I got a 2005 Ford Five Hundred Limited with less than 105,000 miles and honestly the car is impressive though old.
The engine sounds fine, transmission is CVT but working fine and been using it for close to a year now but I have one issue I have not been able to find solution to and it is bugging me because now it is worse and I can't move long distance again especially when there is traffic.
The vehicle starts right up and runs fine until it gets fully warm (almost 1 hour after starting) and after it warms up, the engine starts to shake and then it stalls.
I scanned it (using ThinkCar Bluetooth OBD scanner) and I get the following codes (P0191 - immediately it stalls, P0172 and P0174 - if I keep forcing it to start and running that way, at least just to get to safety usually when it happens on the highway and then P0401)
The scanner has ability to read Datastream and recorded to understand the situation when this happens. What I observed is that the fuel pressure drops so much (desired can be around 60psi and actual is 15psi), short term fuel trim (bank 1 and bank 2) around 20%, long time fuel trim also around 15%.
Based on the above, I replaced the plugs, FRP sensor, fuel pump, coils, EGR, Intake plenum upper and lower o-ring seals, PCV, Brake master cylinder-booster rubber gasket, checked and tighter all vacuum hoses and no visible leak but the issue is still there and apparently getting worse.
The issue was slightly improved when I put the brake master-to-booster gasket (got from a used booster) and the vehicle has more power but still stalls.
I also tried using a smoke machine to fine vacuum leaks but could not detect any leaks as smoke was not coming out from anywhere only building pressure inside the intake manifold (But I usually hear a hissing noise usually when bonnet/hood is closed but could not find any leaks even with smoke machine and some choke cleaner).
Please advise what else to check as it is getting really frustrating but I really want to solve the issue.
I paid for All data and performed almost all the procedures in the TSB regarding intermittent P0191.
Please help
Clean the throttle body and MAF sensor with spray cleaner. Check the fuel injectors. I would also look at the EGR valve.
I have done that several times. cleaned the injectors with both fuel additives (cleaners) and by removing and cleaning both same thing
You may have a faulty fuel pressure regulator.
I have also bought a new Fuel Pressure Regulator and the same issue.
Parts Purchased and installed so far
1. Fuel Filter
2. Fuel pressure Regulator
3. Fuel pump
4. Intake manifold Plenum gasket
5. PCV Valve
6. EGR
7. Fuel Tank Cover
8. Engine Filter
9. Rear Camshaft Seal
10. Valve Cover gaskets
I noticed in the datastream playback that when the fuel pressure drops, the fuel pressure voltage also drops to less than 1v and when the car is fully functional like early in the morning and the fuel pressure is around 60psi, the voltage is usually around 3.3v
It seems the ECU is acting up. Have a pro check it.
That is a scary one to think of.
I am located in Nigeria and getting parts for this car is a nightmare. I order them straight from ebay and amazon and takes approximately 3 weeks for them to arrive. Thinking of replacing ECU will be a very costly option and having people that really understands and works on Ford here is issue let alone a model that is not common even in the US.
I had to subscribe to different forums online and purchased All Data including ThinkDiag, ThinkDiag Pro and Bluedriver scanners just to be able to measure and have accurate diagnosis and resolution.
Don't let me loose up yet but almost crying if it is the ECU
I don't say it is the exact issue and you should not replace the ECU now but it needs to be diagnosed. You already replaced so many parts. It is better to pinpoint the issue and then replace parts accordingly.
Thank you. I don't think there are any specialists here in Nigeria that work on ECU but I have ordered a new EGR and will wait for that to arrive and then fix to see what happens next.
Since getting a pro to diagnose the ECU is almost impossible, (main reason I started getting into the DIY in the first place since I studied Electrical Engineering in the University and supposed this should not be too big a deal), any guide or tools I can use on my own to diagnose?
I am willing to spend the money to learn (I have learnt a lot since owning this car and gingered to continue) and don't mind saving up to purchase the tools needed. My ThinkDiag scanner looks professional enough to control and do bi-directional testing but not explored its full capabilities yet as I am being careful since it is still my daily driver.
I am replacing the EGR because when I initiate the KOER self test, I get the code P1408 with no check engine light and sometimes on the code P0401 and then the check engine. could be the EGR is not to OEM specs.
I'm not an pro in car electronic so I can not give you advice on that. @jack62 may be able to help you more.
If I were to think of ECU replacement for this car, are there other Ford Models that use the same ECU and how can I check?
I am asking this because this particular car is super scarce here in Nigeria but models like Edge and Escape are quite common.
Thanks in advance
Hello @yaser and all
I got a new scanner today (ThinkDiag) which allows me to do actuation test and I tested the EGR by increasing the duty cycle (based on what I have seen on youtube and also read) but the engine sound did not change in response to the change in duty cycle. Most of the videos I have checked, changing the duty cycle introduced a vacuum which caused the engine to behave erratic and eventually stall but in my case, there was nothing.
Also during KOER self test, I get the code P1408.
Do you think the EGR may also be an issue in all the problems?
Also, is the engine not supposed to vary in RPM with the fluctuations in the EGR duty cycle?
Thanks in advance
The stalling could be the EGR issue. Replace it.