C4 running rough

[vetteboy86]

My brother recently bought a 87 corvette. When we bought it the engine light was on, but when we checked it came up the mass air flow sensor or relays. Well i swaped the mass air flow off my 86, unplugged the battery for about 30 minutes, and the light came back on once the car was running for a while. I looked in my haynes manual and it says that the trouble code i am reading is for the burn off or power relay, and it suggests replacing both. The car idles rough, lazy to start, and hesitates sometimes. I think this a good starting place considering he can buy the relays for like 15 bucks. A few year back before i knew anything about the L98 i had this problem and took it to the shop and they replaced two relays, however i do not remember which ones, it has been a while. Our problem is where are these relays located. I was unable to find anything about replacement in any manuals. If anyone has done this before, or know where and how to do this we would appreciate the help

thanks

 

[jrbartholomew]

you need to go to gm and get part #14089936 for both maf and burn off relays.they are rihgt behind the battery. also if this dosent work be sure the metal line from the right side of the throttle body to valve cover is open.last check the idle air control.
good luck
jeff

 

[TALMADGE 1]

Replaced both my relays two months ago, I got them from Auto Zone. My car 1988 was real rough on letting of the gas pedal. It felt like a boat anchor had my rear end loaded down. I replace the relays and back to cruising.

 

[RedRagTop]

Replace BOTH relays mounted on the firewall behind the battery. www.c4vettes.com has a step-by-step. Mine was done 4500 miles ago, no SES light since...

 

[ydphtwl]

Hello, these guys are probably right about relays. I just wanted to share my experience. I started getting weird codes and having similar problems on my 87. What I found was that the battery connectors had corrosion that you could not see until you disconnected them. I cleaned them and replaced and my problems went away. Other than alternator, starter, ac comp, the only trouble I ever had with my 87 was relays. The fuel pump relay drove me crazy. I would go buy gas, shut it off, wouldn't crank back up. I would get out check a few things, get back in and it would start right up. I would recommend changing all the relays that are relatively inexpensive.

 

[vader86]

Replace relays first, always. They are pretty cheap.


Then reconnect battery and see if the codes come back, then replace MAF.

 

[89blkvet]

Isn't there a way that you can check the MAF first before actually buying one?? They are kinda expensive

 

[TerryD]

Is this problem common only on L-98 vettes or could this be a problem on my 96?

 

[caddy]

What can one expect to pay for those relays?
TIA :eek

 

[vader86]

relays together are about $20

yes this can happen on a 96, it has MAF

 

[scorp508]

Do the relays first, we all seem to need to do these at one point or another. Don't forget to unplug the battery again for around a minute when you replace them.

The burnoff procedure superheats the wires in the MAF at engine shutdown to "clean" them of any particles that may of stuck to them with airflow stopped. Make sure the wires in your MAF are intact and not broken if you have descreened the MAF.

Also check your TPS settings, it should be between 0.54 to 0.68 at idle. That sucker can screw SO much up if not right its amazing.