Hi all! Working on a friend's 89 300e. Has 288,00 miles and a very poor (minimal at best) maintenance history. Takes multiple attempts to start cold, when it finally fires it has a low unstable idle and hesitates badly during warm up. Hot restart is fine, did idle somewhat roughly when hot.
Swapped known good OVP from my 89 300TE.
Smoke tested and repaired a couple of small vacuum leaks, replaced all injector and holder seals (leaking badly).
Replaced #6 wire (burnt from manifold)
Gave her 1/8 turn in (rich) on AFR adjustment---now idles great when hot.
Upper chamber pressures right at 5.5 bar, lower exactly .4 lower.
Inspected cap and rotor (not new but close to it)
Replaced partially restricted fuel filter.
Ohm'd coolant temp sensor, airflow sensor, throttle switch-- all ok
Cleaned ground connections at intake.
Checked cold start injector pulse.
Swapped known good FPR from my 300TE
Swapped EZL from my 300TE
Checked air flow "plate" position and for smooth movement
It does hold fuel pressure (2.5 bar IIRC) overnight
Ohm'd crankshaft sensor
A couple of observations; When cranking cold, has good spark, and fuel pressure. Will typically fire when RELEASING the key from the start position (ignition switch failing?) Sometimes the overhead dome lamp flickers (almost like an ignition pulse) when cranking cold. The EHA does have some fuel(?) moisture/residue at its harness connector. Although unplugging the EHA makes no difference on cold start (shouldn't that throw the KE into a strictly mechanical setup?)
Sorry for the length of this post but I wanted to include all the info/diagnostics. Any help would be GREATLY appreciated. This one has me stumped!
Thanks
John
PS--debating whether to pin out the ecu next....but it wont fire off cold on "backup"....and I'm going to put a new EHA on tomorrow anyway because of the leak...
Swapped known good OVP from my 89 300TE.
Smoke tested and repaired a couple of small vacuum leaks, replaced all injector and holder seals (leaking badly).
Replaced #6 wire (burnt from manifold)
Gave her 1/8 turn in (rich) on AFR adjustment---now idles great when hot.
Upper chamber pressures right at 5.5 bar, lower exactly .4 lower.
Inspected cap and rotor (not new but close to it)
Replaced partially restricted fuel filter.
Ohm'd coolant temp sensor, airflow sensor, throttle switch-- all ok
Cleaned ground connections at intake.
Checked cold start injector pulse.
Swapped known good FPR from my 300TE
Swapped EZL from my 300TE
Checked air flow "plate" position and for smooth movement
It does hold fuel pressure (2.5 bar IIRC) overnight
Ohm'd crankshaft sensor
A couple of observations; When cranking cold, has good spark, and fuel pressure. Will typically fire when RELEASING the key from the start position (ignition switch failing?) Sometimes the overhead dome lamp flickers (almost like an ignition pulse) when cranking cold. The EHA does have some fuel(?) moisture/residue at its harness connector. Although unplugging the EHA makes no difference on cold start (shouldn't that throw the KE into a strictly mechanical setup?)
Sorry for the length of this post but I wanted to include all the info/diagnostics. Any help would be GREATLY appreciated. This one has me stumped!
Thanks
John
PS--debating whether to pin out the ecu next....but it wont fire off cold on "backup"....and I'm going to put a new EHA on tomorrow anyway because of the leak...