Car running to lean? Possibly Mass Air Flow Sensor?

Lesabre T-type or other H-body related topics.

Moderators: MICHAEL MEYER, Xtreme/T-Type, custom88, Lo Type

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Wed Jun 29, 2005 12:56 pm

OK, the solenoid was not the problem. I installed it this morning before coming to work and I still had the rough idle all the way here to work. Here are some more syptoms if they help anyone. It only begins to idle rough after the car warms up to normal operating temp, the first 5 mins of driving it idles perfectly. The rough idle seems to be exagerated in hotter weather, in other words the idle is rougher on my way home from work rather than in the morning when it's a little cooler outside. Any load on the battery also tends to make it a little worse such as turning on the AC or the lights at night time. The lights also tend to dim a little during the rough idle.

When I took off the MAF the other day to try to clean it, it didn't look to dirty other than the MAF screen which looked like it had just a little bit of dust on it. The electronic parts cleaner didn't seem to take this off at all and I was afraid to spray intake cleaner in there for fear of damaging the MAF. I'd like to clean the MAF more thoroughly according to the links above but I can't find any way to remove the screen to hose it down with intake cleaner, keep in mind this is on an '87. Is there a way to remove the screen on an '87 MAF or is it safe to use intake cleaner on the MAF itself?

Thanks for the help so far guys, I hope you can help me resolve my idle troubles. I'm actually moving farther away from my job soon and will have an even longer drive to work so I hope I can get this resolved by then.

Mistascott
Advanced Member
Posts: 250
Joined: Wed May 26, 2004 10:57 pm

Post by Mistascott » Thu Jun 30, 2005 7:19 am

Are you still getting the code 32? Have you reset the codes after installing the new solenoid? Has the car stalled since you replaced the solenoid?

I wouldn't worry about the MAF until you are sure it is causing a problem.
Scott
87 GN (SOLD)
87 LeSabre T-Type

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Thu Jun 30, 2005 12:40 pm

I havn't reset the codes yet, but the car has stalled and still has a rough idle since installing the solenoid. I took it back out after a day, it's still in good shape so I gonna return the solenoid and try something else. The EGR system seems to be in perfect working order so I'm starting to think that maybe the code 32 wass thrown a long time ago and has just never been reset. That would mean the the code that is now getting thrown when the car stalls or idles bad would be 44, which according to the chart is probably an 02 sensor. I've found a couple posts on this forum from people that had the same problem and it turned out to be the 02 sensor. I'm going to reset the codes today on my lunch break and drive the car around for a little while til the ECM throws a code again. Hopefully it's only a code 44 and a new 02 sensor will do the trick. Am I thinking along the right lines?

Sorry if I sent you guys on a wild goose chase when this may have just been an old code that was never reset. Although I did learn a lot about this engine while digging around trying to find my idle problem. I've always owned 4 bangers up until now and I can probably say I'll never go back to a 4cyl, I love this V6.

Mistascott
Advanced Member
Posts: 250
Joined: Wed May 26, 2004 10:57 pm

Post by Mistascott » Sun Jul 03, 2005 9:06 pm

I would put the old solenoid on and reset the codes and see if you get a 32. If not, return the new one. If you get a 32, put on the new one and reset it to see if it stays.

As for Code 44 -- o2 is by no means the sure cause. It could be anything, from the MAF sensor to a vacuum leak to bad injectors. So, assuming it is the o2 because it was for other people is not the right way to think about it. However, since you just the got the car, it might be wise to replace the o2 as a matter of maintenance.
Scott
87 GN (SOLD)
87 LeSabre T-Type

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Tue Jul 05, 2005 1:26 pm

I reset the codes and I'm now only getting a code 44. I returned the new solenoid and picked up and 02 sensor, fuel filter and new spark plugs (standard ac-delco). I'll put these on as a "matter of mainenance" and hopefully my problem will go away. If not, I'll be back.

Just out of curiosity, what does a new set of injectors cost? What would be a good place to get them and is there a better brand/model that would give me a little more HP?

Mistascott
Advanced Member
Posts: 250
Joined: Wed May 26, 2004 10:57 pm

Post by Mistascott » Tue Jul 05, 2005 9:02 pm

Injectors will run you somewhere in the $300+ range. I wouldn't replace these unless you know you have a problem or you have some money to work with. (You might need a new MAF/computer chip if you upgrade their size). However, I think what you have listed to replace are good ideas as well as plug wires, PCV valve, and air filter.

The code 44 is the likely cause of your stalling problem. Usually, this is a vacuum leak because there is so much air getting into the system that the fueling cannot keep up and the car stalls. So, it might also be a good idea to replace your old vacuum lines. Good luck.
Scott
87 GN (SOLD)
87 LeSabre T-Type

prodigy_16
Advanced Member
Posts: 822
Joined: Sun Jun 23, 2002 1:00 am
Location: ky maroon 89' LeSabre t-type
Contact:

Post by prodigy_16 » Wed Jul 06, 2005 5:39 pm

quad4 engines used 33pph injectors, you can pick them up at a parts yard for 20 bucks or so, and get a reprogrammed chip, this would let your injectors run the same amount of fuel at lower pressure, wich would give you the potential for more power.
FAST CARS ARE NOT CHEAP, CHEAP CARS ARE NOT FAST.

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Sat Jul 09, 2005 7:26 pm

The hunt continues...

I replaced the 02 sensor, no luck. I replaced all the vacuum lines, still no luck. Most of the vacuum lines were hard lines so I replaced all the rubber couplers between as many vacuum lines as I could find. Most of the lines looked OK until I went to take off the old rubber, then they just crumbled into dust. I hope that the intake manifold gasket is not to blame, I've never taken the intake manifold off of a V6 before.

So what do you think I should check next? I reset the codes and am still getting a code 44 after the car idles for about 1-2 mins. The car idles fine when the engine is still cold but the hotter it gets the worse the idle.

Mistascott
Advanced Member
Posts: 250
Joined: Wed May 26, 2004 10:57 pm

Post by Mistascott » Tue Jul 12, 2005 4:05 am

This still sounds like a vac leak of some sort.

I would get a hold of the vacuum line diagram and make sure you've replaced every inch of it. Also make sure the vacuum block (on top of intake) is sealed shut. Don't worry about taking apart the intake...yet.

Also, check fuel pressure and exhaust leaks.

See the link below for the entire diagnostic flowchart and explanation for code 44.
http://www.syty.org/old/d&e-code44.html

I know it can be frustrating, but keep at it.
Scott
87 GN (SOLD)
87 LeSabre T-Type

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Mon Jul 25, 2005 5:55 pm

I finally got around to going back over the vacuum lines and they are perfect, including the block on top of the throttle body. There doesn't appear to be any exhuast leaks whatsoever. I have never checked the fuel pressure on one of these cars before, what's all involveed?

There are two things I notice that may help to narrow down the cause. First is that the idle does not become rough until the car has been idleing for longer than a minute or two. When I first pull up to a stop light the car will idle fine but after it sits at the light for about a minute then it starts to get very rough and shakes the whole car. Also, when I romp on the gas, the motor tends to ping for about a second or two before really taking off. It kinda sounds like a car that that's struggling to get up a really steep hill, but only for a second, then it takes off.

Is it possible this is related to the battery? I havn't had any trouble starting the car but it kinda makes sense that after the car sits for a minute that the alternator alone is not pumping out anough juice and possibly the fuel pump is struggling. Just a guess.

I've always prided myself on being able to fix all my cars but I'm about to give in and take this one in to a mechanic. If it comes down to that would you recomend going to a dealer or any mechanic that looks trustworthy?

Mistascott
Advanced Member
Posts: 250
Joined: Wed May 26, 2004 10:57 pm

Post by Mistascott » Mon Jul 25, 2005 9:13 pm

If you take it to a shop, they are going to follow the flow chart from the link above because that is right from their service manual. If you do take it in, I'd take it to a mechanic because a dealer usually charges more for labor and parts than independent mechanics.

If you have a brand new oxygen sensor (make sure it is the correct part number and would be best to use Delco or Denso), that helps narrow things down. Just be on the lookout for any other codes along with the 44.

I doubt the battery is causing this. However, fuel pump is a possibility. You would need to buy a fuel pressure tester at your local parts store and hook it up at the regulator to determine whether you are getting enough pressure. Another possiblity is a bad injector or a short on one of the O2 sensor wires. It's up to you if you want to chase it, but remember every code has a cause so it isn't anything so cryptic that you can't figure it out on your own (though it is frustrating).
Scott
87 GN (SOLD)
87 LeSabre T-Type

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Wed Jul 27, 2005 3:42 pm

Following the chart on that page and the diagnostic aids it looks like I may be having trouble with my injectors. The 02 sensor is brand new and there are no exhaust leaks. It says to perform an injector balance test and fuel pressure test. The page says to refer to Charts C-2A and A-7. Is there anywhere online that I can look at these charts or is this in a service manual? If it comes down to it I may just replace the injectors, they're only about $33 a peice at autozone.

Oh yeah, also, I check the codes about every other day and code 44 is the ONLY one I'm getting. I kinda wish I'd get another code, anything to help narrow it down. I'm moving this week and am on a very tight budget so I don't have much money to spend on parts.

luvgm
New Guy
Posts: 16
Joined: Fri Jun 17, 2005 6:55 am
Location: MN

Post by luvgm » Wed Jul 27, 2005 6:17 pm

The injectors rarly go bad starting to throw money at a car when it is like this gets frustrating. If you are at your wits end take it to a mechanic one that you known is repeatable, they will start thowing parts at them two sometimes if they can not figure it out. If not try some of the following. When code 44 is set there are seven things that it could be a bad 02 sensor, grounded 02 sensor wire, restricted injectors, contaminated fuel, low fuel pressure, exhaust leaks, leaking air switching valve in the air pump system for the emission controls(if they have one), and ECM. I just dealt with the same problem in my 88 and it was vacuum, the first time it was a bad line(cracked) the second time I had the problem, the new vacuum hose collapsed on its self. The following is a test to try: Connect a digital volt meter to the purple wire of the ecm. Start the warmed engine and run about 1200 rpms for 2 to 3 minutes while observing the voltmeter. If volt meter reads 0 (or very close) look for a short, look for a grounded purple wire to the ecm (wires that have been wore , frayed, etc.). If the purple wire is not ground they say to replace the ecm. If the voltage remains consistantly below 0.35 volts inspect for vacuum problems, fuel pressure, exaust leaks, and problems in the air pump, contaminated fuel (water, excessive alcohal, so on) if all these check out replace 02 sensor(which you have alredy done). Something that I would try is an old hot rodding trick, take a sqiurt bottle with water in it and spray around any of the vacuum lines, intake, around any area that involves air possibly being sucked into the engine(these are all possable vacuum leaks) do this while the car is running and warmed up. If there are any mynute leaks any were this will become apperant when the idle changes when sprayed with the water. Make sure that the spray bottle makes a fine mist of the water so it sucks in a minimal amout of the water. To make sure that all of the injectors are working use a mechanics stethoscope and place it on each one of the injectors if they are each working you will be able to hear them working. You can check the injector pulse width, this is the time that the injectors are open it is measured in milliseconds this should be between 0.7 and 1.5ms at idle. If the idle is slowly increased this will not change but if you gun the gas it will increase the fuel pulse width. As the injectors become restrictred the pulse width will increase. The formula for this is 1 divided by frequency x duty cycle divided by 100. To get the duty cycle use a dwell meter set on the four cylinder setting connect the dwell meter to the appropriate wire that you are testing then multiply the reading that is aquired by 1.1. To get the frequency use a ohm meter that does a tachometer reading. You will need to swith the tach to the four cylinder setting it works on the 6 and 8 cylinder also but the math is more complex so for testing just use a four cylinder setting you are checking the fuel pulses not the rpms so it will still work. Hook it the desired wire divide the reading of the rpms by 30 and that = the frequency. I know that you have checked some of these items but this might help. I noticed that you have not checked the fuel pressure yet it does not sound like it is the fuel pressure but it eliminates that possiblity(I have seen some weird reactions when the pump has went bad, or the fuel filter). I know that it sounds like I have said some of the same things that have been said previously but the vacuum is what was wrong with my car and it was doing the same thing. Some times there are leaks in the vacuum system that you can not see with the naked eye and the squirt bottle will help figure those out. Checking the fuel presure consists of hooking the pressure gauge to the inlet that looks like a tire valve it is covered by a cap on the fuel rail. You need a gauge that will read up to at least 50-75 lbs of pressure. It needs to have more than 30 but less then 45 psi to be in the range that they need to have. To check when cheing this is a good idea to drive it with the gauge hooked up so that you can watch it. This will let you know what it is doing under load.
Certified I-car technican (steering and suspension, air bag, paint, frame, body, etc.)Certified PPG paint technican
Certified Martain senor paint technican
1987 lesabre, 1988 lesabre, 1991 lesabre.1970 nova, 1989 k1500, 1982 280 zx 1994 GMC ext

Mistascott
Advanced Member
Posts: 250
Joined: Wed May 26, 2004 10:57 pm

Here's a plan

Post by Mistascott » Thu Jul 28, 2005 9:01 am

The above info all seems to be right on. However, if you take it in to a shop, they will likely only charge you 1/2 hour labor to diagnose the problem. This amounts to about $40. I would get a diagnosis before spending the money on injectors, because you don't know for sure that injectors are causing your problem.

Once the shop tells you what the problem is, you can decide what to do about it. Just be sure you find out their charge for diagnosis before you agree to let them look at it (again should be about $40, which IMO is not bad to find out for sure what is wrong).

The flowchart for code 44 relies mainly on the o2 sensor. Since you have that replaced (tell the shop you replaced it) you are pretty much into diagnostic aids -- which as you can see is mostly guesswork.

Please let us know what ends up being the case and don't feel bad about bringing it to a shop; a lot of the diagnosis work involved is time consuming and requires expensive equipment.

In simple theoretical terms, the o2 is reading too much air and not enough fuel. This means that either there is a fuel system problem (not enough fuel -- injectors, pump, fuel filter, or regulator issue) or too much air (vacuum/exhaust leak). Then there are always the sensors like o2 or MAF which could be sending a bad reading to the ECM. The diagnostic aids section doesn't cover every conceivable cause of the code, so you could be looking for awhile. Therefore, I would cough up the $40 and have a shop diagnose it. Then, if you want to fix it yourself, go for it. :D
Scott
87 GN (SOLD)
87 LeSabre T-Type

CrpseGrm
New Guy
Posts: 39
Joined: Thu Jun 16, 2005 1:52 pm
Location: Mechanicsburg, PA
Contact:

Post by CrpseGrm » Thu Jul 28, 2005 12:25 pm

First off, I can't thank you guys enough for the responses in helping me find my problem. Sorry if I've seemed stuborn with checking a few things, it's probably just because I don't have the right tools at my disposal to check things out, but I'm working on that as I go along.

Well, I checked the codes again last night and the code 32 finally came back. For about a week or two after I reset the codes in the first place I was only getting 44, now I'm getting both again. The spray bottle idea is a very good one, I will have to give that a try to see if I'm missing any vacuum leaks at all. Now that the code 32 is back I'm begining to wonder if my vacuum leak is between the EGR valve and the manifold. I assume this would explain getting both codes. Also I'd like to pick up a pressure gauge from the store and check the fual pressure. So it needs to be between 30-45psi at idle?

I'm going to continue my search a little more before taking it anywhere to have it diagnosed. Beleive me I will let you guys know the minute I get it fixed.

Edit: I also noticed that the motor sounds like it is constantly pinging. Everywhere I drive I can here the motor pinging/knocking. Possibly a sign of a vacuum leak? (i.e. more air getting in the intake than what is metered causing a lean condition and causing some engine knock) I may put in some higher octane to cure this for now.

Has anyone heard of using propane to find vacuum leaks? I read on another website that using a small amount of propane (via the spray bottle method) would cause the engine idle to increase. Does this work on these motors?

Post Reply