Car won't go above 2,500 rpm
#21
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omgimali (01-08-2017)
#22
Ok, so I bought the plugs and gave it to my mechanic he changed it but I don't know if he gapped them, I ask him? How can the car run without the correct gapping? Wouldn't it be misfiring 99% of the time? that is just my question..
#23
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To short a gap, it will run sloppy, if at all. To much gap (unless excessive, it may not start), it will idle, but you will have no performance and acceleration will be very poor. Many American cars have a gap range, Jaguars are specific (I think its .44?) and like a cat, finicky because they have the air/fuel mixture so dialed in. Plugs are also so easy to check and important to be correct, which is why you will see many folks here say to check them.
How cold is it up there btw?
How cold is it up there btw?
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omgimali (01-08-2017)
#24
To short a gap, it will run sloppy, if at all. To much gap (unless excessive, it may not start), it will idle, but you will have no performance and acceleration will be very poor. Many American cars have a gap range, Jaguars are specific (I think its .44?) and like a cat, finicky because they have the air/fuel mixture so dialed in. Plugs are also so easy to check and important to be correct, which is why you will see many folks here say to check them.
How cold is it up there btw?
How cold is it up there btw?
weather is bad, yesterday was light snow and sleet, and 25 degrees F, and will be 17 tomorrow at 6am... How bout down there?
Last edited by omgimali; 01-08-2017 at 10:43 AM.
#25
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Its a crisp 41 and clear (was colder last night with the wind), ..coldest its been down here in a few years.
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omgimali (01-08-2017)
#26
wow its pretty cold there
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Here's and older thread with good reading and gap....https://www.jaguarforums.com/forum/x...k-plugs-72757/
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omgimali (01-08-2017)
#28
Here's and older thread with good reading and gap....https://www.jaguarforums.com/forum/x...k-plugs-72757/
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omgimali (01-08-2017)
#30
Spark Plugs gapped to spec. Jim I doubt I skipped timing, I can still drive the car to whatever speed, I can do 70mph and above but just won't go above the 2,500 rpm. Gearbox is smooth. I called my mechanic, and he said it probably could be the MAF or he said it sounds like a failing TB. But he has to see the car first/
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omgimali (01-08-2017)
#32
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omgimali (01-09-2017)
#35
A bit late, but TSB 303-29 revised spark plug gap for ALL V8 4.0 engines to .052, not sure if that's what you ended up gapping to.
EDIT: saw that was in the thread and only applies to AJ26 engines, so you'd need the shorter, later gap.
For a quick and dirty test of the TB, do you have a scanner that reads and/or logs live data? You could watch the throttle position sensor/pedal position sensor readings while cruising and so on, if it doesn't go above a certain amount that could point to the TB.
EDIT: saw that was in the thread and only applies to AJ26 engines, so you'd need the shorter, later gap.
For a quick and dirty test of the TB, do you have a scanner that reads and/or logs live data? You could watch the throttle position sensor/pedal position sensor readings while cruising and so on, if it doesn't go above a certain amount that could point to the TB.
Last edited by nilanium; 01-09-2017 at 10:46 AM.
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omgimali (01-09-2017)
#36
#37
No, mine wouldn't get out of its own way the other day, all sorts of hesitation. Took out the MAF, sprayed MAF cleaner on a Q-Tip, lightly swabbed the temp probe and the two filaments under the sensor top cap, then sprayed the filaments with the cleaner, re-installed, ran like a million bucks (ok, half a mil)
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omgimali (01-10-2017)
#38
If I read the thread correctly then something stands out. In "P" the revs should be "limited" IIRC to something like 2500/3000 RPM, yet you said yours revs fine in park past 2500/3000 (am I mistaken in that?) Yet won't go above 2500 in "D" It almost sounds like it's doing the opposite of what it's supposed to do.
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omgimali (01-10-2017)
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omgimali (01-10-2017)
#40