94 Metro engine problems

[remington7]

Hello,
I have a 1994 Geo Metro, 128,000 miles, 1.0L 3-cylinder engine, automatic transmission, with throttle body fuel injection. The car was running fine until on the way home from work it started to lose power. I was able to get it home only by keeping the accelerator to the floor. These are my current symptoms: 1. Starts hard. 2. After starting it has a rough idle. 3. If you try to "blip" the accelerator either during idle or while driving, it stalls. 4. It tries to cut out when you shift into gear. 5. I can hear light backfiring when letting off from full throttle. 6. It stalls when accelerating from a stop, unless I power-brake it to get the rpm up. It runs ok at mid throttle range but will not go above 55mph on a flat, straight stretch of road at full throttle. Low end throttle it stalls, high end throttle lack of power. I've verified the timing setting, replaced the plugs, wires, and fuel filter with no success. No engine codes stored. Any ideas? Thanks

[DOCTORBILL]

History repeats itself.....

Look at "HELP NEEDED IN A HURRY! Metro 3 cyl DIED this morning, won't restart" at my post (DoctorBill).

Whenever someone presents with a post like yours, I try to convince them to
do a COMPRESSION CHECK.

Maybe I am being obsessive-compulsive, but that test can eleiminate or zero in
on many problems.

If you have burned thru an Exhaust Valve, usually number 1 cylinder on these
3 cylinder Suzuki engines, you get your symptoms.

It happened to me at 157,000 miles with exactly the same engine ('93 Metro).

At least that is what I have gathered by reading on this Forum....

Chime in folks!

DoctorBill

[Hugemoth]

Yes, check the compression.

Q

[HannabilRox]

Sounds like the fuel pump is starting to fail. Exact symptoms when my fuel pump in my 92 Beretta failed.

[remington7]

Originally Posted by DOCTORBILL

History repeats itself.....

Look at "HELP NEEDED IN A HURRY! Metro 3 cyl DIED this morning, won't restart" at my post (DoctorBill).

Whenever someone presents with a post like yours, I try to convince them to
do a COMPRESSION CHECK.

Maybe I am being obsessive-compulsive, but that test can eleiminate or zero in
on many problems.

If you have burned thru an Exhaust Valve, usually number 1 cylinder on these
3 cylinder Suzuki engines, you get your symptoms.

It happened to me at 157,000 miles with exactly the same engine ('93 Metro).

At least that is what I have gathered by reading on this Forum....

Chime in folks!

DoctorBill

Sorry, I forgot to mention that. I ran a compression check last Sunday (2 days after the car became ill) and it was 180 pounds across all three cylinders. I had heard the Metros were notorious for burned valves so I checked that ASAP. Thanks.

[91Caprice9c1]

+1 With the abruptness of the problem and symptoms given, we need to eliminate fuel delivery issues.

What you need to aquire is a fuel pressure guage that you can install inline with the fuel feed line (larger diameter) at the TB via a T fitting. I'll take a picture of the setup I use and post back tomorrow.

Check the hose and connector to the MAP sensor. Make sure your coil wire is well affixed to the cap and esp. to the coil.

-MechanicMatt

[remington7]

Originally Posted by 91Caprice9c1

+1 With the abruptness of the problem and symptoms given, we need to eliminate fuel delivery issues.

What you need to aquire is a fuel pressure guage that you can install inline with the fuel feed line (larger diameter) at the TB via a T fitting. I'll take a picture of the setup I use and post back tomorrow.

Check the hose and connector to the MAP sensor. Make sure your coil wire is well affixed to the cap and esp. to the coil.

-MechanicMatt

Matt,
Thanks for all the info. Where can I purchase a fuel pressure gauge? Will a vacuum type T-fitting work for this application? Coil wire is good to go. Hose to MAP sensor is pliable with no cracks. Thanks, again

-Rem

[91Caprice9c1]

This fuel pressure guage was purchased at sears, you can find similar tools at your local auto parts supply I'm sure, autozone, kragen/shucks, o'reily's, pepboys, etc etc...

I cut the threaded fitting off the end of the guage and stuck a T-fitting (vacuum type stuff is fine) in the end of it. Then took a length of appropriate sized hose and wrapped it around another leg of the T (proper I.D. escapes me, 3/8ths, 5/16thsish). Then when you go to take your reading you disconnect the fuel supply (larger diameter) stick it onto the unused leg of the T fitting, clamp it down, then attach the hosed end of the apparatus to the throttle body and clamp it down. Pretty easy stuff.

Connect guage and:

a) Get a reading with the key-on engine off (KOEO) and see that the fuel pressure holds steady (losing no more than a couple psi over 5-10 minutes)
b) Get a reading with the engine at idle.
c) Rev the motor a few times and see that the guage reacts positively (displaying slightly higher fuel pressure) to throttle snaps.
d) If so inclined, tape the guage to the windshield and take a quick drive and see if any sudden low readings appear with driveability problems.

-MechanicMatt

P.S. The hose on the fuel guage will have a pretty small internal diameter. I had to literally drill the hose out, and use some spray lube in order to get the T fitting inside the fuel guage hose.

[remington7]

Caprice,
Thanks for the pic. I'll put one together today and run the tests.

-Rem

[remington7]

Originally Posted by 91Caprice9c1

This fuel pressure guage was purchased at sears, you can find similar tools at your local auto parts supply I'm sure, autozone, kragen/shucks, o'reily's, pepboys, etc etc...

I cut the threaded fitting off the end of the guage and stuck a T-fitting (vacuum type stuff is fine) in the end of it. Then took a length of appropriate sized hose and wrapped it around another leg of the T (proper I.D. escapes me, 3/8ths, 5/16thsish). Then when you go to take your reading you disconnect the fuel supply (larger diameter) stick it onto the unused leg of the T fitting, clamp it down, then attach the hosed end of the apparatus to the throttle body and clamp it down. Pretty easy stuff.

Connect guage and:

a) Get a reading with the key-on engine off (KOEO) and see that the fuel pressure holds steady (losing no more than a couple psi over 5-10 minutes)
b) Get a reading with the engine at idle.
c) Rev the motor a few times and see that the guage reacts positively (displaying slightly higher fuel pressure) to throttle snaps.
d) If so inclined, tape the guage to the windshield and take a quick drive and see if any sudden low readings appear with driveability problems.

-MechanicMatt

P.S. The hose on the fuel guage will have a pretty small internal diameter. I had to literally drill the hose out, and use some spray lube in order to get the T fitting inside the fuel guage hose.

Matt,
I just finished taking the readings. (1) Key on, engine off-25psi
(2) Idle-22psi
(3) Throttling- 22-32psi responsive
Would this suggest the fuel pump is OK? Thanks.

-Rem

[91Caprice9c1]

That definitely seems low to me, but I can't recall where our numbers should be. I think I recall numbers in the high 30s/low 40s the last time I checked fuel pressure on a metro. Maybe someone else here has the spec. Monday I'll look through my books and tell you what they say if noone else chimes in.

Pinch off the fuel return hose and see if that brings the numbers up at all.

-MechanicMatt

[GM Line Rat]

Originally Posted by 91Caprice9c1

That definitely seems low to me, but I can't recall where our numbers should be. I think I recall numbers in the high 30s/low 40s the last time I checked fuel pressure on a metro. Maybe someone else here has the spec. Monday I'll look through my books and tell you what they say if noone else chimes in.

Pinch off the fuel return hose and see if that brings the numbers up at all.

-MechanicMatt

The 3 Cyl Metro's are TB (Throttle Body) injected engines. Fuel pressure on your car is Normal. Fuel pressure readings in the in the High 30's/Low 40's with the KOEO are normally found on "Port Fuel Injected" engine setups.


Specifications for a 1994 Geo Metro Fuel Pressure:

1. Key on engine off .......(23 psi) 160 kPa
2. Engine Idling .............(22-31 psi) 160-210 kPa


Fuel Pressure & Regulator - Specifications Revised.

Group Ref.: 6E - Engine Fuel & Emission

Bulletin No.: 416521

Date: August, 1994

SERVICE MANUAL UPDATE

SUBJECT:
SECTION 6E2 - REVISED FUEL PRESSURE SPECIFICATIONS

MODELS:
1989-94 GEO METRO WITH 1.0L ENGINE (VIN 6 - RPO LP2)

Circuit Description:

When the ignition switch is turned to the "ON" position, the Engine Control Module (ECM) will turn "ON" the in-tank fuel pump. It will remain "ON" as long as the engine is cranking or running and the ECM is receiving ignition reference pulses. It there are no reference pulses, the ECM will shut "OFF" the fuel pump in about 2 seconds after ignition "ON" or engine stops.

The fuel pump delivers fuel through an in-line filter to the TBI assembly. The integral fuel pressure regulator controls system pressure to about 160-210 kPa (23-31 psi) with ignition switch "ON" (KOEO) and to about 90-160 kPa (13-22 psi) with the engine idling at normal operating temperature. Excess fuel is returned to the fuel tank through a separate line.

[HannabilRox]

My next thing to do would be (since I have a spare) replace the MAP sensor and check all over to make sure there are no vacuum leaks ( hoses that fell off / broke ), especially around the firewall where the metal vacuum hose connector is bolted on, and the hoses to the purge canister. Seems like your compression is fine and fuel pressure is good as well. I would also make sure the distributor is not loose.

[DOCTORBILL]

Has anybody mentioned changing the FUEL FILTER?

How long has the current fuel filter been in there?

If the fuel filter is plugged, it can cause all sorts of problems and still give you
a good fuel pressure reading - because the plugging is often 'intermittent'.

If you are going to change it, why not bypass it next to the fuel tank
(use a section of fuel tubing) and put it up front in the engine compartment
between the firewall and the fuel input barb on the TB...?

Makes for nice, easy changing later......no more gasoline all over you
while laying on your back!

DoctorBill

[HannabilRox]

In the original post, remington7 said he replaced the fuel filter...LoL