Hey all, long time no post. Someone just dropped off an '88 F-150 4x4 with an M5OD and a 300 in it. Its running rich, like trying to run a carbbed engine with the choke stuck closed rich... We got codes for the Map, tps, ect and act. Replaces the map, and tps, still running the same, cold or hot.

I wasn't the one to check the fuel pressure but Im told it was sitting at 50psi with or without vacuum so we swapped it, and still no difference. I'm lost on this one.

I will also add that the last time this truck was driven was in June, it was fine then.

Update, I checked the fuel pressure myself, it is at 50psi and jumps to 60 with the vac line unhooked.

 

After the engine is shut off, watch breed down rate. More than 5 PSI in first minute implies hanging injector(s).

Did you bring engine to normal operating temperature before scanning? (very important!!!)

Did your clear the KAM (kept adaptive memory) after replacing sensors? (Very important too!!!)

 

I watchec that, in 2 min it dropped 2 or 3 psi

 

How about these?

 

Nope, I can't run it that long. The way its running it leave too great of a threat of washing the cylinders and just screwing more crap up.

 

So your codes are KOEO (key on engine off)?
Did your clear the KAM (kept adaptive memory) after replacing sensors? (Very important !!!)

The ECT will code if engine is not at operating temp, however if the code was during the continuous memory part of the KOEO scan, that's a different story, as with the ACT.

Either/ both can screw w/ you air/fuel mix if bad.

 

It was showing up during KOEO. The cel is on as soon as it fires up from cold, even after a reset. I will clear it again and see what changes. at least now the truck is only 20 feet away not 20 miles...

 

How do you clear it?

 

I just pull the negative battery cable for 10 min, same as my Vic

 

Aught to do it!

 

We shall see. The trans and T-case are going into my '86 2wd and the 300 (if I can get it running again) will find a home under the hood of my '90 Crown Vic. I would just prefer to hear it run properly so i won't be chasing that down along with any wiring screwups I may cause during the swap.

 

That makes a lot of sense! Once you swap, you don't need to start w/ an old can o' worms on top of it.

 

Nope thats for sure. There is kind of a time limit on troubleshooting it though as the P.O needs the slave for another one he just got. At worst I will swap a carb and DSII system on and run Propane in the Vic.

 

Here are the codes I got, I cleared the ECM, started the truck and ran it for about 1 min. The CEL was on as soon as it started.

22 MAP/BP sensor out of self test range.

35 PFE or EVP circuit above the maximum limit of 4.81 volts

51 ECT sensor signal is greater than the Self-Test maximum of 4.6 volts.

53 TPS circuit above maximum 4.5 volts.

54 ACT sensor signal is greater than the Self-Test maximum of 4.6 volts.

67 Neutral safety circuit failure.

I get the feeling this may be an ECM problem.