Hack Jobs Happen…
I see some crazy short cut repairs (hack jobs). “Hack jobs” by owners, shade tree mechanics and approved auto repair shops. Then I wonder why, why try, why risk a comeback. Why take the short cut in the first place. Why risk loosing a client when the hack job fails, leaving the vehicle owner stranded on the side of the road.
A hack job will fail, it’s a sub-standard repair.
Today I had an odd repair issue pop into the shop. Ronda had a fuel pump replaced on her 1995 Chevy Suburban about 30 days ago in Sedona Arizona. The truck has a 5.7 TBI fuel injected engine. (Throttle Body Injection System) Ronda only had one issue with the repair, the fuel economy was reduced by 30 to 40% and this was noticed right after the pump was installed. The shop that installed the pump had double checked the fuel system, and said nothing was wrong.
Ronda had moved to Sedona last year.
The client (Ronda) use to live right around the corner from our shop, but had moved to Sedona in 2013. Ronda happened to be in the valley for some doctors visits, so Ronda stopped in to see if we had time to look at this issue.
Testing showed the fuel system was running too rich. The scan tool (a computer that talks to the car’s computer) showed that the PCM (the car’s computer) was subtracting a lot of fuel. The engine computer uses a pair of fuel trim ratio numbers to display fuel system compensation (larger number = more fuel added to the engine Or a smaller number = less fuel, fuel reduced to the engine). A repair technician can view the fuel trim numbers “live” as they update (in real-time) and watch how the system is operating, rich, lean or normal.
Next I attached a gauge used to test fuel pressure to the engine’s fuel system. The fuel pressure gauge showed that the fuel system pressure was around 19 PSI of pressure. (Why?) The TBI system specification is 9 to 12 PSI. So why was the PSI so high?
I suspected it had the wrong fuel pump installed. So, I removed the fuel pump and found a big mess. What I found was a major issue, the person that did the repairs, must have had a huge loss of reasoning. The part was clearly the wrong part for the truck. When I entered the pump part number into a parts jobber, part interchange system. I discovered the part was the wrong pump for the truck.
The shop decided to adjust the wrong part till it would fit in the tank. But wait, that’s not all. The pump was for a 1996 5.7 MPI engine. (Multi Port Injection System) not a 1995 5.7 TBI system. The 1996 MPI system runs at 60 to 66 PSI. This is clearly too much pressure for the system to handle. To bleed off the high PSI. The shop that made the repairs, had removed the hose clamp to the PSI fuel coupling hose that connects the fuel pumps outlet pipe to the metal pipe going out to the engine’s fuel injector’s. Plus the old fuel pump harness was installed on the new pump, and the electrical connector had a broken retaining clip.
The adjustments and compromises should have never happened, but they did.
Just buy the correct part, and if the part arrives wrong, get the correct part. The correct part was available in Flagstaff, less than a 2 hour round trip from Sedona. The client had already waited 5 days, what was one more day to get the right part.
We fixed the truck and it is running correctly, with the correct part. The client is happy and the mileage is back to normal. Plus Ronda will be bringing her truck to us when ever she is in town every 3 to 4 months.
Keeping up on the needs of an older vehicle may seem costly, but if you do the math. The right older vehicle can be cost-effective in the long run. Every vehicle needs repairs someday, new or old.
It’s all good under the hood, heyanthonyaz.com 2014
