computer question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

burnitdown612 · 10-15-2007, 12:56 PM

I was wondering if the computer from my 87s 305 motor incompatible with a350 out of 89 fullsizeblazer. The motor instalation is compltete but the truck just will not run right. I double checked all theplug wires and even did a timing check on it and everyhitng is perfect. The distributer cap and rotor and plugs are all brand new. It runs good at ittle but once you give italittle rev it turns into a flame thrower. i have a feeling the 305 ecm does not allow ittopump enough gass to satisfy the engine. any help would be great - nick

1966gmc · 10-15-2007, 01:08 PM

Are you talking about flames coming out of the carb? If so,you are back-firing thru the intake.That would be a timing problem more than likely.Does your current distributer have a big 4 pin connector coming off the side of it? If so I would replace it with one that is not computer controlled.

**Captkaos** · 10-15-2007, 01:49 PM

The computer is the same, but the chip isn't. If it is backfiring though the TBI, check you timing. It nees to be set with the bypass disconnected. Running with it connected you should have about 15 degrees.

DON'T replace the computer controlled distributor, the ECM relies on it to control you timing.

1966gmc · 10-15-2007, 02:01 PM

Quote:

Originally Posted by Captkaos

DON'T replace the computer controlled distributor, the ECM relies on it to control you timing.

See I bypassed the ECM on my Elky. Thats why I said something about the cc dist. I'll stick to vacuum advance over computer controlled advanced any day. I want to tell the car what to do,not the computer

rfmaster · 10-16-2007, 01:27 AM

Hmmmm. Only if you knew what you are missing....

10-15-2007, 12:56 PM	#1
burnitdown612 Registered User Join Date: Sep 2006 Location: windsor Posts: 21	computer question I was wondering if the computer from my 87s 305 motor incompatible with a350 out of 89 fullsizeblazer. The motor instalation is compltete but the truck just will not run right. I double checked all theplug wires and even did a timing check on it and everyhitng is perfect. The distributer cap and rotor and plugs are all brand new. It runs good at ittle but once you give italittle rev it turns into a flame thrower. i have a feeling the 305 ecm does not allow ittopump enough gass to satisfy the engine. any help would be great - nick __________________ 1987 k10 silverado 305/700r4

10-15-2007, 01:08 PM	#2
1966gmc Why does it taste purple? Join Date: Sep 2007 Location: Cambridge Md Posts: 621	Re: computer question Are you talking about flames coming out of the carb? If so,you are back-firing thru the intake.That would be a timing problem more than likely.Does your current distributer have a big 4 pin connector coming off the side of it? If so I would replace it with one that is not computer controlled.

10-15-2007, 01:49 PM	#3
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: computer question The computer is the same, but the chip isn't. If it is backfiring though the TBI, check you timing. It nees to be set with the bypass disconnected. Running with it connected you should have about 15 degrees. DON'T replace the computer controlled distributor, the ECM relies on it to control you timing. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

10-16-2007, 01:27 AM	#5
rfmaster Registered User Join Date: Oct 2003 Location: OC CA Posts: 1,374	Re: computer question Hmmmm. Only if you knew what you are missing.... __________________ "The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)



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