rrt898

I have 1986 coupe. I know the location of the two relays behind the battery. My question is which one is the burnoff relay?? Also does anyone have the correct part numbers for both? The local parts store wanted to sell me two of the same relays and I thought that wasn't right.

Thanks.

joeld

On a 89 the burn-off relay has 4 wires: 2 orange,1 dark blue,1 black.
The power relay has 5 wires.
On mine the burn-off relay is inboard: closer to engine.

Also on mine the relays are the same, not 100% sure on 86 but thinking they are.

Joel

coupeguy2001

un plug one of them, if it runs, it was the burnoff relay

leesvet

its right.

65Z01

You are correct; on '85-'87 Vette the BO relay differs from the Power relay but is the same as the fuel pump relay.

Same setup on my '88; I recently had to replace the BO relay.

leesvet

Odd.

on MY '87 the power & burn-off are the same. Fuel pump is similar (5-pins inline)to the 2 fan relays that are rectangular not semi-square like MAF relays.(4 & 5 pins square pattern)

Some of you are looking at trans relays and/or fans.

Remember that in 85 or 86 (IIRC) there is a MAF module inside, NOT a set of relays. You may be looking at something besides MAF relays..

FWIW..
the burn-off has nothing to do with how the engine runs. Its more of an automated maint item, not a control device.

tunedport85inject

burn off relais only heat for some seconds the light maf wire to clean it ,the power relais is fuctional.

Maf module for the 85' is a rare and expensive device

i know it i have an 85...

65Z01

Hmmm, interesting; I got that '85-'87 info from my TPIS parts catalog???

leesvet

most aftermarket catalogs do not contain the subtle differences between one yr model and the next.

relays, master cylinders, coolant sensor locations (swapped a cpl yrs)...even the odd ball MAP system is often missed by the catalogs.

Thats what makes the FSM so beneficial, BUT, limited to the one yr that it covers...accurate but narrow.

Cliff Harris

The '86 was the only year that had different MAF power and burnoff relays. The correct part numbers are:

10094701 -- MAF burnoff relay
10067925 -- MAF power relay

You can cross-reference these numbers to generic parts.

The relays are different internally and you can't swap them, even though the connectors are the same. The car WILL run with the relays swapped, but you will not get MAF burnoff and the MAF will eventually get dirty and your car will run really badly (you don't need to ask how I know this...)

rrt898

Thanks....I had a feeling when I was offered the same relays for both. I knew I had to check it out further. Thanks again for the part numbers.

leesvet

as previously stated, more often than not it is a relay thats throwing a MAF code and not the MAF itself.

These MAfs are pretty durable if they have not been modified. Even though the wire type is fragile in the respect that anything that gets sucked thru WILL wipe out the wire element, they hold up very well if the screens are still there to protect them. I've transplanted the 'core' with the heat-sinks and wire to other tubes or bodies, and had them survive the trauma.
The relays on the other hand get wet and they short or the corrosion gets inside and the delicate nano-thin wire gets broken very easily. A good bump will break one.

I wish I had $10 for every good MAF thats been replaced when it was only a relay that had failed...

JrRifleCoach

Power relay is behind the Burnoff relay on my 86e