1985 C4 Corvette L98 Engine Issue
Thread Starter
4th Gear
Joined: Mar 2021
Posts: 4
Likes: 0
1985 C4 Corvette L98 Engine Issue
So I recently just bought a c4 corvette as a project car. I am unklowledgable about engines in general but I have a theory on what's causing my issue but need some more advice. I can start the car but sometimes but it sputter out and dies. But when the car does start it idle but dies as soon as a press on the throttle. I think the MAF has a bad cord and isn't properly supplying the engine with air, that's what the guy who sold it to me said anyways.This is the first car I've ever bought with the intention to build it up. Just looking for some ways to trouble shoot and appreciate any advice you guys can give.
Instructor
Joined: Jun 2019
Posts: 147
Likes: 48
From: Rockland County, New York
Get a few things before you get started. A factory service manual (I have this one https://www.ebay.com/itm/1984-1985-C...Cclp%3A2334524) and a fuel pressure gauge (I have this one
). Also, if you don't know the history of the vehicle I would give it a full tune up before you attempt to diagnose anything. This way you can assure yourself that all the routine maintenance issues are not the cause of your problems. The service manual tells you step by step howto troubleshoot your issue and what to check.
Thread Starter
4th Gear
Joined: Mar 2021
Posts: 4
Likes: 0
Get a few things before you get started. A factory service manual (I have this one https://www.ebay.com/itm/1984-1985-C...Cclp%3A2334524) and a fuel pressure gauge (I have this one https://www.amazon.com/OTC-5630-Fuel...062865&sr=8-12). Also, if you don't know the history of the vehicle I would give it a full tune up before you attempt to diagnose anything. This way you can assure yourself that all the routine maintenance issues are not the cause of your problems. The service manual tells you step by step howto troubleshoot your issue and what to check.
Thread Starter
4th Gear
Joined: Mar 2021
Posts: 4
Likes: 0
Th light does light up. How would I check the codes? If it requires a tool what tool would I need? I'm good with computers but I'm pretty clueless on cars.
Instructor
Joined: Jun 2019
Posts: 147
Likes: 48
From: Rockland County, New York
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
So I recently just bought a c4 corvette as a project car. I am unklowledgable about engines in general but I have a theory on what's causing my issue but need some more advice. I can start the car but sometimes but it sputter out and dies. But when the car does start it idle but dies as soon as a press on the throttle. I think the MAF has a bad cord and isn't properly supplying the engine with air, that's what the guy who sold it to me said anyways.This is the first car I've ever bought with the intention to build it up. Just looking for some ways to trouble shoot and appreciate any advice you guys can give.
Drifting
Joined: Jun 2013
Posts: 1,590
Likes: 60
From: ft myers FL/Munising MI
welcome to the forum....you've already got the best advice....get a fuel gauge and FSM.....unplug the maf.....jump a/b on your aldl and count the flashes.....remove the neg cable to clear codes....search for the procedure on this site....and the explanations of the codes..
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Cruising
Joined: Mar 2021
Posts: 14
Likes: 5
From: Atlanta, GA
I just went through this with mine, It had been sitting for a while. My first issue was the MAF, you can check it with a multi meter and see if the voltage is right. There is a write up on this site for that, but the signal wire is green I think and it should be changing with air flow and somewhere between 0.5 and 5v. If it's not changing, it's bad. Also, check the IAC motor and see if it moves or if it's dirty. Mine was stuck and needed to be replaced.
I replaced the MAF and it ran better. I then did plugs, cap and rotor because they were in rough shape. Wires looked good.
That helped a bunch.
I also replaced the O2 Sensor because I got a code 32 for EGR, I think that was the number, when driving and it was suggested the O2 would help.
I also checked and adjusted the idle speed and adjusted the TPS. After running the tank of old gas out with a can of Seafoam in it and filling it up with fresh gas, she runs like new now.
I replaced the MAF and it ran better. I then did plugs, cap and rotor because they were in rough shape. Wires looked good.
That helped a bunch.
I also replaced the O2 Sensor because I got a code 32 for EGR, I think that was the number, when driving and it was suggested the O2 would help.
I also checked and adjusted the idle speed and adjusted the TPS. After running the tank of old gas out with a can of Seafoam in it and filling it up with fresh gas, she runs like new now.