Help 89 f2 stalls at wot
<hr style="color: rgb(209, 209, 225); background-color: rgb(209, 209, 225);" SIZE="1"><!-- / icon and title --><!-- message --> Its an 89 f250 460efi and timing is set at 11. Fuel filters replaced. Any ideas?

 

Clogged/restricted exhaust...?

Have you checked for codes?
What is static fuel psi? What is engine running psi? What is WOT fuel psi, engine running when you quickly snap throttle?
Conditions of plugs?
How well does it idle?

 

Idles well. The check engine light doesnt stay on, it comes on and off very quickly and intermittently. I can snap the throttle and it will respond but if i put the pedal all the way to the floor it will bog out. I will try to check the psi's tomorrow. All the spark plugs were changed two months ago.

 

The CEL comes on then off immediately? That means it threw codes. As Timbersteel said, pull the codes.

 

As I was driving today, I switched from rear tank to front tank and gave it WOT and it did it fine but only for about a minute. It was my fathers truck who recently passed so it sat for about three years. I believe what is happening is that all the stuff in the gas tank is getting sucked to the pump of each respective gas tank and cutting flow with more gas I give it. Correct me if Im wrong but I'll probably have to pull and clean both gas tanks. Does this sound correct to you guys?

 

Quit guessing at the root cause. Rent a fuel pressure gauge to determine if the fuel pressure is dropping below the normal range. It's a lot of work to drop and clean the tanks to then fine out you have the same problem.

You also need to check for codes to see what is triggering the Check Engine Light. Never ignore the obvious, it is dangerous to your wallet.

 

That's a possibility...

There's different ways of looking at this problem you are describing. Guess at it or diagnose it. If it were me, I would rent or buy a fuel psi tester and gather test info for the questions I posted earlier for you. I would also pull codes either with jumper wire/ analog volt meter or Equus OBD1 code reader. I think an expensive OBD2 reader can be used, my Craftsman scanner can do OBD1.

Post codes, post fuel PSI for each test. I would think if your right about the tanks having crud that is getting sucked into the screen for the fuel pump, but for the '89, I'm not technically savvy with the fuel pump setup. There are the in-tank low psi pumps and then the high psi fuel pump on the frame rail.

There could also be the possibility that the fuel psi regulator is damaged and is allowing enough fuel for cruise and idle, but the demand for WOT psi isn't there due to the regulator failing. Some will damage and spew fuel out of the nipple and get sucked into the intake and as on mine won't allow the fuel psi to be above 25psi. Just enough, but not for WOT demand.

There's a lot of guessing that can ensue so might want to get a plan of action.

I'm sure other knowledgeable members will chime in.

Let us know what you find.

 

RLA beat me as to the reply as I was typing!!

What RLA said.

 

Thank you all for the ongoing good advice. Will test and post.

 

KOEO codes
32 EGR valve not seated closed voltage low
95 fuel pump circuit open PCM to motor
96 Fuel pump circuit open Battery to PCM
KOER codes
77 Wide open throttle not sensed during self test

No fuel pressure test because can't afford the part today, bought the computer. Let me know if this helps at all.

 

Code 32 is probably the one triggering your Check Engine Light. Codes 95/96 could be the cause of your stalling at WOT. PCM is not sensing the fuel pump is drawing current when it should be on. Could be a bad relay, intermittent connection or bad fuel pump.

You can rent a fuel pressure tester at many auto part stores. Put down a deposit, use the tester then return for full credit.