4bangerjp.com
General Forums => The Mess Hall => Topic started by: roksld13 on April 28, 2010, 03:55:31 PM
-
Hi guys i have an issue (or what i think to be an issue) Ive got a 97 2.5l 116000 miles on it, 4.88 gears, banks header, 4.0l tb on 33 bfg's. OK hears the prob, going down the high way through 3rd gears is very slow but not really my prob. When i get to 4th at 3000 rps that's it no more, so i shift and the same thing in 5th. 3000 rps and I'm done it will not go any more and I'm running about 70 mph by then.
The only reason i think this is a bit odd is because when i had my 35's on I don't remember that being a issue.
You think I'm reading into something a little to much or does this sound like something i need to inspect a bit farther?
Also it shakes very bad when and If i do get past 70mph i.e. going down a hill or a good tail wind.
Thanks for the info!
-
Hi guys i have an issue (or what i think to be an issue) Ive got a 97 2.5l 116000 miles on it, 4.88 gears, banks header, 4.0l tb on 33 bfg's. OK hears the prob, going down the high way through 3rd gears is very slow but not really my prob. When i get to 4th at 3000 rps that's it no more, so i shift and the same thing in 5th. 3000 rps and I'm done it will not go any more and I'm running about 70 mph by then.
The only reason i think this is a bit odd is because when i had my 35's on I don't remember that being a issue.
You think I'm reading into something a little to much or does this sound like something i need to inspect a bit farther?
Also it shakes very bad when and If i do get past 70mph i.e. going down a hill or a good tail wind.
Thanks for the info!
i don't think 70mph in 5th is a bad achievement (at 3000rpm). does it go over 3000rpm in 4th or 3rd? - just trying to understand what problem you describe, is it that the engine does not rev over 3000 rpm in any gear or that you can't go more than 70mph in 5th.
-
He has a problem in 3th and 4 th also pretty much will not go over 3000 rpm
-
He has a problem in 3th and 4 th also pretty much will not go over 3000 rpm
maybe lack of fuel in that case (considering that it can rev it fine over 3000 rpm in 1st and 2nd)
-
If your have floor mats or carpet check to make sure that the pedal is not getting caught on anything and won't go any further and stopping the RPM's.
-
If your have floor mats or carpet check to make sure that the pedal is not getting caught on anything and won't go any further and stopping the RPM's.
yeah, never thought of that - on the same lines maybe have someone floor the pedal (with the engine off) and try to open the throttle by hand in the engine bay to see if there's any more travel - could be the cable jacket or plastic holder(s) of the jacket as well.
-
That's strange since you had 35's and went down to 33's. Did you change your speedometer gear so it's not thinking you're going much faster?
-
I can't get mine to register over 70 mph any more without prataclly blowing up the motor, but it's really 15% faster than the reading (80.5 mph) since the speedometer gear is still at stock teeth count. Not having the speedo calibrated also throws the computer out of it's parameters making the air/fuel ratio off as well. (just learned that from Jeffy)
-
Seems to me the drivetrain is slipping.. Do you have an auto? Maybe a slipping clutch?
Or maybe wranglers on 33s shouldn't go 80? You've probably hit the jeep wall I've heard so much about but never even attmpted to reach... I shake at 75 lol
-
Well the big question for starters is will it rev to close to 5 grand in first second and third? if no, start with part 1 if it's a manual get er rollin in first gear then whem it barely rolls stick it in third and floor it, if it does not back fire then the plugs and wires should be ok then it's on to fuel or an exhaust restriction. Thias is the none scientific method, but it gets you pointed in the right direction fairly quick. a fuel supply problem will show mostly in 5 th gear or near the top in 4th it will hold basck at full throttle, but will pick up speed when you ease up on the throttle a little.
-
just occurred to me - could be the catalytic converter too
Seems to me the drivetrain is slipping.. Do you have an auto? Maybe a slipping clutch?
Or maybe wranglers on 33s shouldn't go 80? You've probably hit the jeep wall I've heard so much about but never even attmpted to reach... I shake at 75 lol
if the clutch would be slipping then he would see the rpms going up and the speed not increasing, not the case by what he describes.
-
Well I do have a high flow cat and new cat back on the way, so exhuast retrictions will be fixed if that's it, as for fuel, from what y'all described that may be a good place to start. Should I get a fuel pressure gauge and check it that way?
Jeffy, no I have not changed the speedo gear from factory. I have had a buddy ride next to me and tell me my speed from that but I assume as I go faster the gap from what I see on my speedometer and how fast I am accually going increases. Mabye, it's science!! Lol
bye the way thanks for all the info everyone.
-
Well I do have a high flow cat and new cat back on the way, so exhuast retrictions will be fixed if that's it, as for fuel, from what y'all described that may be a good place to start. Should I get a fuel pressure gauge and check it that way?
Jeffy, no I have not changed the speedo gear from factory. I have had a buddy ride next to me and tell me my speed from that but I assume as I go faster the gap from what I see on my speedometer and how fast I am accually going increases. Mabye, it's science!! Lol
bye the way thanks for all the info everyone.
A fuel gauge would be the ticket to test fuel pressure... As for the speed, change the speedo gear; the ECU uses this input for its calculations, so even if this is not the cause of your problem, you should change it. And the best way to accuratly measure your speed, IMHO, is a GPS; ty borrowing one from a buddy if you dont have one.
Well the big question for starters is will it rev to close to 5 grand in first second and third? if no, start with part 1 if it's a manual get er rollin in first gear then whem it barely rolls stick it in third and floor it, if it does not back fire then the plugs and wires should be ok then it's on to fuel or an exhaust restriction. Thias is the none scientific method, but it gets you pointed in the right direction fairly quick. a fuel supply problem will show mostly in 5 th gear or near the top in 4th it will hold basck at full throttle, but will pick up speed when you ease up on the throttle a little.
I would start here if I were in your position; make sure ignition is not your problem, and if it is not, then move to fuel pressure (wich would be my first guess, but since it is more expensive to test if you dont have a gauge, I would make sure it is not ignition first).
-
Well I do have a high flow cat and new cat back on the way, so exhuast retrictions will be fixed if that's it, as for fuel, from what y'all described that may be a good place to start. Should I get a fuel pressure gauge and check it that way?
Jeffy, no I have not changed the speedo gear from factory. I have had a buddy ride next to me and tell me my speed from that but I assume as I go faster the gap from what I see on my speedometer and how fast I am accually going increases. Mabye, it's science!! Lol
bye the way thanks for all the info everyone.
I would spend the $20 to recalibrate it. Your PCM is cutting back on your air/fuel maps as it thinks you're going faster then what you're actually doing compared to your RPM's. Might not fix the problem completely but it might be contributing a bit.
At minimum you should be using a GPS. Depending on how accurate the other guy's speedo is and how accurate he can read it and any fluctuation you're not getting an accurate reading.
-
Het jeffy, where do I take it to recalibrate it? Like a dealer? Would I still need the speedo gear? And if I fluctuate between 35s and 33s what tooth count would y'all recamenened?
-
Het jeffy, where do I take it to recalibrate it? Like a dealer? Would I still need the speedo gear? And if I fluctuate between 35s and 33s what tooth count would y'all recamenened?
From the FAQ: http://4bangerjp.com/forums/index.php/topic,731.0.html
-
Cool thanks. Ok so 33" is 41 tooth and 35" is 30 tooth. If I go back and forth between the tire sizes which should I go with?
-
If switching between two tire sizes (I do between onroad use and off), I'd highly recommend this $80 speedo signal interface from Dakota Digital: http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm
(http://www.dakotadigital.com/cartimages/prd_zm_126.jpg)
-
Cool thanks. Ok so 33" is 41 tooth and 35" is 30 tooth. If I go back and forth between the tire sizes which should I go with?
you mean 39 teeth for 35'' (i'm guessing it was a typo but just in case)
-
Nice find bounty! I've only seen similar ones for $200+, like Superlifts TruSpeed Speedometer Recalibration device. http://www.quadratec.com/products/16202_000.htm?sgsc=QSHOPGBASE&utm_medium=compshop&utm_source=googlemerchant (http://www.quadratec.com/products/16202_000.htm?sgsc=QSHOPGBASE&utm_medium=compshop&utm_source=googlemerchant)
(http://www.quadratec.com/Assets/Images/24185/24185-md.jpg)
-
There's a little more to the calibration on a Dakota Digital unit, but well worth the $80 and the savings over other products on the market.
-
Well the big question for starters is will it rev to close to 5 grand in first second and third? if no, start with part 1 if it's a manual get er rollin in first gear then whem it barely rolls stick it in third and floor it, if it does not back fire then the plugs and wires should be ok then it's on to fuel or an exhaust restriction. Thias is the none scientific method, but it gets you pointed in the right direction fairly quick. a fuel supply problem will show mostly in 5 th gear or near the top in 4th it will hold basck at full throttle, but will pick up speed when you ease up on the throttle a little.
Art, I've long noticed that my engine seems like it falls off a little in 4th, but especially 5th vs. the lower gears. And It doesn't feel like it's the highway terrain or anything that the engine is fighting. It literally seems like the engine itself is dialing back slightly.
This was happening before I made the change to the Ford injectors and I am pretty sure the Fords I have are 100%. I also change the fuel filter at the recommended intervals. Thinking about what else in the fuel system, if anything, might be causing this.
-
Seems to me a good start would be to make sure that the fuel pressure under full load is up to snuff. Meaning a gauge hooked up so it can be read while driving and then drive it flatout in top gear. A failing or worn pump that does not quite produce adequate volume of fuel is otherwise not that easy to catch
-
x2 I really don't think adjusting the speedo is going to help much (good to do but not to solve this particualr acceleration problem), mine is off a bit and it doesn't cause any acceleration problems.
-
Ok so got my exhuast and everything it good, my next is to go to the fuel managment. I'm going to check into the pressure gauges this weekend. Thanks for the info on the digital meter, that sounds like the way to go, one question is it moderatly easy to hook up? I've been wanting to go with the ford injectors for a while, I read the write up jeffy did, great deal of info. Alittle hard to undestand with all the equations, lol. Anyways that's plus my steering to get working right and I'm going to be broke!!
-
Ok so got my exhuast and everything it good, my next is to go to the fuel managment. I'm going to check into the pressure gauges this weekend. Thanks for the info on the digital meter, that sounds like the way to go, one question is it moderatly easy to hook up? I've been wanting to go with the ford injectors for a while, I read the write up jeffy did, great deal of info. Alittle hard to undestand with all the equations, lol. Anyways that's plus my steering to get working right and I'm going to be broke!!
for the equations: what all that means is that the flow and pressure do not vary on a linear basis and in case you use injectors that have a rated flow at a different fuel pressure than yours you will need to calculate the flow to match with the stock injectors (or go a bit higher but i wouldn't recommend more than 5 to 7% flow increase).
Keep in mind that since you have a TJ the Ford 19# injectors will not work on your vehicle, so unless you find something to match the flow do not attempt. That's where the equations come in, but all you need is to find an online flow calculator if you want to take that route - your fuel pressure is 49psi, you will need the flow and pressure for the new injectors to calculate the resulting flow at 49psi as it is on your Jeep.
-
Seems to me a good start would be to make sure that the fuel pressure under full load is up to snuff. Meaning a gauge hooked up so it can be read while driving and then drive it flatout in top gear. A failing or worn pump that does not quite produce adequate volume of fuel is otherwise not that easy to catch
I'll have to look for one of those gauges with a 6ft hose so I can test/drive at the same time.
-
My probably in 5th gear has been getting worse as now I'm driving mine everyday. I'm going to have to check the cat and the fuel pressure too. I know the speed sensor plays into it, but now mines acting up at lower speeds as it wasn't before. Already did (over the last year and half) air cleaner, o2 sensor, plugs, tps sensor, and had a clean smog test, but 1st gear seems to be almost dieing if I accelerate hard during the hot day. I'll let you know my results. Good luck.
-
What does it feel like when u say "first gear acts up"? Is it like sliping, I know what that would feel like. The reason I ask is I can tell a diffrence in temp the way my jeep performes
-
If I lightly accelerate, it's ok. If I try to go a bit faster (drop the clutch and step on it semi fast) its almost like it looses all power and then slowly surges back.
-
If I lightly accelerate, it's ok. If I try to go a bit faster (drop the clutch and step on it semi fast) its almost like it looses all power and then slowly surges back.
didn't you just replace the tps or was it someone else and i got mixed up?
-
Yes. Only thing left can be fuel or cat. I have to check them. ???
-
Ur 95 has basiclly the same tranny as my 97 right? Assuming it factory and everything. My 97 does something like that, I have to feather the gas plus the clutch let's out way high. I'm not to hot when it comes to transmissions, there a bit frustrating to me
-
Ur 95 has basiclly the same tranny as my 97 right? Assuming it factory and everything. My 97 does something like that, I have to feather the gas plus the clutch let's out way high. I'm not to hot when it comes to transmissions, there a bit frustrating to me
if it's a manual then your tranny has nothing to do with feathering the pedal to get it going. if the clutch is slipping then the rpm would go up and the speed won't increase (or very slightly).
-
Mine is a manual. The tranmission, clutch, other driveline is a non-issue. Strictly power and with a surging either back pressure from the exhaust, not enough air, not enough spark, or not enough fuel could only be causing. Since I've check 2 out of the 4, that only really leaves the two others, and I've sniffed out all the sensor related causes for back pressure, outside of a cat, then its on to fuel. I'll let you know.
It's not my daily driver, and since I'm starting the lemon law on my saturn, (whole other story), I'm driving the jeep a lot to work and noticing the problem that could have been present. Since I've joined this forum, I've only put about 5-6k miles on it.
-
Ok I just thought u were sayn it may be a tranny or clutch prob. My falt, missunderstand. I'd like to know what u turn out because I've got my air flow and exhuast taken care of I'm going to start on fuel next!
-
Cat seems to have been the problem. It looks like the wrong cat was on it (round a narrow with no heat sheild, grrr). Just installed an application specific cat, and it seems better. It's not a rocket, but it doesn't seem to be bogging down as much in 4th or 5th anymore or as I take off at stops. I'll let you know if anything else develops.
I do need to check my fuel pressure, so it's not ruled out. I only tried that cat first, because I ran across deal for an aftermarket exhaust kit that I couldn’t pass up, so threw it on.