Hi all,
I have a 1986 240 that the other day I started it. I would idle OK but when I tried to accelerated it barely moved.
Checked fuel pressures-all OK, but I replaced both pumps & filters as they were original pumps & very old filter.
I checked the cam belt timing, all OK.
Replaced vacuum hoses & cleaned throttle body & Idle Air Control
AMM Cleaned & C0% set
Cleaned Flame trap
Checked & set Throttle position sensor
Found when I connected a vacuum gauge to the manifold it was running around -12"Hg.
I adjusted the timing until I got -19"Hg but I had to turn the distributor fully anti clockwise, about 20 degrees to achieve this.
I put a timing light on it & it was now running at 12 degrees BTDC & would accelerate very nicely.
My concern is what could change the timing that dramatically overnight.
I have also checked the vacuum to the ICU at 1500rpm, it changes when I remove the vacuum.
I disconnected the Coolant Temp Sensor & the timing changed as it should
Changed coil, still the same.
Disconnected Knock sensor, still the same.
Remove distributor & checked gear retaining pin all OK.
Install distributor 1 tooth around but this only put at the other extreme, fully clockwise to get timing at 12degrees BTDC.
Harmonic balancer & cam timing belt have both been replaced last year
Decayed wiring replaced about 6 months ago
Not sure what else to test as everything seems to be in order.
Any suggestions would be appreciated.
Cheers Peter

 

Could it be that your timing belt slipped a tooth? When was the timing belt changed?

 

Hi act1292,
Timing belt replaced a year ago, probably 5000klms.along with a new tensioner
I have the top timing cover off & all timing marks align.with marks on the block