84 won't run right
Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
Likes: 0
84 won't run right
I have a 1984 vette that I built up a little. I put a new cam and lifter kit (.444/.466 lift), renegade intake, edelbrok aluminum heads (64cc) 185cc runners, jet stage 2 chip, magnaflow cat, kbd mufflers. I did get headers but they didn't fit so I sent them back. Anyway here's the problem; when we got everything back together and in their right spots and such it would rev up pretty good in park (has a dead spot at first but it always has) but when in drive it won't pick up. 1st gear doesn't seem too bad but as soon as it shifts into 2nd it just won't go. We thought maybe it was the cam so we took it back out and put the stock back in, no help it does the same thing.
I've been trying to figure it out for a couple days. Did about everything I could with the timing and nothing works. I have to turn the distributor cap to where the rotor is almost pointing towards #8 before it even wants to run. Could I possibly need a custom burnt computer chip?
I've been trying to figure it out for a couple days. Did about everything I could with the timing and nothing works. I have to turn the distributor cap to where the rotor is almost pointing towards #8 before it even wants to run. Could I possibly need a custom burnt computer chip?
Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
Likes: 0
The timing chain what was in there had a lot of play so I replaced it with one I got at autozone, we did tell them 84 corvette but the new crank gear has 3 keyways. We tried each one.
I did have to get new spark plugs for the heads but I gapped them to .045 like the car says the gap is
I did have to get new spark plugs for the heads but I gapped them to .045 like the car says the gap is
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Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
Likes: 0
The timing chain is the exact kind he has in the video and we put it on correctly, the fuel pressure is ok as well, it's always had good fuel pressure. Could the heads and intake possibly require me to get a tuned computer chip?
Le Mans Master
Joined: Aug 2017
Posts: 6,942
Likes: 1,490
From: New Jersey
That big of a jump in compression may make you have to get tuned, however it still should run somewhat.... Are you setting the timing with a timing light with the advance wire (esc) disconnected?
If you swapped back to the stock cam and it still wasn't right you've eliminated the cam. If there are no issues with vacuum leaks I'd make sure all the sensors are hooked up again. The coolant sensor on the front of the manifold will make it weird if it isn't hooked up right. The old one that looks like a knock sensor won't always make a good connection.
Also make sure the map sensor is on the outside vacuum port on the rear throttle body, the center one gives little to no vacuum response.
If you swapped back to the stock cam and it still wasn't right you've eliminated the cam. If there are no issues with vacuum leaks I'd make sure all the sensors are hooked up again. The coolant sensor on the front of the manifold will make it weird if it isn't hooked up right. The old one that looks like a knock sensor won't always make a good connection.
Also make sure the map sensor is on the outside vacuum port on the rear throttle body, the center one gives little to no vacuum response.
Melting Slicks
Joined: Mar 2012
Posts: 2,800
Likes: 456
From: USA
If I was doing this I would go back to the basics.
1. Pull #1 spark plug.
2. Roll engine over till you feel compression coming out the # 1plug hole.
3 Line up the timing marks.
4 Pull the left bank valve cover and make sure the valve on # 1 cyl. are closed.
5. Pull the distributor cap and make sure the rotor is pointing to #1 cylinder.
If not remove and replace distributor to proper location.
6. Check to make sure the plug wires are in the cap in the right order. I had plug wire crossed on my 84 when I rebuilt my motor.
DO THIS TO BE SURE IF YOU HAVE NOT ALREADY DONE IT.
The 84 ECM should run you engine with the mods. A chip is not going to help in this ECM. The ones that are sold are just a waste of your money. (Snake oil IMHO.)
Let us know if all this checks out. Good luck
1. Pull #1 spark plug.
2. Roll engine over till you feel compression coming out the # 1plug hole.
3 Line up the timing marks.
4 Pull the left bank valve cover and make sure the valve on # 1 cyl. are closed.
5. Pull the distributor cap and make sure the rotor is pointing to #1 cylinder.
If not remove and replace distributor to proper location.
6. Check to make sure the plug wires are in the cap in the right order. I had plug wire crossed on my 84 when I rebuilt my motor.
DO THIS TO BE SURE IF YOU HAVE NOT ALREADY DONE IT.
The 84 ECM should run you engine with the mods. A chip is not going to help in this ECM. The ones that are sold are just a waste of your money. (Snake oil IMHO.)
Let us know if all this checks out. Good luck
Thread Starter
4th Gear
Joined: Apr 2018
Posts: 4
Likes: 0
I've tried that with my dad in the garage with me, but I'll go back out tomorrow and recheck everything. And yes I did disconnect the esc wire when using a timing light to time it, still didn't make a difference it has to be advanced almost to where the rotor is pointing at #8 tomwant to run. When timing is set at 0 it idled at about 400 rpm and any kind of throttle would make it backfire and die.
Pro
Joined: Jan 2003
Posts: 706
Likes: 47
From: Denver Colorado
Will it pull steady vacuum at idle? If yes, what vacuum does it pull when idling? In park/neutral and what vacuum in drive with brake set?
Also: what is the condition of the harmonic damper? The ring on the OEM ones can slip when the elastomer gets old and weak and that can mess up timing.
Also: what is the condition of the harmonic damper? The ring on the OEM ones can slip when the elastomer gets old and weak and that can mess up timing.
Last edited by 1984Z51auto; Apr 24, 2018 at 12:50 PM.