Couple months ago, I posted about my 87 F150 4x4 5.0L rpm's oscillating. I replaced the IAC as that seemed to be the most logical problem at the time. Now it won't even start, seemed to get worse right after the IAC was replaced.
I had trouble getting the codes out last time, but managed to get them today. What I got was; 22, 41 & 63. According to a code chart I found on the net:

22 = MAP sensor out of range

41 = No HEGO switching, always lean (MEMORY)

63 = TPS below .6v

Last time, I tried adjusting the TPS out of a slight dead spot & guess it has now bit the dust. Bought a TPS today & will put it on tomorrow & see what happens. I read in some posts that a couple guys were having similar problems & codes & found the Fuel Pressure Regulator bad, so I picked up one of those too, just for grins. This truck in 21 yrs old & 168k miles on it & I've spent almost nothing on it over the past 8 years I've had it, think it prudent to replace a couple things. I did replace the O2 sensor a couple years ago & only put about 3k miles on the truck since then.

So, guess I'll see what happens tomorrow, but in the mean time, any thoughts or suggestions welcomed !

Rick the fix

 

Well for an engine to run, you have to have fuel and spark, so I would start by checking those two things. Pull a plug wire or 3 and check. If you have spark, check for fuel pressure. If you have pressure, put a noid light on the injectors and check for injector pulse. If you have those things, then either the timing has jumped severely, and you can check that with a light, or you magically lost all compression.

 

OK, here's the latest,
Tried starting it again today & it does not start, big surprise there.
I tried for quite a while & it would try to kick over every now & then.
I had removed the negative battery cable & touched it to the positive to zero out the ecm first. Rechecked the codes & got the following:

2-2 / 6-7 / 2-2 / 67 1 / 5-3 / 5-3

I also had changed the TPS yesterday & looks like the 53 is telling me it's installed incorrectly ? ? ?
I also changed the fuel pressure regulator for good measure.

Put the timing light on it & get a strobe, but it's very hard to tell if it is close to time since it there was too much light from the sun. Later tonite, i'll try it again & see where it is, if it's close or not. Then will rotate by hand & remove the dist cap to see if it lines up with the timing mark.

 

You should actually be checking the fuel pressure with a gauge. While the FPR could be a culprit, IF the problem is fuel related it could be a number of things, including the vacuum line to the FPR leaking, or the line that dumps the excess fuel back to the tank being plugged. I think i recall clogged injectors could affect it as well.

The Haynes manual has a good rundown of what/how to check.

If the MP sensor was out of range, you could try picking one up from a wrecker and plug it in to see if it makes a difference.

 

Thanks E,
I did replace both in-tank pumps, the hp pump & fuel filter about 5k miles ago, probably 4 years ago. I've done quite extensive checking of the vacuum lines & found several iffy hoses/connections. The night check of the timing was no good, will do a manual check hopefully this afternoon & then remove & re-install the TPS to make sure it's installed correctly. I'll also do a manual check-out of the MAP sensor using my vacuum gauge & dmm.
Thanks for the tips, & no, my fly is not open!

 

Even if the tps is out of range, it would still start, so I would stray away from that. Like I said, check the spark, (color of spark), and actual fuel pressure.

 

[QUOTE=rickthefix;6240421
I had removed the negative battery cable & touched it to the positive to zero out the ecm first.
[/QUOTE]



who in heavens name told you to do that?

that just sounds wrong.

does it start with starting spray?

 

I have been working on cars with ecm's just about ever since they came out & that is the fastest way to get the ECM's internal battery to drain to get the data to reset, instead of waiting 15 minutes. Several manuals I have had over the years told me to do that ! Why does that seem wrong? The internal "battery" is probably nothing more than a 1 ufd capacitor that will only hold a charge for a short amount of time when power is disconnected.

I checked the timing by rotating the crank to 10 degrees at the pointer & knew if it was still timed correctly, it would put the distributor to either position 1 or 6 & it was dead-nuts 6. So my timing is spot on.

As it so happens, I bought some starting fluid on the way home from work today & it does try to fire when spraying into the intake, so sounds like it's a fuel delivery problem. The inertia switch has already been jumped out since it went bad on me several years ago. As stated before, both in-tank pumps, the high-pressure pump & fuel filter all were changed a couple years ago. That's why I was doubting any of these were the problems. It got dark on me so I'll have to continue at a later date. Also will need to buy some fuel line separator tools to disconnect the fuel line at the pressure regulator to see what kind of flow & pressure I have going into the fuel rails. When the ignition is turned on, the fuel pumps whir for a few seconds, so at least it sounds like the pump is priming.

Rick-the-fix