Thrashingrage
New Member
- Joined
- Aug 3, 2012
- Messages
- 30
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- 0
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- Vehicle Year
- 1990
- Make / Model
- Ford
- Transmission
- Manual
Hey folks,
Just cruised around the Corral and Ranger Station some and saw some of the info under the 2.9 Engine. I figure now is as good a time as any to ask some questions about some 'problems' that I've been having as well as ask for advice on a few other things.
First of all, I have a 1990 Bronco II with the 2.9 engine, Mitsubishi FM 146 manual transmission, and stock axles (guessing 7.5" rear and Dana 28 front). Just about every other major system, excluding the air intake (more on that in a minute) is stock in this truck. I bought this vehicle from my best friend's cousin back in June. As far as I know, it could have anywhere from 175,000 to 300,000 miles on it. It starts every time and runs like a champ. Before I bought it, me and a friend checked the compression and all of the cylinders tested somewhere in the 150 PSI range. I have spent the past two months thoroughly cleaning the interior, performing long-neglected routine maintenance, and otherwise undoing the half-assery that the previous owners foisted off on this Little Bronco. Speaking of them, the first (as far as I know - I'm at least the 3rd) guy supposedly had the transmission rebuilt around a decade ago, for what it's worth. Anyhow, I've replaced the brake master cylinder, PCV valve, valve cover gaskets, ignition wires and spark plugs (the old ones were about a year or two old and all had nice even, clean burns on them), and a whole slew of other little things. I have drained and refilled the rear differential and transfer case, as well as used a suction gun to get all the old gear oil and dirt out of the front differential. I'm planning to drain and refill the transmission as soon as I can get a new seal for the oil pan. I had the local Ford dealer re-do the alignment and put some camber bushings on, as well as adjust the rear brakes. The A/C was also recently converted over to R-134. I also had a local gearhead put new pads, rotors, and calipers on the front brakes, as well as lube the spindles and repack the wheel bearings. Just yesterday, me and my dad rotated the tires and repacked the lock-out hubs (they are stock, which some have told me is rare for the Bronco II).
Anyhow, I have several concerns. The most significant is that my acceleration, particularly at high speeds, seems to be minimal. Getting up to 65 or even 55 when pulling out on the highway is slow at best (Granted, it is entirely possible that this has to do more with the gear ratio than performance issues. I have only owned the truck for a few months and just may not be used to it yet, especially since I did not previously have a truck or SUV as a daily driver). To boot, I have been getting what I think are small backfires at high speeds. These seem to happen only when I either accelerate hard or suddenly decelerate, and do not happen very frequently. They may not be backfires, but the noise that I hear sounds about equivalent to hitting a steel gas tank with a rubber mallet. It is highly likely that they have something to do with the truck's air intake. Back to the previous owner. He installed a Weapon-R cold air intake on the truck and jury-rigged the thing to the max. It clamps on the throttle body from a cut piece of the stock air-cleaner-to-throttle-body hose and comes out about right next to the relay box on the passenger side. Now, this would be fine, except for two things. First of all, he cut off the exhaust pipe right behind the catalytic converter. Though it may have made the truck sound 'cool', it sure as hell didn't help it run cool. To that end, I had a local muffler shop put a Flowmaster on and run a single 2 1/2" pipe out of the back. The second, and potentially bigger issue, is that the guy left the bottom part of the stock air cleaner attached, along with the vacuum hoses to/from it and the intake (or maybe it's an outlet, I'm honestly not sure) to/from the exhaust manifold. In other words, the bottom half of the air cleaner is in there along with with the gaping port that runs to the RH exhaust manifold and connects to the radiator core support. Based on my as-of-now-incomplete understanding, this apparatus may have something to do with the thermactor. If so, I am wondering if it is possible/likely that the backfires are resulting from a lack of air entering the exhaust manifold or possibly a bad thermactor bypass valve or check valve. Now, I also read something in the Library about installing a K&N filter directly to the throttle body. According to that, you are supposed to disconnect the vacuum hose from the exhaust manifold hot air hose and plug the vacuum hose at the engine. As far as I can tell, that vacuum hose runs directly from the baffle/core support intake and attaches to a port on the Weapon-R intake. thus, disconnecting it may not do anything except necessitate another plug for the intake. On that note, I have ordered a K&N Apollo intake to replace the jury-rigged setup that is in there and at the same time rout the intake to a better location, hopefully by the radiator so it can get some more air. When/if I do this, I will need to find a way to fix the issue with the exhaust manifold air hose, etc. and hopefully solve my backfire issue. The other possibility on this one is a vacuum leak. The jury-rigged intake may have one somewhere, especially considering that the vacuum hose to the exhaust manifold isn't plugged. I plan to check for vacuum leaks today for good measure. Any input from you guys with more experience is greatly appreciated on this one. A final note on this: it is entirely possible that the slow acceleration has to do more with the gear ratio than performance issues. I have only owned the truck for a few months and just may not be used to it yet, especially since I did not previously have a truck or SUV as a daily driver. However, it seems more likely that it is a performance issue, especially coupled with the backfires.
You guys are probably rolling your eyes by now, but my next question has to do with timing. Just the other day, I checked the timing in hopes that it could be the cause of my backfires and acceleration issue. I disconnected the spout connector and hooked the light up to the #1 plug and it read exactly 10 degrees below TDC. Based on my situation, I am wondering if I would benefit from the timing change listed in the Library, which is 12 degrees below TDC if I'm not mistaken. If I were to advance the timing by two degrees and run premium, would I risk destroying my stock valves? I am hoping that if I did do this it would either compensate for my current lack of acceleration if not add some performance once I get the other issues resolved.
Finally, it is worth noting that I have to make a 700-mile round-trip to New Mexico in about 20 days. I would truly like to take the Little Bronco for a long spin and am hoping to get at least a few of these problems, especially the ones that are going to trim my mileage and acceleration, licked before then. again, a hearty thanks in advance to any of you who have read this entire post, much less feel like tackling some of these things.
Thanks again and happy driving,
Josh
Just cruised around the Corral and Ranger Station some and saw some of the info under the 2.9 Engine. I figure now is as good a time as any to ask some questions about some 'problems' that I've been having as well as ask for advice on a few other things.
First of all, I have a 1990 Bronco II with the 2.9 engine, Mitsubishi FM 146 manual transmission, and stock axles (guessing 7.5" rear and Dana 28 front). Just about every other major system, excluding the air intake (more on that in a minute) is stock in this truck. I bought this vehicle from my best friend's cousin back in June. As far as I know, it could have anywhere from 175,000 to 300,000 miles on it. It starts every time and runs like a champ. Before I bought it, me and a friend checked the compression and all of the cylinders tested somewhere in the 150 PSI range. I have spent the past two months thoroughly cleaning the interior, performing long-neglected routine maintenance, and otherwise undoing the half-assery that the previous owners foisted off on this Little Bronco. Speaking of them, the first (as far as I know - I'm at least the 3rd) guy supposedly had the transmission rebuilt around a decade ago, for what it's worth. Anyhow, I've replaced the brake master cylinder, PCV valve, valve cover gaskets, ignition wires and spark plugs (the old ones were about a year or two old and all had nice even, clean burns on them), and a whole slew of other little things. I have drained and refilled the rear differential and transfer case, as well as used a suction gun to get all the old gear oil and dirt out of the front differential. I'm planning to drain and refill the transmission as soon as I can get a new seal for the oil pan. I had the local Ford dealer re-do the alignment and put some camber bushings on, as well as adjust the rear brakes. The A/C was also recently converted over to R-134. I also had a local gearhead put new pads, rotors, and calipers on the front brakes, as well as lube the spindles and repack the wheel bearings. Just yesterday, me and my dad rotated the tires and repacked the lock-out hubs (they are stock, which some have told me is rare for the Bronco II).
Anyhow, I have several concerns. The most significant is that my acceleration, particularly at high speeds, seems to be minimal. Getting up to 65 or even 55 when pulling out on the highway is slow at best (Granted, it is entirely possible that this has to do more with the gear ratio than performance issues. I have only owned the truck for a few months and just may not be used to it yet, especially since I did not previously have a truck or SUV as a daily driver). To boot, I have been getting what I think are small backfires at high speeds. These seem to happen only when I either accelerate hard or suddenly decelerate, and do not happen very frequently. They may not be backfires, but the noise that I hear sounds about equivalent to hitting a steel gas tank with a rubber mallet. It is highly likely that they have something to do with the truck's air intake. Back to the previous owner. He installed a Weapon-R cold air intake on the truck and jury-rigged the thing to the max. It clamps on the throttle body from a cut piece of the stock air-cleaner-to-throttle-body hose and comes out about right next to the relay box on the passenger side. Now, this would be fine, except for two things. First of all, he cut off the exhaust pipe right behind the catalytic converter. Though it may have made the truck sound 'cool', it sure as hell didn't help it run cool. To that end, I had a local muffler shop put a Flowmaster on and run a single 2 1/2" pipe out of the back. The second, and potentially bigger issue, is that the guy left the bottom part of the stock air cleaner attached, along with the vacuum hoses to/from it and the intake (or maybe it's an outlet, I'm honestly not sure) to/from the exhaust manifold. In other words, the bottom half of the air cleaner is in there along with with the gaping port that runs to the RH exhaust manifold and connects to the radiator core support. Based on my as-of-now-incomplete understanding, this apparatus may have something to do with the thermactor. If so, I am wondering if it is possible/likely that the backfires are resulting from a lack of air entering the exhaust manifold or possibly a bad thermactor bypass valve or check valve. Now, I also read something in the Library about installing a K&N filter directly to the throttle body. According to that, you are supposed to disconnect the vacuum hose from the exhaust manifold hot air hose and plug the vacuum hose at the engine. As far as I can tell, that vacuum hose runs directly from the baffle/core support intake and attaches to a port on the Weapon-R intake. thus, disconnecting it may not do anything except necessitate another plug for the intake. On that note, I have ordered a K&N Apollo intake to replace the jury-rigged setup that is in there and at the same time rout the intake to a better location, hopefully by the radiator so it can get some more air. When/if I do this, I will need to find a way to fix the issue with the exhaust manifold air hose, etc. and hopefully solve my backfire issue. The other possibility on this one is a vacuum leak. The jury-rigged intake may have one somewhere, especially considering that the vacuum hose to the exhaust manifold isn't plugged. I plan to check for vacuum leaks today for good measure. Any input from you guys with more experience is greatly appreciated on this one. A final note on this: it is entirely possible that the slow acceleration has to do more with the gear ratio than performance issues. I have only owned the truck for a few months and just may not be used to it yet, especially since I did not previously have a truck or SUV as a daily driver. However, it seems more likely that it is a performance issue, especially coupled with the backfires.
You guys are probably rolling your eyes by now, but my next question has to do with timing. Just the other day, I checked the timing in hopes that it could be the cause of my backfires and acceleration issue. I disconnected the spout connector and hooked the light up to the #1 plug and it read exactly 10 degrees below TDC. Based on my situation, I am wondering if I would benefit from the timing change listed in the Library, which is 12 degrees below TDC if I'm not mistaken. If I were to advance the timing by two degrees and run premium, would I risk destroying my stock valves? I am hoping that if I did do this it would either compensate for my current lack of acceleration if not add some performance once I get the other issues resolved.
Finally, it is worth noting that I have to make a 700-mile round-trip to New Mexico in about 20 days. I would truly like to take the Little Bronco for a long spin and am hoping to get at least a few of these problems, especially the ones that are going to trim my mileage and acceleration, licked before then. again, a hearty thanks in advance to any of you who have read this entire post, much less feel like tackling some of these things.
Thanks again and happy driving,
Josh