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-   -   fuel injected running rich, way rich, like Donald trump rich... (http://www.diychatroom.com/f46/fuel-injected-running-rich-way-rich-like-donald-trump-rich-169408/)

thehvacguy 01-17-2013 06:47 PM

fuel injected running rich, way rich, like Donald trump rich...
 
Ok so we just moved from los Angeles to south east Idaho which is about 6000 ft above sea level. I have a 1989 Chevy c3500 with a 350 out of a caprice. It has 2 fuel injectors, each one fires 4 cylinders. I remember it was running a little rich before I left LA but now I can smell straight gas coming out of the exhaust. Is there an adjustment that I need to make for the altitude change? What else could be the problem?

toolaholic 01-18-2013 12:11 AM

There is less oxygen in the air the higher you go in elevation. I would make sure it has a clean air filter. A K&N oil/gauze air filter would help get more air into the engine.

frenchelectrican 01-18-2013 12:13 AM

Quote:

Originally Posted by thehvacguy (Post 1095959)
Ok so we just moved from los Angeles to south east Idaho which is about 6000 ft above sea level. I have a 1989 Chevy c3500 with a 350 out of a caprice. It has 2 fuel injectors, each one fires 4 cylinders. I remember it was running a little rich before I left LA but now I can smell straight gas coming out of the exhaust. Is there an adjustment that I need to make for the altitude change? What else could be the problem?

The MAP ( manifold asbolute pressure ) sensor can go bad and not reading correct altuide setting and also the O2 sensor as well.

As far for the 350 Caprice engine what year is that and did you transfer all the related emminson hardware from the oringal engine to the caprice engine on that truck ?

That will make the differnce there.

Merci,
Marc

ddawg16 01-18-2013 01:25 AM

Check the connection to your temp sending unit.

I have a 93 TBI in my jeep....it's basically the same setup you have.

Wait...what year Caprice? If you have a TBI and not a TPI, then, yes you have 2 injectors but they both pretty much feed all cylinders.

So....assuming you have TBI and it's like my setup....

Your primary sensor are MAP (Manifold Air Pressure), CTS (Coolant Temp Sensor), TPS (Throttle Position Sensor) and your dist (tells the computer what cyl is ready to fire)

In most cases, if your running rich it's because the CTS thinks the engine is colder than it is. About the only real way to know is to hook up a OBDI scanner and look at the reading the computer is getting.

You could also have a bad MAP. You can test that by just measuring the voltage coming out. When you first start the engine, before it actually cranks it measures the voltage...this is basically your altitude reference....after that, the voltage tells the computer how much manifold vacuum you have.

It all comes back to needing a scanner and reading real data to get an idea of what is going on.

thehvacguy 01-18-2013 07:53 AM

Quote:

Originally Posted by frenchelectrican (Post 1096145)

The MAP ( manifold asbolute pressure ) sensor can go bad and not reading correct altuide setting and also the O2 sensor as well.

As far for the 350 Caprice engine what year is that and did you transfer all the related emminson hardware from the oringal engine to the caprice engine on that truck ?

That will make the differnce there.

Merci,
Marc

Quote:

Originally Posted by frenchelectrican (Post 1096145)

The MAP ( manifold asbolute pressure ) sensor can go bad and not reading correct altuide setting and also the O2 sensor as well.

As far for the 350 Caprice engine what year is that and did you transfer all the related emminson hardware from the oringal engine to the caprice engine on that truck ?

That will make the differnce there.

Merci,
Marc

Um... I bought this truck off of some dude and the only information I got about the engine is that it came out of a caprice. I can tell that it is a late 80's model because all of the stuff I been replacing on it. I don't remember what part made me know it was late 80's but nevertheless I do need to change the o2 sensor, I already changed the temp sensor that screws into the top of the block next to the upper radiator hose, and I changed the thermostat. I don't know about the emmissions stuff, all the hoses coming out of the throttlebody are plugged with screws. Where do I locate the MAP sensor? I never heard of that...

ddawg16 01-18-2013 10:50 AM

Oh boy....sounds like that 'dude' did a hack job. There should be at 3 hoses in use off the TB. One in the front should go to a solenoid and the to your evap canister.

In the back, the 1/2" line at the base goes to the valve cover and PVC.

Also on the back but up a little is a real small hose that 'should' go to a black module over on the right side. That is your MAP. With out it the engine runs in open loop limp mode.

Look at my jeep build lin in my sig....you will find some pics of my engine. As soon as I get home I can post more pics.

Billy_Bob 01-18-2013 11:52 AM

With fuel injection, all the various engine sensors input information to the engine computer. And based on that information, fuel is adjusted...

However those sensors along with the specific engine and the engine computer are all designed to work together - sounds like just the engine was switched?

I would sell it and get a vehicle which has not been modified - save yourself a LOT of trouble!

47_47 01-18-2013 12:33 PM

1 Attachment(s)
You realy need to get a scan tool and look at the data stream or just get one of each and start throwing parts at it.

I agree with the others look at the MAP sensor. Sould be mounted on the right side firewall. Check the vacuum hose for splits, cracks proper sealing... and also see if you are getting manifold vacuum. Inspect the electrical connector for corrosion.

Do not run this truck too long or you will damage the cat (s).

Billy_Bob 01-18-2013 01:55 PM

But is that MAP sensor the MAP sensor for a "350 out of a caprice"?

(And is the engine computer and its software for a "350 out of a caprice"?)

From year to year sensors change. For example a sensor for one year might have a "voltage" range from 5 volts to 9 volts. The next year the same sensor might have a range from 3 volts to 7 volts. And the engine computer software would be programmed differently for those different sensors.

So when replacing an engine with something different, you should also change the sensors and the engine computer for that engine...

ddawg16 01-18-2013 02:49 PM

Billy bob brings up a good point. Hoefully the 'dude' swapped the computer with the engine. For the most part, if the engine was pulled with everything attached, as long as he swapped the computer, all should be good.

If he swapped just the long block....then you need to make sure your truck is set for that block. You can look at the VIN to see what came in it. If it had a 5.7L before, then your good. But if oit had a v6 then you have issues...computer will be wrong.

danpik 01-18-2013 06:32 PM

I have to agree with Ddawg16. Sounds like it is running in "limp Mode". Are there any code stored in the computer? Is the "check engine/service engine soon" light on? Does the light even work? If it is indeed running in that mode then it is running real rich as a default setting. Compound that with the fact that there is no air up where you are the fuel mix error is even compounded further. If the truck is worth it, you could buy an aftermarket fuel injection/engine management system from Holley or Edelbrock and replace the stock GM system

frenchelectrican 01-19-2013 12:47 AM

Oh wow one heckva a mess which I have see it more than I really want to recall it.

Basically let me run quick punch list.

Check the MAP sensor as other mention and one of the member posted the photo what it look like and it useally located on the firewall near passenger side on GM trucks ( few will have on right front fender area only on few specfic models so be aware with it )

Second thing what the water tempture it running now it should be 190-195 degress F. that way the computer will sense it and will go in close loop which it will finetune the fuel system to proper mixure. If you used wrong thermosast like 175 or 180 degress F verison the computer will sense the engine still " cold " and will run in open loop which it will cause the fuel/air mixure to run more richer than normal.

Third thing is look at the hood sticker details it should mention what the oringal engine size and I know with C/K 3500 most common will be either 5.7 or 7.4 liter engine.

Do you still have catatic converter(s) on it or it was removed ?

How many miles do this replaced engine have on it now like rough esttame it is now? ( I am not too suprised that the ingition timming / valve timming can be messed up )

Merci,
Marc

paintdrying 01-19-2013 07:59 AM

How is the spray pattern on the injectors. I would pull all that junk out of there and just run a carb.

ddawg16 01-19-2013 09:13 AM

Quote:

Originally Posted by paintdrying (Post 1096997)
How is the spray pattern on the injectors. I would pull all that junk out of there and just run a carb.

That is pretty bad advice.....I personally will never go back to a carb....I've had a lot less issues since I did the SBC swap into my jeep.

ddawg16 01-19-2013 09:21 AM

47 posted a good pic of the MAP.....

This is my engine and if you look where the transmission dip stick goes down, you will see a black square piece of metal...the MAP is mounted on the other side of it....

I would take a better pic...buy my jeep is up at work...

http://i43.photobucket.com/albums/e3...d/DSCN0731.jpg


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