I did some "exploratory surgery" today in preparation for the arrival of my throttle body gasket (along with other items) from IPD.

I have been having really bad hesitation when pulling away from stop lights when the car is hot. It has not yet stalled on me, but it has come close.

Prior to this resurrection (after two years of being parked) it would do this in rush hour traffic downtown. It once took me over an hour to get about six miles because it kept crapping out on me in the 105º local temp. At two locations I had cops threaten to ticket me and have the car towed. The first one was shortly after leaving where I had been for about an hour. Prior to that I had driven pretty hard for an hour to get to town with zero issues. In between these two places where it kept stalling was a three mile stretch of Interstate highway. Once I got it moving (past the last light and onto a mile-long entrance ramp) it was just grand again. But as soon as I took my exit and came to the light at the end of the ramp it died again.

And my brick and I sat there blocking traffic for over a half hour. No start, and so many tries that I was fearing that I would kill my battery's charge.

Shortly after that incident the car was parked unceremoniously at my mother-in-law's to be used as a decoy car. She had just moved into a home and we needed to keep the scumbags guessing as to whether there was actually anyone in the building. It did a great job sitting there doing nothing for 23 months. HA!

So since I turned this thing over and drove her home I have had miserable power/acceleration (especially up steep hills from a dead stop in my neighborhood) but no hesitation. Everything worked great, just really anemically.

Then I Seafoamed the gas and through a vacuum line. I do not think this had ever been done to this block, which is probably at 350,000+ miles. The smoke was delightful, by the way. ;-)

I got a big return for that bit of work. Everything got better, but now the old hesitation problem had returned.

Today I did a very halfway Quick Lube-type of job with a can of CRC Throttle Body Cleaner. All I did was remove the ruined intake accordion hose and the 90º elbow with the two large vacuum ports, the MAF and the top of the air box. I then sprayed in about a half a can while revving the motor by hand. I did not get all the stuff off, nor did I really want to. I plan to do that in a few days. I just wanted to see whether the hesitation would get better at all.

Anyway, next I checked the air filter. Still very clean.

I used the CRC MAF Sensor Cleaner, but it, too, was pretty clean.

[I][SIDEBAR: So, just how fine is that lightbulb-like filament supposed to be? I have what looks like one thick blade or wire in the central flow tunnel (about 1" in diameter) and a small pentagon of wire that is thinner than a hair, it seems. I could see, with effort, four lines of wires, from one of the two bases around to the other one, but could not tell whether the two bases had one between them. I want to say there was not one, so that it was a pentagon minus the bottom line. Is this correct?][/I]

The accordion hose has a small hole and was coated inside with oil and gunk from the elbow about halfway down its length. It is also misshapen due to heat and age, having been squashed a small bit flat on one side from the wiring harness and hoses between it and the fender well.

The elbow is trashed. The smaller of the two vacuum ports (going to the flame trap, I think?) that is closer to the butterfly valve in the mouth of the throttle body is nearly broken off. I tried to temporarily seal it but that failed. It was heavily coated with oil and hardened varnish, especially the aluminum inner sleeve that allows the two plastic tubes to be connected via a band clamp.

The throttle body was gummed up with hard, black varnish that was sticky and nasty and solid, lumpy black.

After cleaning the MAF and replacing some vacuum lines I tried to clean the throttle body in situ, like at the oil change place, knowing that the two small vacuum ports were plugged. (I will do this properly on Wednesday when the gasket arrives.)

The result was that the hesitation got more pronounced.

We took it out for a test drive of about two hours on a US highway where we could get away with a sustained 70 mph without getting a ticket.

After about ten miles things were going well again. We had decided that if things were okay at that point we would go on down to town and get supper. This would require a lot of stop-and-go driving, which would give it lots of chances to hesitate so we could try and figure this out.

And it hesitated a little, once or twice.

After supper we headed home.

More power, more acceleration, better hill climbing, and no hesitation.

Hmm.

I cannot wait to get that gasket so I can take my TB off and really go over it carefully. And we will be putting a new accordion hose/elbow on order with IPD tomorrow morning. (No IPD bashing, please. I like them a lot for my own reasons. I know I could have gotten that part for less. I an not concerned with that right this moment. But thanks.)

I am hoping that the IPD 740 accordion hose includes the elbow with the two ports, as that is what is broken. But if not I will see if I can get that bit from them on the same order. I still need the hose itself.

Does anyone have a clear photograph of the MAF for my car, showing how the filament should actually look? This gizmo looks spendy and I do not want to have to get one.

Anyway, with the increase in power and speed and response to the pedal on hills, it now also has the CEL on full time. And the idle is a bit more rough. So I started a process and am only partway through. I am hoping that everything smooths out and the computer is happy when I am done with this system.

Any comments or personal wisdom to share regarding my experience today?

Thanks!

Wade
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Mama always told me to eschew obfuscation...

I don't recall whether you have an lh2.4 system, but I think so. You haven't posted in this thread what year the car is. But if so, then the AMM is a
xxx... 016.
There are two different ones with the same part no; they seem to act the same however, and I have never gotten an explanation for this apparent difference. One has a simple straight wire from the edge pointing to the center of the AMM venturi. The other, and this sounds like what you have, has a sort of trapezoidal arrangement, sorta like a slingshot, with tiny wires connecting the points inside.

As said, they both are correct and both seem to work the same.

Cannot read it. I *just* discovered my code reading black box. It was nowhere near where people had been telling me to look. I had all sorts of guys telling me on various sites that it was on the front half of the left fender well by the air box. I have a random mystery connector there and no box, so I assumed that at some point this was removed.

But today I finally found it. It lives up under the hood hinge assembly almost on the firewall.

How do I use it? It does have the little red light. I did not see a button. But I did not really look, either. The pin is outside and there are like six sockets in the box. It looks to be like 2.5" long and 1.5" wide. Does this sound correct? I can post a photo, if need be.

What do I do???

Tell me soon and I will do it tonight before I clear the codes to see how long it takes them to return.
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Mama always told me to eschew obfuscation...

I have an 85 with nothing to read. Have you looked here:

http://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm
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Post Back. That's whats makes this forum work.

Reading now...

It too has the incorrect location for the box. Hmm...

About to go pull the codes...

Back soon.
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Mama always told me to eschew obfuscation...

I only have functionality on sockets 2 and 6, which is correct as far as I can tell.

Number 6 is clear: 1-1-1

Number 2 however:

1-1-3
3-1-1
1-2-1
3-2-2

I could not get them to clear off. I will clear them now via the battery. Then we will go for a drive to see if they are old or will come back right away.

Back in like an hour or so.

I will Google the codes later tonight. Thanks again, man!

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Mama always told me to eschew obfuscation...

I had no CEL at all since I started this thing up recently, except when I started it up cold on a couple of mornings and it seemed to be choking on bad gas, firing on only one cylinder, shaking violently and belching smoke. After a few times running like that for about a minute or so it evened out and idled just fine, both mornings. It has not started hard like that since.

The Seafoam in the gas seemed to clear up much of that sort of thing.

Today I ran the motor with the throttle body open to the air (for the CRC Throttle Body spray) and had a lot of the associated vacuum lines off. It threw me the CEL right away while we did this.

The light stayed on though the performance cleared up a lot. But the light persisted.

I took down the codes. I could not clear them off via the black box, however, so I disconnected the negative terminal on the battery for a few minutes.

Then we took a nice nighttime drive in the farmland and through our small town's "strip" so we could catch a bunch of lights to see how the car took off from a stop and to see how she did stopping.

No stalls, no hesitation.

And no codes. None. I checked both 2 and 6 and both blinked 1-1-1 at me.

So if the problems were due to all the stuff I did this afternoon and were cleared up, why did the light stay on? I thought the light turned off if the issued cleared up, but stored the code in memory. I have had problems in the past where the light came on and then went off shortly after, usually right after I did some sort of work.

But that did not happen today. The codes were cleared. The light stayed off. Is this a system where faults in the vacuum system do not show up until a certain number of cold or hot restarts or a certain number of miles have been driven? Will these codes reappear soon if reassembling the air system did not take care of the problems that were detected?
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Mama always told me to eschew obfuscation...

It's kind of tricky to clear codes.

Basically, you "read" all 3 codes (didn't think it could hold 4), then hold the button down for an obscenely long (8-10 seconds) time. You'll get a solid light. Then hold it down for the same length of time, and the light should go out. Then you should be able to get a 1-1-1 code.


There is no direct monitoring of the vacuum system for problems, so any codes will be thrown because they screw something else up - namely the mixture.

Hesitation and running poorly when in really hot (105F) vs. really cool (60F) temps makes me think the AMM has failed, and your car is running on a sort of limp-home mode, which is rich. Some time, when it's running like garbage, disconnect (do not reconnect with the engine running) the AMM. See if it runs better. If so, the AMM is most likely shot.

Buuut, if the accordion hose is also shot, then it could all be because of that.

The wire is about as thick as the wire of a cheese slicer or a piece of 10-15lb fishing line (about .5-.7mm). It should be visible to the naked eye.


I would do this:
Fix all the vacuum leaks (you can test for them with soapy water or with a flammable fuel source (not brake cleaner!).
Clear the codes
Try disconnecting the AMM.


The reference to the plug on the front crossmember is for something else, not the code reading sockets. I remember the FAQ description being slightly confusing, but not outright wrong.

What do all 4 of those codes mean? We could all go look them up, but it would be better to have them posted.

The codes were due to having the thing torn open while it was running. Of the four only two threw the light on. One was due to a loss of signal from the AMM (it was removed) and the other one had to do with the mixture being off. Since a lot of vacuum lines were disconnected I can see why the computer thought the O2 sensor had taken a dump.

The filament in my MAF/AMM seems to be thinner than you describe, nearly invisible, but it was there and was connected at both ends. I guess such a light test fishing line is pretty thin, however. I am guessing, here...

Everything seems to be fine now, however. I drove it last night, but it was cool out. (low 70s to high 60s) and no CEL. Got home and no codes from the AMM or the O2 sensor. I will drive it hard today, but it will be fairly cool outside (only into the 80s, I think).

Here is what I got last night:

1-1-3 = Fuel trim (lambda control) too lean or rich (This code turns on the CEL.)

3-1-1 = Signal missing from speedometer (my speedo has been intermittent for years and only came back on two days ago, so that code is from before all this)

1-2-1 = Faulty signal to/from Air Mass Meter (This code turns on the CEL.)

3-2-2 = Air Mass Meter wire burn-off signal absent or faulty (This also makes sense as a result of it being unplugged. It cannot do the burn-off cycle if it is not present.)

I think my AMM is probably fine. I will keep checking my codes for a while, though.

Thanks!


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Mama always told me to eschew obfuscation...

Look close at your AMM connector. The pins sometimes don't make good contact and the female ends may need some cleaning/pinching. Also been know to back out. My AMM the wires are so thin if I don't hold it just right, doesn't look like they are there.
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Post Back. That's whats makes this forum work.