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Hi guys I am usually over on the 61-66 forum but I have a beater 92 F250 4x4 351 (5.8) and a ZF 5spd. This truck is my yard cleanup shop rebuilding buggy and is no trophy truck for sure. On Saturday I was out on the freeway on my way to get some landscaping pavers when it started losing power. I downshifted into 4th and made my exit. When I got to the first light and started to turn left I barely made it through the intersection rolling in second. I pushed the clutch in and was able to rev the motor over 3000 RPM but with stumbling and sputtering. I had to nurse the truck to my destination in first gear and I could have walked faster on my hands. The only way I can think of describing it in writing is that it was like trying to start out in 3rd gear with no clutch slippage so it actually moves but falls flat on its face without stalling. It was about 24 celcius out ( 75 F ). A $210.00 dollar tow home I let it sit overnight. The next day it was only 6 C ( 43 F ) out and I had no pressure on the fuel rail shrader. I cycled the key and I could hear the rear pump working (the front tank is dead and not in use). I figure what the heck I tried to start it and it fired right away. Warmed it right up and revved over 4000 rpm easily but on its way back down to idle it would pop bang a bit.. Today on Monday I had the same results with with it a few degrees warmer. I jumped the diagnostic and if I read the blinks correctly I had error 117 and 334. The coolant does feel like it is not that warm but the heater blows hot air. Sorry for the long write up but here are my two questions:
1) What is the best all around fuel system tester for all makes and models and what pressure am I looking for?
2) Any ideas on what this can be from your own experiences?
Sounds like a failed fuel pump to me. Should have ~40psi at the shraeder valve with no vacuum applied on the regulator, and about 32psi at idle with vacuum on the regulator. Change the filter first, and recheck pressure.
I jumped the diagnostic and if I read the blinks correctly I had error 117 and 334.
Were those codes displayed during the Key On Engine Off (KOEO) tests or were they displayed during the Stored Code (CM) display?
If those were KOEO codes then it means the ECT output is currently low (117). This can be caused by not fully warming up the engine before running the KOEO tests. If from CM that means at some previous point in history the ECT output was too low. Code 334 (KOEO) means the closed EGR Position feedback signal is too high (>0.67 VDC) when the EGR is supposed to be closed. If this was a CM code it means at some point in time the EGR Position feedback was too high.
That's why it's important to know when they were displayed. Could be a current issue (KOEO) or historical (CM).
Originally Posted by RangerMercMan
Sorry for the long write up but here are my two questions:
1) What is the best all around fuel system tester for all makes and models and what pressure am I looking for?
2) Any ideas on what this can be from your own experiences?
You can rent a fuel pressure tester at many auto part stores. Any speculation on what the root cause is right now would be dangerous to your wallet thickness.
Thank you to all for the replies. I thought I was thorough with my 1000 word essay but I get a C- 😂 ha ha. The codes were extracted with koeo and yes I warmed up the engine at least according to the gauge and heater air but not so much touchy feely on the rad. The coolant level is right up. Tool rentals at auto parts stores in Canada are less common and I do not mind having some tools around. I know the truck needs tlc it I do not want to thin the wallet rebuilding it as I expect to be done with it this fall. I have been suspecting the fuel pump losing pressure. One more question, should the fuel rail maintain pressure even with the engine off for days with this injection system? I will attach some pics of the old snarly beast later tonight
There are two parts to the KOEO tests and the Stored Code display. The first portion is the KOEO tests. If anything tested is out of specification you will get the failed test Codes. If nothing fails you will get the System Pass Code 111. Any codes from the KOEO tests will be displayed twice.
Once the KOEO tests and codes are displayed there is a pause then a single separator flash. Some codes readers interpret this as Code 10, which is false. After the separator flash any Stored Codes are displayed. If there are no Stored Codes you will get the System Pass Code 111. Just like the KOEO codes, these are displayed twice.
Since you are stating: ' The codes were extracted with koeo " I am ASSUMING you got Code 111 for the Stored Code display.
If this is correct Code 117 indicates the Engine Coolant Temperature (ECT) was out of test range. So either you did not warm up the truck enough or the ECT sensor could be faulty. As stated previously Code 334 indicates the EGR position feedback signal is above the closed EGR valve value of 0.67 VDC. Could be a bad EGR Valve Position (EVP) sensor or the EGR valve itself could be bad. Some times carbon builds up inside the valve which prevents it from seating completely.
An ECT sensor that is way out of specification can make starting and running difficult. You can try unplugging it to see if the engine will start and/or run. It can also be measured with a DVM: Ford Fuel Injection » Engine Coolant Temperature Sensor (ECT)
As far as the fuel pressure goes it should stay above 35-40 PSI with the engine off for several minutes. The last truck I tested it stayed above 30 PSI for at least 30 minutes. I disconnected it after that.
Thanks again for the quick reply. I did the jump the connector trick and the flashes were all over the place so I did it again. There could be mistakes and there seemed to be enough ones blinked that it could have been 111. There was definitely a pause and then a quick single flash and then some more codes. The previous weekend had some intermittent check engine lights come on so that might explain stored cm codes. I will retry the code count next weekend as weekdays are busy for me.
Here are some promised pics of the old beast. I bought it three years ago for less than $1000 which is cheap for around here. I had to replace the windshield, wiper motor and one horn to pass an inspection for insurance and have done nothing else to it. It did tow on a trailer that beautiful Merc parts truck sitting beside it. The ID tag on the drivers door jamb is long gone so I do not know what diffs are in it or what the gear ratio is.
Update: I was not able to find the time to count blinking lights this past weekend. I loaded the truck up with what ended up being 500kg of construction waste and tonight I drove the truck to the dump and back. I have done NO repairs to this truck. The distance was about 30 km. I have ordered a fuel pressure tester kit but I am suspecting the idle air control ( IAC) motor. I have at times an erratic idle from 500 RPM to 1300 RPM. It goes up and down as if I am bouncing the gas peddle. I will have to get an IAC removal tool and spray it down with air intake cleaner. Will update again in a couple of weeks.
Update #2: I finally found a fuel pressure tester that actually fit my rail. It did not show pressure from just cycling the key on and off even though I could here the pump running. I had the schrader out for about a week and a half so no pressure can be expected. I went for the full start and when the pressure built up it started and showed 37 psi. I let it warm up and then I revved it up (I was only watching the pressure tester not the tach) to about 3000 RPM and the pressure shot up to 75 psi and started rapidly fluctuating the needle. The engine ran like a bag of crap almost equal to the day it died. The engine would not idle down to curb idle worth a damn and the only way I could smooth it out was to hit the release bypass on the tester into my jerry can. Once I did this the engine immediately smoothed out at an idle. I shut the engine off and the pressure dropped from 37 to 21 in abount 90 seconds and then maybe 8 minutes later it was down to 10 psi at which time I grew impatiant and bled the pressure. I am now going to try replacing the regulator and see what happens.
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