I'm from Moscow, Russia. I bought Chevrolet CamaroRS 1992 V6 3.1 Automatic recently. It's a nice car and in perfect condition
and very rare for Russia considering snow winter.
But there are several problems indeed.

The problem I have I can not resolve locally due to lack of specialists. Maybe you can help me out.
Here it is:

1) It seems that too much fuel in the A/F mixture, black smoke from the exhaust, fire into exhaust, black scurf on the plugs
2) rough idle, engine stops at idle
3) lack of power
4) oil level increased (I assume that it is gas in the oil)
5) high idle (1000-1200 rpm)

In general: too much fuel!
What I have checked:
1) MAP, CTS, TPS are within its characteristics and shows correct data. IAT shows that the outside air temp is +60Ñ
2) Oxygen sensor have not been checked
3) Ignition timing is 10 degrees as specified in the label under the hood.
4) Spark plugs - new
5) EGR and EEVC are blocked at the intake manifold
6) Fuel injectors are not leaking and have appropriate spray pattern
7) Fuel pressure regulator seems to be OK. I opened it and it looks like brand new.
8) Fuel pump gives 300 kPa pressure, which is higher than normal
9) Pressure in the fuel rail is 300 kPa
10) fuel filter has been replaced recently

What is to be checked next?

I'm worried by the following:
1) Fuel pressure after fuel pump stops rapidly drops to zero
2) When I clamp return fuel line, then turn on ignition but not start I hear fuel pump works. Pressure as specified above. Pump switches off. Pressure drops to zero.
Result - fuel goes back to the tank through feed fuel line. Pump???
3) When I clamp feed fuel line, then turn the ignition on but not start I hear fuel pump works. Pressure as specified above. Pump switches off. Pressure drops to zero.
Result - fuel goes back to the tank through return line. Regulator???

I have no Idea what happening. But I don't want to think of replacing of fuel pump.

What I need to check and what you suggestions in such situation???

Thanks in advance,
Peter

 

Check that the exhaust manifold bolts are all there. The back
passenger and front drivers like to break. This will allow air
into the exhaust with the ECM thinking that the AFR is lean.
The result is the ECM adding fuel.

The IAT. (+60xx) funny character after the 60. The IAT should
be very close to the outside air temperature. It will affect
the AFR if incorrect.


Fuel pressure. It shouldn't drop when the pump turns off. This
would only be your problem if it were due to a leaking injector.


!!Just thought of something!! There is a hose (small tubing) between
the fuel pressure regulator and the throttle body. If there is
a leak (a pinhole) in the regulator diaphram then fuel will leak
into the intake manifold.

Disconnect the hose from the throttle body and see if there
is fuel in it. Can even turn on the ignition to run the fuel pump
to assist in checking.

HTH's,

RBob.

 

 

IAT sensor will be ~2.8K ohms at 25c.

I realize that you've looked at the FPR, just double checking
for leakage at the vacum connection is easy and quick.

Another item to check is that the ECM has the correct memcal
in it. I take it that the SES lamp is functional and not on?

To check the injectors & wiring can remove the spark plugs and
run the fuel pump. Look for fuel pouring out from a plug opening.
Then tap the starter and look for fuel again. There may be a wire
pinched or shorted someplace also.

RBob.

 

IAT sensor will be ~2.8K ohms at 25c.

***OK

I realize that you've looked at the FPR, just double checking
for leakage at the vacum connection is easy and quick.

***OK - No leaks

Another item to check is that the ECM has the correct memcal
in it. I take it that the SES lamp is functional and not on?

***SES is off

To check the injectors & wiring can remove the spark plugs and
run the fuel pump. Look for fuel pouring out from a plug opening.
Then tap the starter and look for fuel again. There may be a wire
pinched or shorted someplace also.

***Injectors are OK. And wiring too. We removed fuel rail with injectors and watched how they works when cranking the engine.

 

Doesn't seem to be much left. The 300KPa fuel pressure is 44.1
psi. This is correct with the engine off.

Does the SES light come on with ignition on, engine not running?
(it should).


Can try running it with the O2 sensor disconnected. This will keep
the ECM in open loop. Eventually the SES light should come on.


RBob.

Flat out of ideas.

 

Petrovich, I saw your email last night as I was leaving work; figured i'd reply today, but since you've posted this here, I'll answer here!

Here's a chart of IAT/MAT resistance versus temperature:

Temp C...Ohms

100...185
70...450
38...1,600
20...3,400
4...7,500
-7...13,500
-18...25,000
-40...100,700

The fact that the return line is clamped and fuel pressure drops would seem to suggest the pump's check valve is broken, but you mentioned that there could be gas in the oil. If there is gas in the oil, like Rbob said, this could be a leaking injector. There's one other possibility that happened to my father's old car ('87 oldsmobile 2.8 MPFI).

I did the same tests on his car, and with the return line clamped shut, fuel pressure dropped to zero. It looked like the fuel pump- but I never checked the oil. I was busy that week so he brought the car to our mechanic to change the pump. Our mechanic looked at the car first, and found gas in the oil. He found out that the ECM was broken, and was locking the injectors open. When the fuel pressure dropped, it was because the computer was keeping the injectors open, and flooding the crankcase with gasoline. Gasoline hurts bearings! Luckily, the engine bearings were okay after an oil change.

Have you pulled the rail from the engine, but keep the fuel lines connected? Try your tests then. If the fuel injectors become locked open, you will see the gas spray from them.

We put a junkyard computer into the car, and it worked fine.

Do you have the GM service book? You appear to know a lot about the car, which is good!!

Also, look at all the vacuum lines. A vacuum line that is broken can affect the vacuum seen at the fuel pressure regulator.

Remember that gasoline can damage the catalytic convertor. If your engine is running very rich (too much gas), the gas can get into the exhaust, and hurt the catalytic convertor. If this happens, the "pellet bed" inside the catalytic convertor breaks into pieces, and will clog the exhaust pipes. You could remove the exhaust pipe at the Back of the catalytic convertor and look inside the convertor with a flashlight to check it.

Gasoline can also damage an oxygen sensor. However, the computer does not look at the oxygen sensor until:
1. Engine run time is at least 2-3 minutes
2. Coolant temperature is above 77 degrees F (25 degrees Celsius)
3. Computer sees a changing value from the oxygen sensor

For #3 to occur, the exhaust must be hot. With a cold exhaust pipe, the oxygen sensor is too cold, and gives one value to the computer. When the oxygen sensor gets hot, it starts to work, and gives the computer many values. This is how the computer knows that the oxygen sensor is hot enough.

So if you have the same problems with the engine cold, the oxygen sensor is not the problem.

 

Hi TomP,

Thanks for such a complete answers!

Petrovich, I saw your email last night as I was leaving work; figured i'd reply today, but since you've posted this here, I'll answer here!

Here's a chart of IAT/MAT resistance versus temperature:

Temp C...Ohms

100...185
70...450
38...1,600
20...3,400
4...7,500
-7...13,500
-18...25,000
-40...100,700

***I'll check again.


The fact that the return line is clamped and fuel pressure drops would seem to suggest the pump's check valve is broken, but you mentioned that there could be gas in the oil. If there is gas in the oil, like Rbob said, this could be a leaking injector. There's one other possibility that happened to my father's old car ('87 oldsmobile 2.8 MPFI).

I did the same tests on his car, and with the return line clamped shut, fuel pressure dropped to zero. It looked like the fuel pump- but I never checked the oil. I was busy that week so he brought the car to our mechanic to change the pump. Our mechanic looked at the car first, and found gas in the oil. He found out that the ECM was broken, and was locking the injectors open. When the fuel pressure dropped, it was because the computer was keeping the injectors open, and flooding the crankcase with gasoline. Gasoline hurts bearings! Luckily, the engine bearings were okay after an oil change.

***Hopefully I mentioned it in time and used engine carefully. But anyway I need to change oil.

Have you pulled the rail from the engine, but keep the fuel lines connected? Try your tests then. If the fuel injectors become locked open, you will see the gas spray from them.

***Yes, I did this test. When I turn ignition key in on position, then the pump starts. Injectors are not leaking. When I crank the engine - ingectors spray fuel periodically. I can not say that the fuel pattern is OK or not but it is 20-30 degrees wide and not like a fog.

We put a junkyard computer into the car, and it worked fine.

Do you have the GM service book? You appear to know a lot about the car, which is good!!

***Thanks. Yes I have Chilton repair book which I bought from Amazon. And expirence I got when I was a child and repair my farther's car together with him. But my car is a part of my hobby. Actually I'm not professional in this area and let all hard work to service.

Also, look at all the vacuum lines. A vacuum line that is broken can affect the vacuum seen at the fuel pressure regulator.

***Looks like OK. I also block all vacuum lines (EGR and EEVP too) at manifold besides MAP, FPR and idle just to check that no leaks in the intake manifold. In this case MAP shows 3 V at idle.

Remember that gasoline can damage the catalytic convertor. If your engine is running very rich (too much gas), the gas can get into the exhaust, and hurt the catalytic convertor. If this happens, the "pellet bed" inside the catalytic convertor breaks into pieces, and will clog the exhaust pipes. You could remove the exhaust pipe at the Back of the catalytic convertor and look inside the convertor with a flashlight to check it.

*** I do not have any catalityc convertor.

Gasoline can also damage an oxygen sensor. However, the computer does not look at the oxygen sensor until:
1. Engine run time is at least 2-3 minutes
2. Coolant temperature is above 77 degrees F (25 degrees Celsius)
3. Computer sees a changing value from the oxygen sensor

*** As I understand - when the engine in open loop mode


For #3 to occur, the exhaust must be hot. With a cold exhaust pipe, the oxygen sensor is too cold, and gives one value to the computer. When the oxygen sensor gets hot, it starts to work, and gives the computer many values. This is how the computer knows that the oxygen sensor is hot enough.

*** I suppose that O2 sensor is damaged. I need to replace it. But when you remove it computer chooses average F/A mixture. Idle should be stable anyway.

So if you have the same problems with the engine cold, the oxygen sensor is not the problem.

*** Problem goes bad when the engine is hot.

***At this car the fule pump as repleced. I have an idea that fuel lines could be mixed. There are four of them. I checked return line by blowing into it. It is not easy to do as with the line that goes to EEVC. Is it OK or not?

***Could you give me a map of fuel system for V6 Camaro if you have any. In the manual have there is not any.

*** If you know how to test (step-by-step algo) fuel pump (fuel system) let me know. I really do not to keep in mind an idea that I would need to replace fuel pump.

***Anyway, how is it dangerous to have a fuel pump valve broken? If the pump gives normal pressure and leak the fuel back to the tank when it is off should I drop this stuff?

Thanks again,

Peter.

 

TomP,

Could you also provide me with CTS readings. I'd like to chek it again too.

Thanks,

Peter

 

Petrovich, sorry, I don't have a CTS table here at work. I'll see if I can get it for you tomorrow. My book is at home (GM Service Manual from http://www.helminc.com - good book!!)

Because you say the fuel injectors are not leaking, I think it can only be the fuel pump valve. Are you sure that the return line was closed completely? I will check my GM book to see if there are other problems besides the pump valve.

The pump valve might cause the pump to be overworked. The valve keeps pressure in the line. With a bad valve, the pump would always be working.

Is this the kind of map you want? Or do you want a map of the charcoal canister vent lines?

 

It is possible that you have an export version of the
calibration that ignores the O2 sensor. Does the
fuel you have there have lead in it? If so that
would ruin the O2 sensor. Typical export vehicles
have the O2 wire cut and closed loop disabled in
the calibration.

If the calibration is a non-export version this
may be the problem. Do you have the equipment
to read the EPROM? If so I'll take a look at it.

There are two other possibilities:

A bad ECM. A bad injector.

I would recommend that you disconnect the O2
sensor and see if the problem goes away.

If that doesn't make any change then beg, borrow
or steal (no, don't do that) another ECM. It
is possible that once the ECM heats up it is
no longer functioning properly.

Most likely the ECM is a 1227730. That is what
the US version of this vehicle use. That number
can be found on the outside of the unit.

If neither of the above fix the problem I would
swap out the injectors.

You mentioned that the problem occurres once the
engine has been running a while. Everything heats
up, the ECM, injectors. Then things go bad.

RBob.

 

Have you check every vacuum hose?
Have you replaced any yet?
Those rubber sections age & cause funny things to happen, especially in certain engine operating electrical mode (cold engine mode compared to hot engine operating mode).
The hoses can be repaired with 5/16" windshield washer hose.
The back one, by the distributor base on the egine block, driver side, is 1/2" heater hose, short section.

Next, your ECM could be messed up.
Hoses are simple check (LOOK AT UNDERSIDE passenger side hoses, especially!).
Where is the local GM Regional Rep of your area?
That person can obtain line art illustration to show many different engine parts.
I would ask for the PVC hose routing illustration.
Fuel line illustration.
Electrical wiring harness illustration.
HELMS BOOKS (GM Service Factory Shop manuals) ARE THE BEST, too. Pricey, tho, be warned.
That large Chiltons ain't bad either!

Russian Babes must love being in that American Muscle Car!
Do they look like the Blonde Russian Babe I recall in James Bond's "From Russia With Love"?

 

You need to isolate your fuel leak. This is your number 1 problem. It's possible that the pump check valve is bad BUT would it cause a rich condition???? Probably not.

A better test: have 2 people available. One person turns the key to ON. The other person QUICKLY clamps BOTH FUEL LINES. This takes the pump check valve out of the equation. If fuel pressure still drops with BOTH lines clamped, you have isolated the leak to the front of the vehicle. Most likely the fuel pressure regulator because Bosch/Multec style injectors don't stick open very often. I've seen it but it's rare. What they will do is short internally and not open at all.....but that won't cause a rich condition.

 

Here's the CTS table BTW:

--------------------------------------------------------------
F*--- *C --- OHMS
--------------------------------------------------------------
210 --- 100 --- 185
160 --- 70 --- 450
100 --- 38 --- 1,800
70 --- 20 --- 3,400
40 --- 4 --- 7,500
20 --- -7 --- 13,500
0 --- -18 --- 25,000
-40 --- -40 --- 100,700


The bold numbers are NEGATIVE.

Heh, I just remembered.....the IAT and the CTS are the same exact sensor in regards to resistance values.

 

Thanks,


Petrovich, sorry, I don't have a CTS table here at work. I'll see if I can get it for you tomorrow. My book is at home (GM Service Manual from http://www.helminc.com - good book!!)

Because you say the fuel injectors are not leaking, I think it can only be the fuel pump valve. Are you sure that the return line was closed completely? I will check my GM book to see if there are other problems besides the pump valve.

***Thanks. Injectors are definitly NOT leaking. Checked it again. Could you say what the correct spray pattern shoud injector have?

The pump valve might cause the pump to be overworked. The valve keeps pressure in the line. With a bad valve, the pump would always be working.

***I thougth that FPR is doing that job

Is this the kind of map you want? Or do you want a map of the charcoal canister vent lines? [/QUOTE]

***Yes, that makes life easier. Do you have pump assembly diagram also?

 

Thanks Bob,

It is possible that you have an export version of the
calibration that ignores the O2 sensor. Does the
fuel you have there have lead in it?

***No. It is 92 octane fuel. Unleaded.

If so that would ruin the O2 sensor. Typical export vehicles
have the O2 wire cut and closed loop disabled in
the calibration.

If the calibration is a non-export version this
may be the problem. Do you have the equipment
to read the EPROM? If so I'll take a look at it.

***I do not have but I'll try to finâ it on service. Do you know any freeware for engine diagnistics?

There are two other possibilities:

A bad ECM. A bad injector.

I would recommend that you disconnect the O2
sensor and see if the problem goes away.

***looks like it becomes more serious when I disconnect O2 sensor.

If that doesn't make any change then beg, borrow
or steal (no, don't do that) another ECM. It
is possible that once the ECM heats up it is
no longer functioning properly.

***:-)))) Ok, just point the car.

Most likely the ECM is a 1227730. That is what
the US version of this vehicle use. That number
can be found on the outside of the unit.

***I'll check.

If neither of the above fix the problem I would
swap out the injectors.

***Injectors are not leaking, but I'm not sure they have correct spray pattern. What I could say, that all injectors have the same spray pattern.

You mentioned that the problem occurres once the
engine has been running a while. Everything heats
up, the ECM, injectors. Then things go bad.

***:-((((( Trying to make my car running. thanks for help :-)

RBob. [/QUOTE]

 

Hi KED,

Thaks for help,


Have you check every vacuum hose?

***I blocked all of them at manifold. So no vacuum leaks.

Have you replaced any yet?

***They do not look like to be replaced

Those rubber sections age & cause funny things to happen, especially in certain engine operating electrical mode (cold engine mode compared to hot engine operating mode).
The hoses can be repaired with 5/16" windshield washer hose.
The back one, by the distributor base on the egine block, driver side, is 1/2" heater hose, short section.

***Do these hoses have any influence on A/F mixture?

Next, your ECM could be messed up.
Hoses are simple check (LOOK AT UNDERSIDE passenger side hoses, especially!).
Where is the local GM Regional Rep of your area?

***There are some. But the repair strategy of these services is replace things till the car starts work propely. They usually do not do analysys job. And I do not want to pay for replacements that my car does not need.

That person can obtain line art illustration to show many different engine parts.
I would ask for the PVC hose routing illustration.
Fuel line illustration.
Electrical wiring harness illustration.

***Many thanks.

HELMS BOOKS (GM Service Factory Shop manuals) ARE THE BEST, too. Pricey, tho, be warned.
That large Chiltons ain't bad either!

***Unfortunately is doesn't have detailed assembly diagrams of some parts

Russian Babes must love being in that American Muscle Car!

***:-))) Yeap. It very easy to pick up some having such a car. Even easier than having a Mercedes C600, which is ordinary thing on Moscow roads.

Do they look like the Blonde Russian Babe I recall in James Bond's "From Russia With Love"? [/QUOTE]

***Much Better. Come to Moscow and you will see.

 

haha, that's because it's a stock V6, lol

 

I think visiting Russia would be one of the coolest trips I could ever make. I want to be driven around in those "Capitalist" cars from the Stalin-Kremlin era.

Reason way they "throw parts at them" is that that's the way it "works" these days.
After playing with these cars alot, ya figure out what part is the main problem, weakest link.

Right now....
I have my SES light come on almost real quick.
Code 32. Helms says check this & that.
I have slight low idle vacuum signal. I have a guage installed for monitoring/driving/gas milage help.
I'll bet my EGR valve finally has a leak in the rubber diaphram. It also says to check the "EGR relay". EGR valve replacment is way easier.
The GM/Bosch electronics are rather good, to a certain point (and longevity, too)

I don't doubt even the fuel pressure rubber diaphpram is worn, also.
"Your" gas can play funny tricks on American spec'd rubber stuff. You need a special type of tool to access the internal rubber in the fuel pressure regulator on the fuel rail.
FYI, the rubber diaphram, internal on the fuel pressure regulator is generic for the V-6 rides.
Dan, am I correct? I rebuilt mine using the 1995 3.4 stuff in my 1985 pressure regulator. Fit perfect.

Should I just follow the Russian River in California to find Russia?

Catherine the Great was one Special Babe.
She was one really SMART WOMAN ruler!
Her carraige didn't look so shabby, either!