87 IROC not firing
Thread Starter
Junior Member
Joined: Apr 2009
Posts: 19
Likes: 0
From: reidsville nc
Car: 92 B4C/91 Z28
Engine: 5.0/5.7
Transmission: 5 SPD/700R4
Axle/Gears: 3.42/3.23
87 IROC not firing
87 iroc was converted to a carb some time back and jus replaced the 305 with a 350... drove IT awhile and it started shuttn off . run a lil and shut off. no fire to the plugs...changed and checked coil..ignition module.. ground and positive to the coil,, rotor turns when motor turns over( did keep the same distributor from old engine)...
any one have ideas of whats goin on
any one have ideas of whats goin on 
Supreme Member
Joined: Sep 2002
Posts: 9,192
Likes: 20
From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: 87 IROC not firing
You state using the old distributor - you can't use a computer controlled distributor with a non-computer controlled carb - you have to get a vacuum advanced distributor - so unless the distributor has been swapped to a vac-adv distributor, you'll have major issues.
How is fuel supplied to the carb?
A 1987 FI car had an intank pump for the TPI system, and thus needs a return-style fuel pressure regulator (like a Mallory 4309) in order to drop the fuel pressure down for a carb. If a non return-style regulator was used with the feed line only, then you'll have issues there. Also, an FI car gets the fuel pump controlled by the computer, which is no longer working if there's an aftermarket carb - thus might be an issue with the fuel pump not running - we need to know how that was all wired up to work.
A 1987 carbed car also had an electric in-tank fuel pump as well as a mechanical pump on the block - if that complete system was used and is still working, then fuel should be good.
Also - just for knowledge - if the car is an automatic with a 700R4, you need to verify that the TV cable was properly installed on a good sturdy throttle cable bracket with the right geometry corrector. And, unless someone rigged something, you no longer have any torque converter lockup function since all that was computer controlled as well.
Bottom line is, an aftermarket carb means no computer control of any other computer functions (like distributor advance, TC lockup, etc.), and those things would have needed to be modified with the swap. So - we need alot more info on what exactly you've got there and how it was rigged (if it was rigged) to function before we can help diagnose why it's no longer working.
How is fuel supplied to the carb?
A 1987 FI car had an intank pump for the TPI system, and thus needs a return-style fuel pressure regulator (like a Mallory 4309) in order to drop the fuel pressure down for a carb. If a non return-style regulator was used with the feed line only, then you'll have issues there. Also, an FI car gets the fuel pump controlled by the computer, which is no longer working if there's an aftermarket carb - thus might be an issue with the fuel pump not running - we need to know how that was all wired up to work.
A 1987 carbed car also had an electric in-tank fuel pump as well as a mechanical pump on the block - if that complete system was used and is still working, then fuel should be good.
Also - just for knowledge - if the car is an automatic with a 700R4, you need to verify that the TV cable was properly installed on a good sturdy throttle cable bracket with the right geometry corrector. And, unless someone rigged something, you no longer have any torque converter lockup function since all that was computer controlled as well.
Bottom line is, an aftermarket carb means no computer control of any other computer functions (like distributor advance, TC lockup, etc.), and those things would have needed to be modified with the swap. So - we need alot more info on what exactly you've got there and how it was rigged (if it was rigged) to function before we can help diagnose why it's no longer working.
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