Hi all. I'm coming to the forums for some help with my truck. I have a 1989 F150 5.0L XLT Lariat that I cannot get to start. The starter will turn over, but the truck does not attempt to crank at all. Below is the history of how I got here.

I bought the truck and it was running. Took it to a local mechanic that works on my father in laws vehicles and he replaced the entire air conditioning system. He told me he patched all of the vacuum lines because they were all burnt through. He wasn't lying. I ordered new vacuum lines and replaced all of them but found that the truck was hunting idle and would die at stops often after it got warmed up. You'd have to wait for it to cool before it would start again. I replaced the TPS, MAP, IAC, HP, temperature sender/sensor, fuel pump, and fuel filter. I've also replaced the spark plugs, ignition coil, and spark plug wires, for general maintenance.

After a lot of troubleshooting, and replacement of the parts mentioned above, I found that the gasket on the rear of the lower intake manifold was blown wide open. I replaced the gasket, put everything back together and now my truck will not start at all. Not even with starting fluid (to be fair I'm using carb cleaner as a stand in, but that shouldn't matter). I have spark as I tested with a spark tester ( light bulb type). I assume I have air because I can put my hand over the throttle body and it's suctioning. The only thing I don't know that I have is fuel. My fuel pumps turn on when the key is turned on. I have pressure on the rail (~50psi when the key is turned on). I just replaced all of my injectors because I did notice a couple of them were leaking around the o-rings and I wanted a good baseline anyways.

It went from a simple manifold gasket repair to a (seemingly) major issue. The only code I'm able to pull KOEO is code 23, and that pulls with the old or new sensor.

I don't like the shotgun method of troubleshooting, but I'm not sure what else to check at this point. Thanks in advance for your assistance.

 

It's a bit unfortunate you've replaced so many things at once. That makes it a bit harder to know if something (even new) is malfunctioning.

Code 23 throttle sensor out of range or throttle set too high

Unplug your TPS and try to start it, TPS codes shouldn't be ignored.

 

I'm pretty sure if you hold the accelerator to the floor, the computer will turn off the injectors, so yes, check the throttle position sensor. It might be telling the computer that you've got it floored.
Crank and turn over mean the same thing to me. The crank shaft is turning. The engine is turning right?

 

My thinking exactly. If it starts with the TPS unplugged, that's our issue.

 

https://www.fullsizebronco.com/threa...stment.203080/
Here's a good TPS thread.

 

Welcome, first time post and all that.

It is very helpful to get accurate descriptions of what the problem is. Are you saying the starter motor runs, but does not engage the ring gear which would allow the engine to turn over and possibly start?

 

That is what I get out of the description but who knows?

The starters are different if you have an automatic or manual transmission. Could the wrong starter have been installed?

 

Im assuming the engine is cranking, because he mentioned that it's "suctioning"

 

Thanks all for the replies.

For clarity, I did not replace all of those parts all at once. I was trying to eliminate the idle "hunting"/truck dying at stops and replaced them one at a time until I found the lower intake gasket leak. The truck started and ran with all of those parts before the gasket replacement, it just didn't run well.

However, I did unplug the TPS sensor and did not have any luck. I also rented a noid light kit to check my injectors and I'm getting signal when I attempt to start the truck, so that left me more confused.

When I say "turning over" I mean when you turn the key and the starter turns, but it is not attempting to crank (fire, combust, I'm not sure of any better descriptive words here). In short, It's not firing at all. Crankshaft is turning, everything seems to be moving like it should, just no fire. Does that make sense?

The starter has not been replaced yet as an aside. Also, it is a automatic transmission.

Thanks again for the replies.

 

Well it's sounding like time for a compression test.

If it has fuel, spark, and compression, it should run. Considering it won't even run on starter fluid makes me think there's not enough squeeze going on.

 

Sounds like a timing issue. Is the distributor 180 degrees out?

 

Well, if it has not started since you had the intake off, I would re trace your steps with that repair
Starting by re-rough timing the engine
Put a wad of paper towel in the # 1 spark plug hole and turn the crank clockwise until the paper towel pops out
That will be #1 on the compression stroke
Then bring the timing mark up to TDC or ten degrees before and set your distributor
Also note, there is crank and start. Your problem is cranks but will not start
The terminology you will learn over time, and that will make discussions easier
Good luck