Hi Gang,

I was having an issue with the '84 C4 I just acquired: every now and again, it doesn't want to start. Crank, crank, crank and it won't catch. When this happens, I usually have to cycle the ignition 3 to 5 times before she fires up. When she does, she idles high too until I rev it. Alternately, it will sometimes chug, chug, chug until it "warms up."

I haven't noticed any pattern to this. When there's not start issue, the car fires immediately up. But I can drive it for 30 minutes, no issues, park it, and then the same thing of not wanting to start.

A Vette friend told me he suspected the rotor was going bad/getting loose, like the rotor was having not synching up with the timing. So today, I put in a new high-performance cap and rotor set. I transferred the coil though. The previous cap and rotor didn't look that old at all, and it certainly wasn't original. But upon installing the new system (which was easy and without issue), much to my disappointment, this did not remedy the start issue. The car gave me the same "I don't wanna start easily" upon first crank.

I will say that once the engine caught on, and I took it for a spin, there was an improvement in what I perceived as a "smoothness" to the engine. So the repair wasn't for nothing. BUT ...

Anyone have any idea what the next culprit might be for this issue? Is the ignition going? Is my timing slipping? Any ideas?

Chris

 

You will need to determine whether it's a fuel problem, or an ignition problem. I love the '84, because it's so easy to confirm that you're getting fuel as you try to start the engine! Later Corvette's are a pain!

Remove the top of your air filter and watch the injectors as you try to start the engine. You should have a good solid spray pattern from both injectors, like this, which will pulse as you crank the engine.



How do the spark plugs look? Show us a photo, if you need some help.

 

Hey Roy,

I was looking at this very picture you posted in another thread before regarding someone who had their idle high. Turned out to be a cruise control issue for them.

As for my car, the previous owner took out the fuel injectors and installed a 4-barrel carburetor (and disconnected the cruise control too). As for me, I'm a tech, but not a "car guy", so though I'm great with tools and systems, I have no experience with motors. So, if I take off my air filter, should I still see what you have pictured?

I did notice myself that while driving this evening, my idle is high too. Tach should be around 9 in neutral, and it's between 15 and 21.

Chris

 

You probably remember the famous line in the Broadway play "Music Man": "Problems, we've got problems, right here in River City!"

So you've got a butchered '84. So sorry to hear about that. I have no idea how to help you. A too fast idle may be caused by a vacuum leak, or it may be that your carb needs adjusting. My question on the spark plugs still stands. Does your distributor have a vacuum advance unit? (The original '84 does not.)

 

Yeouch ... “butchered”, eh? Bit strong of a judgement, no? The previous owner swapped out the fuel injectors for a carburetor; they didn’t “circumsize” the car mate.

New spark plugs were installed by the previous owner in August. I will have to look to see if there is a vacuum advance on the distributor. The idle speed only changed upon swapping out the new distributor and rotor. As I mentioned, I am a tech, not a car guy .... yet. I have all the skill and intelligence it takes. Just not the experience. I will in time.

I’ll keep researching.

 

Is the choke adjusted properly? A carb is supposed to high idle until you blip the gas as it warms up. You need to depress the gas pedal when cold before you start car to set high idle and it also squirts some fuel down carb into manifold to start car. Is chock electric? What brand carburetor on it? Or heat stove type? Carbs are easy. Post or pm me a few pics of what you have . Ill walk you through it. I have many a converted 84 C4s and a few not also.

 

Also , The fuel pump must have a return style regulator on it to reduce fuel pressure at carb now. If it doesn't its putting way to much fuel pressure on inlet seat of carb and will cause flooding issues,...chugging as you say if able to actually start . Again can walk you through it.

 

Hey Highwayman.

Sorry for the late reply, but you put me in the right direction. The carb is a Summit Racing Street & Strip carb, based on the Holley. It does appear to be electric choke. The previous owner said nothing about depressing the gas pedal prior to cold start, and damn if that wasn't the trick! So I thank you for that.

As for the idle issue I was having, after more research and some video education on You Tube, it seems the only thing that needed adjustment was the curb idle screw. Backing it off brought the RPMs down across the board, so the car is behaving in a much tamer way now, and I'm no longer riding the brakes.

Thanks for your help!
Chris

 

Sweet!! Your welcome

My Happy Place !!