Hello-

I've recently come across a problem with my 1996 Disco 1 (195k on the clock) that seems to have appeared out of nowhere. I had my vehicle in to get detailed and the starter died in the shop. I replaced it but after sitting idle for 3-4 days waiting for a starter motor I had to limp it home as it was constantly backfiring and stalling at stop lights. Prior to the starter giving up the ghost I occasionally needed to tap the gas upon cold start first thing in the morning ( it's winter in Colorado and mornings have been below freezing lately). Anyway- prior to a new starter motor I put in new plugs/wires from AB and changed the oil (T6 Shell Rotella).

Upon start up the engine will idle normally at around 800 rpms then after a minute the idle starts to fluctuate, engine misfires and white smoke appears out the exhaust - the engine will then run for a few more minutes then stop. I just measured the fuel pressure and it's 31-33 at the rail ( installed a new fuel filter too). I cleaned the air idle control valve and MFS and even swapped the MFS with another one from my other 96D1 (105k). Still the fluctuating idle continues.

I initially thought it could be a vaccum leak but I don't know where to look as all the hoses look good. I had the plenum gasket replaced within the last two months and everything was normal until this week after the starter motor quit.

I have a new copy of the workshop manual from AB and I'm planning on doing my head gaskets and other needed work on my other 96 D1(105k) when time permits but I need to solve my idle issue first on my 96(195k) D1.

I'd appreciate any su​​​​​​​ggestions on where to look next.

Regards

Cmpeng

 

1) I meant to say MAF sensor not MFS in my original post.

2). The 96 D1 with 195k was in a local shop about 2 weeks ago for some suspension work and the tech made note of my cold start issues. His comments are as follows in his vehicle report: " no faults- performed dynamic data and found idle rpm reference at 65280. Reset adaptive's and started vehicle- reference at 951 and IAC at 100. Much too high for both. Performed smoke test and found vaccum leak at fuel pressure regulator. Replaced hose and retested. Rpm ref now at 780 and IAC at 80. Engine performance and starting drastically improved.

I don't know what the reference number 65280 is or what type of scanner I would need to reset adaptives. I just have a $60 scanner from NAPA.

Brian

 

I came across a post that recommend unplugging the IACV and listening if the idle has changed and I did just that. Now I get a steady idle at 900-950 rpms( a little high but rock rock ). When I plug the IACV back in and start her up the idle fluctuates again.

Now what?

Can I reset the IACV without buying a $400 iLand diagnostic tool from AB? They have a video on how to do it via their iLand tool app.

Thanks

Brian
​​

 

The timing of the issue might be correlated with open loop/ closed loop. The ECU will start the truck with a set of 'standard' values for air/fuel mix and then use a different map after warming up.

The white smoke is a concern. Does it smell 'sweet' like coolant?

This could be anything from an IACV issue to a head gasket so you'll likely need to try a couple of things to narrow it down. Start with the cheapest stuff and move up the ladder progressively.

Clean the PVC thingy on the passenger side valve cover. Pull the hose, gently pull the plastic piece out. Be sure not to let it crack into multiple pieces. Clean and replace.

A simple OBD reader will be very helpful.

https://landroverforums.com/forum/di...02/#post581013



and an ECU re-flash might also be one of the earliest steps (no cost).

https://landroverforums.com/forum/di...acement-83233/


after that, if a new IACV is the call...
https://landroverforums.com/forum/di...pensive-81775/

finallly, all the workshop manuals and documentation can be found in the google drive linked in my signature. Help yourself to whatever you like.

 

Almost sounds like mine. Bad gas, bad canister purge valve. It took a lot of purse swinging for me to reach that conclusion. I did replace that IACV with the Jeep equivalent and it seems to work fine. I just drove the truck from central Florida to Ft Campbell Ky. That GEMS reader app worked well for me to reset adaptive values. Like Walt says, check the cheap stuff first.

 

thanks for the replies. Here's an update.

I found a starter from a scrap yard for $35 shipped and the seller had many so I bought 2x for $70- score. Installed one today and it works fine . Prior to starting I had 4x new O2 sensors destined for another D1 but decided to install them on my problem vehicle just to be safe

I changed the oil, reset the ECU by shorting the battery leads and started her up. She ran with a constant 800 rpm idle for 2 minutes so I decide to take her for a drive. She ran fine for a few minutes then started to intermittent my backfire when I gave her some gas. Her idle started to become less constant the longer I drove. I parked her in my driveway and shut her down. Everytime I reset the ECU by shorting the battery leads she runs great for a minute then the idle starts to become unstable. When I unplug the IAC it's rock solid.

I thought resting the ECU resets the adaptives? I have a workshop manual which just states to use Textbook to tune the engine.

I've heard there is an app written by a forum member to do this. I've not tried since I'm not sure what I'd be getting myself into. What hardware is needed to communicate with my GEMS engine? Do I just have to by an wireless OBD 2 donagle and download the GEMS app?.

Thanks for the help.

Brian

 

You need an android device and a elm327 compatible bluetooth reader


https://play.google.com/store/apps/d...ms.gemsutility

there is a lot of chinese junk for sale that claims elm327 compatibility. The $8 one on aliexpress might work, this one is much higher quality and I recommend it

http://www.scantool.net/obdlink-lxbt/


and shorting the battery does nothing to a GEMS truck. The way the relay is designed it disconnects the ecu from the battery about 5 seconds after you turn it off. If you listen close you can hear the click from under the hood. It doesnt use volatile memory for adaptive tuning.

 

Thanks for the quick response. There are many to choose from on Amazon. Does it matter which one?

Brian

 

Thanks

 

no problem

i have used it with the cheap clear blue chinese ones, but they are a gamble and dont work so well on other makes. Something in Acura obd2 port wiring caused it to let the smoke out


the one I recommended has some additional features that the app is designed to use if available (simpler header format on the obd2 packet) so it saves something like 1 second. Kind of useless, but I didn’t discover that it works with the standard format until after I started writing it. Anecdotally the simplified header format is what the td5 speaks so if those folk needed a phone app its the scanner to use