Howdy Mud,
I made the acquaintance of an older man with a '94, US spec, FZJ80 recently. His 80 is way down on power and he's fired the parts blunderbuss at it without success. He's not a computer type of guy so I want to try to bring the power of ih8mud to his efforts via this thread. My current information is a little limited as I've not gotten to look at the 80 but he provided some interesting clues:
Additional backstory on the situation:
What ideas do y'all have on this? Any other causes for an early FZJ80 to fall flat on minimal accel like this?
Any additional questions that would be easy for me to pass to him or look into if/when I drop by?
I'll add that checking for a torn intake tube seems worthwhile and that based on the hill climb story I'm curious about his fan clutch but I'd guess he would have noticed the intake tube already and that overheating is not currently a factor even if running hot initially triggered the issue. These are two things I'll check if I stop by.
Thanks,
I made the acquaintance of an older man with a '94, US spec, FZJ80 recently. His 80 is way down on power and he's fired the parts blunderbuss at it without success. He's not a computer type of guy so I want to try to bring the power of ih8mud to his efforts via this thread. My current information is a little limited as I've not gotten to look at the 80 but he provided some interesting clues:
The most relevant detail, if accurate, is that timing is dropping to around 8 or 10 degrees ATDC when they throttle up from idle. It sounds like timing was set correctly at 3 degrees, including the jumper step. They then pull the jumper but have kept the timing light out to see how timing advances but have found it instead retards what sounds like about 15 degrees, roughly, as soon as the engine accelerates above idle.
My first question for the forum is, what mechanisms lead to timing reduction like this? Knock sensors are the only input signal that I'm aware of off that can trigger a cut like that but I assume there may be others. If this is knock sensor related I wonder if there is a knock sensor issue or if an actual knock issue could be present at such low load/rpms with 3 degree base timing? Can anyone point me to a thread on knock sensor testing for a '94? Additional backstory on the situation:
- He lives on a mountain that is about a 900 foot climb to the top and then a few miles level driving to his house. On a recent drive up mountain all was fine until about a mile after he had reached the top. After that mile of mostly level/easy driving the engine lost a lot of it's power, and still behaves the same way at this point.
- He's changed oil, fuel filter, fuel pump, AFM, etc. etc.
- He noticed that the top of the original AFM was hot to the touch which is why he replaced it with an apparently aftermarket unit.
- He said temps never left the middle/normal range but he didn't have more detailed temp information other than the stock gauge.
- He has kept all of the original parts
Any additional questions that would be easy for me to pass to him or look into if/when I drop by?
I'll add that checking for a torn intake tube seems worthwhile and that based on the hill climb story I'm curious about his fan clutch but I'd guess he would have noticed the intake tube already and that overheating is not currently a factor even if running hot initially triggered the issue. These are two things I'll check if I stop by.
Thanks,