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Discussion Starter #1
Hello all,

I was wondering if yall can give me some advice and/or help. I tried to find some previous threads and cant find anything that sounds like solutions to my problem.

I was waiting at a red light about to get on the 76 freeway, it was running fine. When the light turned green, I went and then the Bronco started bucking and was really sluggish. I made it through the intersection, pulled over on the shoulder and the truck died. I tried restarting it, it wouldnt start. I tried again and again for about 5 minutes, got nothing. I let it cool down with the hood up for about 10 minutes, tried to start it again and it started. got in the truck and drove for about 5 minutes when the bucking started again. I pulled over and let it cool down. Started after 5 minutes, then I drove to a parking lot where I turned it off and waited for my mom and a tow truck. The other day I went to pull codes and it started but then died before reaching operating temp. Now it wont even start.

When it dies, it just shuts off. no reving and then dying. The fuel pump engages but it seems like the engine is getting no fuel.

The codes I pulled were:
23 KOEO
31 C

My dad is about to come into town for a week. I have been driving his Tahoe in the meantime. He needs it when he gets back. So if I can get my Bronco running before he gets back, that would be great.

Looking forward to the feed back,
Chemkid
 

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is there any spark at the distributor? i had kinda the same problem when i had a msd ignition module. it turns out that the module was bad and would only work when it wanted to. so i had to remove the msd all together. maybe you should check your ignition system. hopefully thatll work for ya.
 

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I am just taking a shot in the dark, but I had the same thing happen one time while I was on the freeway in my mustang. Long story short the motor was blown.

I am not saying this is what has happened to you, but what you describe was the same thing that happened to me. One of my cylinders just broke apart on me & caused the whole motor to cease up.

Good news was that I hadn't blown a hole through the block or wrapped the heads, or anything that bad. I just had to get a rebuild kit & have the engine machined a little & was back on the road for under $800 with in a weeks time.
 

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Ya it might, it all depends on your version of "bucking" I guess. Should have thought about that before I posted. It could also be that the catalytic converter has gone bad & is clogging the exhaust but if that was the case it would crank. If it is the cat it would explain the fact that it shut down once it got up to temp.
 

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I had the same problem and it was the fuel pressure regulator.
It was running wide open and flooding itself out.
check all of your vacuum lines since the FPR is vacuum operated.
 

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Hello all,

Chemkids dad here,

here is a litle more info for your consideration.

Engine:
complete top end rebuild a couple thousand miles ago (under 6,000 miles) to correct the #8 exhaust valve issue.

exhaust and car:
New exhaust and high flow cat 1 year ago,

engine components:
new IAC, new TPS, new fuel filter (All 1 yr ago, May 09) throttle body cleaned, most vac lines replaced or repaired.

I plan on looking at the fuel filters, (replace) fuel pressure regulator and pumps. then go from there, any other suggestions would be appreciated.

Chem
 

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Ok so I was wrong, but thats a good thing because those 2 things can cast some coin. You know I did have a bronco once that would not stay running & I went through everything on the truck. I mean everything & what it ended up being was a trans solenoid shorting out. I know you all might think I'm nuts but thats what the problem was, once it was replaced I never had a problem again.

I am not saying this is it, but if you exhaust everything else then check it out.
 

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Discussion Starter #10
Thanks for all the input everyone.

I will start looking at it today and the next couple of days. I will keep you updated on the status of how it is coming along. I will look up how to test FPR and check for spark.

I dont know if this will add anything to the problem but before I took it out for a drive to school, it was sitting in the street for about a month and a half with about a quater of a tank of gas. Before that, when I drove it regularly, it would be driving with a kind of stumble, when I get to a complete stop it would surge and then die. It would start up again and then die again. The only way I kept it from dying was I kept my foot on the gas to keep the rpms up. It would only act that way until it got up to operating temp.

Like I said I dont know if this would add to the problem or have lead to it.

Chemkid
 

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Keeping the RPM's up, in my opinion, still points to that Fuel pressure regulator running open.
Three hours and 30 bucks....
 

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Discussion Starter #12
Update

I just went to go see if I could figure out what was wrong with my Bronco and I think I know what the problem is.....but im not sure.

I was following the Haynes manual instructions to test the FPR. I wanted to start the Bronco first to see if it would start, it did, but for about 5 seconds. So I know that there is a spark, so nothing is wrong with the wiring. It most likely seems might be the FPR. I dont know if it is, but it seems like it.

If yall can tell me how to test it or should I just buy a new FPR.

The lines look fine, it looks like there is no leaking from it.

Looking forward to the input

Chemkid
 

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Don't assume you have spark just because it fired for a couple of seconds. I've had problems like this with my Mustang a couple of times and it was always caused by the TFI module.

Check your fuel pressure first. It should be around 40psi with the vacuum line disconnected. Sometimes when the FPR goes fuel will leak out the top when the vacuum line is pulled off. As far as I can remember it should run at idle with 40psi.

Use a test light or volt meter to test the ignition. Measure the resistance of the coil (specs should be in the Haynes manual), and look for voltage on the coil. I've never seen a really good way to check for spark at the plugs, but you can pull a plug with the wire on it, touch the electrode to a ground, and crank. It should be pretty bright.
 

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Robert,
What is this bone stock stuff under your avatar.

Bronco Info: 87 Eddie Bauer, 302 EFI, AOD, BFG 32", rebuilt top end, bone stock besides that (For Now)

I rememeber a day of wrenching on that beast. I wish I knew more about the 80's models. I would check the fuel pressure as stated above. How is the fuel pump? Usually they are a go/no go. Do they prime like the later models?

How old is the gas in the tank?? Not that it goes bad, but it may be worth trying to siphon or pump it out and get some fresh stuff in there.

When is your dad coming back?
 

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Discussion Starter #15
Ryan87LX

I will check the fuel pressure today or whenever I have time. Thanks for telling me that it might be the TFI module. I will also check the coil. Thanks for the advice.

Tony R

What it means by bone stock is that the engine is the original engine, except for the rebuilt top end, same tranny, same seats, same axles. That info is kinda old, I put a K&N filter on, and a 6" lift. I think thats about it. The fuel pump does prime, I hear it when I turn the key to on. The gas if I remember correctly is probably 4 or 5, maybe 6 months old. I will try to siphon the fuel and put some new gas in. Your right, it wont hurt to put some in. My dad is getting here probably Thursday night, definitely Friday afternoon.

Will keep you updated
Chemkid
 

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yo
Fuel Pressure Regulator (FPR) Test; altho there was no gas in it; was there an odor?

"...Pull the red vacuum line & check for gasoline...There shouldn't even be the ODOR of gas in it."
Source: by Steve83 (Steve, That dirty old truck) at FSB

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23 KOEO TPS out of range
Bad TPS, throttle body base idle mis-set (has anyone touched that screw?..hope not.), dirty/sticking TB, no dynamic response
Check for testing in my site @ http://www.broncolinks.com/index.php?index=137

31
EVP - EVP signal is/was out of range = EGR is sticking or EVP is bad. EVP sensor indicates EGR is not opening properly
EGR is bad, and/or there is a vacuum leak.
Check for testing on both in my site @ http://www.broncolinks.com/index.php?index=146
 

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Discussion Starter #19
Update

Still no solution:cry

My dad and I replaced the fuel filter and the FPR. Went to go start the truck and it seemed like it wanted to start so we kept the key in the start position for about 2 minutes, just long enough to permanently close the starter solinoid. We replaced that. Still wont start. The engine is getting fuel, I checked it at the fuel rail valve.

My dad and I searched to see if someone had the same problem. It most likely points to be either the fuel pump in the gas tank or something else. We are going to get it checked out at a dealership to have a expert do a diagnois and tell us what the problem is.

Will keep yall updated
Chemkid
 

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Did u address tps as mentioned above? Might need new dizzy.
 
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