Fossicker
I've got a v8 Disco 1 that's got a problem with power, I can drive it around ok, though it sounds like its chugging. It struggles over 60, especially under real load (like steep bridges - thought i was going to lose it completely over the west gate!). The symptoms are much like this post:
92 Classic 3.9 Running Rough under load
It was running well previously, but I'd had problems in the past with idle when the engine got hot and coming into summer decided to do Bee Utey's Bosch 024 remote amp fix. He supplied an excellent kit, which I installed without removing the dizzy, getting the old amp off the side using a screwdriver to prise it off. I then wired the new coil up wrong, mixing up the wires in the existing loom going to the coil points, got there eventually but it was running rough
Lucas ignition amplifier replacement by Bosch 024
Adjusted the air gap in the dizzy to much smaller.
Messed with rotating the dizzy to try and find best timing, no good so decided to buy a timing light.
Advanced timing slightly more than prior (as new coil requires, thx Bee Utey) now set to 9BTDC at idle.
Replaced dizzy cap and rotor with genuine Lucas.
Adjusted TPS and MAF plug voltages to within the ranges suggested in LOVEMYRANGIE's document (0.34 and 1.3 VDC respectively).
Replaced spark plugs using NGK BPR6ES (one step hotter than spec as most of my driving is stop-start city), old ones were sooty (at 150k imagine fuel injectors need replacing but were working fine previously, get to this next).
At idle used pliers to pull off each of the spark leads in turn, each gives me a clicking sound when held next to the plug or body, and pulling each affects idle (though #4 not as much as some others maybe).
Already established Vacuum Advance is shot, getting this reconditioned at Performance Ignitions soon, but this shouldn't be causing the symptoms.
Now, being a total amateur, I'm stuck. Any suggestions as to what to try next would be appreciated.
Cheers, Simon.
Last edited by simon_m; 4th December 2011 at 03:59 PM. Reason: additional info
AT REST
There is a temperature sensor for the ECU, it has a plug like an injector plug and is behind the thermostat housing. Check the resistance of this sensor is in the order of 300 ohms with the engine hot. If it is open circuit the engine runs full rich all the time.
Fossicker
Thanks again Bee Utey. I had a poke around, is this the plug?
I tested it with the power off and a warm engine, got about 270 Ohms.
While looking, I also noticed the plug going into the fuel injector on number 1 cylinder was loose - heat had cracked off most of its plastic locking mechanism, and it was just sitting on top. It must have been disturbed when I was testing the voltage on the TDC plug, and just a little nudge in the loom had unseated it! I pushed it back on and low and behold, all 8 cylinders are working properly.
It's not sitting in there tightly, and god knows if the others are in a similar way too, most of the plastic shrouds in the engine bay seem pretty brittle now (150,000 kms) - surprised it doesn't happen more often!
AT REST
Yup, that's it, seems to be OK.Originally Posted by simon_m
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