Hello all, I have read through a lot of great posts referring to the MAF sensor and how it should work, troubleshooting, etc. Some really good stuff on this forum. Reaching out to see if anyone else has had this issue: drive car for 15 minutes, shut off the engine and the MAF burn off coil only glows red for @1 second, relay clicks then goes off. I read it should glow longer than 1 second. 1989 gta 5.7. Both maf and burn off relays replaced to no avail, possible maf sensor issue or bad analog ground? Thanks.

 

Are you getting a code 36 ?
Do you have constant power to the burnoff relay key off.

 

I initially had a code 36, but cleared it by disconnecting the battery when I replaced the maf sensor relay and it hasn’t come back (yet). I have constant power to the burnoff relay key off. (Terminal E) I hear a click when the burn off stops, maybe losing power to the burn off relay coil?

 

When I shut down my 88, after a couple seconds, I can hear the MAF burnoff relay cycle. It burns the MAF for only about a second or so. Pretty short.Maybe 1.5 seconds. Less than 2 seconds for sure, it's quick.

 

I'd have to look at my 89's service manual but IIRC the burnoff cycle varies in length on due to several factors.

 

You don't need the burn-off function. It was an over-engineered feature (Bosch - Ze Germans) that was deleted from all modern designs. Delete it in the ROM if it's troublesome. Waste of time to bother fixing that "feature". Use a quality air filter and clean the MAF wires with brake clean whenever you change the filter.

GD

 

Really?? More info please. In my 88 you can clearly hear the burnoff relay cycle after engine shutdown, if you are in a quiet area. It is always very quick, about a second or so. I've never seen it go longer.

 

GD, is there a recommended procedure for MAF cleaning? I've wrecked one by spraying MAF cleaner into it. What is the secret to cleaning the thing without damaging it?

 

Well that varies according to who you ask. You can buy MAF cleaner, but generally I just use brake cleaner. Never had a problem. A small metal handled "acid" brush can be bent in many orientations to brush the cleaner onto the elements..... And surprisingly a lot of guys including myself will actually scrape the contaminants off the element with a pocket screwdriver and a magnifying glass. The latter usually works the best.

AND the BEST way of all to clean a MAF - replace the ECU with an EBL Flash II and chuck that piece of expensive failure-prone garbage as far as you can.

GD

 

There is no burn-off in a "modern" MAF because they have all transitioned to TFT sensors instead of a hot wire. That same technology was once available for our type MAF units, but they seem to be elusive today. I'm very glad I changed when I had the opportunity.

 

Not entirely true. Subaru and other asian cars still use hot wire MAF systems. Subaru in particular has used hot wire MAF systems since 1987 and has never implemented a burn off function in over 30 years.

Ford also used a lot of hot wire systems in the 90's that didn't burn off either. The whole burn off concept was dropped after the 80's. Hot wire systems built after that era simply eliminated it. Relying on periodic manual cleaning or replacement instead.

GD

 

Although the burn off only occurs for only @1second, the coil seems to be pretty clean. What about yours Tremo?

 

Good information, GD. I was unaware of those manufacturers still using hot wires and current sensing.

 

If you have good filtration, it's not really going to get dirty anyway. As I have been pointing out, the burn off function is superfluous.

GD

 

Clean