elcam84

Just informational...


It's repeated many times that the MAF power and burn off relays can use the same part. Well not exactly.

The MAF power relay has a couple added resistors to it that the standard 5 pin relay does not. You can see one of them in the inserted picture. There is also another resistor under the coil that you cannot see.

In the picture an original MAF burn off relay is on the left and an original MAF power relay is on the right. The added resistor is obvious.

If they were really interchangable GM wouldn't have made the modifications to the MAF power relay. They would have just thrown in a standard 5-pin relay. Also the aftermarket would have been the first to jump on that as their primary motive is to reduce part numbers.


Now the fuel pump relay and MAF burn off relay can be used interchangably but there are differences but not enough to cause an issue.


The correct GM part numbers for the relays are. GM Borg Warner and GP Sorenson.

GM 10067925 MAF power
GM 10094701 MAF burn off
GM 14078914 Fuel pump


BW R3009 MAF power
BW R671 MAF burn off
BW R761 Fuel pump


GP MR22 MAF power
GP MR82 MAF burn off
GP MR5 Fuel pump


My TPI has been doing some goofy things and it was at the time I did the swap and replaced the relays. I dug out the old relays and checked the current part numbers. Since the MAF power one was not the same number I needed to open it up and find out why.
I had always thought that the GM relays were pretty much one of two types 4 terminal or 5. After a little research they are minor differences in some applications. Yes any 5 terminal will work in pretty much all apps but they may not be exactly right and could cause issues due to missing internals.

Well after putting the correct power relay in my goofy issues have been solved. So make sure you buy the right relay. (my current relays were a year old and show no resistance with an ohm meter)

S10Wildside

It should be mentioned that this information applies to years prior to 1989.

Formula350Scott

iTrader: (3)

Are the Maf power and burn off relays the same part number on the 89's?

IROCThe5.7L

Hmm, interesting. I have the same part number for both my power and burn off and no problems. That's good to know though, I always thought they were the same.

S10Wildside

The relays for the 1989 system can be the same, GM # 14089936

This is the newer weatherpack style relay.

elcam84

I'm not sure why the difference. They are both controlled by the ecm in the same way. It stumps me why the difference.

All I know is that when I went to a GM relay with the same guts it runs better.

IROCThe5.7L

What was the problem before you replaced the relay?

elcam84

I replaced all the relays whan I put the TPI in. Ran the same one for both MAF relyas like others have. Never ran quite right. I never could find a reason for the problems so I changed the power relay for a GM one and the drivability issues have cleared up.

The relays only had a few 100 miles on them. The relay in the picture is the original from the TPI that I dug out of one of my boxes to compare.

Stephen

iTrader: (12)

On my 87 GTA, I was getting a SES code of my MA burn off, so I switched the connections for the fuel pump relay, suspecting that the relay was the cause. I figured if the fuel pump gave me issues, that would pretty much decide it, huh?

Well, the SES went away, but the fuel pump hasn't given me ANY problems.

I switched the connections back, as a double check...SES MAF burn off again. So, I switched the connections again, and that was around the end of last year. So, around 8 months now, with no problems.

IROCThe5.7L

Hmm, interesting. I have three relays on the driver side. I was informed the two round style ones were for the power/burnoff, and the square one is for the fuel pump. I actually have a brand new relay in my room with the part number: GM 10067925 and it is square, so I figured it was wrong (bought it for the MAF Power). But according the the part numbers posted in this thread, it says it is for the MAF power.

Stephen

iTrader: (12)

Here is a pic of the relays I'm referring to, showing the 2 I switched the plugs on. The left, (inner most) one is stamped with MAF POWER.

The middle and right one, marked in the pic, are both 14078907.

Stephen

iTrader: (12)

Found my notes...

They are both 14078907 relays. My SES code was code 36, MAF burn off relay.

By simply switching the plugs, my SES light went off, and I've had zero effects.

gta_knight

So all you have done is plug the burnoff connector into the fuel pump relay and vice versa ? i might try that ! ive had a code 36 on my 87 GTA for ages now.

JB22

I will just post to say that those arent the right part numbers for my 88.

Mine are the rounder style.

thunder85

iTrader: (1)

I have an 88 GTA, and my relays are the rounded off type as well. they both were the same part number. i am having an issue with my maf reading 5g/s when the engine isn't running... would this be a power relay issue? i have changed the burnoff relay (which resolved my 33 and 34 engine codes, just stuck now with incorrect maf values).

IROCThe5.7L

My car runs fine. And when the car is on and not running, the MAF reads 5g/s. I think that's normal.

patgta

Nice post guys. I been having this code 34 problem for years. I have replaced the maf sensor and still no success, the code only comes up maybe once a month but it is still annoying. So i guess its either a bad relay, ecm or bad wire connection somewhere. I'll try to solve this problem with this new information. Thanks Pat

thunder85

iTrader: (1)

well, i am running a bit rich.. i have changed my coolant temp sensor, both relays, cleaned my maf, replaced ign module, etc. its not REALLY rich, just enough that when starting cold, i have to try several times to get it fired up. i can smell the gas, so i know its a rich condition.. and stepping on the gas to open up the butterflies helps it start quicker. any ideas? i can get more sensor values if it would help

skewbbasteve26

I am so glad I founf this site... I was wondering if you could send me or post a picture of what color wires are going to these three relays MR22 MR82 and MR5. I have taken my relays off and don't remember the order in which they go. I have drawn up a picture of the pigtails and need to know what relay goes on what. I dont want to damage anything if I put them in the wrong place. 1986 Trans Am TPI 305.

resinlake

Really interesting posts. I swapped an 88 Iroc into an 85 that was just about 100% rust free and eliminated my heat/ac and all smog. I am getting Code 34. I de-screened the MAF, no loose wires or anything, how would I actually test to see what it is, relays or sensor that would be throwing the code? The cars just about ready to be put on the road but I'm concerned about drive-ability and yes even mileage if the MAFs f'd up. Thanks guys.

thunder85

iTrader: (1)

which relays did you use? the 85 maf burnoff and relay are not the same as those used in an 88.

resinlake

It was a fully swap, engine harness and body harness. Nothing remains in the car that was 85. It is all 88 except for the steering column.

pandin

If you open up the relays you will see the contacts are different sizes.

Control type relays have smaller contacts and power relays have bigger.

DC relays include a diode across the coils to prevent the coil EMF from spiking the driver transistor and shorting its life or arcing the controling relays contacts.

Resistors are added to control power flow (restrict in rush currents "soft start"). Also added with capasitors to filter the power harmonics (AC).

It is these spikes that cause random gliches in electronic circuits (MAF).

If you are controling a motor (fuel pump/fan) the contact inrush can be very high and the contact cut off spike very large (acts like a small welder).

resinlake

Interesting. I swapped in a CS144 alternator last week from a Fleetwood with 2 guage wire for the (+) and when I went to put the (-) lead on the ground post it was obviously acting like a welder if you know what I mean, there was a short somewhere or a great spike. Anyway, I let the car sit for a day and then tried again the next and was able to put the wire on the post with no arc back. Just made me go hmmm. I was even wondering why when I jump A and B on the diag port to read the code and turn the key my cooling fans come on. I know theyre hard wired to both run when the engine is running. Im obviously not an electrical genius. The fans were set up that way when I bought the car back in 02'

pandin

This info comes off the AutoZone Web Page

MR82


MAF burn off
Part Number: MR82
Weight: 0.154 lbs.
Note: O.E.M. #10038792, 10094701, 14078907, 14078979

Gp-Sorensen / Relay - Anti-Lock Brake
MR82
Gp-Sorensen / Relay - Fuel Pump
MR82
Gp-Sorensen / Relay - Throttle Control
MR82
Gp-Sorensen / Relay - Fast Idle
MR82
Gp-Sorensen / Relay - Mass Air Flow Sensor
MR82
Gp-Sorensen / Relay - A/C Compressor Control
MR82
Gp-Sorensen / Relay - Radiator Cooling Fan Motor
MR82

MR22
https://www.thirdgen.org/forums/atta...1&d=1216175175

MAF power
Part Number: MR22
Weight: 0.15 lbs.
Application: With 4 terminals

Note: O.E.M. #10067925, 14039663, 14073412, 14078915

Gp-Sorensen / Relay - Fast Idle
MR22
Gp-Sorensen / Relay - Blower Motor Cutout
MR22
Gp-Sorensen / Relay - Fuel Pump
MR22
Gp-Sorensen / Relay - EFE Control
MR22
Gp-Sorensen / Relay - Air Pump
MR22
Gp-Sorensen / Relay - Upshift
MR22
Gp-Sorensen / Relay - A/C Compressor Control
MR22
Gp-Sorensen / Relay - Mass Air Flow Sensor
MR22 Note: Optional
Gp-Sorensen / Relay - Throttle Control
MR22
Gp-Sorensen / Relay - A.I.R. Control
MR22


MR5
https://www.thirdgen.org/forums/atta...1&d=1216175175

Fuel pump
Part Number: MR5
Weight: 0.149 lbs.
Note: O.E.M. #14078902 (14078914)

Gp-Sorensen / Relay - Amplifier
MR5
Gp-Sorensen / Relay - Aux. Engine Cooling Fan
MR5
Gp-Sorensen / Relay - Radiator Cooling Fan Motor
MR5
Gp-Sorensen / Relay - Fuel Pump
MR5
Gp-Sorensen / Relay - Anti Diesel
MR5

Notice all three will run fuel pumps (large inrush and large magnetic cutoff, EMF) , and the MR82 weights the most.

The MR82 has larger relay contacts then the MR22, and did not see the extra resistors in the GP relays.

pandin

Maybe this pic (from GM manual) will help to show how the resistors are used.

They are the zig zag lines across the coils (D & F) on the Maf relays. When used this way the resister helps to bleed off power when the control circuit breaks the connection.

It also makes up a LR circuit (type of filter) which is tuned to some frequency that will dampen oscillations when the circuit is energized.

Coils of wire act like electrical flywheels, slow to start and slow to stop (they store energy that can be used when the coil collapses).

Capacitors act like electrical springs (also can be seen as small quick discharging batteries).

Resistors are like a narrow place in a pipe (they limit the electrical flow and cause the power to turn into heat).

Note that the Maf power relay is controlled by the Fuel pump relay and is tied directly to the fuel pump motor. Any issues (shorts and intermittent connections) with the fuel pump and/or wiring will effect the maf power relay.

The Fuel pump motor is a brush motor, like a portable drill, ever see the lightning storm inside the motor, when running the drill under load.

mark wells

Interesting indeed..I have been getting terrible fuel economy ever since my 2 second prime went away when doing a cold start. Fan has been running as soon as the car starts as well. I think this is some how all related. 1st fan was running as soon as the car starts, then the two 2nd prime went away and fuel economy suffered terribly. I had no Idea that the fuel pump relay was tied to the same system as the MAF burn off relay. I am not able to find where my fuel pump relay is located but I was thinking it was the same as the MAF burn off relay for this is the only relay near my brake booster.

Chevy86 IROC-Z

iTrader: (17)

elcam84. where exactly are the resistors connected to on the MAF Power Relay? Im thinking about soldering a resistor to the MAF Power Relay that I just bought at NAPA. The type that I bought doesnt have the resistor that jumps across the relay. The part number of the NAPA MAF Power relay is AR227SB. Here is a post of the relay so that you can see what Im talking about. https://www.thirdgen.org/forums/tpi/...omparison.html

Twin_Turbo

iTrader: (25)

On my non molested 100% original 88 I had codes related to the MAF, replaced the power relay witha generic 5 pin I had lying around and the car idles higher and doesn't always do the cold startup high idle right after the engine runs, sometimes it dies after a blip of the throttle. Start it again and it's fine. For gigles I tested it on my buddies 83 w/ that 406 super ram and swapping in different relays definitely changes the idle RPM and that one is a speed density car. Time to get some proper burnoff and power relays.

Chevy86 IROC-Z

iTrader: (17)

So you replaced the MAF Power Relay and you got a high idle while at park right? Does the replaced MAF Power relay have the resistors or is it just a plain 5 pin?

Twin_Turbo

iTrader: (25)

Yes higher in closed loop and lower in open loop right after startup (cold) and picks up then. It's really very weird.

I think it's just a plain 5 pin, it's the oval shaped type but I haven't opened it. I have a whole bunch of them, all different numbers. The only stock power and burnoff relays are shot. The power relay will trip a CEL every now and then, same for the burnoff. Replacing them keeps the CEL away but the engine does not idle as smooth as with the original ones (if they don't trip a code, say..out of 5 starts they'll trip a code 2 or 3 times) I got a code for low MAF signal during cranking and one for the burnoff. Replacing the burnoff with a generic one didn't result in issues but the maf power is a different story. Going to have to change it for a proper one.

The ones on my 87 are non interchangeable since they are the square type.

resinlake

Twin Turbo, you just explained exactly what I have going on, high idle at cold start on my 88, goes away as soon as it warms up, the stock relays trip codes now and again, go away pretty quick. Car runs great, after a perfect setting on the TPS and idle, thats the only quirk right now, that and my tires seem to spin a bit easy with full throttle, still trying to figure that out. hehe. eh, but the connection going into one of the relays is a bit hmm, not good looking. Exposed wires, and one of which is loose and can be pushed in and pulled out just a bit, going to replace that and the two relays. I do like the newer Maf with the board (if its old from the 90s but *new*, all the same to me) vs the old element.

IROCKman

hi i have a 87 iroc with a 5.7 i have owned this car about 16 years anyhow i have replaced maf power relay 10067925 which i my car is on the side near the engine and the middle relay #14078907 which has been changed to #10094701 and the relay next to the fender has no part number on it i have read 10094701 replaced the old one but now i read there is another one i am confused as my shop manual shows burn off relay by the engine and fuel relay in the middle and power relay next to the fender i guess i need to know the wiring diagram or colors of the wires for each relay so i am sure that they are right thanks for any help guys

hawkdriver

I thought one was for MAF power, one for the fuel pump relay, and the other one was for the cooling fans....and that the fuel pump and cooling fan relay was interchangable....at least on an 87 TPI

y84pauloflondon

O.K. guys, so 3 relays Right?! First one on the right(closet to fender) is the Maf Burnoff Relay which was part#14078907 and a Up Date to a Service bulletin adviced the relay to be change to part#10094701. Middle relay is the MAF power #10067925. The third relay, far left side, closest to the engine is the Fuel Pump realy, part #10094701

The relay for the MAF burnoff and the fuel pump ARE the same!!! MAF Power relay is DIFFERENT!!!! (This is how a 100% stock/factory set up is supposed to be on a 87 TPI).

Stephen

iTrader: (12)

Yeah. When my MAF starting throwing codes, I swapped the plugs on thise 2 relays & all was good. One has 1 more wire than the other & whatever the problem was, the problem musta been in that circuit. Niether the pump nor the MAF have given me a problem since (knock on wood)

IROCKman

Hi and thanks for your help i least know now i am looking at the right part numbers my only problem now is that my mas power relay is the one next to the engine and i have tried switching them and then i get a light this car has run good for many years with the relays set up like this i am wondering if someone put them on in reverse meaning the wiring it is long enough to switch i guess i still need to no what are the wire colors for the relays so i know i have them right thanks for all your help guys

y84pauloflondon

OK, so you need colours EH!

*Fuel Pump relay: 12GA Orange, 16GA Orange, 12GA Tan w/white stripe, 16GA Black w/white stripe, 16GA Green w/white stripe (5 wires)

*MAF Power relay: 12GA Orange, 12GA Tan w/white stripe, 16GA Black w/white stripe, 16GA Blue(solid), 16GA Red (5 wires)

*MAF Burnoff relay: 2x 12GA Orange, 16GA Black(solid), 16GA Blue (4 wires)


Note: GA, refers to the GAUGE(thickness) of the wires used!!! Ex. 10-12GA is thick......16-20GA is a much thinner wire. The lower the # the thicker it is!

P.S. I am GUESSING at the size of wires, the sizes listed here MAY NOT BE 100% ACCURATE!!! I am comparing the relay wires to my own supply of wires in my garage.

HOPE THIS HELPS YOU!!!

Chevy86 IROC-Z

iTrader: (17)

Burn off and Fuel Pump are the same. the reason for the resistors in the MAF Power Relay is limit the current that is applied, reducing arcing. Think of it as a arc welder. have you ever welded and when you get to close or move to slowly and the welding rod gets stuck? Same concept. It rarely happens but its the reason behind the resistor.

Now if you buy the Fuel Pump Relay and the MAF Burn Off Relay from Autozone, check out the part number. Type in the "Product Search" box on the upper right this part number "19844". They are the same as well as a lot of other types of relays. Here is the kicker. The original Fuel Pump Relay did not have the resistor in it. The Autozone type does contain the resistor.
One is the Fuel Pump Relay and the other is the "Fast idle Relay" AKA MAF Burn off relay.

The internet can help out a lot of people. But not everything is accurate. In the Haynes Underwear Book , I mean the Haynes repair book it shows the entire wiring harness for diferent types of Camaro's. Well here I provide a color coded diagram that I found on the net along with a complete black and white diagram for the 3 relays. Now when I traced my wires, I found out that the color of the wires were different so be carefull. My best suggestion is to order the parts from a GM dealer because let me give you an example. I bought a MAF Power Relay from Napa. When I got the part, I opened the relay infront of the guy and told him that the part was wrong. He told me that it is a MAF relay. So I whipped out the original MAF Realy that was in my IROC and I showed him the relay that had the resistors in it. You should of seen the look on his face. My point is get the correct part from the dealer. Now keep in mind, the original relays actually had the part number stamped on them. If there is no part number on the relays that are currently in hte Camaro, then they obviously been switched out. This is where the wiring diagram comes in handy. Now in my 86 IROC Z, there where a few colored wires that were not as represented on the diagram. In other words, you may have to open up the wire looms and trace the wire to its terminal end to verify if it is what it should be. So here are the diagrams. According to the diagrams, the MAF Burn-off has the 4 wires, not the fuel pump. One more thing. the relays could be in either of the 3 locations. My MAF power is next to the engine, Fuel pump center, and Burn off closest to the fender. The previous owners must of unscrewed all of them at the same time and mixed them up when he or her put them back. Food for thought. Good luck.

resinlake

ok here, is one more question, who would be the best source for a replacement Maf Burnoff and Maf Power Harness ends/plugs? Mine have exposed wires and move around too much. I think that is half if not the whole problem I'm having with mine. Thanks

Chevy86 IROC-Z

iTrader: (17)

MAF Burn off - http://cgi.ebay.com/ebaymotors/ws/eB...d=370136177890

MAF Power - http://cgi.ebay.com/ebaymotors/ws/eB...d=370136178191

Here you go.

y84pauloflondon

Now lets be fair... Could the previous owner of your car unscrewed all of relays and mixed them up! LOL

Anyway, some of the reasons why I feel that my relays are in the correct order is because, and like you said, GM org relays had the part #'s stamped on to the relay themself. All 3 of my relays had the GM #'s stamped on them. And both the MAF burnoff and Fuel Pump were still using the Old Org. relay #14078907(thats 22 yrs old). Which in a GM bulletin was updated to change the burnoff relay to #10094701 which I had to do this summer!

So IF all are org. relays and working, WHY move them and mix them up
??? It just doesn't make sence to me. This is the first time that I've touched them since owning the car for the past 10 yrs!

y84pauloflondon

Well buddy, I just doubled check my relays using your diagrams, my car from left(engine) to right(fender) runs fuel pump relay, MAF power relay, MAF Burnoff relay. And I re-edited my post from earlier! Thankx Chevy86 IROC-Z

IROCKman

Hey thanks so much this is just what i needed now i will know for sure that i have the right relays on the right way and or wiring thanks so much you have been a big help
tomorrow i will check it out and know for sure thanks again

55mikey55

iTrader: (1)

ok, well has anybody got any idea what the part # is for a 86 firebird 305 tpi, cooling fan relay?

Chevy86 IROC-Z

iTrader: (17)

Chevy86 IROC-Z

iTrader: (17)

Wrong question. This question should be asked in Tech / General Engine , or Electronics . Just Kidding. I dont know buddy. Seriously though, go to Electronics and drop in the same question and hopefully someone will know that part number. Electronics is of course directly related to electrical. You may ask yourself the same thing too, Why are relays being examined in the TPI section right? Mainly because these relays are exclusively for the TPI system. I think just about any relay would work IF you know how to wire it up yourself. Good Luck

y84pauloflondon

Dude, you just read that now!!! I posted that last year!!! LOL.

*Stupid joke, I know....couldn't resist, sorry. lol.*

Chevy86 IROC-Z

iTrader: (17)

Actually, yes, I just read the post. I should hit myself huh? .....There we go. No problem. No offense taken.

Ward

iTrader: (1)

Since no one has posted a pic of the 88+ relays, I figured I'd post this. Pic is from my 88 GTA, 305TPI/T5. The part number on both oval relays is:
#14089936