Hi folks,
I am new to this forum and upon reading many Q&A examples and how thorough most are I thought I would seek some of your expert wisdom on a little problem I am having.
OK here is the senario:
Whenever trying to start my vehicle (HOT or COLD) it always takes no less then 3-4 times of cranking for 15 to 20 seconds before it will fire up. Sometimes depressing the throttle dureing cranking once or twice seems to help a bit but I am not 100% sure if this is just coincidence.
Upon researching the fuel circuit it appears the fuel pump is functioning as it should and the pressure regulator appears to be working OK as well. I am currently get 29lbs running and 35+ with the vacuum line off of the regulator.
Upon reading Doug's Fuel circuit Test procedure, one thing does appear to be slightly different on my vehicle, and that is I am unable to get the fuel pump to run when the car is placed in Drive and the key placed in the run position. Not a big problem I think bought thought I would mention it anyway.
I guess what I am most concerned with is it seems like once the vehicle is shut off the fuel pressure drops immediately to 0 and I thought it was suppose to hold in order to make starting easier, ie not having to recharge the fuel system? Am I mistaken on my thoughts here or?.
Any assitance/feedback would be greatly appreciate.
PS: New Fuel filter installed as well.
Robert
Submitted by carbuyerseller… on Mon, 12/10/2012 - 13:26
Submitted by dougdwyer1@com… on Mon, 12/03/2012 - 20:54
Re.: 87 XJ6 Fuel Pressure?
Edited on 2012-12-03 20:56:38
"and that is I am unable to get the fuel pump to run when the car is placed in Drive and the key placed in the run position."
>> the fuel pump is it not supposed to operate by putting the key in the "run" position. It should operate if the key is turned to the "start" position, though. If it doesn't, that's an important clue.
" guess what I am most concerned with is it seems like once the vehicle is shut off the fuel pressure drops immediately to 0 and I thought it was suppose to hold in order to make starting easier, ie not having to recharge the fuel system? Am I mistaken on my thoughts here or?."
>> There is an anti-drain valve in the trunk to prevent this from happening. It's located on the large brass fitting near the fuel filter.
>> Pressure should hold for at least a few hours but, in actually, a healthey fuel pump will recharge the fuel rail in 2-3 seconds so it's not the end of the world if the pressure bleeds off....unless it's leaking into the cylinders, of course.
"Any assitance/feedback would be greatly appreciate"
>> Is the cold start injector working?
>> Have you checked your coolant temp sensor?
Cheers
DD
Thank you so much for your reply Doug. As for the hard start Hot or cold, I believe I did find that the non-return valve was dirty/stuck. I removed it and cleaned it out and it now seems to have made a significant difference when starting. It now only takes a single crank cycle of about 15-20 seconds when warm and sometimes just two crank cycles when really cold. Again a vast improvement.
As for the cold start injector, I still need to test this but it does appear to be getting fuel when cold. This was one of the first times I looked for. I had already taken it out and cleaned it up a bit.
As for the Coolant Temp Sensor, the gauge does act quite strange, meaning that the needle bounces up and down on a regular basis after it is warmed up. It usually does this between 70-90C. Not sure but it acts like it is a ground or resistance issue but I haven't diagnosed it as of yet. Being new to these cars, to be 100% honest with all of the sensors on the Intake manifold I am not 100% sure which one it is.
LOL. I guess it is probably about that time I buy the Service and Parts manuals/catalogs. Smile