MikeESoc2
NAXJA Forum User
- Location
- Staten Island, NY
Last night I almost had to get towed due to following:
Engine cranks over no problem;
ignition spark when cranking no problem.
When cranking but no start, can hear fuel pump buzzing in back and while ignition-key in on-position I crawled under there and sure enough fuel pump was buzzing to point the fuel hoses near the gas tank were slightly vibrating.
Then after the battery nearly drains down to zero I call for a tow while leaving the ignition-key in on-position ... all of a sudden the fuel pump sound goes from "buzzing" to a louder "tick-tick-tick", so I crank with what little battery power is left ... and ... the engine starts right up !!
To me, the problem is possibly not the fuel pump itself since it is ~ 2years old (less than 20K miles), and, with fuel pumps going bad in the past I experienced that they fail to keep the engine idling ... which did not happen here ... the entire 37 mile drive home last night was 100% A-OK (at highway speeds mostly).
So I have been reading this manual today:
http://www.lunghd.com/Downloads_and_Links/Jeep_Renix_Fuel_Injection_manual.pdf
and am now going to start checking:
- connections on the fuel-pump relay;
- connections on the starter-relay (since it feeds the fuel-pump relay);
- connections on the fuel-pump ballast resistor;
- maybe just replace the fuel-pump relay (inexpensive enough).
However, what is not making sense to me is why was the fuel-pump sounding with a "buzz" (and vibrating) when it would repeatedly not start ... what was powering the buzzing fuel-pump if the problem was relay related ... and what "kicked-in" to change the fuel pump sound to a stronger "tick-tick-tick" that then caused the engine to start
(?? is an intermittent ballast resistor failure the problem, or, maybe there is some debris that got stuck in the fuel-pump mechanism ??).
Since maybe dirt in the fuel-pump mechanism I am considering filling-up the 13.5 gallon tank along with a bottle of SeaFoam (if/when I get it started again if I don't find any electrical connection problems).
I am also assuming that since the no-start cranking included strong ignition-spark (no doubt), that the crankshaft position sensor is not the problem ...
... or, maybe I'm wrong on that ?
... with 326K on this '87XJ (it usually runs 100% A-OK) and purchased it with 112K in 1997 I have never changed the crank position sensor ...
... but, when I had to change the crank position sensor on my son's '99XJ couple of year ago, from what I remember those problem symptoms included no ignition spark.
I'll feedback whatever I find over the next couple of days ... in the meantime, does anyone have any suggestions for a problem such as this for a Renix 4.0L 4-speed automatic ?
Engine cranks over no problem;
ignition spark when cranking no problem.
When cranking but no start, can hear fuel pump buzzing in back and while ignition-key in on-position I crawled under there and sure enough fuel pump was buzzing to point the fuel hoses near the gas tank were slightly vibrating.
Then after the battery nearly drains down to zero I call for a tow while leaving the ignition-key in on-position ... all of a sudden the fuel pump sound goes from "buzzing" to a louder "tick-tick-tick", so I crank with what little battery power is left ... and ... the engine starts right up !!
To me, the problem is possibly not the fuel pump itself since it is ~ 2years old (less than 20K miles), and, with fuel pumps going bad in the past I experienced that they fail to keep the engine idling ... which did not happen here ... the entire 37 mile drive home last night was 100% A-OK (at highway speeds mostly).
So I have been reading this manual today:
http://www.lunghd.com/Downloads_and_Links/Jeep_Renix_Fuel_Injection_manual.pdf
and am now going to start checking:
- connections on the fuel-pump relay;
- connections on the starter-relay (since it feeds the fuel-pump relay);
- connections on the fuel-pump ballast resistor;
- maybe just replace the fuel-pump relay (inexpensive enough).
However, what is not making sense to me is why was the fuel-pump sounding with a "buzz" (and vibrating) when it would repeatedly not start ... what was powering the buzzing fuel-pump if the problem was relay related ... and what "kicked-in" to change the fuel pump sound to a stronger "tick-tick-tick" that then caused the engine to start
(?? is an intermittent ballast resistor failure the problem, or, maybe there is some debris that got stuck in the fuel-pump mechanism ??).
Since maybe dirt in the fuel-pump mechanism I am considering filling-up the 13.5 gallon tank along with a bottle of SeaFoam (if/when I get it started again if I don't find any electrical connection problems).
I am also assuming that since the no-start cranking included strong ignition-spark (no doubt), that the crankshaft position sensor is not the problem ...
... or, maybe I'm wrong on that ?
... with 326K on this '87XJ (it usually runs 100% A-OK) and purchased it with 112K in 1997 I have never changed the crank position sensor ...
... but, when I had to change the crank position sensor on my son's '99XJ couple of year ago, from what I remember those problem symptoms included no ignition spark.
I'll feedback whatever I find over the next couple of days ... in the meantime, does anyone have any suggestions for a problem such as this for a Renix 4.0L 4-speed automatic ?