Wont Start

[Twitch]

Just replaced the fuel pump (In Tank), and the starter in my 85 bronco, 302 Fuel Injected, 4 Speed.

We have spark, fuel is getting to the cylinders, but it wont start.

I am on day 3 of trying to get it to start, with no avail.

Just got done fiddling with it for the last 5 hours, and didn't get any headway.

I haven't even got a cough from the engine like it wants to start... The engine spins, but there is no combustion going on...

Any ideas?

I'm not wanting to trailer it down to the local shop to get it worked on, because I dont have that kind of money to do that.

 

[BroncoJoe19]

are you sure fuel is getting to the cylinders? Did you remember to reset the inertial switch?

Make sure you have approx 35 psi at the fuel rail, otherwise I think the next step would be to check compression.

How was it running before? and how long ago was that.

Oh yeah one more thing... you can pull codes.

Oh.. and another another thing.

Pull Diagnostic Trouble Codes (DTCs) From your onboard computer.

Your engine and transmission are computer controlled.

The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.

Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.

Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.

Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.

SO here you go...

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

 

[Seabronc]

Just replaced the fuel pump (In Tank), and the starter in my 85 bronco, 302 Fuel Injected, 4 Speed.We have spark, fuel is getting to the cylinders, but it wont start.

I am on day 3 of trying to get it to start, with no avail.

Just got done fiddling with it for the last 5 hours, and didn't get any headway.

I haven't even got a cough from the engine like it wants to start... The engine spins, but there is no combustion going on...

Any ideas?

I'm not wanting to trailer it down to the local shop to get it worked on, because I dont have that kind of money to do that.

Did you check the high pressure pump to see if it is running? It is located on the frame rail just about under the driver seat. If it is not running you won't have high enough pressure to run the engine.

Good luck,

>-

 

[Twitch]

I've reset the inertial switch. Still nothing.

I'm smelling gas coming out of the exhaust pipe.

I'm just about to run codes here in a few min.

And... I have a buddy coming down in a bit to check the pressure at the fuel rail.

I will post with results from the codes here in a little bit.

 

[Twitch]

The codes that came up were:

24-o: Intake air charge temp sensor or vane air temperature

22-c: Manifold Absolute Pressure (MAP) or BARO sensor out of range

31-O/C: EGR Valve control Sensor Fault (ex. V8 Models) or EVAP Control System below minimum range.

 

[BroncoJoe19]

Hi Twitch,

I don't know if a vacuum leak would cause all three of those codes or not, but I am thinking ... maybe.

I'll post a reminder of what to look for regarding vacuum leaks in a minute.

You'll probably have two fuses, and two fuel pump relays, one for each pump. You may want to check to make sure that they are both working. Also check your electrical connectors for each of the components listed above regarding your codes.

Checking for vacuum leaks.

Some of the sensors and some of the actuators either read the amount of vacuum, or use vacuum to move controls, therefore it is important to the proper functioning of the engine that your vacuum system is fully intact. Otherwise one may get codes falsely indicating that there is a problem with a controller/actuator, or a sensor when in reality it is caused by a lack of vacuum.

Look at your rubber vacuum hoses (they are about 1/4 - 3/8 inches in diameter, if they are dry rotted or cracked, replace them. IF they slip on/off of their connectors too easily, they may have stretched out a little bit, cut the ends off, and put them back on.

IF you have a vacuum pump, you might pinch off sections, apply vacuum and see if it holds.

You may test vacuum actuators by applying vacuum to them directly and watching to see if that work.

If you can get her started,

You may listen for a leak. Sometimes using a cut off piece of garden hose is a good aid to listen with. Sometimes a cardboard tube (like from gift wrapping paper) is helpful. Just remember that whenever you stick your head inside a running engine compartment, that you are not wearing any loose clothing or jewelry that can get caught.

Another suggestion is to use a spray can of carb cleaner and spray around the bottom of the intake manifold, and the base of the throttle body assembly. IF there is a leak, you should hear a change in your engine.

Keep a fire extinguisher handy, or use water instead of carb cleaner (it works, but not as well.) Be aware that if you use water and the wires get wet and it runs worse... your wires may be bad, and the water is allowing them to arc instead of jump the gap of the spark plug.

Another suggestion is: to take a propane torch, turn it on (but don't light it) and move it over the vacuum hoses and connections. The engine RPM's will increase if there is a leak and the propane gets sucked in.

Don't forget to check the PCV valve, hose and grommet.

 

[Twitch]

I've checked all the vacuum hoses, all of them look to be in good shape.

One thing i forgot to mention, when the bronco got parked about 4-5 months ago, they weekend before it died, I did run through a mud puddle, that ended up being a small lake (3 feet deep or so), i made it through, but at the end of the puddle, i somehow had sucked water into cylinder number 8, I have replaced the spark plugs and wires since then. No water in the oil, and it ran after i had dried out the engine. (drove home about 40 miles or so)

But the final straw it seems if i remember right, was I ran out of fuel on the way to the gas station, but after putting 5gal or so in the truck it ran again. Next day when I was driving to a friends house, to work on the truck, I drove about a mile and a half and the truck wouldnt run any more. But once it cooled down a bit, it ran again.

But the truck ran when i parked it, even after i replaced the spark plugs/wires. But it ran like crap. it would start after about 5-6 seconds of turning the engine over, then once the idle died down a bit, it wouldnt stay running....

So I figured replacing the in tank fuel pump would help, and I just recently had enough money to get the fuel pump and the time to do it. (getting laid of sucks)

But if push comes to shove, I am probably going to end up taking it to the local shop tomorrow, since the owner is a ford fanatic.

Ill check the fuses here in a few, If i dont get dragged off to go help weld some stuff up for my buddies jeep.

 

[92bronco_in_progress]

check the fuel pump relays and stuff like that.....check the starter solenoid, ignition switch, idle air control valve......everything that has to do with starting.....alot of things have to be working right for the truck to run

 

[Twitch]

8 am tomorrow its getting hauled off to the shop...

Ill keep you updated.

 

[Twitch]

So, i got the beast back from the shop.

The firing order was all out of wack, (chiltons lies my friend)

Ignition Coil was shot.

And the timing was horrible.

Took it to the exhaust shop, got a performance cat on it, and a straight pipe after that, sounds like *** on the beach.

But it runs good now.

Thanks for the help /emoticons/[email protected] 2x" width="20" height="20" />

Now to start gathering parts for the straight axle.

 

[BroncoJoe19]

So, i got the beast back from the shop.The firing order was all out of wack, (chiltons lies my friend)

Ignition Coil was shot.

And the timing was horrible.

<snip>

That'll do it every time! /emoticons/[email protected] 2x" width="20" height="20" />

Glad you got it taken care of.

You may want to recheck for codes.

 

[Seabronc]

So, i got the beast back from the shop.The firing order was all out of wack, (chiltons lies my friend)

Ignition Coil was shot.

And the timing was horrible.

Took it to the exhaust shop, got a performance cat on it, and a straight pipe after that, sounds like *** on the beach.

But it runs good now.

Thanks for the help /emoticons/[email protected] 2x" width="20" height="20" />

Now to start gathering parts for the straight axle.

That is why you should invest in some books that have to do with your particular year of truck. Chiltons and Haynes are a "Readers Digest" version of the real thing and tries to cram information covering several years into one book. It leaves a lot of important stuff and is confusing in regard to things that have changed over the year range they are trying to cover. At minimum get yourself an EVTM (Electrical and Vacuum Troubleshooting Manual), for the 85 Bronco.

There were non of those problems you couldn't have solved yourself if you had the proper set of books and saved yourself a bunch of money spent replacing perfectly good parts.

If you seriously intend to ever be able to do anything beyond an oil change, you should invest in a real set of shop manuals for your particular truck.

Good luck,

>-

Oh yah, if the garage didn't do it for you, reset your computer codes so you don't have a bunch of junk hanging around in there to confuse you the next time you get a check engine light. Just pull the negative battery cable for a about 5 minutes and reconnect it.

 

[BroncoJoe19]

I've been told that one should not pull the battery cable to clear computer codes because that also clears the fuel trim table, UNLESS one replaced fuel/air related parts. Then one should pull the battery cable to reset the fuel trim table.

One can clear computer codes and leave the trim table intact by setting a jumper wire, and turning the key on. Before the codes are finished being flashed to the dash, disconnect the jumper wire.

 

[92bronco_in_progress]

I've been told that one should not pull the battery cable to clear computer codes because that also clears the fuel trim table, UNLESS one replaced fuel/air related parts. Then one should pull the battery cable to reset the fuel trim table.
One can clear computer codes and leave the trim table intact by setting a jumper wire, and turning the key on. Before the codes are finished being flashed to the dash, disconnect the jumper wire.

View attachment 8060

yeah but after a drive cycle the computer re-learns the fuel trim table

 

[BroncoJoe19]

One point I wanted to make is that people should learn how to pull codes. IMO far too often people just want others to tell them what is wrong with their truck and which part/s should they change. One does not learn much by pulling the battery cable.

Second, while it is true that the computer will RECREATE a fuel trim table. I think it takes about ten drive cycles for it to refine it a bit, it now is doing so with sensors that are many years older than when it was originally created. It is my understanding ... That is NOT optimal, and that it would be better to maintain fuel trim tables that are based on the sensors when they were younger. Is this splitting hairs? Perhaps. I'm not the engineer who wrote the original specs, so I can only report what I have read.

 

[Seabronc]

Yup, you are splitting hairs Joe /emoticons/[email protected] 2x" width="20" height="20" /> . I do that all the time, never hurt anything yet. So does my mechanic. In fact it is nearly impossible to follow most maintenance and repair procedures without disconnecting the battery. Where did you read that ? I'd like to read :-B that article myself.