Knocks on warm up
08-24-2018, 11:00 PM
#46
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Renix really doesn't act that way with vacuum leaks. If anything, they idle low with a vacuum leak.
The 2000 RPM spike on starting with a Renix indicates a faulty signal from the TPS to the ECU.
You can always try starting it with the TPS disconnected. The flat 3 wire connector. Not the square 4 wire one.
08-25-2018, 05:10 AM
#47
CF Veteran
Renix really doesn't act that way with vacuum leaks. If anything, they idle low with a vacuum leak.
The 2000 RPM spike on starting with a Renix indicates a faulty signal from the TPS to the ECU.
You can always try starting it with the TPS disconnected. The flat 3 wire connector. Not the square 4 wire one.
The 2000 RPM spike on starting with a Renix indicates a faulty signal from the TPS to the ECU.
You can always try starting it with the TPS disconnected. The flat 3 wire connector. Not the square 4 wire one.
08-25-2018, 07:40 AM
#48
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The HOs seem to go ***** out to redline if there is a good sized intake leak. Like when guys change the intake gasket and don't get the manifold seated over the guide pins.
08-25-2018, 08:22 AM
#49
CF Veteran
LOL Well I'm about to go fire my new valve job up this morning (am as nervous as a hen in a fox den) so I will let you know if I failed to get anything centred. Truthfully I was aware of that and made sure it didn't happen. Honestly I don't know how it CAN happen, you would spot t hat a mile away if you were only half awake. That said, not all years have the guide pins. But, I shall check once more before hitting the key.
08-25-2018, 08:27 AM
#50
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LOL Well I'm about to go fire my new valve job up this morning (am as nervous as a hen in a fox den) so I will let you know if I failed to get anything centred. Truthfully I was aware of that and made sure it didn't happen. Honestly I don't know how it CAN happen, you would spot t hat a mile away if you were only half awake. That said, not all years have the guide pins. But, I shall check once more before hitting the key.
08-25-2018, 08:36 AM
#51
CF Veteran
LMAO Thanks buddy! I have heard too many people say "dont put a valve job on that 200k engine, you'll blow the rings down to the bottom of the oil pan@!
HOWEVER, this is not what I was taught, and have seen many a valve job go on an old motor, one of mine included, that worked just fine for years to come.
Same goes for new lifters on old cam, the cam people say no, but I was taught and my machinist agrees it's fine, and Ive done it and 2 of my buds did it, no prob.
Nonetheless there is plenty of oil on it, new oil chage and zddp stp on everything. Its the first 20 mins that scare me. crossing fingers
HOWEVER, this is not what I was taught, and have seen many a valve job go on an old motor, one of mine included, that worked just fine for years to come.
Same goes for new lifters on old cam, the cam people say no, but I was taught and my machinist agrees it's fine, and Ive done it and 2 of my buds did it, no prob.
Nonetheless there is plenty of oil on it, new oil chage and zddp stp on everything. Its the first 20 mins that scare me. crossing fingers
08-25-2018, 08:41 AM
#52
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I know. So many old wives' tales that live on.
That's why I came up with this canned response years ago:
Why is it that those of you who HAVEN'T done something are telling us that HAVE done something, that it doesn't work the way we have experienced by actually HAVING done it?
That's why I came up with this canned response years ago:
Why is it that those of you who HAVEN'T done something are telling us that HAVE done something, that it doesn't work the way we have experienced by actually HAVING done it?
08-25-2018, 10:15 AM
#53
CF Veteran
Im here to tell you, although this should be on my ongoing lifter and valve job thread, since you are the Senior Officer on Deck, ...I just fired it up and it was all quiet.. first time ever. Lifter clattered for about 10 seconds only. Ran a high, varying idle for 15 mins but I had to shut it down cause the coolant got low and I don't have any. All indications are good. Whew. If that cured my 40k mile knock Ill be pleased indeed.
08-25-2018, 03:55 PM
#54
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Im here to tell you, although this should be on my ongoing lifter and valve job thread, since you are the Senior Officer on Deck, ...I just fired it up and it was all quiet.. first time ever. Lifter clattered for about 10 seconds only. Ran a high, varying idle for 15 mins but I had to shut it down cause the coolant got low and I don't have any. All indications are good. Whew. If that cured my 40k mile knock Ill be pleased indeed.
Keep us in the loop. There are some other things we can try.
The high idle needs to be solved though.
08-25-2018, 04:05 PM
#55
CF Veteran
LOL MY high idle was intentional, its sop for new lifter break in. Speaking of break, I did blow a front brake line on my initial test drive. So that was fun. Otherwise it runs textbook.
08-25-2018, 04:12 PM
#56
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