Mystery Banging from Drivetrain? HELP! - Defender Source
Defender Source  

Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions


Reply
 
Thread Tools
  #1  
Old November 25th, 2008, 07:38 AM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Mystery Banging from Drivetrain? HELP!

I've checked other posts, but was unable to find anything exactly like this problem.

I was driving back home a few days ago at 55 mph to 65mph. After about an hour of driving a very odd issue started. The accelator pedel would be depressed but a surge or a small bang that would jolt the entire vehicle would happen for about 1 second, flicker the check engine light and would continue about 3-4 times and stop. It happens randomly and about 2-4 times and then stops for about 5 miles. When it happens, the rpms do not surge, they hold constant. At one point it would only allow me to travel 35 mph. The OBD showed a 03 code. Any ideas what that is?? It was almost like the tranmission wasn't hitting top gear for some reason, and then it would slowly climb back up to speed. Also, it only does this when I have been driving for more than 30 minutes. It doesn't sound like it's coming from the engine, but seems like the source is more from the transmission. It's strange cause the engine doesn't lose power, but power surges from the wheels.

Now a brief history. A 95 with a 97 auto transmission/t-case. The alternator has just been reworked in the past 3 weeks and the batteries are in decent condition. Also, when I start it up, the battery light stays on for about 3-5 minutes and the tach takes about the same time to start up as well.

Any ideas??? All helps is greatly appreciated.

Thanks,
Wes
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old November 25th, 2008, 08:14 AM
steinhnj's Avatar
steinhnj
Status: Offline
Neil Steinhagen
1990 Perentie GS
Member
 
Join Date: Apr 2006
Location: Periscope Depth
Posts: 759
Wes, I know this is low hanging fruit that you've probably already checked, but verify that your battery connections are clean and tight and as well as the connections to your alternator. If you had a shop do the alternator work, they most likely disconnected all of this and may have been hasty in reconnecting them.

Does it only occur when your trying to accelerate or are you just trying to hold a constant speed?

How does it run at idle?

How long since your fuel filter was replaced?

Just trying to rule out the engine completely, but it sounds like it's a battery/alternator issue. RPMs come off the alternator, and the fact that your RPMs don't respond right away sounds fishy. Have your RPMs always been slow to respond, or only since the alternator work? Same question about the battery light.
Reply With Quote
  #3  
Old November 25th, 2008, 09:02 AM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Thanks for the response Neil. All battery connections are in good condition and at the alternator.

It seems to occur completely randomly regardless of the acceleration/constant speed. But when it does happen, the vehicle declerates until the truck decides to return power to the wheels. The engine does not surge or anything. It seems to run flawlessly.

When at idle, it runs like a big block Chevy...the hood shakes with the engine, but you might say that it's 'supped up' by West Coast British a few years back. It sound good for a 3.9.

I'm not sure how long it's been since the fuel filter has been checked. I'll check on it.

I sent the alternator to a shop in Birmingham to have it reworked. It was previously only pumping out about 10 volts. I'll check what it's doing now. The RPMs respond quickly to the downshifting of the transmission, but it is odd that they do not seem to be affected by this. Of course when it does bang, I let off the pedal and about a second later you can feel the truck jolt when the power is restored back to the wheels.

The battery light still comes on for a few minutes after a restart even after I put the reworked alternator back in.

Thanks
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old November 25th, 2008, 09:10 AM
flippedrover's Avatar
flippedrover
Status: Offline
Tyler
'94 D-90
Member
 
Join Date: Dec 2003
Location: Ashburn,va
Posts: 3,125
Stepper motor probably needs a good cleaning.
__________________
Can't you feel 'em circlin' (closin'in) honey?
Can't you feel 'em swimmin' around?
You got fins to the left, fins to the right,
and you're the only bait in town.
You got fins to the left, fins to the right,
and you're the only girl in town.

Jimmy Buffett


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #5  
Old November 25th, 2008, 09:23 AM
steinhnj's Avatar
steinhnj
Status: Offline
Neil Steinhagen
1990 Perentie GS
Member
 
Join Date: Apr 2006
Location: Periscope Depth
Posts: 759
You said "batteries". Do you use an isolator or are they wired straight parallel? You could try to run just one battery and see if that changes anything. Bad isolator maybe?

I have an alternator for a '95 that has a squeky bearing. I replaced the alt and was going to see if a shop could just replace the bearing so that I'd have a bench spare. I could send it to you for the cost of shipping if it would help you troubleshoot. The unfortunate part is that I'm in CT and the part is in VA. Earliest I could send it would be Monday. If it ends up being the problem, just keep it until you get a replacement.

Concerning the "banging", are you sure this is just not normal driveline clunk? I've heard that the auto trans smooths things out a bit, but there is still a lot of play in the driveline. Whenever you take power away and it returns suddenly, could this be your bang? Did you own the truck when it had a manual trans?

So it sounds like it's either a problem with your transmission or an electrical problem. Or I'm clueless. I'm sure I'll get some agreements on the last part.
Reply With Quote
  #6  
Old November 25th, 2008, 09:30 AM
MonLand
Status: Offline
Loic Fabro
95 D90 - 96 Disco -06 LR3
Member
 
Join Date: Oct 2003
Location: Herndon, VA - USA
Posts: 1,642
Registry
Quote:
Originally Posted by midturtle
Also, when I start it up, the battery light stays on for about 3-5 minutes and the tach takes about the same time to start up as well.
Don't know if that would create any of the issues you described, but there is definitely something wrong with the alternator. It should not take any time for it to start charging / generating the signal for the tach. Could be simply a bad connection or could be bad components in it (either dead or on its way out already). Might also be a belt not at the proper tension?
__________________
Quote:
I have an ex MoD and an ex wife. The two no longer conflict with each other.
Quote:
it is not hoarding it is selective collecting
---
MonLand
1995 D90 NAS
1996 Discovery NAS
2006 LR3 NAS (hers, but comfy! :) )
Reply With Quote
  #7  
Old November 25th, 2008, 05:58 PM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Well who would have thought that a reworked alternator would have taken a crap on me as fast as it did?? Should have expected it.


Neil, I appreciate the offer for borrowing the alternator, but I think I might have almost have my hands on a new one. Hopefully this will end the troubles. Thanks for you help and I'll post back once I've got it installed.

Wes
Reply With Quote
  #8  
Old November 25th, 2008, 07:15 PM
evilfij's Avatar
evilfij
Status: Offline
evilfij
I have never seen a rover in person
Member
 
Join Date: Oct 2003
Location: on the internet
Posts: 14,688
Replace alternator with a new (not reman) bosch or MM model.
__________________
*not legal advice*
Reply With Quote
  #9  
Old November 26th, 2008, 12:46 PM
agavelvr

Guest
 
Posts: n/a
If your oil light is staying on and the tach is not reporting correctly, I would check the alternator and related wiring. The alternator sends RPMs to the tach and the oil light stays illuminated until the alternator puts out more juice than the battery. A passenger side exhaust leak where the manifold connects to the down pipe can cook your starter electronics & wiring really good too.
Reply With Quote
  #10  
Old December 12th, 2008, 04:27 PM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Well, the issue has been fixed. I put in a new alternator and realized that the current wasn't getting past my isolator, so I put in a new isolator as well. The battery is now getting the charge it deserves and all related dash lights have not decided to flash (knock on wood). This should take care of the my electrical issues. Thanks for all the help
Wes
Reply With Quote
  #11  
Old February 12th, 2009, 11:49 AM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Well, I guess I may have spoken too soon. The banging has subsided. The idle on the vehicle fluctuates going from about 300 to 1000, and this morning was the first time it died on me while at a stop light since the previous issue. What is the normal idle? When I start the fuel pump comes on, so maybe the fuel filter is the culprit? I should get a chance this weekend to check the wiring to make sure nothing is corroded. Can someone tell me the location of the fuel pump? Any suggestions on what could be causing this? Thanks.
Reply With Quote
  #12  
Old February 12th, 2009, 12:40 PM
MonLand
Status: Offline
Loic Fabro
95 D90 - 96 Disco -06 LR3
Member
 
Join Date: Oct 2003
Location: Herndon, VA - USA
Posts: 1,642
Registry
Somewhere between 700 and 800 rpm? That's from memory. But definitely not from 300 to 1000. Something is wrong and the ECU is trying to compensate the problem (which creates that fluctuation).
Is that fluctuation happening when the engine is cold or at operating temp or all the time?
Fuel pump is in the fuel tank.

Follow-up Post:

Quote:
Originally Posted by midturtle
The OBD showed a 03 code. Any ideas what that is??
BTW, that code is not listed on http://www.fourfold.org/LR_FAQ/Defen...ult.Codes.html which is a little weird. Can't take a look at the WSM right now, but if someone does, might be worth checking.
__________________
Quote:
I have an ex MoD and an ex wife. The two no longer conflict with each other.
Quote:
it is not hoarding it is selective collecting
---
MonLand
1995 D90 NAS
1996 Discovery NAS
2006 LR3 NAS (hers, but comfy! :) )
Reply With Quote
  #13  
Old February 12th, 2009, 02:35 PM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
The rpm fluctation happens only when it's at idle. Earlier I was parking, put it in reverse, and it died...wouldn't start up. Came back in about 30 minutes, started up just fine. You think maybe any loose connections from the mass-air sensors could be a culprit.

I've found this thread and Kris was/is have the exact same issue that I'm having (well almost, I have an AT). There are some insightful suggestions that I need to explore.

http://www.defendersource.com/forum/...ht=fuel+filter
Reply With Quote
  #14  
Old February 12th, 2009, 04:04 PM
MonLand
Status: Offline
Loic Fabro
95 D90 - 96 Disco -06 LR3
Member
 
Join Date: Oct 2003
Location: Herndon, VA - USA
Posts: 1,642
Registry
Make sure your air pipe/tube (whatever the correct name is) is well in place and not cracked. If the air flow sensor is not measuring the amount of air actually getting into your engine, this can create large amount of problems.
Now, if could also be fuel (fuel pump or fuel filter).
Since I only have manual transmissions, I can't start talking about the AT stuff, but IIRC, there is also a sensor (multiple sensors?) that the ECU uses as well. You already checked the road speed sensor, right (could explain the up and down _if_ it's putting out signal when you are not actually moving, but that's a strech in my mind since they typically fail by not outputting anything instead)?
__________________
Quote:
I have an ex MoD and an ex wife. The two no longer conflict with each other.
Quote:
it is not hoarding it is selective collecting
---
MonLand
1995 D90 NAS
1996 Discovery NAS
2006 LR3 NAS (hers, but comfy! :) )
Reply With Quote
  #15  
Old November 9th, 2009, 09:25 AM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Well, I thought I had the problem kicked...until Sat. I was driving down the road at about 60 with the rpms hitting about 2500-3000. I heard a bang, and all the sudden the power to the wheels stopped. The engine was still maintaining the revs, but power wouldn't engage back to the wheels. I pulled to the shoulder and the engine died when the speedo hit about 20. I tried to start it again (about 5 times) and it wouldn't go, and then on the 6th it went, but sputtering. There was the smell of gas. I made it back home, but the trucks rpms were fluctuating from 200 to about 1000 at idle. Any ideas on what could be the root of this issue? It choked out on me again yesterday as I was winching down trees in the backyard, but started right up again without as many tries.

Basically the idle won't maintain a constant 700. When stopping at a light, the revs drop to about 200-300 and then ramp back to 1000 and then down to 700. Is this an issue with the timing?

Thanks in advance for the help.
Reply With Quote
  #16  
Old November 9th, 2009, 11:11 AM
LRover's Avatar
LRover
Status: Offline
J. Michael McCaig
D90 ST, LR110, Series IIa, RRC
Member
 
Join Date: Oct 2003
Location: VA
Posts: 479
From what you are describing it seems to me that the bang you hear is the engine backfiring in the intake manifold. Hard start and erratic idle is often caused by a vacuum leak and the engine ecu tries to compensate and dumps too much gas...then the backfire after it builds up in the manifold. Timing just doesn't change by itself but I would check the vacuum advance. The diaphram could be bad which would throw the timing off and cause a vacuum leak.
Reply With Quote
  #17  
Old November 9th, 2009, 01:16 PM
MonLand
Status: Offline
Loic Fabro
95 D90 - 96 Disco -06 LR3
Member
 
Join Date: Oct 2003
Location: Herndon, VA - USA
Posts: 1,642
Registry
Quote:
Originally Posted by flippedrover
Stepper motor probably needs a good cleaning.
I would either get a new one (temporarily or permanent). If you want to find out if this is a sensor issue, just unplug it (to force the engine in "limp mode") and see if you have the problem again.
But based on what you said so far, I'd think the stepper motor is the problem. My symptoms were the same when the engine was cold, and RPM raised up to 1500 when engine was warm. I'd guess symptoms depends where the stepper motor gets stuck.
__________________
Quote:
I have an ex MoD and an ex wife. The two no longer conflict with each other.
Quote:
it is not hoarding it is selective collecting
---
MonLand
1995 D90 NAS
1996 Discovery NAS
2006 LR3 NAS (hers, but comfy! :) )
Reply With Quote
  #18  
Old November 9th, 2009, 05:49 PM
midturtle's Avatar
midturtle
Status: Offline
Wes
'95 90 SW #234
Member
 
Join Date: Apr 2008
Location: Nashville, TN
Posts: 70
Thanks for the responses.

The banging I'm referring to is more of a mechanical bang from the engine/drivetrain area. I'll have to check on the stepper motor. Could this possibly have something to do with the an air flow sensor?
Reply With Quote
  #19  
Old November 9th, 2009, 06:41 PM
MonLand
Status: Offline
Loic Fabro
95 D90 - 96 Disco -06 LR3
Member
 
Join Date: Oct 2003
Location: Herndon, VA - USA
Posts: 1,642
Registry
Here is what I would do:
- get a new (or borrowed) stepper motor and swap it in (get a Buick replacement part or check the cross ref parts that'd fit)
- if that does not fix it, then unplug it and see if the problem stays
=> if problem does not occur => check what other sensor could be at miss (air flow, etc.)
=> if problem occurs => this is not a sensor plugged on the ECU

Now as others said, if you can reproduce the "clang" by driving at 3000 rpm, release the accelerator and push it again, this is not a "transmission" issue per say.
__________________
Quote:
I have an ex MoD and an ex wife. The two no longer conflict with each other.
Quote:
it is not hoarding it is selective collecting
---
MonLand
1995 D90 NAS
1996 Discovery NAS
2006 LR3 NAS (hers, but comfy! :) )
Reply With Quote
  #20  
Old November 9th, 2009, 06:53 PM
xrover's Avatar
xrover
Status: Offline
Len Cater
1997 D90
Member
 
Join Date: Jul 2008
Location: Brampton, Ontario, Canada
Posts: 103
How about the good old gas cap trick? Mine was doing the same thing with the idle, and after checking everything in the engine, it ended up the gas cap lost it's ability to seal. Easy test, when you open the gas cap, do you get the whoosh of air? I didn't. Replace gas cap. Probably the cheapest thing on the list to try right now.
Can explain the banging though.
__________________
'97 D90 NAS
'06 Argo Avenger
Reply With Quote
Reply

Lower Navigation
Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Griding from drivetrain when i hit the clutch? oldscratchggf Defender Technical Discussions 6 November 29th, 2005 01:59 AM
1990 Range Rover w/37" MTR's and Toy Drivetrain lwg For Sale - Vehicles 0 October 17th, 2005 03:06 PM
109 rolling chassis, drivetrain bulkhead $500 evilfij For Sale - Vehicles 1 June 20th, 2004 07:50 PM
Defender in Paris, and Mystery Guest Doug Misc. Chit-Chat 20 June 18th, 2004 01:52 PM
banging in drivetrain prospector Defender Technical Discussions 8 June 14th, 2004 11:17 PM


All times are GMT -5. The time now is 06:13 AM.


Copyright