I wanted some input from you guys on who makes a good quality MAF sensor. I am in need of one and want something of good quality, prefer new, not rebuilt, and if possible, since I have to buy a new one, I would like something that flows better than the stock one. I was looking at Granatelli in Summit, is there any other good MAF sensors out there? It's an 88 Iroc 5.7 litre if you need to know. I appreciate any input, Thanks, Larry.

 

Wells su-145 IIRC. Some people seem to have had problems with them, particularly with CAIs. Some people have gotten Bosch units instead when ordered (IIRC in Canada). f the search function were working properly, I'd tell you to search as it used to bring up pages. Don't know what you'll find now.
I've yet to hear any good on the Granatelli's.

 

Thanks for the reply Red Devil. Right now my car has a Bosch unit on it so it has been replaced in the past and it is now acting up and giving a code 34, stalling etc... so I am thinking I want to stay away from the bosch unit. I mentioned the Granatelli because I have heard they are popular with the LS1 guys but I don't know for sure. I was hoping there were more choices out there, I am new to computer controlled cars so I don't know where to look for good parts such as this. I have done a search as you mentioned but nothing really jumped out at me other than people wanting to rid themselves of it and go to a map sensor, I am not interested in doing that at all. I am hoping some people here can give there own personal experience with MAF sensors, or give me a web site name or name of a good MAF sensor that I can buy. Sorry if this sounds silly but I am drawing a blank as far as where to find something other than a cheapy autozone unit which I really don't want. Thanks again, anyone else have a suggestion? Larry.

 

Try checking the MAF relays. They are notorious for getting people to spend money on unnecessary new MAF sensors.

 

Thanks Red Devil, I was thinking the same thing. Although I have a slight problem with that I hope you can shed some light on for me.
I found the MAF power relay by the brake booster. It says MAF power relay right on it so that was obvious. Right next to that are 2 more relays that are identical to each other, niether of them say what they are for but they both have #7236 and then #14089936 on them, are these the burn of relays or is that somewhere else. I am assuming there is only one burn off relay but I am unsure what these 2 relays are. Once I figure that out I will run up to the store and go ahead and replace them since they are cheap enough anyway, and I might get lucky and fix the problem before I spend money on a maf sensor.
Anyway, I am stumped on the burn off relay, where is it?
Thanks for any help, Larry.

 

One is the burn off, the other is likely the fuel pump relay. I can't remember which wires go into each. If you post up that question on the electronics board (or try your hand at a search- if it works) Trickster will more than likely have the answer on the tip of his tounge once he reads it.

Borrowed from Vader:





Don't know if that will help as many cars by now have had a hand or two in the engine compartment, but you can see the wires to the fuel pump relay in there. IIRC that is an '86 TA.

 

Uhh, Bosch is OEM on at least some of the MAF TPI, if not all. So it's likely it HASN'T been replaced.

If you are getting a code 34, figure out what the cause is, and what the service manual troubleshooting flow chart says to test to fix the problem.

If you suspect it's the relay, just swap the wiring plugs between two identical relays. If the problem goes away and is transferred to something else, you know the relay is the issue. If the problem doesn't go away and manifest itself elsewhere, then you don't have a relay issue.

A relay may only be $5-10, but taking an unnecessary drive to the store, and spending the time to replace an undamaged part, adds to cost and wastes time...to me time is valuable. It's very easy to let cost alone get into the $100's of dollars and still not have fixed it by throwing parts at a problem. Diagnose instead of replace. Someone may have already posted the code 34 troubleshooting flowchart on this board in the past (likely) but since search doesn't work (apparently) you won't be able to find it if it is here.

I tried to get the wells unit listed above a few months back, but I couldn't get it locally. It seemed to be the most highly regarded MAF replacement out there from what board members had said.

 

Bosh has been on every thirdgen v-8 I've seen... they have also been every re-manufactered one I've seen. If I remember right, Vader had a big write up on the Wells one before, but I can't seem to find it in the search???

 

Bosch was the OE supplier for the MAF sensor on all thirdgens, Corvettes, and some other assorted GM models.

If you really want to replace it, get a rebuilt with a lifetime warranty so when it breaks again you can just go get another without spending any more money. Buying a new Bosch will not get you enough warranty to get out of your driveway.

 

Thanks for the pics Red Devil, that should help alot although I don't think my relays are in that order, this should help me figure out which is which though. Mine should be in the factory location as the car is very low mileage and unmolested, only tires and a battery have been changed. I just wish GM would have labeled the rest of the relays like they did the MAF power relay.
As far as diagnosing it, I have run through the trouble chart in the GM manual and according to it the MAF sensor is faulty, it took me a while to find the problem because it has been intermittent and by the time I get home to diagnose the problem it is gone and shows nothing but a stored code and tests revealed nothing at all. I finally caught it the other day while it was doing it, ran through the tests and it narrowed it down to the MAF sensor. I bought the relays anyway since they are cheap, would not hurt to have them around for future problems.
I was not aware the Bosch MAF was a factory unit, thanks for clearing that up. I checked at some local auto parts stores and all they seem to carry are remanufactured MAF units, I would rather have new so I will run to the local GM dealer tomorrow and check on cost etc....I tried the Granatelli web site and they don't seem to have an MAF for my car listed. I have tried looking for the wells unit also with no luck, I have found alot of tech articals on it talking about how great it is but so far, have not found anyone selling it. Thanks for all the help so far guys, I will keep you posted as to what I find. Larry.

 

If the flowchart says bad MAF, if you haven't done so already, check all the contacts and make sure they are clean and tight.

Tapping the MAF may sound stupid, but twice I've had the vehicle just stall on me for "no reason", and I suspect it has to do with the MAF going dead for just a split second. Bad contacts in the MAF circuit seem to be one of the major problems, and if it's intermittent, that very well could be the case for you. I'd suspect an intermittent IN the MAF itself would be pretty easily evidenced by tapping on it while the engine is running.

Also make sure to run the flowchart twice under the same conditions, just to make sure you didn't test one wire wrong, etc. Easy enough to do, and with the cost of a MAF, worthwhile. The flowchart was right in my case, but only if I did every test exactly correct.

 

Thanks for the input, I believe what you are saying, I have not bought the AMF sensor yet, right now the car is running fine again, I may wait until it acts up again and run through the diagnosis one more time.
I have checked the connections, had the plug on and off of the MAF several times, even removed the maf in an attemp to clean it and inspect it closely, then clear the code and drive the car. Sure enough after 40-50 miles it would set the code again.
You gave a very good suggestion that I completely forgot about, tapping on the MAF. I have been so wrapped up in this thing that I completely forgot the obvious. Right now it is running fine, I will go out there and tap on it and see if I can get the engine to stall or stumble. Thanks a million, Larry.

 

Wait till you hear the dealer's price on the MAF. You might want to sit down so you dont hit the floor in shock or laughing.

Trust me, buy a rebuilt/reman. And chances are, its fine. Often it is, its some other problem.

 

Thanks Madmax, I don't have a problem with the price, I am figuring it will be well over $300 which is fine with me as long as it is good quality. I was considering the Granatelli which is between $3-400 but cannot find a listing for an 88 5.7 litre.
The reman sounds tempting, I just wonder how well it is done, I know that some have a lifetime warranty which is nice but I don't want to have to replace it every 6 months either, depedability is very important to me, I can't be on a trip 1,000 miles from home and have to worry about this thing breaking down. That was really my only concern with reman stuff, price does not matter that much to me. I pay good money for stuff all the time on my other old cars as long as I feel I am getting good quality. Do you have any idea of good quality reman MAF sensors, certain stores or brands that you have had good luck with?
Anyway, as you said, alot of times it is something else and not the sensor, that is why I thought I would take a shot at the relays first, so I bought those but have not put them on yet, right now the car is running perfect again, go figure. I tapped on the sensor and all the relays with no change at all in idle quality. Drove it around tonight and it is fine at the moment. Goofy car.
If not the relay or sensor, what else could it be Madmax? I read in the GM manual that a dirty throttle body can also cause a code 34, that is the only other thing I know of, all the wiring and plugs appear to be fine, nothing loose or torn.
I guess the throttle body could use a good cleaning anyway, it has never been apart and has 56,000 miles on it. If you have any other ideas I am open to suggestions, keep it coming, you guys are great, glad I joined this board, I would be lost on this computer controlled car without this site. Thanks again, Larry.

 

Just to add, I love to read on this site and hear about everyones experiences with certain things, it really helps me to make better decisions on this car. I am very old school and mainly drive and restore/rebuild old cars of at least 30 years old so this computer stuff is new to me, sorry if I sound green, Just want to thank everyone for there input, Larry.

 

The next time my MAF dies, I'm going with a MAP setup.

A bit more hassle initially, but MAP sensors are somewhere around $20.

 

Where are you finding MAP sensors for 20 bucks? Last I looked, they are more like 50.

TB cleaning
Check for vacuum leaks
Check your TPS setting

 

That isn't necessarily the case. The original MAF units were manufactured by Bosch, and included the Bosch part number on them as well as the GM part number.

This is the factory stock MAF from my '86 T/A:

 

Incidentally, the stock MAF is a very robust unit. Unless the hot wire sensor itself is cracked or burned off, the rest of the package is almost indestructible.

Further, if your problem is intermittent, and you cannot induce the problem with the "tap test", chances are the hot wire is intact and you have a different issue. I'd suspect the electrical connections at the MAF, MAF power relay, and MAF burnoff relay. Lacking that, the connections at the ECM could be a problem. The ECM has a very low tolerance for MAF errors, and will set a code and enter Backup Fuel Mode if the MAF reports an erroneous signal for no more than 600mS. If it's a hot wire problem, it won't fix itself. Additionally, if the hot wire is damaged, you'll experience a "36" error as well as the "34", since the hot wire cannot become incandescent during the burn off cycle.

Another common cause of a "34" is an under-reporting MAF due to factors outside the MAF sensor itself. Leaking air intake ducts, vacuum leaks (common and not-so-common leaks), incorrect TPS adjustment, and even the installation of a breather type oil filler cap can cause a "34".

Perform a bit more diagnosis of the system before replacing anything.

You mentioned that you prefer the older cars? MAF systems have been around for over 20 years now. Next year, I fully intend to change my license plates for "antique vehicle" plates. It will qualify.

 

Looks like price has gone up a bit in the last few years, but it's still MAP $40 new vs. MAF $188 remanned from the exact same store.

 

Thanks Vader, you gave me many more places to look, I am going to start by removing the throttle body and giving it a good cleaning along with the iac motor and then reassemble everything and adjust tps etc... according to the book, I'd say it probably needs to be done anyway, if for nothing else just for my own satisfaction in knowing it is done.
As far as what I meant about old cars, I forgot these 3rd gens are old cars to most of you, to me they are still pretty new.
I meant much older, none of my other 6 cars have any computer device at all, no maf sensors, nothing. I restore and rebuild them (engine, drivetrain, body and paint) and the wife and I enjoy driving them everyday, they are our sole transportation, we go on vacation in them etc....very easy to maintain and quite simple to keep running. I even still have a couple of them that are running points ignition and they have served me perfectly for more than 20 years. Not to mention they get a ton of looks, and they are a blast to drive.
Anyway, back to the maf problem, it has only set the code 34 so far, when I went through diagnostic in GM manual, it also said to unplug the maf and run engine and see if it sets code 33, which it did just as GM manual said it would. After plugging in maf sensor and clearing codes it went right back to just setting code 34. I wrote down everything you said Vader, I truely appreciate everyones help here, I will check the things you mentioned and keep pecking away at this thing until I have a definitive answer. Thanks guys, Larry.

 

You can check the burnoff function pretty easily...remove the MAF from the air filter so you can see inside it, turn the key on for a few sec, then off...you should see the wire filament glow red briefly as the MAF burnoff relay does its thing. You'll hear the relay click on and then off.

 

Cool Kevin, I didn't know that. One more thing I can try. Thanks a bunch, I am learning something new everyday on this car thanks to this site. Larry.

 

Who do you know that sells a MAF sensor with a lifetime warranty?

 

no chain store remans, i have seen, sells a thirdgen maf with more than a year warranty. the units are more than likely a cardone reman unit.

 

I have an extra MAF from autozone "Cardone" and it only came with a 1 yr. I have never heard of a lifetime on any Maf sensors

 

I bought mine at Kragen, has a lifetime warranty. Got it about 5 years ago.

 

do me a favor see if they are still selling them with a lifetime warranty. I don't have one around here

 

My two cents on MAF's

The ACDelco Part # 213-163 is a new sensor that is actually the Bosch style but made by GM to correct the problems on the orginal bosch unit's higer failure rate. These are new but will cost you about $360.

You can get a rebuilt Bosch unit from Cardone at Autozone for $163 but like any rebuilt electronic part their is some risk involved and some cor's are better then others. So look at the part before buying to make sure its not to beat up. They just test the electronics on them and if they pass ship them out.
part # 74-4712

Borg Warner and Neioff also makes a new replacement that goes for about $330.

The Grantelli is a piece of garbage do not buy it. I returned mine.

 

Best bet is the Well's SU-145 Maf for about $160 and a lifetime warranty. Only problem is trying to locate one now days. I bought mine a few years back from World Discount Auto Parts in Buffalo NY. It was NOT listed on the Net but phone order were accepted. Still the best replacement MAF out there.

 

Thanks, I jotted that down. I installed the 2 relays the other day and so far the car has been running perfect, no codes etc... I am still waiting for it to throw a code 34 again and then run through the trouble shoot chart one more time, but right now it seems to be fixed, (fingers crossed) if it turns out to be an MAF I will try to hunt down the Well's unit you suggested, thanks, Larry.