VERY PERTINENT info that he MUST HAVE in order to get your chip done correctly for you.
 
The information that i posted on my engine combo is what he received from me. he set me up with the injectors and knows about the bored TBI.

I am intouch with him at this time with this problem, he hasnt suggested that it could be the chip. i had the same problem in the first rebuild with 5.7 injectors and his chip.

Am I correct in thinking that the problem is between the MAP and chip?

could the MAP be bad without throwing a code?

So
 
I'll lay money that it's a chip problem. MAP will generally throw a code when there is either a no vacuum issue or an electrical issue with it.

Just for reference i'm running a 350 +.030" with a Comp Cams hydraulic roller (8-484-4) 9.489:1 CR with AFR180 heads and a 454 TBI with 454 injectors that have been flow tested at 98 lb/hr at 18psi (which i'm running) and my truck runs like a raped ape. Like i said i had to deal with Brian 5 times on a chip burn before i was happy with the results.
 
Were did you get the 454 TBI from?
I'm thinking of getting one from SPR Performance, TBIPARTS.com this is were I got the 454 injectors. I wasn't happy with the Xtreame TBI from the start.

I'm going to talk to brain about the chip.

Thank you very much for hanging in there with me. I need all the help I can get.

Ed
 
I found a 454 TBI at the local wrecking yard and then i had a customer give me another one. I used one on my rig and then traded the other off for some chip burning hardware (before you even ask i haven't even played with it yet). :D
 
Have you tested for any injector leaks? Presurize your fuel system with out attempting to start the motor (you may need a friend to cycle the key a few times) and keep a close eye on the injector pods. Look for any fuel leaking and dripping past the injectors. Make certain that the o-rings are installed and seated correctly.

Also look at your coolant temp sender - CTS - at the top, front of your manifold. Are you sure that it is the correct one and wired in correctly?
 
its the original coolant temp sender. everything plugs right in. all grounds are grounded. No injector leaks.
It idles but runs ruff and unable to accelerate, it showed a code 33, replaced it with a new MAP sensor and still showing a code 33.
 
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