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S Chassis Technical discussion related to the S Chassis such as the S12, S13, S14, and S15.


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Old 04-21-2012, 12:02 AM   #1
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Question SR running VERY rich + idle vac low

My SR (redtop) is running rich as hell and is pulling low vacuum at idle(10-13 for 1k RPM) and it breaks up and bogs throughout the RPM band up to about 4k and have no leaks and comp test came up with 140,135,135,140. But when i unplugged the MAF while running today the vac at idle went to 16-17(950rpm) and idled for about 30 seconds then cut off. Do i need a new MAF?, and if not what do you think might be the issue. Also checked all injectors, put in new 7es plugs gapped at .28, checked TPS for correct voltage(PASSED) and replaced the coolant temp sensor. Any help is great Thanks. One more thing, it seems to drive smoother after its been in the higher RPM for awhile, like highway driving. MPG Highway = 20-23
City = 10-12
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Old 04-21-2012, 09:11 AM   #2
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Does it do it warm/cold/indifferent? How's your timing? Sounds like the MAF is done for... Have any local buddies that you can swap a known good one with?
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Old 04-21-2012, 10:58 AM   #3
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I still have to make a plug wire thing to check my timing and as far as temp goes it seemed to only do it when war until i changed my CTS then it ran PERFECT for 1 day then the next day it it did it always(warm,cold) and seemed worse(bogging more). I'm working on the swapping MAF thing. What cars can i get a MAF from if i needed to buy a new one?
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Old 04-21-2012, 11:42 AM   #4
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I'm not familiar with SR Maf compatibility... I've been MAP for along time now. Someone else may know, search it as I know it's been covered.
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Old 04-21-2012, 12:47 PM   #5
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sohc, or z32 with a ecu tune
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Old 04-21-2012, 09:59 PM   #6
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Stock ka24e maf works with the sr. Check the coolant temp sensor. Also for vacuum leaks.


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Old 04-22-2012, 09:58 AM   #7
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^Checked both, and waiting on word back about a MAF.
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Old 04-22-2012, 10:06 AM   #8
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Do you have a gauge? Is that how you know you're running rich? Like pegging 10.0 at idle? Maybe a leaky injector?


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Old 04-22-2012, 04:50 PM   #9
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No gauge, but i know the symptoms of running rich and have them(fouled plugs, low mpg, black smoke from exhaust sometimes, bogging, back fire/flames out exhaust during regular driving, etc.) I was trying to figure out a way to test my o2 sensor but this is my first time dealing with a skinny so i was thinking of just unplugging it and seeing if it runs any different(worse). How would i check for a leaking injector without special tools?
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Old 04-23-2012, 07:20 PM   #10
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Pull the rail and turn the fuel pump on. That way the fuel pump primes but the injectors don't get a signal. There shouldn't be a leak at all.

Possibly a bad o2....possibly.


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Old 04-23-2012, 11:53 PM   #11
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OK, will do. No word back on the MAF so I'm just gonna buy a new one and probably an O2 also. I'm really leaning toward it being a faulty MAF due to the fact that with it unplugged EVERYTHING ran PERFECT, vacuum was good, RPM were good exhaust smell was normal, no smoke, no bogging and popping on free rev. So I'll have to wait and see this weekend when i go pick up the new one. Will keep updated(also about to Google how to run test on a hotwire MAF sensor) Thanks for all the help so far.
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Old 04-24-2012, 12:29 PM   #12
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Ran some test today and have results. Injectors are not leaking and continuity on the MAF wires is good. But when i did the continuity test i opened the connector some and it wasn't making a good connection and when i checked the other 2 they were loose also. So i pushed down the backside of the connector on all three and plugged it back up and it idled fine, vacuum was a little low for my taste but was smooth so i took it to get some gas and it drove smooth and on the way home i turned the tru boost back on and it boosted fine 12-13psi(Almost got me a ticket) no bogging, studdering, smoking or any of that. I will know for sure if all is well on the drive to work in an hour.
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Old 04-24-2012, 06:31 PM   #13
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Resolved
Plug wires were loose inside and weren't making good connection, runs great now. Thanks again for all the help everyone.
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