First Post - Chimaera Misfire

[Rugbyfester]

Hi guys this is my first post on PH - I been reading a few posts with similar issues to mine but none quite the same so after some advice.

I have a 97 4.0 Chimaera, I have two issues that I know of maybe related but....

1. Temperature gauge doesn't go over about 65deg fans seem to cut in at just under 60 according to the gauge, I am presuming that the temp gauge is lying to me.

2. Car runs fine until it starts to get warm then the misfire starts - the car pulls like a rocket but the misfire is quite annoying, it pulls like it's on/off very quickly, if I hold the revs around 3k it seems to go away but both above and below it comes back.

I have read other posts with similar issues and as such replaced both the Temp sender (twice) and both cleaned then replaced the stepper motor with a brand new unit. The car already has Magnecor HT Leads fitted. The car starts first time and after about a 3-4 second turn of the key. I keep the battery on a battery conditioner charger when in the garage this indicates the battery is fine.

I have not unplugged the ECU but note it has a Land Rover label on it and some writing in white pen (suspect it has been changed at some point with a second hand unit).

Although I have no experience of using one I have ordered an ECU mate from Steve Heath, which should arrive any day now, I Intend to play with it at the weekend to see how it works and what if any issues I can discover.

I intend to put in in for a service but would like to sort this out for my self first, the car had a service 1800 miles ago (but 2 years or more ago).

Any ideas??

[5.0ltr]

Mine did similar, throttle pot, ecu reset cured that one. Good luck.

[MPoxon]

Welcome to PH :thumup:

I would start with the simple things first...try replacing the distributor cap and rotor arm. It might also be worth seeing if you can borrow another set of HT leads just to make sure yours are not causing the issue. If no joy at least you can cross these items off the list and continue your investigation elsewhere.

Mine had a similar missfire a number of years ago.... it turned out to be condensation in the dizzy cap.

[Quietlybonkers]

I can lend you a set of leads - just clck on my profile, email me and send me you address and I will post them.

[Rugbyfester]

Quietlybonkers said:

I can lend you a set of leads - just clck on my profile, email me and send me you address and I will post them.

Thanks - I have emailed you and will take you up on that offer cheers.

[Rugbyfester]

MPoxon said:

Welcome to PH :thumup:

I would start with the simple things first...try replacing the distributor cap and rotor arm. It might also be worth seeing if you can borrow another set of HT leads just to make sure yours are not causing the issue. If no joy at least you can cross these items off the list and continue your investigation elsewhere.

Mine had a similar missfire a number of years ago.... it turned out to be condensation in the dizzy cap.

Yes I have considered this could be an issue, I will order replacements wont hurt.

Cheers.

[Alun450]

If your lucus stuff is old, I'd replace the lot incl coil if you can, to me it always pays off in better running and costs, the technical bit, only misfires when warm, for the guru's of us doesn't that narrow it down abit? A plug seems to be my instinct but sadly I'm not sure. Layman here sorry.

[Quietlybonkers]

Rugbyfester said:

Quietlybonkers said:

I can lend you a set of leads - just clck on my profile, email me and send me you address and I will post them.

Thanks - I have emailed you and will take you up on that offer cheers.

I will look out for it and get them in the post. They worked fine before I swapped them.

[Rugbyfester]

Alun450 said:

If your lucus stuff is old, I'd replace the lot incl coil if you can, to me it always pays off in better running and costs, the technical bit, only misfires when warm, for the guru's of us doesn't that narrow it down abit? A plug seems to be my instinct but sadly I'm not sure. Layman here sorry.

Ordered a coil as well as a dist cap and rotor, - plugs too it seems eh? will try at the weekend and report.

[Quietlybonkers]

If you are changing the plugs, I can send you my old set of standard 7s if you like. I changed mine for Iridium 6s. I will get you the exact product code tomorrow. If you are going to try new plugs then try te Iridium 6s. Chimp of Darkness suggested them. They make the throttle so much more responsive.

Edited by Quietlybonkers on Tuesday 5th February 22:37

[pwd95]

Quietlybonkers said:

If you are changing the plugs, I can send you my old set of standard 7s if you like. I changed mine for Iridium 6s. I will get you the exact product code tomorrow. If you are going to try new plugs then try te Iridium 6s. Chimp of Darkness suggested them. They make the throttle so much more responsive.

Edited by Quietlybonkers on Tuesday 5th February 22:37

Doing a service soon so....

[Rugbyfester]

Well chaps thanks for all your help.

I seem to have sorted it out, but not totally sure exactly where the problem was.

I replaced the Distributor cap and rotor arm, whilst replacing to coil the mounting bracket was lose. One of the air plenum bolts was lose....(for how long?)

I noticed the rotor arm was quite pitted, as the terminals were corroded a little, so where was the problem?....Not sure dist cap and rotor arm looks like they needed replacing but due to location I couldnt quite see how bad they were until removed, I am sure that the lose air plenum bolt didnt do anything to help but dont know if it was losing or sucking any air incorrectly.

Thanks to all those who gave some advice.

[Rugbyfester]

Quietlybonkers said:

If you are changing the plugs, I can send you my old set of standard 7s if you like. I changed mine for Iridium 6s. I will get you the exact product code tomorrow. If you are going to try new plugs then try te Iridium 6s. Chimp of Darkness suggested them. They make the throttle so much more responsive.

Edited by Quietlybonkers on Tuesday 5th February 22:37

The HT leads and Plugs havent arrived yet but will send them back to you with compensation for your postage when they do. I have ordered new plugs and will upgrade to Iridium when I get the car serviced in a few weeks.

Thanks again.

[Rugbyfester]

BTW

ECUmate confirms my suspicions the temp gauge was lying to me it was reading 78 degrees for water temp on a run and the dash gauge was reading somewhere around 65.

Looks like a previous owner has moded the fans to come on earlier.

Only bought this car at Christmas starting to become an expert already....well nearly.

Edited by Rugbyfester on Friday 8th February 15:40

[QBee]

Rugbyfester said:

Quietlybonkers said:

If you are changing the plugs, I can send you my old set of standard 7s if you like. I changed mine for Iridium 6s. I will get you the exact product code tomorrow. If you are going to try new plugs then try te Iridium 6s. Chimp of Darkness suggested them. They make the throttle so much more responsive.

Edited by Quietlybonkers on Tuesday 5th February 22:37

The HT leads and Plugs havent arrived yet but will send them back to you with compensation for your postage when they do. I have ordered new plugs and will upgrade to Iridium when I get the car serviced in a few weeks.

Thanks again.

Sorry, only just managed to get them into the post - half day closing on Wednesday, 19 hour day yesterday getting the alarm changed, nowhere near a post office during opening hours. Posted today first class, so should arrive tomorrow. No worries about the postage - hope you sort the problem