Won't Start

[pjwells]

Alright, I'll try to keep this simple. The last several days my Disco II will start right up half the time, and the other half it won't. Until today, the times it wouldn't start right away, I would wait a few minutes and try again and it would start fine. When it doesn't start, it turns and turns like it's trying to start but doesn't fire up. After a few seconds of holding the key in III position the "turning" sound of the engine begins to slow and I let off. I noticed a little corrosion on the positive connector to the battery, cleaned and lubed it, but that hasn't seemed to make a difference. This morning it started fine when I left for work, but now it's time to go home and it won't start. The "turning" sound of the engine has slowed enough that I know I'm beginning to drain the battery. Any suggestions???

[parrie]

Hey pj, I'm having more or less the same issue w/ my 99 DII. My symptoms have progressivly gotten worse...in addition to not starting at all now the green "mode" and "sport" lights are flashing. I've been chasing this for several weeks w/ no concrete answer to the cause other than it could be one of several things...possibilities include bad battery, bad MAF, bad crankshaft position sensor, bad XYZ gear shift switch, low transmision fluid. The one item that continues to come up is the battery and it's condition...most say that the rover ECUs are easily effected by low voltage which can cause all kinds of crazy problems that don't seem to make sense. One forum suggested that anything under 14v while running could cause ECU problems. Another forum suggested installing a battery w/ a minimum 1000cca.

In my case the truck turns fine but won't start, M&S lights are flashing, 3-amigos are lit-up but when I hook-up my brand new shiney code reader there are no codes reported. As I mentioned, I've been chasing this for several weeks...thought I had it nailed down to a bad crankshaft position sensor, installed a new one and no go. My last resort is the XYZ switch but before I do I'm going back to the beginning and start by getting my battery and alternator checked to confirm that they OK. I'm thinking this would be a good place for you to start.I'll post my findings.

[ThePhotographer]

Parrie, unless you have the ABS amigo it won't tell you the ABS codes.

[parrie]

Hey Zack, I've had all 3 amigos since I purchased the truck 2 yrs ago. Since the check engine light did not come on I assumed that the amigos came on when the PO removed the air suspension. Check engine has come on twice in the past 2 years; 1st time an O2 sensor came up and an ABS code come up once recently (i beleive the code was P1509), I cleared the code and it hasn't come back. After I extract my broken key from the ignition I'm going to start back at the beginning and confirm the battery is good, alternator is good and dbl check tranny fluid again. Any other thoughts would be greatly appreciated.

[pjwells]

Thanks Parrie, I'll give those a look. As some added info: I recently replaced the throttle body gaskets, and in the process may have not securely reconnected the Mass Air-Flow sensor so I'll give that a good check. Update soon...

[parrie]

PJ, good news/bad news, finally got mine running yesterday...dbl check your battery. My battery was turning the engine fine and tested at over 12volts but apparently it was low enough to cause the ECU to go haywire. I put a fresh battery in and all is well, M&S lights went out & no check engine light. Unfortunately I developed a new problem...when I accelerate the engine rpms continually increase and will not return to idle when I let of the accelerator. It acts like the throttle body is sticking open but I can see that it is in the idle position. Not sure what the cause is. Do you have this issue?

[pjwells]

Parrie, well, still havent been able to get it started. Glad to hear you've got yours started, bummer with the rpm issue, though. I've never had that problem myself, but I would check into replacing your throttle body potentiometer. It's not cheap, but that's what senses and regulates the throttle. It's very easy to replace, though.
As for my battery, I had a buddy try and jump me off yesterday, but it still wouldn't start, which makes me think it's not the battery. I've never heard of a battery being bad, but still not being able to at least be jumped off. I'm still going to take the battery in to my local parts shop and have them test it, that'll be tomorrow, so I'll be able to let you know how that goes. Fingers crossed that's all it is.
Let me know how it goes, I'll do the same.

[parrie]

Hey PJ, not sure what the heck is going on with mine. Up until now the thing has ran like a dream. Going to tear into the throttlebody this evening.

I've actually had several bad batteries over the years...same thing, couldn't even be jump started. As far as LRs are concerned, from what I understand the low battery voltage causes the ECU go haywire causing the vehicle not to start. I hope a new battery does the trick for you.

[pjwells]

well looks like its not the battery. i bought a new one and still wont start. my buddy thinks it's a fuel issue. i really dont want to replace the pump. you know if a Disco II has a fuel filter? i keep finding sources showing it's inline but i dont think that's right.

[parrie]

The only fuel filter that I am aware of is in the tank, I think the DIs have an in-line. Have you checked the the fuel pump fuse and relay in the under-bonnet fuse box? There are several relays that are interchangable, just check the number on top of the fuel pump relay and swap it with a matching relay. If that doesn't work the next step will be to confirm that you have #1: fire, #2 fuel. Do you have a code scanner? I'm wondering if you may have some codes that could shed some light on the situation.

My saga got a bit better...went back over the throttlebody and confirmed that it was clean and not sticking. Removed/inspected the TPS, all looked fine. Put it all back together & fired it up, perfect idle, hit the gas and it went up to +/-2200rpm but then slowely after about 45seconds the rpms dropped to about 1500 but wouldn't go any lower. I'm leaning toward a bad TPS but a bad IAC is also a possibilty. Guess it's time to open the wallet again...

[bkreutz]

I can't see how a bad TPS would make the idle speed hang up. All the throttle and cruise actions are mechanical as opposed to electrical (at least at the throttle body). Does the idle speed not return if the truck isn't driving? If so, rev the engine up and watch the position of the throttle where the cables attach to the throttle body, if it returns to the idle position but the engine is still idling fast then I would suspect the IAC, to verify that this is the problem, pinch off one of the hoses that goes from the intake pipe to the IAC (they make special pliers but a vice grip and a couple of pieces of wood will work in a pinch (pun intended)). If after pinching off the hose. start the engine and rev it up. If it returns to idle immediately, then the problem lies in the IAC system. Have you cleaned the IAC valve? They can get gummed up.

[parrie]

Hey Gale, from what I understand the TPSs can go bad and cause iratic idles. Upon starting the truck idles fine wether it is in park or in gear...the problem only arrises when I step on the accellerator, it acts as if the throttle is stuck but I confirmed that it is in the fully closed idle position. I like the sounds of your IAC test (and your pun), going to give this a try this afternoon. I'll post the results.

Oh yeah, forgot to mention that someone on a different forum had mentioned a bad idle sensor? Guess I'm not familiar, could this be a possiblity?

[Les Parker]

Parrie,

Have you checked to see if there is a vacuum leak on the inlet manifold? Yes, Rovers Efi's appear to prefer 12.8 to 13.4v for the ECU's.

[bkreutz]

Hey Gale, from what I understand the TPSs can go bad and cause iratic idles. Upon starting the truck idles fine wether it is in park or in gear...the problem only arrises when I step on the accellerator, it acts as if the throttle is stuck but I confirmed that it is in the fully closed idle position. I like the sounds of your IAC test (and your pun), going to give this a try this afternoon. I'll post the results.

Oh yeah, forgot to mention that someone on a different forum had mentioned a bad idle sensor? Guess I'm not familiar, could this be a possiblity?

What the TPS does is sense the throttle position to let the ECU know how much fuel to squirt into the engine from the injectors. the only time I've ever seen a TPS make the idle stick is when it gets stiff and won't allow the throttle plate return to idle. The variation of idle speed to load is controlled by the IAC by bypassing air around the throttle body. Just as a check, take the hose off the throttle body, have somebody operate the accelerator, and verify that the plate is indeed closing completely. This has to be done with the engine not running. This shouldn't be this complicated. the system on this truck is pretty crude compared to the new stuff. (fly by wire throttles, maybe that's why I retired from this business) BTW, I agree with Les about checking for an intake leak, a big enough one could act like the IAC though normally a vacuum leak will cause the idle to be poor, but the IAC may be compensating for that. HMMM, now I'm thinking out loud again.

[parrie]

Thanks again guys. Last evening I went over everything that I can see and could not find any obvious intake leak. Also confirmed that the plate is closing. I removed the IAC for inspection but not really sure what position valve should be in...the valve itself moves freely however it is not in the closed position (should it be?). I cleaned it up and re-installed but there was no change, starts & idles fine, hit the gas and the rpms rise w/o returning to normal. Gale, I did your air hose squeeze test with the engine stuck on high rpm and sure enough the rpms dropped down to normal idle. If your theory is correct it looks like I need a new IAC wouldn't you say?

PJ, if your still out there, how are you making out getting your started?