Motor Age Garage: The IRAQ Camaro

The IRAQ Camaro No, I didn’t mean IROC.Ron and his family live two houses down the road from me, and his son Jim joined the Indiana National Guard when he graduated from high school last year. His unit was called up for deployment to Iraq. They have been in northern Iraq for about six months now. A FAST LITTLE NUMBER

VEHICLE: 1991 Chevrolet
Camaro RS
DRIVETRAIN: 5.0, automatic transmission
MILEAGE: 90,378 miles
COMPLAINT: Lack of power, then starts and dies.
(All photos: C. Marsh)

Ron told me that he was coming home at the end of the month on two weeks leave and then would head back over there. He also told me that the ’91 Camaro, for which he had traded his Bronco just before he left, needed some work. It seemed that it didn’t have much power. Ron said that he would try to drive it to the shop, but asked for the phone number of the wrecker service that we use, just in case.

When the Camaro arrived, it was on a hook with Ron following it in his car. He said that now it would start, but would die immediately. We brought it into the shop, connected a scan tool and pulled a Code 44.
Code 44 is a lean exhaust code and can mean several things. The first is that there is not enough gasoline in the air/fuel mixture and the exhaust is truly lean. The second is that the oxygen sensor has gone south and is sending a false lean signal that results in the powertrain control module (PCM) commanding an overly rich mixture. An overly rich mixture will definitely cause a lack of power and can eventually load up the plugs enough to cause a start-and-die condition or even a no-start. Of course, so can an overly lean condition.

When we fired up the V8, it “felt” lean as it died, so Keith grabbed a can of choke cleaner and added some fuel when I started it. The choke cleaner was enough to keep it running.

Here is the original fuel pump amperage waveform.

This car doesn’t have a fuel pressure tap, so it’s a pain to check the fuel
pressure; however, an amp probe and voltmeter will tell you a lot about the condition of the system. We connected the amp probe to the digital scope and clamped it around the fuel pump feed wire.

We found out that the pump was only pulling about 3 amps and that the pump speed was normal. Next we checked the voltage available at the pump while cranking the engine and found 11 volts, which is sufficient. The voltage drop across the pump ground was 53.9 mV, which is acceptable; we decided it needed a fuel pump.

A voltage drop across a fuel pump ground of 53.9 volts is acceptable.

Ron gave his approval for the work and said, “You probably ought to go over the car with a fine-tooth comb and fix whatever you find because Jim’s going to be ready to raise Cain when he gets home. I’m sure that he’ll be able to break anything that’s ready to be broken on the car. By the way, I noticed that the radiator fan runs whenever the key is on.”

Why would you do that? Keith was anxious to get started on the pump. He’s been working with us about a year and a half and had never experienced the joy of replacing the fuel pump on a late-model General Motors F body car. I told him to go ahead and drop the exhaust and rear sway bars.

He looked at me like I was crazy and said, “Why would you do that? There’s an access panel above the tank.”

This access panel might not be factory, but it sure saved us a lot of time.

I then looked at him like he was crazy and laughed. He still contended that he saw an access panel while he was underneath connecting the amp probe and voltmeter. I humored him and told him to go ahead and pull up the carpet in the back to check.

He pulled up the carpet, and — grinning ear-to-ear — he called me over to gloat. Sure enough, there it was: an access panel. It wasn’t factory, but it was there. Someone had been there before, cut a nice, neat hole in the floor of the hatch and then patched it back in with sheet metal screws.
When Keith removed the screws and raised the panel, he noticed that one of the screws was hitting the tank. That problem could be easily solved by using shorter screws. The metal fuel lines had been cut and reconnected with high-pressure fuel hose.

After we replaced the pump, the engine fired up and ran normally, and
the amperage waveform looked fine. I’m not sure that cutting an access panel is factory-approved, but it sure saved a lot of time.

Here is another time-saver that someone used.If it’ll go, it has to stop The back of the Camaro was still in the air from our initial testing, so I thought it prudent to check the rear brakes. It definitely had a V8 engine under the hood; the lack of tread on the rear tires proved that. When we got the wheels and drums off, we found that both wheel cylinders were leaking bad enough that the rear shoes were contaminated beyond cleaning. I called Ron again, and he told me to take care of whatever we found. He said that he knew that we wouldn’t do anything that we didn’t think was necessary to bring the car back into reliable condition.

We stock the brake shoes but not the wheel cylinders, and without the cylinders on hand, the shoes weren’t going to do us much good. Before ordering the cylinders and shoes, I wanted to check the front brakes and front-end parts.

The brake pads and calipers were in good shape, as were the ball joints; however, it needed a right inner tie rod end and idler arm. We also checked the belt, hoses and fluids right away. We found the upper radiator hose getting a little soft and the coolant in need of changing.
Remember the thin tread on the rear tires? That might have been the reason that the transmission fluid was dark and smelled burnt.

Can you tell that this Camaro has a V8 engine?

The necessary parts were ordered, and we started on the rear brakes. The brake lines came loose from the wheel cylinders without any problems and the parking brake cables were free and smooth, so there wasn’t any hassle getting the brake job done.

We replaced the tie rod end and the idler arm; we flushed the transmission and torque converter and replaced the filter. Once it was back down on the ground, we flushed the cooling system and replaced the upper radiator hose.

Let’s check the fan circuit I never cease to be amazed at the time and trouble some people will go to in order to effect a “Mickey Mouse” repair when it would be quicker, easier and less expensive to repair a problem correctly in the first place. It was hard to forget about the cooling fan that Ron had mentioned. As he had said, the fan came on as soon as the ignition key was switched on. We got the car back in the air to check the fan switch, which is located under the right bank exhaust manifold on this engine.

When I rolled under the car, I noticed that someone had added an extra ground wire between the radiator fan motor ground and the main battery ground wire. I’m not sure why they added the wire because the motor ground was clean and tight. In addition, I couldn’t figure out why they had cut a section of insulation from each wire and then twisted the added wire around the bare sections. I removed the added wire and taped up the bare spots.

If we could have caught the leaking wheel cylinders in time we could have saved the brake shoes.

When I inspected the fan switch, I discovered that the wire had been cut and an eyelet terminal had been crimped to the harness side and then bolted to the block. I also noticed a rebuilder’s tag on the side of the block. When I pulled the connector off of the fan switch, I discovered that both the connector and the fan switch had been broken. We stock that particular switch, but we had to call and order the connector pigtail.
As I was replacing the fan switch, it dawned on me that we hadn’t checked the tune-up parts. I pulled a couple of spark plugs and found them to be almost new. The air filter was clean, and while checking the fuel system, we noticed that the fuel filter appeared to have been replaced recently.

After the fan switch connector pigtail was delivered and soldered into the harness, we fired up the engine to check the fan operation. The fan came on at the proper temperature and shut off at the proper temperature, so it was finally time for a test drive.

It’s almost finished When I took it out on the test drive, I noticed a slight stumble on part throttle acceleration, but the car was quick and strong on full throttle acceleration. I wondered to myself if that little 5.0-liter had been “chipped.”

It’s no wonder that the radiator cooling fan ran whenever the key was on. This wire should have been connected to the radiator fan switch, not the engine block.

I stopped and pulled the vacuum hose off of the exhaust gas recirculation valve (EGR) and tried a part throttle acceleration again. The stumble was gone. When I got back to the shop I didn’t feel like burning my fingers feeling the diaphragm plate on the EGR valve to see if it was a backpressure-style valve, and if it was, whether it was positive or negative backpressure, so I took a piece of chalk and wiped over the stamping on the top of the valve.

The “NEG” told me that it was a negative backpressure valve. When I pulled a vacuum on the valve with the engine off, it opened, and when the engine was started, it remained open. I ordered a new valve because the backpressure port was apparently plugged, and I’ve never been able to successfully clean out a backpressure port. After the new valve was installed, the Camaro ran fine on part throttle acceleration.

Come and get it I printed the invoice and called Ron. I told him that the only thing it needed was two new rear V8 tires. I also asked him if Jim was aware that it had a rebuilt engine. He said that Jim had been told that a rebuilt engine had been installed and that they thought it might be a 5.7L instead of the original 5.0L. I told him that as quick and strong as the car was, it was either a 5.7 or a 5.0 that had been “chipped.”

When Ron and his wife Judy came in to pick it up, I told them to tell Jim to enjoy, but to be careful because it was quick and strong.

Judy said, “Oh gee, that’s just what he needs! He’ll be raring to go when he gets home.”

Ron and I just looked at each other and grinned. We had both owned quick, strong cars in our younger days and had been there, done that.

Click here for a downloadable PDF of the
June 2007 Motor Age Garage Test.Click here for the Motor Age Garage Test Answer Key.
(Answer Key available Aug. 15, 2007)