Hesitation when first started
Discussion
As some of you may know, I picked up a 94 xj40 off ebay for button money. Having done around 3000 miles in her now i've got my moneys worth already but she has started to play up a little.
When left standing for a while, or when restarting after switching off for a few minutes, she feels very hesitant when building speed. Accelerating hard will get rid of the loss of power feel, but with a larger "kick" on gear change when up in higher revs.
After about 2-3 minutes she is running perfectly normally again, smooth gear changes at any level of acceleration and no feeling of artificial power restriction.
In the past 2000 miles I have replaced the oil, plug and filters, so i'd hope that rules those out.
any ideas?
When left standing for a while, or when restarting after switching off for a few minutes, she feels very hesitant when building speed. Accelerating hard will get rid of the loss of power feel, but with a larger "kick" on gear change when up in higher revs.
After about 2-3 minutes she is running perfectly normally again, smooth gear changes at any level of acceleration and no feeling of artificial power restriction.
In the past 2000 miles I have replaced the oil, plug and filters, so i'd hope that rules those out.
any ideas?
trooperiziz said:
As some of you may know, I picked up a 94 xj40 off ebay for button money. Having done around 3000 miles in her now i've got my moneys worth already but she has started to play up a little.
When left standing for a while, or when restarting after switching off for a few minutes, she feels very hesitant when building speed. Accelerating hard will get rid of the loss of power feel, but with a larger "kick" on gear change when up in higher revs.
After about 2-3 minutes she is running perfectly normally again, smooth gear changes at any level of acceleration and no feeling of artificial power restriction.
In the past 2000 miles I have replaced the oil, plug and filters, so i'd hope that rules those out.
any ideas?
Fuel filter partially blocked? Does the XJ-40 have the little swirl tank just below the fuel tank like the XJ-S, this has a filter that can cause slight starvation issues. Also might want to stick a pressure gauge on and see what you're getting delivered. That old XJ-S I had once had a regulator problem where at idle, the vaccuum was so weak it didn't drag enough fuel in. Open the throttle and away she went! New reg fixed it.When left standing for a while, or when restarting after switching off for a few minutes, she feels very hesitant when building speed. Accelerating hard will get rid of the loss of power feel, but with a larger "kick" on gear change when up in higher revs.
After about 2-3 minutes she is running perfectly normally again, smooth gear changes at any level of acceleration and no feeling of artificial power restriction.
In the past 2000 miles I have replaced the oil, plug and filters, so i'd hope that rules those out.
any ideas?
As a matter of course, I would change the dizzy cap and rotor arm as well. Degrading plug leads are also known to degrade causing odd problems. If do do consider changing them, do go for original OE "Rists" set only.
Something relatively simple that cost nothing is to clean out the throttle body. On the air inlet, there is a large rubber belows linking the pipework from the air filter box to the engine. Remove this carefully (secured by two large jubilee clips) and clean out any gunk. It accumultes from the crankcase breather system. The throttle body is the item which bolts to the inlet manifold and has the throttle cable and kick-down cable attached on top. The throttle potentiometer is underneath. It is usuall red. Find this and trace the wiring back to an in-line multi-connector and disconnect. Remove all the other hose and cable connections. The throttle body is secured by 4 nuts. Remove it from the car. Carefully, remove all traces of oil/gunk using carb cleaner. With the throttle closed, there should be a small gap between the inside of the body and the butterfly valve. It should be 2 thou measured with feeler guages. Adjust if required using the screw adjuster on top. In Haynes speak, reassembly is simply a matter of reversal of removal.
When you come to put the rubber bellows back, ensure it is free from any holes or splites, and ensure it is properly fitted particularly underneath. Anywhere air can be sucked in will upset your fuel mixture. This apparently is a common problem!
Good luck.
Something relatively simple that cost nothing is to clean out the throttle body. On the air inlet, there is a large rubber belows linking the pipework from the air filter box to the engine. Remove this carefully (secured by two large jubilee clips) and clean out any gunk. It accumultes from the crankcase breather system. The throttle body is the item which bolts to the inlet manifold and has the throttle cable and kick-down cable attached on top. The throttle potentiometer is underneath. It is usuall red. Find this and trace the wiring back to an in-line multi-connector and disconnect. Remove all the other hose and cable connections. The throttle body is secured by 4 nuts. Remove it from the car. Carefully, remove all traces of oil/gunk using carb cleaner. With the throttle closed, there should be a small gap between the inside of the body and the butterfly valve. It should be 2 thou measured with feeler guages. Adjust if required using the screw adjuster on top. In Haynes speak, reassembly is simply a matter of reversal of removal.
When you come to put the rubber bellows back, ensure it is free from any holes or splites, and ensure it is properly fitted particularly underneath. Anywhere air can be sucked in will upset your fuel mixture. This apparently is a common problem!
Good luck.
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