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Discussion Starter #1
ok a little background on the bronco. I got her a little over a year ago and when I drove her home she struggled to get above 60, and the rpm range sucked. Something like 1500 - 2800 there was no play. In other words, I was either rolling at 1500 or above 2800, nothing in between. In the following days after I got her home, she got the treatment, plugs, wires, rotor, coil, new headers and a full new exhaust. This fixed alot of the problem I was having. She still struggled a little in the 2200-2800 range but it didnt affect me much at all. Recently I got new edelbrock aluminum heads and put the edelbrock performer upper and lower intakes on it and I noticed a big difference in power both bottom and top end.

So now onto the issue if thats what you want to call it. I went to Mammoth Lakes this weekend, elevation of around 8-9000 ft and up. I made it to the 4000 mark (over about 250 miles) with no problems. Then in a strech of 6-10 miles roughly it goes from 4000 to 9000 feet. And let me tell you she struggled up the hill. She was trying to stay at 1500 rpm, which gets me nowhere going up a hill like that. I would slowly push the pedal to the floor with little to no response, and if I punched it, it would take 4-5 seconds to respond, would jump to 3200+ rpm and only run that for a few seconds and then drop back down to 1500. So as you can see it was very literally an uphill battle, and on top of that she got warm, warmer than I wanted her too but still not too bad. :cry

So, I guess overall my question/s are as follows. Anyone else have this problem, or fixed it? How? Where should I start? Am I doomed with this til replacement of the motor? (Which I believe this motor has maybe 100k, if not less)

Thanks for the help guys. If you have questions ask, I will try to respond in a timely manner
 

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About the only thing left is fuel or compression. I think Harbor Freight has tools for measuring both of those.
 

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Air gets perty-thin up around 5000 feet. I doubt that your engine and computer are calibrated for the loss of air pressure. At that altitude ya don't have a lot of cylinder vacume going on either.....kinda makes a 351 motor act more like a 300 motor. Plus....9000 feet is a steep climb for a 5000# truck, especialy with the mods you made which undoubtably pushed your torque curve higher-up in the RPM scale.

I aint saying that there's not something you can do to help. Just saying not to expect miracles once you get a mile up.

DGW
 

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aka: kemicalburns
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What gears are you running? is see in your sig you have 35" tires on there. should run 4.56 min and 4.88's if you want real performance. you wont see any change in performance until this is addressed unless of course you install a KenneBell SC on there.
 

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OK, you've had this BKO for over a year with "power problems" and you haven't attempted to read a Haynes Manual or "pull codes" (www.fordfuelinjection.com) from the vehicle computer to give you an idea of what's going on and maybe how to diagnose it...?

Knowing this why would you push the vehicle to the point where you might due serious damage to the engine AND transmission.....$$$$$$$. :barf

Spend some time using the "SEARCH" and www.broncolinks.co to find other threads with similar issues and possible answers.
These fuel injected vehicles if ignored can develope a number of problems related to either sensors or emissions systems....a vacuum leak "anywhere" can cause a lack of power, a failing ignition module and old ignition components or low fuel pressure with bad/dirty fuel filter/s can also make for poor performance.....:banghead

Add a wet/dry compression test to your list if nothing pans out with fault codes in the computer or tune up upgrade..

Create a basic regular service maintenance to "do check list" with your BKO so you know exactly where the BKO performance is based on what you've done at regular intervals. Take of it and it will take care of you, otherwise your just stumbling around in the dark....:rofl:

Good Luck ~ :thumbup
 

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Discussion Starter #7
Air gets perty-thin up around 5000 feet. I doubt that your engine and computer are calibrated for the loss of air pressure. At that altitude ya don't have a lot of cylinder vacume going on either.....kinda makes a 351 motor act more like a 300 motor. Plus....9000 feet is a steep climb for a 5000# truck, especialy with the mods you made which undoubtably pushed your torque curve higher-up in the RPM scale.

I aint saying that there's not something you can do to help. Just saying not to expect miracles once you get a mile up.

DGW

Ya, I kinda figured as much with some of that but thought maybe there was some other trick.

What gears are you running? is see in your sig you have 35" tires on there. should run 4.56 min and 4.88's if you want real performance. you wont see any change in performance until this is addressed unless of course you install a KenneBell SC on there.
Actually right now I am at the stock gears, because I have finished the 9 inch yet, but I am still running 410s out of the 9 inch and soon to be dana 50 front stub. I looked into the gears and the 410s seemed to suit pretty well for what I am doing


OK, you've had this BKO for over a year with "power problems" and you haven't attempted to read a Haynes Manual or "pull codes" (www.fordfuelinjection.com) from the vehicle computer to give you an idea of what's going on and maybe how to diagnose it...?

Knowing this why would you push the vehicle to the point where you might due serious damage to the engine AND transmission.....$$$$$$$. :barf

Spend some time using the "SEARCH" and www.broncolinks.co to find other threads with similar issues and possible answers.
These fuel injected vehicles if ignored can develope a number of problems related to either sensors or emissions systems....a vacuum leak "anywhere" can cause a lack of power, a failing ignition module and old ignition components or low fuel pressure with bad/dirty fuel filter/s can also make for poor performance.....:banghead

Add a wet/dry compression test to your list if nothing pans out with fault codes in the computer or tune up upgrade..

Create a basic regular service maintenance to "do check list" with your BKO so you know exactly where the BKO performance is based on what you've done at regular intervals. Take of it and it will take care of you, otherwise your just stumbling around in the dark....:rofl:

Good Luck ~ :thumbup
Sorry I forgot to mention that I did have (but no longer have) vacuum leaks. All those little BS issues were fixed before this trip, the engine does not throw codes and yes I checked. The filters are all changed, clean and good. I have not checked fuel pressure because on lower altitiude and all that I have not had problems. I have done plenty of searching around and research and wasnt finding much so I chose this route. I maintain my vehicle very well, and before I did this 1000 mile trek I redid lots of stuff and checked everything needed to be sure that the trip was gonna be safe. I have not had this particular problem at any altitude so I wasnt worried about it.
 

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FSB's Dirty Jersian
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as far as the rpm lagging to 3500 then dropping back down, sounds like my truck when i had the timing issue and it jumped a couple of degrees (though not at 3500 rpms). as for running crappy in high elevation, i was up in the mountains at probably about 6-7000 ft and my truck sounded like a diesel and ran like shit. its just part of high elevation.

and 4.10's will suffice. 4.56's are what i plan on running. they are closest to stock.
 

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Discussion Starter #9
as far as the rpm lagging to 3500 then dropping back down, sounds like my truck when i had the timing issue and it jumped a couple of degrees (though not at 3500 rpms). as for running crappy in high elevation, i was up in the mountains at probably about 6-7000 ft and my truck sounded like a diesel and ran like shit. its just part of high elevation.

and 4.10's will suffice. 4.56's are what i plan on running. they are closest to stock.
Oh another thing, once I got up the hill and ran around the town at around 9000 feet I had NO issues whatsoever. It ran great, accelerated pretty good. And of course going down hill and back to the house it was fine too.

Oh and as for the gearing, it may change later but the 9 inch I found and bought already had a detroit and 410s, and courtesy of redneck renegade I will have the 50 stub, already geared to the 410s, as well this weekend
 

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Sounds good Brother, what shape is the "transmission/torque converter" in and when was the most recent filter and fluid change including the TC...........?

Definately test/replace the FPR, how many fuel filters does your 92 BKO have, mine has 2 with one up forward of the fuel pump on the frame rail and the other "reservoir" with filter is under the transfer case skid plate on the frame rail...PITA location.....lol lol....so for me if the pressure valve in the reservoir is fubar the fuel won't flow beyond that point....:rofl:..not sure you have one of these..

Any trouble with the rear brakes binding or adjustment problems etc....?

Distributor ........?

Keep us posted, I'm curious to know what this could be...

Good Luck ~ :thumbup
 

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Discussion Starter #11
Sounds good Brother, what shape is the "transmission/torque converter" in and when was the most recent filter and fluid change including the TC...........?

Definately test/replace the FPR, how many fuel filters does your 92 BKO have, mine has 2 with one up forward of the fuel pump on the frame rail and the other "reservoir" with filter is under the transfer case skid plate on the frame rail...PITA location.....lol lol....so for me if the pressure valve in the reservoir is fubar the fuel won't flow beyond that point....:rofl:..not sure you have one of these..

Any trouble with the rear brakes binding or adjustment problems etc....?

Distributor ........?

Keep us posted, I'm curious to know what this could be...

Good Luck ~ :thumbup
FPR??? Im sure I know what it is but am drawing a blank, and if I dont know what it is then I have learned something new today :thumbup EDIT: Fuel Pressure regulator hahaha I havent checked it but will do so.

I only have one filter as far as I know. I did replace it too. I searched before replacing it and all the results showed just one. I hope thats all is on there haha

As for the Tranny and filter they were not changed long ago. Maybe 8 months or so, but the truck hasnt been run too much in that time either. When I pulled the tranny pan the magnet did have some shavings on it but I have the tranny guys look at it and they said it was normal. The TC on the other hand could be an issue, but I havent had it checked so I dunno. But also havent had any problems so i wasnt thinking in that range

I dont have any problems with the rear brakes binding or anything but on occasion I do show a brake light along with rear abs light, it only seems to happen with hard braking or alot of braking in a short distance. but that is another deal for later, since the rear end is gonna be replaced. The dizzy was just checked, but not replaced seemed like it was in good shape and my mechanic agreed.

I mentioned it in another of the posts but once I was up the hill and back to somewhat level area (not so much uphill) she ran fine. So I was maybe thinking the sudden alt change in a hurry the computer may not have caught up but once I was up there it did and it ran fine. Who knows.

Thanks again for the input
 

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aka: kemicalburns
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how does the tranny talk to the computer since you removed the 8.8?

4.10s is bare minimum for 33's let alone 35's. I run the 4.88s and find it to be great around town and even better on the hwy. the e4od doesnt hunt and i can still drive 70mph at 2400rpms. Towing is even better.
 

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Discussion Starter #13
I havent replaced the 8.8 yet. Was that a question asking literally how does it talk, or more like its not gonna talk. I guess thats the easiest way to ask you haha
 

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last time fuel filter was changed?
 

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aka: kemicalburns
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do you have the e4od? if so you cant run that 9" rear end with out a vss relocation kit which i believe runs around $300+. the e4od needs the signal from the rear diff to shift properly and for your speedo to work.
 

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Discussion Starter #16
last time fuel filter was changed?
Under 10,000 miles ago

do you have the e4od? if so you cant run that 9" rear end with out a vss relocation kit which i believe runs around $300+. the e4od needs the signal from the rear diff to shift properly and for your speedo to work.
i DO NOT have the 9 inch installed yet. I am still doing the research on parts and whatnot so it hasnt been installed, and therefore cannot be causing problems at this point
 

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Let us know what your FPR PSI is.......lol lol....PSI = pounds per square inch......


Good Luck ~ :thumbup
 

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FSB's Dirty Jersian
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some guy had the same problem with going uphill and all he replaced his dizzy and cap and it solved it the problem
 

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It's a possibility but he indicated there were no "fault codes" generated and I would have to believe if the dissy was having an issue it would have kicked out a code from either the ignition module, PIP sensor or even IDM resistor....

I had a similar problem some time back where I had loss of power, bucking/shuddering going uphill and stop and go traffic until the rpms came up. It turned out to be a check valve had rusted and burned thru from moisture over time, the valve sits on top of a exhaust cross over tube bolted to the back of the cylinder heads causing a vacuum leak like it was missing...this is part of the emissions, Thermactor Air System and a real PITA location....check valve cost $20.00.....

I'm sure he'll figure it .....

Good Luck ~ :thumbup
 

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Discussion Starter #20
THanks for all the help guys, Ive got a few things to try today, I was also told to check the TPS to see if maybe it had a slight malfunction. I will report back as soon as I know anything. Thanks again
:beer
 
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