Hi all - newish owner of a 97 Disco and have been fixing lots of issues, but this latest one is leaving me stumped and hoping y'all can provide some guidance. I inherited this truck from a friend, and it had been sitting for years. Prior to that it ran great (according to friend) so this is apparently a new issue.

Issue: the truck starts up great, idles fine, but when I attempt to accelerate it sputters and won't exceed 1500 RPMs. After 30-45 mins of slowly driving around a parking lot (or letting it sit in idle) it will gradually start to allow higher RPMs and then eventually it drives great and allows full acceleration. I've read through a number of threads around misfires and potentially ECU, crank sensor position, MAF issues, but none of them really mirror what I'm experiencing. What would you suggest as a likely culprit or plan of attack in diagnosis the issue?

Thanks!!
Mike

 

I had a similar issue on my 97 it turned out to be some of the teeth that the crank position sensor uses were bent. Take off the lower inspection cover that bolts to the transmission flywheel housing rotate the fly wheel manually and make sure that the teeth are all straight and have a gap of a 5mm use a 5mm allen wrench to verify the gap. There is one spot that has more of a gap that is normal as that is used by the crank position sensor and keeps track where it is.

 

A faulty crank sensor (or bent teeth) most likely would not resolve themselves after 30 mins. So I have my doubts.

If the truck has been sitting I would start with fresh gas.

 

I had a similar issue. it turned out to be a head gasket unfortunately. I checked injectors, ECU (swapped another in), Fuel pump relay, new CKPS, reluctor ring teeth, did a seafoam, and a bunch of other stuff. Probably with sitting so long id do a seafoam, and fresh gas

 

Yes check for bad gas. I went through all sorts of grief getting mine to run before I ended up siphoning out the tank and replacing the fuel. Seems fine now. I think mine sat for a while, plus I found there was no gasket where the fuel pump housing sits it the tank. I filled it up when I bought it back in October, and drove it home, but it wasn't long before it started acting up. Don't know if the gas that was in there was bad or I bought it from the gas station bad, but once I got it all out, it ran so much better. Still have some issues ( evap system not working properly, Panhard bar bushings shot from leaking PS fluid), but at least now I can hop in, start it, drive it to the store for some beers before I sit and ponder what will happen next. Check your oil too. I had a lot of unburnt fuel in my oil pan from the engine not burning it. One thing wrong seems to start a domino effect if not dealt with in a timely manner. Good luck.

 

thanks all. It has fresh gas and a recent oil change. i could try the seafoam...in the tank or through air intake? i wouldn't think bent CPS teeth or head gasket as root cause since it eventually resolves itself...but maybe it's more complicated than that. So would you advise the following in order? Check injectors, ECU (swap another in), Fuel pump relay, new CKPS (what is a CKPS??).

thanks!

 

First thing is to get an OBD dongle and a smart phone app. You'll be able to see what the sensors are saying to the ECU and that alone will likely lead to a bunch of clues/issues. It is the best $30 you'll ever spend on this truck.

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

Then download the workshop manual and other documentation from the link in my signature.

The CKPS is the LR abbreviation for crank position sensor.

 

Yep - I've got an OBD tool. The codes I see are :
P0300 - Random/Multiple Cylinder Misfire
P0340 - Camshaft Position Sensor Circuit Malfunction

sooo, try replacing the CKPS first? Also, the truck has 110k miles on it and I don't know if/when the wires and plugs were last replaced...could that also be the culprit? Prob need to replace those as routine maintenance anyhow.

Thanks again!

 

I'd leave the crank position sensor alone.

Plugs and wires are a good idea in all cases.

As far as the CMP (camshaft position sensor), the part# is NSC100840...
Check the wiring. Sometimes things get burned, coated, and otherwise abused in the engine bay so examine the wiring carefully and the connector as well. Maybe add some dielectric grease in the connector.

The goal with these trucks is to find the solution economically. I'm not one to throw parts at something without a good reason to do so.

The thing is crazy expensive to replace. Best pricing on a new unit appears to be at LRDIRECT.com. They are based in the UK but I've order various things from them with good results. For a non-moving part such as this I might take a shot with a used unit from the likes of Paul Grant or Will Tillery if their pricing is substantially lower.

 

Hello. We have a 97 Discovery as well. SAME issue. Have you been able to uncover the cause? We are still in the thick of trying to resolve it. Thanks!