I have a 87 Camaro with a 350 IROC TPI engine and have been having some issues with it running smooth. Sometimes when I am driving on the freeway or at least 45 MPH, I will let off the gas and the car will slow down a lot and the RPMs will drop significantly.

Also, I have had the engine seem like it stalled (no power, put the pedal on the floor and still lose speed) and then a few seconds later it jerks and has power again. Right after I get power again, the check engine light comes on. When this happens, it makes the first problem I talked about even worse.

I think it is some kind of sensor malfunction, but I don't know how to figure out which sensor. The car doesn't smoke, but one time when I was sitting at a light, it started stalling out and I saw smoke in the rear view mirror that looked white (it was night so it was hard to tell). I tried taking it to autozone to have it tested, but of coarse its "too old" (had some not so bright fellow tell me it doesn't have a computer ).

My question is, does anyone have a theory on what the problem might be? Also, how can I get the codes off the computer? Thanks

 

What engine code are you getting? That's a good place to start.

 

I don't know how I can get the codes, thats part of what I was asking. I took it to some car parts places and they told me its to old to test. Not really sure what I can do.

 

There's a way to use a paper clip and jump two terminals on diagnostic connection (under the steering wheel to the right I think). That will make the check engine light flash out the codes for you. Look around on the site and there's probably instructions on how to do it. If not PM me and I'll send you all the info I have.

 

all u need is a paper clip

 

Locate the ALDL terminal under your dash. It's basically a rectangular electrical connector with about 12 connection points (should be 2 high by 6 wide). Take a paperclip or some stiff wire, and connect the "A" and "B" terminals. They are the two furthest to the right on the top row.

Then, turn your key on. Your "Check Engine" light will flast once, pause, then twice, then pause long. This represents "12" (one-two), and is just a diagnostic check that doesn't mean anything. It will do the one-two flash three (3) times, and then will start flashing the engine code you're getting. Every code you have will be flashed three times.

Tell us what codes you pull and we'll go from there.

 

Well, I tried it out and got kinda confused. It flashed a whole lot. It alternated 3,4,3,4 six times and then did the flash...flash flash again. I am going to check on it again, but thought this might mean something

 

As far as I know, it shouldn't give the same code twice in a row, so you may have a 34 AND a 43. This is more likely than you would think. Just so you're prepared, here's what you should expect:

- Flash once ("1")
- short pause
- Flash twice ("2")
- long pause
<<Repeat the above two more times (3 total)>>

- Flash <code digit #1> times
- short pause
- Flash <code digit #2> times
- long pause
<<Repeat the above two more times (3 total)>>

Then, it will flash additional codes in the same manner, and then start over again by flashing "12."

Remember, there are short pauses between digits of the same code, and long pauses between the codes themselves.

12
12
12
long pause
code1
code1
code1
long pause
code2
code2
code2
long pause
code3
code3
code3
long pause
.
.
.
.
12
12
12

and so on. Let it cycle a few times so you really get it nailed down.

 

would like to know too

 

After looking at it again, I am definitely getting a code 34. Anyone know what that means?

 

If you've got a 350 TPI, it means that you have a problem in the MAP circuit. Typically this means that you've got an open in the circuit or the sensor is bad.

First, locate the MAP sensor - it's the black rectangular part (about 1" x 3") that is connected to side of your intake plenum near the back on the passenger side. It should have an electrical connection to it and a vacuum tube that goes directly into the intake plenum. Make sure these are hooked up, then come back and I'll help you diagnose it further.

 

First off, what year car is your engine and ECM from? I'm guessing it's a swap because the car in your sig doesn't look like an '87 IROC.

If it's from '87 - '89, you have a Mass Air Flow sensor.
If it's from '90 - '92, you have a Manifold Absolute Pressure sensor.

Here's a list of all the trouble codes: http://www.iroczone.com/specs/TroubleCodes.htm

I had a code 34 a few weeks ago. Turned out the connector from the harness to the MAF itself was bad. I replaced it, and now it's fine. Whatever you do, try the least expensive parts first i.e. MAF burnoff and power relays and the MAF connector. But this only applies if you have a MAF sensor.

 

FYI, "MAP" stands for Manifold Absolute Pressure - it tells the computer the amount of vacuum in the intake manifold, which helps it determine the load on the engine and therefore how to adjust the spark and fuel for best performance.

 

My car is an 87 sport coup with an engine swap with a 350 from an 87 IROC. I guess that means its the MAF issue? Where can I find the power relays, connectors, and burnoff? Also, how do I check them, as in what to look for?

Thanks for the help

 

There should be a row of relays on the drivers side of the firewall. Two of them will be the MAF burnoff and power relays. GM wasn't very consistent with the placement or types of relays they used, so it can vary from car to car, year to year. They should look something like this though;



Your engine being a swap could add to the confusion. Did you do the swap
yourself? You can check the voltage at the relay connections, but I just replaced mine. (Only $25 for both relays)

The MAF connector is the connection that plugs into the the MAF itself. With the engine idleing (If you can get it to idle, with my code 34, it wouldn't) try wiggling the connector to the MAF to see if the situation improves. If it does, the connector is probably faulty and needs to be replaced.

Also, make sure the connections at the relays and the MAF connector are tight, if they're loose, this could be causing the problem. Check your intake ducting and make sure everyting's tight too.

Try contacting a guy on here that goes by the name of vader. He really knows his TPI stuff and can probably help better that I can.

 

I checked for power to the MAF sensor and it had power on the very left prong, but none of the others. I am assuming that this is normal.

I haven't had a chance to test anything else since my speedometer cable decided to get lose (god knows how) and break. So now my main priority is trying to get a new speedo cable in. Not looking forward to having to take off the brake booster and all

Thanks for the info so far

 

Get a Helms manual and follow the diagnosis chart for that code. You could always have somebody upload the chart for you (don't have it, sorry), but trust me you won't regret having this manual.

You might not have to fix your speedo cable first, either. I would assume that you can diagnose it in park, and just manually work the throttle body if need be.

 

Well, I checked the codes again because the check engine light was lit all the time now and found codes 24, 33, and 34. Code 24 is just because my speedometer cable is sheered off at the end.

So now it seems I have a MAP and MAF sensor malfunction. I idled the engine without the air intake tubes hooked up last night, could this cause the code 33 (MAP Circuit)?

Since there is power to the far left **** on the hookup for the MAF sensor, does that mean it is working correctly?

Thanks again

 

You don't have a MAP, you have a MAF. Look at the code chart again - there is a Code 33 for both MAP and MAF, and the same for Code 34. Looks like you're getting too high and too low of a signal on that circuit. This pretty much indicates you have a bad MAF sensor if its failing both directions.

Just to be sure, though, you should fully investigate that circuit - see if someone can upload the 33 and 34 (MAF) diagnostic charts for you. I would, but mine are for MAP.

 

Well, I haven't had a chance to get a good look at all the parts of the circuit yet. I called my local GM dealer to get a price on a MAF sensor and went into denial. I heard, "seven twenty" and said, "as in $7.20". The response, "No, $720.00".

...I laughed but apparently he wasn't joking

 

I would assume you can get them for less, but I've never had a MAF so I wouldn't really know.

Have you tried to find anybody on the board that would post the diagnostic charts for you?

 

u can get a remaned MAf for about 170 ish i believe

 

I haven't found anyone yet. Do you know someone who would have them?
That sounds a lot better (still pricey, but I guess thats just the way it is), would it just be from a parts store such as autozone?

Thanks

 

You're probably not going to find a much better price on the MAF.

For the diagnostic chart, I would probably just make a new post with a title that mentions you need someone to scan the MAF Code 33/34 diagnostic charts.

 

Actually code 12 does mean something, it indicates the ECM does not see a RPM signal but is expected since the engine isn't running. It is not just a diagnostic check.