So the engine idling fine and the problem only happens under accelerating or under a load?
SO its pinging under a load?
What is the front o2 sensor doing when this is happening?
What is the short term fuel trim?
What is the baro pressure on your scanner?
WHat is the engine load when its pinging?
O2 sensor is at 40? 40 what? 40 millivolts? Is this under full throttle or when accelerating?
So the engine pings while idle?
Ok... what about wide open throttle? What was the o2 sensor voltage under load?
WHat is the engine vacuum under load?
Without propane added, under load what is the fromt o2 sensor milivolts?
What is engine vacuum at 2500 rpm?
So when it bogs down with your foot on the gas pedal to the floor, what is the o2 sensor reading?
Ok... good... this under under a load...correct?
And you cannot get it up to 2500 rpm?
SO it sounds like its less engine vacuum than at idle? If this is the case, I would suspect plugged exhaust.
If not, then check ignition timing on your scanner. Maybe the harmonic balancer or the trigger wheel some on shifted causing wrong ignition timing?
Also, I would recommend to check valve timing. Make sure the marks are dead on.
If all checks out, I would lean towards a fuel deliver issue. If fuel pressure is up to par, maybe your mass air flow sensor is at fault here causing all of this trouble.
Another idea would be the egr valve sticking open causing an internal vacuum leak?
(Just had a friendly expert bring this theory up to me.)
Let me (us) know what you find! :)
I am sure that there are a lot of eyes on this post.
What about the egr valve? Have we checked this as well as for other vacuum leaks? Have we smoked the intake?
What about the fuel pressure regulator? This engine has a fuel pressure regulator....correct? Not leaking?
Sorry for the delay!
That is very odd. Can you scope the crank sensor? Is the harmonic balancer loose? WHat about the timing belt gear that sits on the crank? Is the key way nice and secure?
Also, watch the timing retard on your computer to see if the computer is actually purposely retarding the timing maybe because of an input like the knock sensor? If the engine is making noise maybe the knock sensor is picking it up and retarding the timing? I have also come across the know sensor torqued too tight causing it to be way to sensitive and it will cause the computer to retard the timing causing a drive ability issue.
Just a thought.
no is not lose Ijust replased the timing belt tentioner and I just re checked everything and seams fine.
Here is some information on engine pinging.
Likely Causes Ignition Timing, If Adjustable - Incorrect ignition timing can cause the engine to ping or have spark knock. NOTE: OBD II vehicles do not have adjustable ignition timing. Exhaust Gas Recirculation (EGR) Valve - Lack of EGR flow can cause the engine to ping or have spark knock. Knock Sensor, If Equipped - A failed knock sensor can cause the engine to ping or have spark knock. Fuel - Low octane fuel can cause the engine to ping or have spark knock. Cylinder Head - Carbon deposits in the cylinder head increases the compression ratio which can cause the engine to ping or have spark knock. Radiator - An overheating engine will increase the likelihood of spark knock or pinging. Overlooked Causes Injector(s) - Any injector(s) with poor spray pattern or restricted flow can cause pinging.
Here is a awesome test to help us pinpoint this problem. It will tell us which way we should go in this diagnoses. Lean, Rich or a mechanical. Its called the flat raters test drive.
Get the engine to act up under wide open throttle and look at some of the parameters on your scan tool and compare them to the readings I have below.
Here is the test. ( have to be off line for an hour or two. I will check in with you later tonight.)
The flat raters test drive..........
Under safe road conditions, a wide open throttle acceleration is performed. Try to maintain WOT for at least 5 seconds. 10 to 20 seconds would be better.
What will the pre cats do?
Will indicate rich
Should the barometric pid change?
Should remain stable! Very important!
What will air flow do?
Max out. Volumetric efficiency. Engine load 100% (Engine load Parameter on scan tool should go close to 100%)
Poor acceleration, rich exhaust, and good Barometric pressure = restricted exhaust or late ignition timing.
Poor acceleration, rich exhaust, low or decreasing Barometric pressure = intake path restricted
Poor acceleration lean exhaust and good barometric pressure = fuel delivery concern.
Poor acceleration, lean exhaust and low barometric pressure = air flow measurement error. (Ford has this problem with Mass air flow sensors)
Note: Some vehicles Barometric pressure is not updated until Wide open throttle.
Hey! tanks for all the effort and you help with this problem.
I won`t be able to do anyting moreto this car till tomorrow so I will have an enswer for you bright early tomorrow tanks againg and hope to find you online tomorrow.
THat is just fine. I will be on line all day tomorrow. Let me know what you find.
You can hit the accept button any time and we can still continue our conversation. I will stick with you until we get this thing handled!
Talk to you tomorrow!
THanks for the accept!
I know we tried hard to get ot the bottom of this thing and we did all we can do.
Please let me know if you have any further questions!