Got a new issue with the bronco

Hey boys,

I'm back with a new issue /emoticons/[email protected] 2x" width="20" height="20" /> . I will try to explain as best as I can. Here goes nothing, I recently have been having several issues with the bronco that I think I get solved but then a week later it is doing the same thing. :-&

Here is what it is doing right from the start.

First time- started bucking but touch gas and would even back out and drive fine then parked it and would not start back up come to find out that the sending unit shit the bed again it is only 9 months old . Replaced that and she fired right back up didnt have a problem for a day or two.

Second time- went to pick my kid up from school and she bucked again a couple times but again was able to give it some gas and leveled back out to normal for a little ways then the RPM's dropped down to nothing but was still running feathered the gas a little and RPM's went back to normal and drove fine. :wacko:

Third time- was driving normal when all of a sudden she died right out and would not start back up for nothing it was getting late at this point so i decided to let it sit over night and come back in the morning to try and figure out what the issue was. Got there in the morning and decided to try and move it to a level spot to work on it at and she fired right up and I was able to drive it home. Drove it for a couple of days and then it did the same thing RPM's went crazy and bucked a couple of times then dies right out but if I let it sit over night it will start right up and be fine. /emoticons/[email protected] 2x" width="20" height="20" />

Fourth time- this time she bucked a couple of times then RPM's when crazy and nothing I did made a difference and stalled right out and would not start back up til the next day.

I have replaced the sending unit, pick-up coil, ignition control module, cap and rotor, and the ignition coil, also put a new fuel filter on also.

She is definately getting gas you can smell it when you turn the key and we tested for spark and we have that but I am at a complete lose as to what it might be hopefully one of you have come across a situation similiar to this and can help me out or at least point me in a direction to start.

Happy Muddin

Broncogurl

When it dies and you can't start it, does it still seem to be getting fuel? You might have to check the fuel pressure when it's running normal, then when it dies. you'll need a special gauge for that, but it should tell you if you have a fuel problem, like a bad fuel pump relay or pressre regulator. Second thing to check is if you're getting spark to the plugs. I use a spare one to slip into one of the plujg wires and ground it to the frame or engine, turing the key and looking for blue spark. you can also try to pull codes by looking for BroncoJoe19's instruction topic to see if anything shows up. A loose ground wire can give you lots of headaches. But just from your description, it seems that after driving and the motor heats up, it dies out and won't start until it cools down for at least 30 minutes? That seems like more of a fuel dielviery problem to me than igintion, JSM84

One thing that comes to mind, Could have rust and crud in your fuel tank. The constant sucking of the pump can pull the rust and crud to the "sock" and plug it up, causing fuel starvation. When the truck dies from no fuel the crap will fall off the sock because there is no suction. Then you refire it up and the suction will gradually pull the crap back to the sock and plug it up.

Yardape said:

One thing that comes to mind, Could have rust and crud in your fuel tank. The constant sucking of the pump can pull the rust and crud to the "sock" and plug it up, causing fuel starvation. When the truck dies from no fuel the crap will fall off the sock because there is no suction. Then you refire it up and the suction will gradually pull the crap back to the sock and plug it up.

Click to expand...

thats exactly what i was thinking, you beat me to it

I Know seriously Yardape back off LOL ) Wonder if the injectors are ok as well after sucking up all that crap.

how long have you owned the truck, and when you bought it was it doing this??

92BM

Hey BrocoGurl86,

Welcome Back! /emoticons/[email protected] 2x" width="20" height="20" />

Sorry that old beast is giving you problems again.

When you dropped the tank last year, did you take a look inside?

Yardape's suggestion certainly is very plausable.

When you say that you changed the sending unit.. you're referring to the fuel pump... right?

With an '86 you have two of them, a high pressure one on the frame rail, and a low pressure one in the tank. The in tank one should deliver a measured amount of fuel in ten seconds or so. The high pressure one should pump the pressure up to about 35 psi.

IF you jumper the fuel pump connection to ground in the self test connector (which is labeled in my pull codes thread), the pump/s will run continuously so that you can test them.

Your intermittant stalling may also be a vacuum leak to your MAP sensor.

Rough idle could be a sticky/dirty IAC.

Maybe clogged ports to the EGR valve? I really don't know about that one.

Here's the thread on pulling codes.

and a couple of others /emoticons/[email protected] 2x" width="20" height="20" />

How to check a fuel pump relay

http://broncozone.com/forums/index.php?showtopic=14905

how to check for power to injectors

A noid light is a small incandescent bulb in a socket with pins that plug directly into the wiring harness leading to your fuel injectors.

Popular Mechanics: Auto Clinic Expert Q & A -- Fuel Injection - Popular Mechanics

A picture and more information is inlcuded in the above link.

How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway

Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more

I just looked it up in my Haynes... low pressure pump should deliver a min of 6oz in 5 seconds. They state that it is very sensitive to voltage, and therefore one should be sure connections are clean and tight. Before testing, one should raise the front a little higher than the rear to prevent siphoning of fuel when the fuel line is disconnected, and that it should be disconnected at the frame mounted fuel reservoir.

Hey Boys,

I have had the bronco for a little over a year now and this is the first time that I have had this issue since owning it. As for the changing of the sending unit in my bronco the pump in the tank is attached to the sending unit so that they are one big unit. I know that there is no "crud" as you all put it in the tank because when I dropped the tank originally I put a brand new one in to replace the old rusted out one and at the same time put a new sending unit in. When I was messing with the fuel system before I put all new parts on it with the exception of fuel lines but when I pulled inline fuel filter there is nothing but fuel coming out of there is no pieces or sludge in it.

As for the stalling and not starting back up it needs to sit for atleast 12 hrs before it will start back up. The one time I tried it a couple different times letting it sit for 30 minutes or so at a time and it would fire but stalled right back out. Left it alone over night and the next morning started right up and drove it home. There have been a couple times when I was able to start it but would stall out but after letting it sit for atleast 12 hrs she pops right off and I am able to drive it for a couple days before it does it again.

And yes I can smell gas when I try to start it right back up after it stalls out on me. I is almost like it is not getting fire because it will roll over but will not fire but I have checked that and it is getting spark.

One thing I can tell you is that I didnt have this problem until I changed the sending unit/pump combo. So I dont know if maybe I got a faulty sending unit which would not surprise me after getting one previously that was bad from the get go and then having one that I put in less than a year ago go bad on me too. This time though my gas gauge works where previously it did not. Also had the fuel pump on the rail tested and that tested fine worked great spewed gas everywhere lol.

Hopefully this all helps will try to answer your question as they come in

Happy Muddin'

BroncoGurl

And yes I can smell gas when I try to start it right back up after it stalls out on me. I is almost like it is not getting fire because it will roll over but will not fire but I have checked that and it is getting spark.

broncogurl

so you have gas and spark. You also need air.

Chek your air filter. and try cleaning the IAC and check the connectors to it.

Check and clean your IAC

http://www.fordfuelinjection.com/?p=39

NExt time it won't start, floor it, and crank it, then let your starter cool for a minute, then try to start it. IF that works, it is quite likely the IAC.

IF it is not the IAC... time to pull codes /emoticons/[email protected] 2x" width="20" height="20" />

When it is running, at idle, does it sound "wet"? I know it sounds strange but it is the only way I can describe it. Do you see black smoke coming out of the exhaust? If yes to both I would say it's time to replace the Fuel Pressure Regulator.

I've had stalling issues along with a few other problems with my Beast over the last few years. She would run fine then all of the sudden just die, from a dead stop and going wide open she backfired through the throttle body and took out the timing chain, dizzy and a few other components. Long story short, what I was thinking was a relay issue ended up being a bar "FPR" and a dirty "IAC".

Mind you I am still having problems with the relays but thats another story for another thread...

Good luck