Have you checked the wiring harness yet? If the MAP senses no vacuum, it thinks that you are supposed to be at full throttle and dumps in a lot of gas. I don't know if that was bad or not. There is a way to test it with a volt meter or a tachometer, depending on which MAP sensor you have. If you have a haynes manual, I would look in there for electrical checks to test the condition of the wiring harness.

 

I need a Tach to check mine. (I don't own one yet) I am going to check all of the connections at the EEC and the continuity between the EEC and the sensors that is Saturday afternoon. I am going to try to wrangle some help out of a buddy of mine.

I will update this weekend...
Mike B

 

Well... I have been beat..... I give up....I have suceeded in making the problem so bad that it doesn't want to start, when it does, it wont idle, and when I can get it to run (for about a minute) it barely lopes along then dies. I may have screwed it all up by screwing with the timing. Now I can't get it back to where I started.

I am now going to take all the new parts off that I just put on and sell them and crush this MFing truck. Here is what I have done in the last two weeks. Fuel filter, plugs, wires, rotor, cap, ignition control module, Fuel PUMP, TPS, IAC valve, MAP sensor. The only thing left is the EGR & position sensor. But I feel like that would be just dumping more cash into this POS.

Later,
Mike B

 

hate to hear it dude

 

I had a similar problem with my 91 F250 with a 460 and it turned out to be my fuel pressure regulator on the injector rail.

When I pulled the vacuume line off the regulator while a buddy feathered the throtlle, gas came spurting out of the regulator. And I mean a lot of gas came out. Appartently the diaphram was leaking and the engine was getting flooded through the vacuum lines.

If you can't start it, you might try a vacuum tester pump on the regulator. It should hold pressure and be dry.

I also had a ton of error codes and replaced several sensors before finding it.

If it is your regulator, your engine may be flooded and pulling some of the spark plugs(The ones easy to get to) and let it breath a while might help to get it started.

I hope this helps- Hate to see you loose a truck over something like that.

 

I dont think it is the regulator. I have pulled the vacuum line while it was running (won't even start now) and the idle went up a bit, which according to my manual it should. Also I did a pressure test on the fuel system that is how I found out my pump was going bad. The second part of the test is where you block off a return line and see if the pressure shoots up. Mine did not. So that says that the regulator is good.

I really messed up the timing bad and I don't know how. All I did was rotate the distib a little while it was running to see if I could get the idle to level out. Instead it died and now won't start at all.

Oh well, That was $500 poorly spent, I should have used it toward a new truck 4 weeks ago.

Thanks again for all of your help! It really was nice being able to bounce things off you guys.

Mike B

 

TopDeadCenter,

Hey man, Sorry you are having such a tough time with that truck. Most of us who work on a lot of vehicles have been there too.

It is really not that hard to get the timing back where it belongs. Especially if you have not pulled the distributor. Just pull #1 spark plug. Put your thumb over the hole.Bump the engine over until you feel pressure. Then manually rotate the engine , clockwise looking at it from the front, while using a flashlight to look into the hole, or use a smalll screwdriver, small dowel, etc, anything that you can use to determinge when the piston is at top dead center. (Since you felt pressure against your thumb, this will be on the compression stroke.) Pull the distributor cap and turn the distributor so that the rotor is pointing to plug #1. Tighten the distributor hold down bolt. Pull the SPOUT connector. Connect a timing light. Crank the engine and set to base timing, 10 degrees BTC.

Shotgun parts replacement is a bad approach to this type of problem. You may very well have multiple problems. Fix them one at a time. If you have fuel, compression, spark, and correct timing the engine will run. Now troubleshoot those #%$@#$ sensors to find out why it is not running smoothly. Just a note about one of my experiences, I put a brand new set of plugs from NAPA into a 88 Mustang 302 and it ran like *****. Pulled the new plugs and put the old ones back in and it ran fine. Do not assume anything.

Good Luck.......Never give up....Tough problems build character...Hang in there.

 

Problem Update:

Major damage. The problem was caused by a failing timing chain/belt what ever they have. It skipped a little causing the initial problem, missing at idle and missing through out acceleration. It gave way Sunday afternoon while I was trying to readjust the timing. Major noise (breaking sounds and things coliding in the head and know the engine is junk.

My Pa is trading me his 92 Mazda Navajo (Exploder) plus some cash. He is going to long block the F150 and use it on the farm or sell it for some quick cash.

Seriously thanks for all the help!

Mike B

 

Sorry to hear all that bad news. It seems your electronic problems were masking the real problem here. Maybe we can all learn from this.

My regards.

Dan.

 

yeah sounds like ya broke the timming parts and the pistons slapped the valves

 

I had a truck that ran that way and it turned out to be the catalitic converter was plugged. I didnt know they ever did that, Turns out it's common.