My 1986 302 EFI F150 has died a couple of times on me lately and would not restart until later. I replaced the throttle position sensor because I got a code of 63. Its still giving me that code--doesn't disconnecting the battery clear the codes? After replacing the TPS it solved the idle problems I was having. There are no other codes in the KOEO test.

However, once before I changed the TPS, and then once after, the engine died and would not restart. The first time it ran really rough, then died and would not restart. It sat for a half hour, then ran ok for about 2 miles, then ran really rough. When cold, it ran fine. The second time, with a new TPS, I started it warm, it ran 2-3 minutes fine, then ran rough and died. It would not restart. I had it towed to the shop and when they got around to it it would run fine for them.

The common variables for the two incidents is this: the air temperature was over 100 F, I had driven for a while (over an hour first time, about a half hour second time). I then parked on an asphalt parking lot in full sun for about a half hour. The symptoms occured after this.

As I said, it has a new TPS which helped old problems. It also has a new Ignition Control Module (about 4 months old). When the ICM acted up on me it was much sooner and with less heat than what we have had lately. From the research I've done, vapor lock normally doesn't happen on an EFI engine; the presssure side of the fuel pump is not supposed to be as vulnerable to heat as the suction side, and on these that is well away from engine heat. As far as I know the fuel line is routed the way it came from the factory.

Any ideas?

 

When it won't start, check for spark. Also keep checking the codes, and make sure you check the codes in memory.

 

How full was your gas tank? You can get heat soak which will cause pockets of vapor if your fuel system isn't in peak condition. How new if your fuel filter? I had a similar problem like yours in my Buick, where it would stall out like vapor lock on very hot days. Found out it was the fuel pump in the tank that expanded when hot and would not pump at pressure. Replaced the pump and all if fine.

 

The gas was fresh, I had refueled two days prior in the second instance. The rear tank was full and the front tank had about 3/4. The fuel pump in the front tank was replaced about 4 months ago. The first time it happened, in addition to waiting, it seemed to help switching tanks. But then again I only got two miles or less before it acted up.

I was so frustrated I didn't check for spark, I just thought it was the gosh darn computer (I may have used different language). I was going to start carrying a fuel pressure gauge with me, but the store was out of stock of course.

Right now my plans are to be ready to check fuel pressure and spark if it happens again. I have already added a can of Heet to each tank. The shop thought maybe bad gas or fuel pump going bad, but it ran fine for them. I'm in Missouri, and all gas has 10% ethanol in it--I don't know how much of a factor that is in my problem.

The fuel filter is pretty new with less than a thousand miles on it. And I have vented gas caps so there shouldn't be any pressure buildup in the tanks.

I will try to get all the codes again, including when running. I got a 77 (I think that was the number) that said it couldn't do the engine running test due to operator error.

 

EFI is never going to vapor lock. The fuel is under pressure like you mentioned in your first post, and also it has a fuel return system, so any air bubbles migrate back to the tank. At idle and slow speeds, most of the fuel just re-circulates from the tank, up front, and then back to the tank.

Yes, do some checks for spark. That will eliminate that whole system. You also have the right idea for checking the fuel pressure also. Just beware some of these early EFI trucks don't have a test port on the fuel rail.

 

I had an 86 f150 302 EFI that had the same symptoms. When in hot weather (summertime) would just crap out, die while driving and run rough or not start at all. When cool ran fine. Can't remember the code, as I sold it for Cash for Clunkers. No vapor lock on EFI.
Only cure was a rebuilt distributer for about $65. There is an electronic part in the distributer (can't remember the name) that acted up when the motor got really hot....wasn't overheating though. Easier to just replace the distributer than put in the part.
Every couple of years needed new distributer.

 

Yes, that's the Ignition Control Module (ICM). I had it replaced about four months ago. The original was acting up, giving me some rough running and loss of power, but it still ran good enough to get me where I was going.

The replacement was from Autozone. If I had it all to do over again, I would have gotten a Motorcraft. The ICM is on my list of suspects. I read on here somewhere that you could cool them with a can of dust remover like they use on computers. You turn the can upside down and the propellant comes out cold. I may get a can and carry it.

 

NO, it's not the ICM!!!
There is another part down inside, requires rebuilding the distributer.

 

Could be called ignition pickup or stator.
I tried changing ICM, I always had a spare and timing light in the truck.... no difference.

 

When you changed the module out, did you use plenty of the heat sink white grease on the back of it? If you didn't, it will cause the new module to overheat.

 

I always did.... didn't make any difference....until I changed distributor.

 

I had it in the shop for other problems, so I had them do it. I hope they did--I had bought the module and grease and gave it to them to install. I was in a hurry and the timing marks are not all there, so I was afraid to pull the distributor and do it myself.

 

Dave, I am new here but needed to do some searching for my own problem and found this thread.

<O</OI have a 94 E350 7.5 class C RV and did have a vapor lock issue! I need to respectfully disagree with your statement “EFI is never going to vapor lock”.

<O</OHow could you say never?

There may be situations when EFI cannot overcome fuel boiling due to heat or atmospheric conditions. Case in point my 94 class C RV recently had a stall condition on a hot day, 96 degrees with the A/C running and there were no codes present.

It stalled as I had downshifted into low gear approaching a stoplight and when the light turned green I stepped on the gas to go and it fell flat as if no fuel was available. I managed to barely crawl through the intersection with the engine sputtering as I tried to keep it running in neutral feathering the gas as the engine sounds when wide open without fuel and starving, you know the sound and pulled to the side of the road where it died!

It would not re-fire and I did not hear the fuel pump turn for 1-2 seconds on as it should when turning the key back to the on position, this lasted 30 minutes with 3/8 fuel in the tank and the gauge is correct. I towed it home and let it sit for 2 hours and then it re-fired and drove fine. I gassed up later and drove it for 3 weeks without ever getting a code or reproducing the stall.

This occurred the last weekend in June 2011. Two months after that we departed for Yellowstone National Park, the last weekend in August 2011 from California and pulling a TOWD, Toyota Rav4 on a dolly.

As we drove through the hot Nevada desert averaging about 95 degrees the exact problem occurred again. Upon decelerating down some hills and stepping on the gas to accelerate back to hwy speeds the engine died and would not restart. When it did it sputtered and died and would not run until cool about 20-30 minutes later, this with ½ tank of fuel. We filled up at the next stop 5 miles down I80 and all seemed fine for a while until we climbed several grades and the condition appeared again.

We were able to limp into a Wells, Nevada and found a NAPA parts store and bought all parts I could consider a problem, ICM, fuel filter, pump relay and fuel pump in case mine was failing or had failed and to have on hand since remote location may not have parts nearby if needed so I had them at my disposal.

I replaced the ICM and relay on the spot. The ICM was of the fender well mount type on a heat sink. After I replaced them it had cooled enough that it started, we drove it, fueled up and continued another 4 hours as the evening cooled and didn’t experience the issue again that day.

The next day again it happened and I changed the fuel filter after it died on the side of the road and found only mild restriction when blowing through it. This filter had been changed at 30,000 so it only had 18,000 on it. By the time I was done it had again cooled enough to get us up a 6% four mile grade in Idaho and seemed fine until we hit some other grades about an hour later and had coasted down and upon accelerating the engine fell flat and died again! I was able to coast into a gas station and fill up with another ½ tank and it eventually started after about 20 minutes. We finally stumbled into our campground in Yellowstone doing the same thing, it was quite embarrassing! I had concluded due to the elevation and hot temps the engine and fuel were hot!

While in our camp site I was able to get an internet connection and searched for info concluding I was vapor locking! But how, EFI is not supposed to vapor lock!!! I know this as I was an ASE certified master technician and also a Jaguar certified and schooled in EFI before any domestic techs had dealt with EFI. I know this stuff pretty well and though I no longer work on cars for a living I haven’t lost my diagnostic skills.

While in Yellowstone and searching for info I found a ford TSB that pointed to a faulty pump http://www.irv2.com/forums/attachment.php?attachmentid=13267&d=1314232412 though my chassis is not an F53 it does have the same engine and in tank pump that the F53 has to the best of my knowledge.

<O</OA few days later we drove the Rav4 and stopped at a shop in Canyon village and spoke with a mechanic who had worked there 18 years! This place is at 7900’ elevation so RV’s pulling the steep grades on hot days is the perfect place to have a problem if it can happen. The mechanic stated that in the 90’s when he first started out there were days they saw 6-7 of these Ford RV’s a day at time during the tourist season all exhibiting the same symptoms, all that I had stated and they could not figure out what the problem was.

Eventually they got to someone at Ford in Detroit and explained what was occurring. The Ford Engineers concluded it was a fuel pump issue due to heat and vapor locking and the only work arounds at that time were different fuel octane to raise the boiling point by using a lower octane rating or to add Marvel Mystery oil to the gas in the correct ratio or a quart of diesel to keep the fuel from boiling and vapor locking and don't let the engine idle long as the pump couldn't stay cool.

Eventually Ford release some TSB’s relating to the issue which seems to be a different style pump assembly.

<O</OOn our return trip we again experienced the vapor lock issue when about 90 degrees and with the Marvel mixed with the fuel. After cooling down we again stumbled to our destination 1 mile away. We left next morning early and returned home before the heat of the day safely without incident.

<O</OWhat I don’t understand is why we never experienced this issue before as we have driven it many times in hot weather pulling a TOWD or boat trailer with A/C on. This has only happened recently with 48,000 miles on the odometer.

<O</OWhat would change and cause the fuel pump to fail now vapor locking with this mileage, it never had an issue before?<O</O

For anyone else who may stumble on this thread here are links that point to additional info.

http://www.irv2.com/forums/f23/f-53-...res-75723.html

http://www.irv2.com/forums/f23/fuelp...-a-101184.html

http://answers.google.com/answers/th...id/386964.html

 

You haven't figured out what the problem is yet. You found this general statement that the "Ford engineers" think it's something wrong with the pump, and or possibly the fuel boiling in the tank. Do you know how much heat it would take to boil all that fuel in the fuel tank? A lot. And the pump is mounted down low in the fuel(it's supposed to be). It sounds like you tried one of their "fixes" (more like a bandaid) and it didn't work. I know the Ford engineers are supposed to be the most knowledgeable of the vehicles they make, but I have worked with engineers for many years, and I can tell you they put their pants on just like you and me, and they can be lazy and make mistakes.

All this may be true, and the fuel is boiling in the tank on this vehicle, but this is a very unusual case with this particular setup, and it sounds like a design problem. Something like the exhaust is too close to the tank or something like that. If they or you think the fuel in the tank really is boiling, why not make some sort of heat shield for the tank to keep heat away from it. No other vehicles that I know of have this problem if they are efi. I hope you get it fixed.

 

Dave, perhaps the pump itself is what is getting hot and causing the issue? I have been trying to get additional info on the pumps for the TSB and the F53 chassis. I am finding that the PFS48 is the pump that goes into the F53's and specifically 1991 Econoline's. I do not believe there should be differences in the EFI 7.5 Econoline's but then again I don't have the resources yet to be sure. I cannot find specific info why this pump fits F53's and only 1991 E350's.

I hooked up my Snap-On MT2500 and pulled a code 14, Ignition pickup (PIP) was erratic. Could they be related? If the engine was trying to run in a lean condition could it run so erratic it threw a 14? As it tried to run it chugged, bucked and barely ran, but it did run until it died and the check engine light wasn't always on when this occurred.

Could a defective or failing Ignition pickup module also cause the fuel to shut off and exhibit what seemed to be vapor lock? I ask this because I did not hear the pump prime as previously stated when turning the ignition key to on while hot. So IF the Ignition pickup module were hot and open circuiting would it effect anything else? I also noticed the A/C would shut down at times just prior to detecting the engine going flat and out of power as in what seemed to be vapor locking?

I had a similar issue with my boat about 6 yeas ago when the Mallory ignition pickup module was bad from the factory in my blown 454. It did not do anything like 460 is doing. The Ford would try to run if it set for just a few minutes like it got a little fuel then try to run like a vapor lock, the boat would only crank when its module failed.

I can replace the Ignition pickup module easy enough and see if this fixes my issue If I get any HOT temperatures again before Fall and November.

Do you have any suggestions?