Hello everyone. I'm new here and have a particularly interesting problem on my hands. The car is an '86 IROC with a transplanted crate 350 of unspecified year. I'm guessing 91 or 92 as it had a TBI system installed. I removed the TBI system and dual port manifold and hurled them into the nearby woods and replaced them with an Edelbrock 650cfm carb and correspoding manifold. The ignition system consists of an HEI style distributor with 8mm wires and shorty plugs. Now here's the problem... The car's last moments of life were as follows- 1) the car is hard to start and seems to be cold natured 2) the car is nudged to life with heavy throttle manipulation 3) the engine will not idle and is sputtering and missing heavily 4) car is finally moved into an adjacent shop after several attempts to nuetral dump the vehicle into motion and having to restart the engine every time. The engine will not run with any load on the tranny. 5) the car hasn't run since. Now.. things I have tried.. The plugs will not fire while they are in the block; however, if you remove a plug boot and place it near its corresponding plug the spark will jump the gap and fire the plug and the engine will cough. I even had a friend hold two boots in this fashion while i held two others and the engine coughed itself to life on four cylinders. The HEI distributor and all of its internal components have been replaced. The motor has a ground strap. The wires are new. I have un-wired the alternator to be sure its not feeding reverse voltage and have checked the battery for reverse voltage. IF your still reading this book do you have ANY idea what else I can try?

 

Might be a simple problem, not directly related to ignition. When you removed the FI unit and put on a carburetor, did you install a fuel pressure regulator before the carb? If you didn't, part or all of your problem is that the fuel pressure is too high, pushing gas past your needle and seat, and the engine is flooding out. Your Edelbrock wants to run at 5.5 psi, and no more than 6 psi. Your original FI electric fuel pump is putting out way more than that.

 

The fuel system in the 86 utilized a mechanical fuel pump so I installed a 6 psi inline fuel pump to supply my carb on the new powerplant. I can create an air gap between either the boot on the cylinder end or the boot on the distributor end and the spark will jump that air and the engine will try to cough to life. There is no fire if there is a direct path between the block and coil.

 

Not saying this is the problem then, but let's get the fuel supply thing out of the way first. From the factory, your IROC was equipped with a TPI fuel injection setup. The TPI, and the TBI (that you said was on it) has to run off a high pressure in-tank mounted electric fuel pump (which is what originally came with your car), not a mechanical pump. So, was the original electric fuel pump removed, bypassed, or disconnected by somebody somewhere along the line?

 

The 1986 IROC Camaro that i purchased was equipped with a Rochester 4 barrel carb with a mechanical fuel pump. The donor motor was taken from a 91 camaro that contained a crate motor which was using a dual port TBI system. The TBI system and manifold were scraped before the motor was installed in the 86. A low pressure inline fuel pump was installed to supply the 650cfm Edelbrock. If you remove a plug boot and place it near the spark plug cap the energy will jump the air gap and fire the cylinder. The car WILL run if enough cylinders are firing in this fashion. Once the boot is reconnected the engine will not even cough, spit, or sputter. Nothing...

 

I understand what you're saying about the carb and pump, but my question is was the original in-tank high pressure pump either disconnected, bypassed, or removed? It's a secondary thought, but still...
Was the engine running at all before this problem?
Is your distributor a stand-alone unit, or a computer controlled one?
Have you checked your timing, and are you sure you dropped the distributor in with the #1 cylinder at TDC compression stroke?
Any chance you may have put the distributor in 180 degrees out?
Are you sure your plug wires aren't crossed?

 

The donor 91 camaro had an in-tank high pressure fuel pump. I only took the powerplant from this vehicle. The 1986 recipient camaro had a mechanical pump assembly on its original 305 so I installed an in line pump using the factory fuel lines. The distributor is new and is a stand alone unit with a vacume advance. I have encountered crossed plug wires before and the engine will try and do something (pop, cough, etc.) This is also true with a 180 out scenario. I used an inductive timing light to determine if my timing was out only to discover that there is no fire for the timing light to detect. If I pull the boot and place it near the plug the the timing light will detect the spark and blink, but this will ONLY happen when there is an air gap to jump. My initial post desribed the last time the car ran and what its symptoms were... But here is what gets me.. No matter where or how the distributor is dropped in or how horribly out of sequence the wires are or if there is 1000psi of fuel pressure there should still be spark.

 

You're still not understanding what I'm asking. Your 1986 IROC (recipient Camaro) came with FI and an in-tank electric fuel pump from the factory. My question is....did the person who originally converted your car over to a carburetor know what the hell he was doing, and bypassed the electric pump? I know it had a mechanical pump when you got it, but you can't have both with a carb.
And the reason I asked about checking the timing is because jumping a spark across a gap like you're doing slightly retards your spark.
Is your distributor a new or used one, and known to work well?
While cranking the engine over with the distributor cap off, does the rotor turn normally?
Pull a plug and look/smell it to see if the engine is flooded.
Your plugs could be badly fouled/gas soaked if the engine is getting flooded (another reason to clarify your fuel pump situation).
When you look down the throat of the carb and pump the throttle, do you get a good squirt of gas?

 

• Available engines
  • 4 Cylinders 2 2.5L TBI
  • 6 Cylinders S 2.8L FI
  • 8 Cylinders F 5.0L FI (found in 45% of 1986 Chevrolet Camaro)
  • 8 Cylinders G 5.0L 4BL HP (found in 1% of 1986 Chevrolet Camaro)
  • 8 Cylinders H 5.0L 4BL OHV (found in 54% of 1986 Chevrolet Camaro)

As you can see 54% of the camaros from this year came factory with a 4BL rochester carb. No FI on this car ever. I will pull the plugs again and make double sure that they are in working order and do not look fouled. I'm def getting a good squirt from the accelorator pump. If i remember correctly the distributor has been replaced and the problem remained. This is a problem that is driving me crazy. I sold this car to my friend while it was up and running and then a few weeks later it did this. I will get him to pull the cap and spin the motor to verify the rotor is spinning. I can't imagine not already checking that but its been awhile since I looked at it. The car used to run like a scalded ape and one day developed this infuriating illness. My apologies if I come off sounding unappreciative of the help you are offering. Thanks for giving this a stab.

 

OK, I guess I should have asked you what type of transmission your car came with, you must have a 5 speed manual then.
The IROC with a manual trans came equipped with a 4 barrel, and automatic transmission models got fuel injection.
1986 IROC Specs