95-MTX: Power Falls Flat @ Secondaries

[luigisho]

Ha. I get the airbag beeping too. I've ignored it for a while as I don't have time to check if it's just the module or the clockspring. These things are ooold, especially electrically now.

 

[BRD]

I've ignored my airbag warning, same as you, but it only chimes in every 1:20/30 startups. Scares the **** out of new passengers, lol.

I just tried the paperclip test to read the codes and didn't have any lights on the dash flashing anything. So I assume it has no codes, as seen with the OBD1 reader.

I'm back to driving it daily, so maybe the CEL will come back on......

 

[luigisho]

That's the only way to be sure. No driving issues when it flashes?

 

[BRD]

That's the only way to be sure. No driving issues when it flashes?

The only noticeable issue was it not wanting to open the butterflies, and after easing into the throttle and holding it down; it hesitantly crept up into higher rpm's. (When quickly jamming the throttle, it quickly revs to 4500 and then just holds there.)

To get the code, it took at least 30-45 seconds of flooring the throttle for it to creep from 4500 to 5500, and I could feel the butterflies fluttering. Afterwards, previous attempts returned mixed results. occasionally they will open up and the car flies.......

 

[zoomlater]

There is a module (IMRC) that controls the butterflys opening. Can you verify the butterflys closes when you first start the car. You can see there is a little lever that moves to the closed position. When the car is off, the lever is not in that position.

https://shoforum.com/index.php?threads/secondary-butterfly-vacuum-canister.132683/#post-1453906

 

[BRD]

There is a module (IMRC) that controls the butterflys opening. Can you verify the butterflys closes when you first start the car.

I believe they are in the closed position when the car is running, I will double check.

Thanks for the link too!

 

[rubydist]

Let's clarify a couple things. Whenever the check engine light comes on, even for a brief time, it sets a stored code. Period, end of story. So, if you were driving it and saw the check engine light come on, then there are stored codes. So, you need to take the paper clip, connect it properly and pull those codes.

If you cannot get codes out of it when you know the check engine light has been on, then you either have bad wiring to the test port, or a bad pcm. When you connect the paper clip and turn on the key, the cooling fans run for a couple of seconds. Is this happening? If not, either you have the paper clip connected incorrectly, or the wiring to the test port is messed up (or the cooling fans never run).

Please confirm what happens when you connect the paper clip.

 

[ISHOU]

I had similar symptoms as yours on my 94ATX and swapping the MAF cured it. It never threw a code.

 

[BRD]

zoomlater: The butterfly levers on the intake appear to be in a downward position, which looks the same with the car running or not running. When accelerating the throttle by hand under the hood, if I were to increase it slowly both would open, however the rear one did seem to stick, or fail move in sync with the front one a couple times, and then if I were to jam the throttle, neither would move and the motor would bog.

rubydist: I don't recall the fan kicking on, just the typical dings from the dash and buzz from the fuel pump. I'm going to assume I plugged the paperclip in incorrectly. I will try again today.

ISHOU: I just pulled the MAF off my 92, and will see if that makes a difference.

The issue is now showing up a little on light acceleration from a stop, but that cleared up once everything warmed up. I'm not finding anything lose, leaking or rattling.

 

[luigisho]

https://web.archive.org/web/20041215140400/http://www.shophoenixproject.com/eec/eec.htm

link for paperclip

 

[BRD]

luigisho: Thank you!!!! I was definitely doing it wrong. I was touching two ports within the triangle shaped plug as I thought I saw on another thread, not on two separate plugs, the triangle and a small gray one.

 

[luigisho]

always double checking! save that link for yourself. It will come in handy later. The website is gone but archived google link

 

[BaySHO Performance]

I use that same Innova code reader, and it's always been flawless. Perhaps you got the operating sequence wrong:

Plug the code reader into the self test port. Don't forget the single wire as well. Turn the ignition on but don't start the car. Turn the code reader on and press TEST/ HOLD. If done right, the first thing that will happen is that the fan will run for a couple of seconds.

The codes will come out: on demand codes followed by stored codes. Each set of three digit codes will be repeated once before moving on, with a '10' between the sets. Once finished, press TEST / HOLD again, and turn the reader off. This will erase all stored codes.

Be aware that very few codes throw the CEL. If you can't get the code reader to work, try the paper clip method:

http://wiki.wikisho.com/wiki/EEC_Self_Test_Procedure

There's a link on that page to another page that lists the three digit code meanings for a '95.

Back to your basic symptom. Sounds like the butterflies are working. They are open engine off. Note that the tabs on the butterflies are in the down position. Start the engine: the tabs should now be up, indicating that the butterflies are closed. Goose the engine to above 4K to verify that the butterflies open again.

Now take it for a test drive. This time mash the accelerator at around 3K, well before the butterflies open. Does it bog down under those circumstances? If so, nothing to do with the butterflies. I've had a few cases where the car runs fine under gentle acceleration, but bogs down when you mash it. Turned out that a dirty MAF was screwing up the A/F ratio. Cleaning the filaments cured the problem. Can also be caused by a vacuum leak.

 

[FastCAD]

I picked up an ODB1 scanner, and no codes were available. I drove it and was able to get a check engine light to come on by hammering the throttle and holding it on the highway, but the light went back off before I could get pulled over to test, and then no codes showed again.

I tried to remove the TPS from both (92MTX & 95MTX), but they didn't budge.



OK, thanks. I'll have to research how to do that.

One thing I noticed is the connector with one wire, a gold wire on the intake, barely has any covering on it. Is this a ground or something and/or should it be fully wrapped?

View media item 708

I believe that your (P)ower (C)ontrol (M)odule is OBD-II.

 

[luigisho]

No, OBD II started in the 96 models

 

[zoomlater]

see BaySHO's response above, he covered whether your butterflys are opened or closed and what happens when you rev past 4K

On my 94, the levers never moved after starting the engine. Car ran fine, just didn't notice the secondaries not opening when they should have

 

[BRD]

Well, I tried the paperclip, and the OBD1 again and didn't get any codes, but did see what part of my problem pulling codes was, I was trying the ABS connector. (Shouldn't that have showed a code since the ABS light comes on occasionally)

As for my loss of power, swapping in my old MAF fixed it!!! WooHooo!!! As soon as I started the car it was obviously different, and now it feels twice as fast, even before the secondaries kick in. Just a light tap of the throttle at idle in neutral, and you can feel it revving smoother and quicker.

Previously I tried punching the gas at 3k (per BaySHO's recommendations) and it didn't bog until right after the secondaries kicked in, and a little stammering from an idle when cold.

I'm now wondering if it doesn't have computer issues since it never registered a code, but I'll leave it alone since its running great.

Thank you all again for all the help!!!

 

[FastCAD]

No, OBD II started in the 96 models

Thanks for the correction luigisho.
I have the Innova OBD1 also. It works very well and not expensive. You do have to follow directions though same as the paper clip method. It helps if you get the extension cable for a one man operation.
I had a mysterious bad running '91 recently but no codes or flashes. Fortunately I had a known good PCM that I swapped and got the code right away-bad TPS. Installed a new OEM unit and the SHO runs real well again.

p.s. I noticed other posts about the air bag light from **** w/bells lol. I had the same for a very long annoying time.
My mechanic gave the SHO a work around. The air bag system is inactive as it is with a flashing light but there is no flashing light or bells. The SHO runs as though nothing happened.
If anyone is interested I'll get a write up on the work around and post it.
Thanks again,
Best to All.
Joe

 

[luigisho]

Thanks for the correction luigisho.
I have the Innova OBD1 also. It works very well and not expensive. You do have to follow directions though same as the paper clip method. It helps if you get the extension cable for a one man operation.
I had a mysterious bad running '91 recently but no codes or flashes. Fortunately I had a known good PCM that I swapped and got the code right away-bad TPS. Installed a new OEM unit and the SHO runs real well again.

p.s. I noticed other posts about the air bag light from **** w/bells lol. I had the same for a very long annoying time.
My mechanic gave the SHO a work around. The air bag system is inactive as it is with a flashing light but there is no flashing light or bells. The SHO runs as though nothing happened.
If anyone is interested I'll get a write up on the work around and post it.
Thanks again,
Best to All.
Joe

I think the workaround would be helpful!

 

[BRD]

If done right, the first thing that will happen is that the fan will run for a couple of seconds.

BaySHO, thanks for pointing out that the fan would kick on shortly. This was a clear indicator that I
wasn't aware of, and it helped to know I had it hooked up correctly.

If anyone is interested I'll get a write up on the work around and post it.

I would be interested in a work around too, because the beeps will probably only get worse. Fortunately it's not too bad yet, they almost make me feel like I'm operating a fighter jet, lol.