Car doesn't have power under 2500 rpms
06-21-2004, 03:40 PM
#1
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Location: Miami, FL
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Car doesn't have power under 2500 rpms
as the subject stated, my car feels like it lost power under 2500 rpms. my car stalled out on me yesterday, so i replaced the plugs and the car started back up. thing is... it sounds like it's misfireing now, and the car seems to have lost power off the hole. when im driving, the car seems to shake a little under 3k, and when i step on it from a stop or rolling slow at around 10mph or more, like i said before, it feels like ive lost power. i checked the timing and it was at 12*btdc, so i changed it to 8*btdc. i have a laptop and datamaster, so if anyone needs me to log the car, i'll do it and post the files on my server. im really upset because my car shouldnt be this slow. it feels pretty much the same after my rebuild, but the thing is, i had my heads ported, put headers on, and had a comp cam 502 cam installed. also had a custom prom put in, as well as 24# svo injectors.
atleast i should be running in the 13's since i was running 14.5 stock... but today, i barely beat an audi a6 2.7l biturbo... i don't know exactly what they run, but online i found a place that says they run 14.6, and a place that says they run 15.2... so i dunno. if anyone can help me figure out why my car is missing and why it feels like it lost power below 3k, you have no idea how much i would appriciate it. it sucks to have a mechanic you trust just to realize he isnt as good as you first thought =\
atleast i should be running in the 13's since i was running 14.5 stock... but today, i barely beat an audi a6 2.7l biturbo... i don't know exactly what they run, but online i found a place that says they run 14.6, and a place that says they run 15.2... so i dunno. if anyone can help me figure out why my car is missing and why it feels like it lost power below 3k, you have no idea how much i would appriciate it. it sucks to have a mechanic you trust just to realize he isnt as good as you first thought =\
06-21-2004, 04:55 PM
#2
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Location: motor city
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Firing order? did it shake before you "tuned" it? cracked plug? I assume that alll the wires are in good shape and not laying on any exausht pipes? cylinder 5 & 7 are easy to switch and wouldn`t miss too much at idle??
06-21-2004, 05:30 PM
#4
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the plugs and wires are brand new. the guy who burned my chip told me to put the fp to 39 psi w/ the vacuum hose disconnected since he programmed the chip to work with my 24# svo's.
btw, when i got the car back from my mechanic, i told him to set the fp at 39 psi and timing at 8*btdc... i checked everything last night, fp was at 42, and timing was at 14*btdc. i corrected everything to the propper specs, but i still hear a slight miss. maybe the firing order is goofed and i need to switch around a few wires. ill let you guys know in a few when it stops raining if the firing order is incorrect.
btw, when i got the car back from my mechanic, i told him to set the fp at 39 psi and timing at 8*btdc... i checked everything last night, fp was at 42, and timing was at 14*btdc. i corrected everything to the propper specs, but i still hear a slight miss. maybe the firing order is goofed and i need to switch around a few wires. ill let you guys know in a few when it stops raining if the firing order is incorrect.
Last edited by dj haf; 06-21-2004 at 05:34 PM.
06-21-2004, 08:17 PM
#7
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Location: Miami, FL
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yeah, i have an msd 6al box and i gapped my spark plugs at .050. i dont think they're gapped wrong because it feels better gapped there than at .035
what else can cause a miss? my mechanic told me i had a extremely small tiny crack in the heads, so he had it soddered and fixed and put back in my car. do you think that may be causing my my car to miss?
what else can cause a miss? my mechanic told me i had a extremely small tiny crack in the heads, so he had it soddered and fixed and put back in my car. do you think that may be causing my my car to miss?
06-21-2004, 08:58 PM
#9
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how would i go about checking the injectors?
and im thinking about doing a compression test as well. my friend has the tools to do it, but he said he can't do it for me. does anyone know of a site or something that can show me how to do a compression test?
and im thinking about doing a compression test as well. my friend has the tools to do it, but he said he can't do it for me. does anyone know of a site or something that can show me how to do a compression test?
06-21-2004, 09:10 PM
#10
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unless u have a noid light you''ll probaly have 2 go back 2 ur mechanic.... i dont know if this has been adressed yet but have u checked the fuel pressure... there is also a fuel injector balance test to c if there all spraying out the same amount of fuel.... have you checked ur fuel filter lately?
06-22-2004, 08:09 PM
#13
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Location: Pocono and Millersville, PA
Posts: 201
I am basically having the same problem. I rebuilt my 350TPI because of this problem. I thought the crate cam was not to specs for the computer so I put a comp cam in. Put 24lb injectors in also. Started her up and she seemed ok. Got the timing set perfect and everything. I take her out on the road and the car will bog under 2k. Once I hit 2,000RPMs the car has power again. Also the tach will go crazy bouncing up and down while its under 2k. I thought it might be the TPS but just bought another one and it didnt solve the problem. So far I know its not wires, spark (Because I checked), injectors (because their new), TPS, cam. I am starting to think its something with the ignition though. Anyone else have this problem before?
