1986 Bronco II EB 4wd 2.9 gas - warmed up dies no run for 20+ minutes

[Old&Cranky]

Also try Green sales near Cincinattie,Ohio---They also buy alot of parts from Ford Dealers that close shop. They are fast and courtesy service too. They also have HUMANS THAT ANSWER THEIR PHONES AND DO NOT HAVE YOU SELECT BETWEEN ENGLISH OR SPANISH. They do not have you punching a bunch of numbers. THEY ANSWER THE PHONE. Type them in the address bar and watch their videos--you,ll be glad you did.

If we run into any more issues I will look them up...I'm looking forward to getting her back on the road...thanks for your help!

 

[Tpremru]

Did you figure out the running and not running problem? Looks like we have the same model!

 

[Old&Cranky]

Did you figure out the running and not running problem? Looks like we have the same model!

Like I said in an earlier post. I had a 1986 manual 4x4 that I bought new in 86 and had for 18.5 years, sold in 2005. It had your problem. Turned out to be loose distributor. Ran fine after fixed. I bought this one in February. No problems, other than itvwas old like me , so it is being rebuilt.

 

[ragtop69]

Headed to Bakersfield for the March meet to drag race this weekend, Ill check the codes when I get home.
Cheers

How did you do at Bakersfield? ETs and trap speeds?

 

[johnnyreb]

Thank you so much Motech for your professional advice! I can check out the PIP sometime this week! I was thinking the same on the idea that somehow all those wires at the ecm need to be checked most importantly when the issue is occuring especially the grounds. 2 out of 3 places said they "ohmed out" the pins, i think that means they just checked continuity. 1 place said they checked for voltage drops at the tank pump but i'm sure that's not checked at time of issue but they said the pump is dead. I'm going to ask the latest guy about the breakout box - i am thinking of a couple other places i can call about that. Thing is the latest guy did work at Ford years ago, the last place the owner went to Ford school for eec iv way back then which makes me think they need to keep moving things along with bigger fish to fry so they threw a lot of parts at me $$$$ and rather work on easier big name baseball players toy classic cars that are an easy buck. (rant over)

I don't want to buy a breakout box myself and learn how to use it, but, i might. Meanwhile is this idea a waste? -> Because the lift pump asmbly has been replaced 5 times, and now has a NOS OEM, I want to run 2 wires out my cab and splice into the grnd and hot very close to the lift pump and connect a 12v lite bulb so i can see it in the cab lit and tell if there is a drop during the issue which maybe causes bad amps destroying the pump sooner rather than later. In my mind if the bulb flickers etc then there could be a bad ecm, wire, icm, sensor or other electronic component but not a bad lift pump. I learned how to grnd pin 6 on the OBD1 and i can obviously hear the HP pump, but i really can't tell about the lift pump because of the even hum the HP pump is sending throughout the vehicle. I put my hand on the top of the lift pump and can't feel any vibration either. KOEO just code 11 meaning all is good.

Are you useing AIRTECH---FUEL PUMPS? iF SO--THAT MIGHT BE YOUR PROBLEM. I went through 5--straight from the store and they are junk--get a Carter-AC/Delcoe or a name American made one. You might also want to make a small tank set up on the outside of the tank and shorten the line (buy pass all the old line and tank. Have a small jug were can watch and see what happens. If you replaced alot of parts(most parts now days are China junk. Try Green Sales or another company the sales ORIGINAL AMREICAN MADE PARTS. Good luck.

 

[L\Bronco]

How did you do at Bakersfield? ETs and trap speeds?

It went really well, we made the finals and shut off on the starting line because of a grounded mag wire.
But thats racing!


This was the semi final slip, we are car 666

 

[johnnyreb]

It went really well, we made the finals and shut off on the starting line because of a grounded mag wire.
But thats racing!
View attachment 31260

Well you had a nice and safe time and little things like that. Makes you a better mechanic . Get a little note pad and start writing down a check list and the others too. Its real easy to forget or over look something. Better luck next time. When will you be going to Bristol and if and when. Will you be going through W.Va. I only live about 20 miles from 19 south( I-77) AND (I-79 south)

 

[L\Bronco]

Well you had a nice and safe time and little things like that. Makes you a better mechanic . Get a little note pad and start writing down a check list and the others too. Its real easy to forget or over look something. Better luck next time. When will you be going to Bristol and if and when. Will you be going through W.Va. I only live about 20 miles from 19 south( I-77) AND (I-79 south)

Sorry Johnny, Ill let you know when we figure our travel plans.
We might fly in for both races.
Cheers

 

[johnnyreb]

I really did get to do the PIP test a couple minutes ago. Here are lots more details:
I am wondering why throughout the 3 years consistantly run a little longer every few months. It first would mostly be 18 minutes then a year later up to 30 minutes. This past 2 weeks, 2 times it now runs for 80 minutes before the issue. The last mod increased it from 30 minutes to 80 minutes. Here are lots of details:

In July I idled it for 30 minutes until it died then I went to remove the ECM and it was so hot you could not touch it without getting burned. I let it cool and left it alone was not able to work with it until a couple weeks ago when the mech reproduced the problem at his shop he found the 2 grnd wires next to the ECM, 1 insulated 1 not insulated (he knew what they are for) was hanging by 3 strands, surprised I did not catch that as many times I removed ECM, but he fixed that connection up really good. I had not previously told him about the heated up ECM. Now we run 80 minutes and when it dies the ECM is only as expected "very warm". I had also noticed in July after 20 minutes there is a sound in the dash that could be the sound of the HP pump but only after 20 minutes. At time of issue the sound changes from a hum to a rougher hum. I still wonder if the LP pump burns out because of bad amperage from bad wire and the HP pump can actually run the 2.9 although it's not supposed to, for as long as it can. The other day I did the pin 6 ground to turn on the fuel pumps. I can easily hear the HP pump but I can not tell at all if the LP pump is on. I even climbed underneath and put my hand ontop of the send unit and could not feel the slightiest vibe. The issue just happened for my second time in 2 weeks after idling for 80 minutes.

I now have a video of dash as it looks when cranking after the die out. I can hear the HP pump prime but no start. I am also puzzled a litte more about the lights. Why does the parking brake light come on during crank? The P brake light comes on as supposed to when park brake is on. Also, the Check Engine bulb is not present, i have some photos of last year when i had the dash apart for umteenth time for various reasons, but i was changing over to LEDs and there is a photo documenting what bulbs are present and only the ones i replaced. I am going to have to upload the PIP test video to an external link. B2 dashview lights for heatup and won't run issue-->

I read some where that putting led lights in a older vehicle can cause problems. Did the problems start afte you put the led bulbs in?

 

[johnnyreb]

I read some where that putting led lights in a older vehicle can cause problems. Did the problems start afte you put the led bulbs in?

You say you can hear the pump running,but it won,t start. Maybe the sock(screen) on the end of the pump clogged up . Maybe from the pump to the motor is a SMALL leak -to wear its leaking in the frame and mud is soaking it up and not allowing it to run on the ground. I,m trying to figure out mine to(on a 78) and with some of these parts from China --most are junk and its the problem too. Good luck. Keep us posted.

 

[Old&Cranky]

If any of you want to see how my rebuild went that was started March 3rd and finished in late August, see my thread:

Rebuilt 1986 2.9L 4X4 5 speed manual located in Trail Talk Lounge

 

[gsimon767]

I am wondering if any resolution was reached with this problem. I have an 86 BII with the same issue. I have owned the truck since 1990 and it always ran great until the issue of starts and runs great for about 20 minutes until fuel pressure drops to 0 and engine quits. Let it sit for 30 minutes to cool and it restarts and runs normally until the cycle repeats. I should Mention the problem began after replacing both fuel pumps. This was probably not necessary as the original in-tank pump hose between the pump and line had deteriorated and cracked causing an intermittent no start. While I was doing the pump replacements I noticed the four pin electrical connector to the in-tank pump had considerable corrosion which I cleaned as best I could.

I am wondering if the corrosion was hidden in the connector and the connector and wire is heating up from increased resistance blocking current to the new pump. I am getting a new connector and will be installing it as soon as I have time to drop the tank again.

i should mention I have shot the parts cannon and have new distributor and module, new fuel regulator, new EGR valve and sensors, new thermostat and more I don’t remember. None of those “improvements” made any difference in the run stall cycle.

The catalytic converter is not plugged according to local muffler shop. The OBD scanner shows no codes. I am about to give up as I have had this issue for over a year now and can’t reliably drive the truck.

 

[L\Bronco]

I am wondering if any resolution was reached with this problem. I have an 86 BII with the same issue. I have owned the truck since 1990 and it always ran great until the issue of starts and runs great for about 20 minutes until fuel pressure drops to 0 and engine quits. Let it sit for 30 minutes to cool and it restarts and runs normally until the cycle repeats. I should Mention the problem began after replacing both fuel pumps. This was probably not necessary as the original in-tank pump hose between the pump and line had deteriorated and cracked causing an intermittent no start. While I was doing the pump replacements I noticed the four pin electrical connector to the in-tank pump had considerable corrosion which I cleaned as best I could.

I am wondering if the corrosion was hidden in the connector and the connector and wire is heating up from increased resistance blocking current to the new pump. I am getting a new connector and will be installing it as soon as I have time to drop the tank again.

i should mention I have shot the parts cannon and have new distributor and module, new fuel regulator, new EGR valve and sensors, new thermostat and more I don’t remember. None of those “improvements” made any difference in the run stall cycle.

The catalytic converter is not plugged according to local muffler shop. The OBD scanner shows no codes. I am about to give up as I have had this issue for over a year now and can’t reliably drive the truck.

Hey gsimon:
Sounds like you are on the right track.
I'd suggest a voltage drop test at the pumps, but access is limited. So My suggestion is run it till it dies and quickly lest fuel volume at the line before the high pressure pump to see if the low press pump is delivering. (spec is 1\2 quart in 30 sec.) look for a good stream when you cycle the key on. Your symptom sounds like classic low press pump failure.
I've seen many bad pumps out of the box as well.
Good luck
Cheers