97 Expy P1131 After Fuel Pump Replacement

[tedallen]

The original fuel pump failed in my 97 Expy failed at 301,142 miles. Fortunately, it decided to do so in my driveway a couple of weeks ago. I finally got around to working on it yesterday. I dropped the tank (fought with the rubber fuel filler hose and a couple of emission hoses on the tank as well as the "quick" disconnect on the larger fuel line connection at the pump).

I replaced the entire pump hanger assembly (had to reuse the sensor in the top of the hanger assembly) with an aftermarket Airtex pump from Advance Auto Parts. The reassembly went relatively smoothly. However, after priming the pump with a few cycles of the ignition, I attempted to start the vehicle and the engine would start to turn over and stop, almost like a problem with the starter or insufficient charge or heaven forbid something in the engine trying to seize.

I called a couple Ford service departments to see if they thought anything I could have touched in replacing the fuel pump could cause this behavior and they said no.

After a while of fighting this, it finally turned over and started, but an unusual amount of white smoke was coming out of the tail pipe. I thought this could be from oil leaking past the valve stem seals while sitting that long, but there was a bit of an odd odor to it.

I then took it for a drive and a mile or so into the drive the smoke coming out of the tailpipe appeared to clear up. Unfotunately, after going about 10 miles or so (which inlcuded a fill-up with non-ehtanol gas), the CEL came on. The engine didn't seem to be running rough. When I got home, I checked and it was a P1131 Ford manufacturer specific code.

One of the potential causes for this is low fuel pressure. I'm really hoping I don't have to siphon out 20+ gallons of fuel and drop the darn tank again for a defective Airtex fuel pump.

If anyone has any thoughts as to what I might check first, I'd greatly appreciate any ideas.

Thanks,

Ted

 

[stamp11127]

Not being a smart ass but check the fuel pressure. It is the easiest at this point. If your in spec then go back over your work.

 

[tedallen]

I should have mentioned that I plan to do that tomorrow, provided I can find a break in the storms before/after work. I'll let you know what I find.

Thanks,

Ted

Not being a smart ass but check the fuel pressure. It is the easiest at this point. If your in spec then go back over your work.

 

[tedallen]

I checked the fuel pressure at the fuel rail today and it looks good. Specs call for 30-45 psi at idle and it was holding steady at 30-31 psi. When accelerating and increasing idle to 1800 rpm and holding, pressure remained constant. It also held constant during deceleration. After disconnecting the vacuum line to the fuel pressure regulator, specs called for an increase to the 40-50 psi range and mine increased to 40 psi and held constant. After turning off the ignition, the pressure held (actually increased a few psi to around 33) after a 5 minute wait. Based on these readings, I'm thankful that it sounds like it isn't a pump issue.

I did see the unusual white smoke in the exhaust while performing the test today. I don't know if this is related to the odd non-crank condition after first replacing the pump or not. The tank looked clean. I don't know if there could be some sort of oily residue in the new fuel pump assembly that is getting flushed out and burnt. If so, maybe this could be doing something to the O2 sensor to trigger the P1131 code.

Any thoughts? I cleared the code and am going to drive it again today.

Thanks,

Ted

 

[stamp11127]

Here is an interesting read on that code:

p1131 Code 1997 Ford F150 - F150online Forums

 

[tedallen]

Thanks stamp. I took a look at the link you supplied. Interesting that it states the following:

Entry Conditions
The test will be carried out when the engine load is between 20 and 60%, it is at least 180 minutes since start up. The exhaust temperature is assumed to be 800° C

The code appeared about 15 minutes after initial start up, no where near 180 minutes. I drove the vehicle yesterday and today and the code has not returned. Furthermore, the white smoke in the exhaust has not occurred again during the last couple days since clearing the code and checking the fuel pressure.

I am really wondering if the new fuel pump/hanger assembly could have been coated with something to prevent it from rusting/oxidizing during storage and as the fuel pumped through it it eventually "cleaned" it off the internals of the pump/hanger lines and there is no longer enough present to produce the white smoke or foul up the sensor readings?

The installation instructions with the Airtex pump/hanger assembly mentioned nothing the that effect, but it sure seems suspicious.

The issue with the engine acting like it was being prevented from completely turning over and has disappeared as well after it started for the first time.

I will give it a few more days and if all is well I will update this thread.

Thanks,

Ted

 

[tedallen]

I have now driven 450+ miles since the fuel pump replacement and all has gone well. The odd issue with the engine not wanting to turn over, the white smoke during the initial several startups, and the P1131 have not returned.

I have to think at this point that the white smoke was related to some sort of coating in the new pump/hanger assembly and this resulted in the P1131 code. As for the engine not wanting to completely crank, I have no clue. Unless something happens, this will be my last post to this thread. Thanks to all that read and/or replied.

Ted