Says my baro circuit is bad. First, where is it? Book says it's in the engine compartment on the firewall, but I can't see it. Second, is it the baro or egr? I know I have an egr issue, so do I need to replace the egr or baro? (L98 5.7L)

 

Plus, I'm a little confused about the baro/map sensor. My car has a map sensor, I can see it. If it has a map, does that mean it does not have a baro sensor? Or are they different names for the same thing? That would make life easier. My symptoms are rough idle, dash light and it dies after it starts, takes a while to get it going. Those could be baro or map, so I need to know which I have if not both. This is something else I'm learning about with this car......

 

The Map sensor measures Barometric pressure as well as Manifold Absolute Pressure {MAP}. This is so the fuel system will be able to compensate for changes in barometric pressure as well as engine load, e.g.. climbing a mountain pass. Check for Vacuum leaks , you can google the location of the sensor.....intake manifold.

 

Forgot to address the EGR issue, if it is stuck open or leaks exhaust into the intake , your mentioned symptoms may occur. Best to remove the EGR and see if it leaks when closed [no vacuum supplied], you will most likely need a new EGR gasket if you remove it. Hope i am helping......

 

Yeah, that's helpful. I was getting an egr code before, or so a friend who checked the codes before me told me. I just bought the car recently. But, the only code I get now is the 32. I see no "code" for an egr in the book, so is this the code he was talking about? Also, is removing the plenum to get to the egr difficult? I saw some videos on YouTube that seemed like it wouldn't be too bad. Not a 5 min job, but not rocket science either. Runner bolts, brake assist, throttle body/cables, vacuum lines, etc. Any pitfalls there? I've been planning to replace the egr when I got a free day. I see the map sensor, it's on the plenum, but does that mean the bar and map are the same thing on my car? I'm getting the impression map is a newer version of bar, and then MAF replaced map. But my trouble is, the engine code for a map failure is 33. I'm getting a 32, so maybe it is the egr and it's fooling the ECM? A lot of this crap is new to me, it's why I joined this forum.

 

I have a 1988 factory manual, 5.7 TPI does NOT show a MAP sensor, they have a MAF sensor [mass airflow sensor], it is located in the intake duct between the air filters and the throttle body. Code 32 is a code for EGR circuit fault, the EGR has a electrical solenoid controlled by the ECM, the black with pink wire should have battery voltage to it with the ignition on and the grey wire is grounded by the ECM on a duty cycle as required.So the circuits need to be verified... grounding the grey wire with ignition on should activate the solenoid, if the engine is running vacuum should turn on and off to the EGR valve. Disconnect the vacuum line to the valve to feel the results. BTW there should be no EGR when in park or neutral... so no vacuum should get to the valve at idle in park or neutral. This should get you started. Please read my first post again, barometric pressure will change when climbing hills,[BARO]...your ears will pop.. Once again this info is for 1988 models.

 

Now I'm really confused. First, yes, I understand about altitude, that's not the problem. Second, what you just told me contradicts what another poster told me the other day about map and MAF. I was told 92's use map. I do not have an intake duct, it was removed by the PO, and replaced by a K&N filter which is attached directly to the throttle body. I plan to put the stock intake back on soon because I'm not sure this is a good setup, although the car ran fine like this til just the other day. As far as I know there is no MAF sensor inside the duct, it's just a simple square plastic tube, but I will look. It's the one that runs off to the passenger's side to a canister below the coolant overflow tank, not the kind that runs toward the nose and that has a MAF sensor. Last, my car has a map sensor on the passengers side of the intake, I was just looking at it last night. It's connected to a bracket with two 7 mm screws, has a connector with 3 wires and a vacuum line underneath.

 

You sure my egr has an electrical solenoid? Looks like it's run by vacuum to me. No electrical connections, a vacuum line nozzle only.

 

My map sensor is there in front of the notch in the distributor cover. Here's a pic.

 

90 -92 are MAP

 

The ECM on yours uses readings from the MAP sensor to determine if the EGR is operating when commanded ; there is no direct sensor
( a EGR temp switch ) for EGR operation like there is on the MAF cars

If the MAP sensor was faulty you would have MAP fault codes 33 or 34 showing
If you have a DTC 32 you have a EGR problem

Best you can do is work through the DTC 32 diagnostics linked here

http://www.chevythunder.com/egr_code_32.htm

remembering you don't have the temp switch mentioned

 

Check your facts. a 1992 model like what the OP has is a MAP car not a MAf car.
Please do not share wrong information 1990-92 cars are all Speed Density cars using MAP sensors. 89 and older use MAF

 

The terms MAP and Baro are interchangable.

Like the picture, your EGR valve only has one vacuum port. There is a solenoid located under the ignition coil that allows vacuum to the EGR valve when the computer commands it.

Removing the upper plenum is not that big of a job. Well within the range of the average do-it-yourselfer. After you remove all the bolts, you might have to pry or rubber hammer the plenum loose. And when reinstalling, finger tighten all the bolts completely in so that the whole assembly is nice and relaxed before you finally tighten them home.

 

Ok, that's helpful. I think the egr is clogged/failed, and it's making the computer throw a 32 baro code. I think the map is ok, I'll just have to dig that egr out and either clean it or replace it. I've known for about 3 months it was on the way out, so no shocker.

 

A code does not condemn a part, a code is an alert that the computer sees something in the circuit that's out of whack. Your EGR valve might be the problem, but it might also be the solenoid, wiring, or vacuum lines. Another common problem (especially with a colder than stock thermostat) is that the EGR tubing might be coked up, which is a nice fix becuase all it's going to cost is the price of the gaskets to take it apart and clean it.

 

Yes, it could just be dirty. Im hoping so, especially since this egr has no electronic parts.

 

Did you read the link I posted for you ???

As eseibel67 stated above the problem may be with the electrical side of it's operation ; not a actual problem with the valve itself.
Dismantling half the engine to replace / clean the EGR valve is a bummer when you later find out the problem is a bad wire

 

Yeah, I looked at it, and it might as well be in Chinese. LOL I just don't understand wiring and wiring diagrams etc. I hate wiring. God help me if it IS a bad wire, because I'd have no clue how to start finding which one. I'd much rather spend the afternoon taking the plenum off and replacing the egr! We'll see.......But yeah, I'll look at it again. I'm smart enough, but not always very patient with stuff like that. Thx.

 

Actually the flow chart is easy enough now that I look at it, but a lot of that looks like it's dealing with MAF, which I don't have. I run MAP, therefore I don't have an egr temp switch as it's described there. The diagram below it is also MAF, so how much of that translates to my system?

 

Here's one more clue. This may mean something to some of you. Always, you have to drive about 5 miles before the engine light will come on.

 

No surprise. Car has to be moving over 50 MPH at steady throttle position before it will run (and in your case fail) the EGR test.

 

Ok, thx. Something else I learned today.

 

You still the electronic control of the EGR solenoid ( by the ECM ) which controls the vac that operates the valve

https://www.thirdgen.org/forums/post...01-post20.html
https://www.thirdgen.org/forums/post...98-post30.html

Do the wiring tests to the solenoid and check all EGR associated vac lines

 

A bit of what's in those links is over my head, but I think I understand the concepts. Sounds like the valve is either stuck open or is being left open by faulty solenoid or vacuum? The car does have an after market exhaust, at least cat back anyway. One guy told me he thought that might be why I'm getting an egr code, but I don't think so because then the car was running fine, and now it's running like crap. So, there really is a problem besides that, and I don't think I have a crossover pipe. This link is about Vettes, but it shows the solenoid beneath the plenum and how to test it. Looks helpful.

http://tech.corvettecentral.com/2012...egr-diagnosis/

 

I'm done.
Go ahead and replace the valve

What you are failing to appreciate is the code is from a failure of the ECM to SEE the valve operate when it is told to;
nowhere does it indicate the valve itself is actually faulty.

And in the majority of non valve failures, the cause is the opposite to what you guess; no vac or no power to the items that control the valve so it remains closed and doesn't work when commanded as shown by you having to drive some distance before the code appears (the time when the ECM tries to operate the valve. )
A EGR valve that is open fulltime will display other problems like a cr*p idle

 

Well, I guess you can be done. I didn't know the purpose of this forum was to insult each other, but if you notice I also said it could be the solenoid or a vacuum problem. Considering that 24 hours ago I had never even heard of most of this and can now explain the difference between N Alpha, Speed Density and MAF tells me I'm at least making progress. I'm actually going to have to buy a multimeter and vacuum pump to do these tests because I own neither right now. I joined this forum because I know so little about these things, and I want to learn so I can take care of my car. I had the problem of driving some distance before getting the code, now I've got the crap idle--so it's both. Otherwise, thanks for your input, you have been helpful.

 

mine has a map and its an 89.. it depends on what type of fuel injection and air breather are installed

 

if your car is accually dying and refusing to run i would inspect fuel pressure and fuel systems. i can unplug my map and egr and the car will still run. seams to me that something else may be going on and its just giving you that code because that system is not running optimally..

 

Yes, I'm learning that......Some cars older than mine have MAF.

 

Awesome.....and how do I do that? It will run, it just runs very rough, sort of coughs etc. I still think it's egr related, but you could be right. It ran ok til last week. I'd get the 32 code after about five miles of driving, but there was no discernible change in performance. But last week it started idling rough, and it's gotten worse since.

 

Because it is TBI ; not the TPI being discussed in this thread

Already observed above ; 90 - 92 TPI are MAP cars

Once again ; irrelevant.
All having no EGR does is throw a code because it is not working as it should ; has little effect (that you will notice without datalogging )
on on the engine operation
A faulty ( leaking ? ) EGR valve as the OP appears to have will effect the operation ; unplugging it will not change anything

 

We are trying to help you here. This "guy" is guessing with your time and money. He might guess right, even though he has <1% of the knowledge that vetteoz has on TPI. In the end, it's your choice of who to take advice from. Personally, I would go with the guy that has the right answers.

 

these guys are so sweet to everyone. word of advice, when it comes to a car problem, everybodies a mech...lol.. that being said. your best option is as always start with the cheapest easiest things to check first and work your way up from there. vacuum lines are cheap and for $20 you can replace every one of them(always gud for the 20-25yr old car. the egr can be roughly tested by pushing up on the diaphram inside to see if the spring is tight,functioning and sucking air(ofcourse thats only a rough test/ and also would advise(like others have said/ check your electrical connections. a bottle of electrical spray cleaner(autozone/ does wonders on 20 yr old connectores-check you wiring prongs,etc. and lastly if one of these simple tests does no change you can rent a fuel pressure meter from autozone and make sure u have proper fuel delivery. that is the order of what i would do before putting out any real $$$replacing parts. js. goodluck

 

Actually the guy in question was a mechanic with years of experience, who is the owner of his own shop. He also had not fully investigated the issue, he was helping me with something else, noticed a 32 code and he wasn't sure what it was, said it might be the egr, but also might be associated with the after market exhaust. I never had him pursue it further because I was doing other things at the time, and he never offered to do anything else. Furthermore, it was something I posted in response to another poster's suggestion about exhaust that was mentioned in the link he sent me, as a crossover pipe caused a 32 code in an example case. Lastly, when have I rejected anything vetteoz has offered in favor of "some guy"? I think he got a little short with me simply because he doesn't understand how new I am to all this, that's why I joined this forum--so I could learn. I posted last night that he has been helpful, and I also appreciate all the help I get from posters on this forum who have a lot more knowledge than me. Peace.

 

It's fine. I can take anything they dish out. If they knew what I did for a living, they'd understand that stuff doesn't bother me in the least. I'm also in an online sports forum on Boston.com under the same moniker where I've done battle with troll Sox fans and Yankees fans alike. I dish it out and take it big time over there. No biggie. Anyway, thanks for the advice. I've never done all those tests before, so I'll have to investigate and research it. But, it's doable, and I need to learn it.....

 

ooohh. by the way. make sure after you check things that you take the bat neg off for about 10 sec to reset comp and reset codes or else the comp might still try to compinsate for something you may have already fixed.. :-)

 

Good point. Thx. But would it clear off the code even if I don't fix it? For example, would it clear the code off until I drive it enough for the comp to know there is a problem again? They weren't as smart in 92 as they are now, so I just wondered.

 

yes. it will clear it off until it recognizes the problem again

 

Not dishing out anything.
We are just trying to get you understand that a system fault code does not necessarily indicate that the item of that system itself is faulty .
Investigation required to identify the cause of the code

Looking to save you the time and cost of EGR replacement ( a big job ) when it may not actually be required

 

Haha, it's fine Vette. No worries, I'm just kidding around. :-) Thanks for all your help.

 

Here's a small update.......Went out and fired her up, no rough idle. That went away on its own at least for the time being. Meanwhile I stopped at Autozone to run the issue by them, along with some of the things you guys suggested. They said it's more likely the egr itself than something electrical, although it could be electrical. They said before I started doing electrical and vacuum testing, to try a can of Seafoam. I bought it (I'm sure someone will post "never use that stuff") and tried it. It seemed to work pretty well, blew black smoke out the wazu for several minutes. I then road tested it. Blew smoke for a minute or two before clearing, so there were definitely some deposits in there that needed cleaning out. There was a noticeable difference in power I thought, and a little quicker response. So if nothing else, the Seafoam at least did that. I eventually did get an engine light, but it took just a little longer than usual, and--I forgot to clear the comp out before I left, so there's a chance it was an old code--though I doubt it. I'll find out for sure when I drive it to work Tuesday. But I don't think there's any vacuum issue. Seemed to do well on vacuum while it was sucking up the contents of that can. Oh, and one more thing, I had it pressure tested a few weeks back and it passed. I forgot to mention that, sorry. But who knows, right now it's running pretty good.

 

you better thank the dieity of your choice you don't have a MAF car. forget the can they are a whole bucket of worms. good luck

 

LOL....yes I do thank God for my car. But I've learned a lot just with the course of this thread. I'll get it all eventually.

 

Vac at engine doesn't mean the vac is going through the EGR solenoid ( a faulty solenoid / wiring controlling it ? ) to operate the EGR valve ;
just saying .

 

Yeah, I'll have to check them out one by one I guess. I'll track it down eventually and post about what I find. Thx.

 

I also get code 32 after i reset my computer but it comes on 10 seconds after i start the car, when there should NOT be any demand for EGR. my EGR and solenoid are both new...any ideas?

 

That's what I had been dreading too. Bad electrical connections to the solenoid or ECM can also cause that, and that can be like chasing a ghost. I changed my egr this week, don't know what the big deal was about it being a lot of work or expensive. It was neither, easiest work I've done. Mine came on after driving about five miles, I haven't taken it out for a long enough drive yet to know if it will still do it because I'm on vacation this week and enjoy the idea that I fixed it. LOL...But I'll take it out and face reality soon. If I still have the problem I'll be in the same boat you are--except I haven't changed my solenoid yet.

 

Going to check the wires again and hopefully find a short somewhere tn, keep ya posted