LQ9 swap; rough idle problem... need help diagnosing!
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LQ9 swap; rough idle problem... need help diagnosing! First off, thanks for any help you guys can provide. I have a 68 Camaro just completed my swap to a fuel injected 6.0LQ9/TKO600; all stock internally with L-92 heads and cam (595 lift, 230 dur.) Did upgrade to 36lb inj's (used from eBay) Motor and heads were all set up by a professional machine shop.
Car starts and will maintain idle, but when in neutral I try to give the car gas it bogs down and almost sounds like a misfire. Can't get the car to rev past 15-1700 rpm tops plus its very rough sounding (damn near like a diesel.) The car has brand new MSD plug wires and iridium spark plugs (can't remember the brand) So far I have swapped coil banks, checked each individual plug and wire to ensure a good connection and checked for any intake leaks with no luck. My injectors were purchased used off of eBay, I'm thinking that is my next step chasing this gremlin.
Any other ideas what I should check for? Thanks in advance!
-Nick
Car starts and will maintain idle, but when in neutral I try to give the car gas it bogs down and almost sounds like a misfire. Can't get the car to rev past 15-1700 rpm tops plus its very rough sounding (damn near like a diesel.) The car has brand new MSD plug wires and iridium spark plugs (can't remember the brand) So far I have swapped coil banks, checked each individual plug and wire to ensure a good connection and checked for any intake leaks with no luck. My injectors were purchased used off of eBay, I'm thinking that is my next step chasing this gremlin.
Any other ideas what I should check for? Thanks in advance!
-Nick
since you have fuel injection that means your running off of a PCM, so my question is to you is did you tune for the upgrade 36lb injectors. If not your flooding your motor with fuel, if i was you i would stop running it until you get a tune for your upgrades.
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Yes Sir it was tuned for the bigger injectors. I'm hoping for a ground or fuel issue... (fingers crossed anyways)
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Update Last night:
1- I pulled each plug wire to ensure all had spark, all were good and strong
2- Used noid light, all injectors were recieving a pulse
3- Compression check: ZERO compression on #1 cylinder.... I have not removed valve cover yet, my engine builder is coming to look at it today. I checked another cylinder and 1 cylinder on my buddies LQ9 to ensure the cheapo compression tester from Autozone was working, it was fine.
I forgot to mention with the L92's and bigger cam that valve clearance was "tight" as I was told by my machine shop/engine builder but that it "should" be fine. I can't remember the exact measurement but he did measure for clearance without a gasket on the head and he said it was good to go. SO I droppped $1700 for a complete tear down, cleaning, valves and reassembly of this motor and set up of the heads. I'm pretty much blown away at this point, he's coming to my house to look at the car himself tonight.
Any recommendations on what I should do or say when he comes to the house tonight? Needless to say I'm pissed, but I don't want to burn any bridges either
1- I pulled each plug wire to ensure all had spark, all were good and strong
2- Used noid light, all injectors were recieving a pulse
3- Compression check: ZERO compression on #1 cylinder.... I have not removed valve cover yet, my engine builder is coming to look at it today. I checked another cylinder and 1 cylinder on my buddies LQ9 to ensure the cheapo compression tester from Autozone was working, it was fine.
I forgot to mention with the L92's and bigger cam that valve clearance was "tight" as I was told by my machine shop/engine builder but that it "should" be fine. I can't remember the exact measurement but he did measure for clearance without a gasket on the head and he said it was good to go. SO I droppped $1700 for a complete tear down, cleaning, valves and reassembly of this motor and set up of the heads. I'm pretty much blown away at this point, he's coming to my house to look at the car himself tonight.
Any recommendations on what I should do or say when he comes to the house tonight? Needless to say I'm pissed, but I don't want to burn any bridges either
I would say You have nothing to worry about ,,,,,most likely there are a cpl lifters that have'nt got set to the correct pre-load and are probably holding 1 or 2 or more valves open just a few thous ,,,,,,,,I've seen this before . I'm guessing You probably have'nt had it running for more than maybe 5 or 10 min.
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Update #2 Engine builder came out and found that I needed a small spacer under my rockers; with my Morel link bar lifters/custom ground cam and 7.4" length pushrods I wasn't getting compression in a few cylinders... My car runs much smoother at idle now and idles fine.
My next thing is when you give it gas, it's still not running right. Won't rev up and past 15-1700 rpm and sounds like a diesel.... My buddy has a running LQ9 and we were going to start swapping sensors one by one to check for bad:
1) IAC
2) TPS
3) MAF
4) computer tune
Any other recommendations? Thanks!
My next thing is when you give it gas, it's still not running right. Won't rev up and past 15-1700 rpm and sounds like a diesel.... My buddy has a running LQ9 and we were going to start swapping sensors one by one to check for bad:
1) IAC
2) TPS
3) MAF
4) computer tune
Any other recommendations? Thanks!
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Update #3 Bad ECM and/or tune! Found out I have a bad ECM and/or tune. I won't put his name on blast, but this is the 2nd ECM I recieved from him with an issue. The first ECM I recieved from him the VATS wasn't turned off. I'm not sure what the problem with this one is. I took my buddies ECM out of his car (LQ9 with a different cam) and the car started up and ran great, revved up great and everything. The funny thing is that my ECM and my buddies ECM were tuned from the same guy??! So I emailed him today asking what the possible issue could have been...
Any ideas what could have possibly made my car run like total crap with my ECM/tune?
Any ideas what could have possibly made my car run like total crap with my ECM/tune?
