3k hhhesitation
11-04-03, 08:28 PM
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3k hhhesitation
Ok, so after 500 miles on a rebuild, I start getting the 3k hesitation back. I figure it has to be a loose ground, so the first one I check is the one on the UIM. I notice it's copper and it's shaped to maintain pressure on the bolt. I also notice that if you overtighten it, it will lose that pressure. I notice that it has a lot of buildup on it. I clean it, steel wool it, bend the pressure thingy back, clean the bolt, and put it all back together and MY 3k HESITATION IS PRETTY MUCH GONE ! I can still feel the transition to the secondaries, but I haven't cleaned the other side of the connection, or the other grounds. Obviously Mazda wanted this to be a good ground with the copper and the pressure tab, but it's not built to last.
11-04-03, 09:17 PM
#2
Recovering Miataholic
Fred,
Our '94 has the same 3K rpm hesitation; I cleaned a few grounds and it went away for about a week. Not the ground you mentioned, though. It's a persistent little devil, isn't it? When the car was new, it wasn't there, and gradually came on around 20 - 30K miles (has 78K miles now). Lots of theories; the one I like best is the "double throttle control" story.
Congrats on getting rid of it (so far)!
---- Bill
Our '94 has the same 3K rpm hesitation; I cleaned a few grounds and it went away for about a week. Not the ground you mentioned, though. It's a persistent little devil, isn't it? When the car was new, it wasn't there, and gradually came on around 20 - 30K miles (has 78K miles now). Lots of theories; the one I like best is the "double throttle control" story.
Congrats on getting rid of it (so far)!
---- Bill
11-05-03, 04:45 AM
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If you really want to keep that connection solid, try something like this:
http://www.mgchemicals.com/products/846.htm
You can find something similar at a local electronics shop... just make sure it's *electrically* conductive grease (sometimes called switch grease), not thermally conductive heat-sink grease.
It prevents corrosion and keeps a better connection on dissimilar metals.
The kind I have (which I can't find at the moment) is green, and is a molybdenum type grease.
http://www.mgchemicals.com/products/846.htm
You can find something similar at a local electronics shop... just make sure it's *electrically* conductive grease (sometimes called switch grease), not thermally conductive heat-sink grease.
It prevents corrosion and keeps a better connection on dissimilar metals.
The kind I have (which I can't find at the moment) is green, and is a molybdenum type grease.
11-05-03, 05:47 PM
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Where did that damn "l" go? 
Hey, didn't realize you're in Fountain Valley!
Try J&K Electronics in Westminster. That's precisely the same place I got the stuff I'm using. I don't think it's same brand as in the link. It's in a white tube.
Hey, didn't realize you're in Fountain Valley!
Try J&K Electronics in Westminster. That's precisely the same place I got the stuff I'm using. I don't think it's same brand as in the link. It's in a white tube.
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11-06-03, 12:26 PM
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Well, I just added a PMC and it didn't help. Still working on the grounds, and I'm trying the 44k fi cleaner. 3000 - 4500 still have various slight 'pauses' on part throttle.
11-06-03, 08:33 PM
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Originally posted by wstrohm
Would someone please spell out "PFC" and "PMC" for me? Thanks!
---- Bill
Would someone please spell out "PFC" and "PMC" for me? Thanks!
---- Bill
PFS is Peter Farrel Supercars
PFC is Power Full Computer by Apexi (meaning NOT piggyback)
Also PFS PMC is a repackaged EFI PMS.
Confused yet ?
11-10-03, 01:40 PM
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Originally posted by Fred Sickert
PFC is Power Full Computer by Apexi (meaning NOT piggyback)
PFC is Power Full Computer by Apexi (meaning NOT piggyback)
http://www.apexi-usa.com/electronics_fc.asp
11-10-03, 11:23 PM
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New O2 sensor ? I think mine was replaced not long ago. I can feel a couple of very slight flat spots now, 3k is most noticeable. It seems that closed loop mode is creating most of the problem. Not sure why this would happen after 500 miles. Does the ECU adjust over time ?
11-10-03, 11:25 PM
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Originally posted by rotary-tt
I thought the PFC was a Power Fuel Computer
http://www.apexi-usa.com/electronics_fc.asp
I thought the PFC was a Power Fuel Computer
http://www.apexi-usa.com/electronics_fc.asp
11-11-03, 11:09 AM
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Originally posted by wstrohm
Sounds like you need a new O2 sensor! Did you have any diagnostic codes, or does your new "PMC" not have those outputs?
---- Bill
Sounds like you need a new O2 sensor! Did you have any diagnostic codes, or does your new "PMC" not have those outputs?
---- Bill
11-11-03, 04:14 PM
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Originally posted by Fred Sickert
I read in a past post that someone fixed his 3k hesitation by grounding the secondary fuel rail. Anyone else try this ?
I read in a past post that someone fixed his 3k hesitation by grounding the secondary fuel rail. Anyone else try this ?
I'll tell you what didn't work:
Ground exhaust system
New rear subframe ground
New TSB ground from intake to firewall.
Additional ground from intake to ABS bolt.
Additional ground from battery to shock tower(i.e. Pettit).
Cleaning up factory ground from fuses to shock tower
Additional ground from battery to motor
Cleaning up main ground to trans
Resetting the ECU
New battery
New O2 sensor
Pulling apart as many connectors as I could and cleaning.
All grounds above were sanded off and sprayed with either battery terminal spray or electrolytic grease.