Car stumbles after changes
05-25-2017, 02:58 AM
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Car stumbles after changes So, first off I'll give a rundown of what has happened in the past 6 months that my car has been down:
1) Painted (not related, but was the impetus for everything else)
2) New wiring harness created and installed
3) Upgraded lifters
4) New pushrods for upgraded lifters
5) Ported heads installed (swapped over springs/valves from old head, had valve seats cut and heads resurfaced, new valve stem seals installed)
6) New head gaskets / bolts
7) New plugs, gapped to 0.55
Prior to this I did a cam swap with TSP 228R and did a street tune on it that was running great. After I got the car back, I started to reinstall everything to work out any bugs, and thus far there hasn't been anything major...except when I got to drive it, at which point it wants to stumble and bog down and is barely driveable.
I initially thought it was the O2 sensors crapping out because I checked the scanner and saw that they would start off low voltage and then start to climb up to about 900+ mV, however once the car got up to temp they would start cycling. There was also a period where the LTFT for bank 1 showed 25% and bank 2 was -1.6%, both of these constant and unchanging, with the STFT being 0% on each side without any change. When the car finally got up to temp the as well, this seemed to resolve with them averaging about 3-5%.
I do know that the car is absolutely dumping fuel. Black soot out the tailpipes and a horrendously strong smell of fuel, enough so that just being behind the car burned the eyes and was noxious.
Now, the heads were just some hand ported 241s, nothing wildly major from the stock 241s I had on there, and with these being installed I would *think* that I would just run slightly lean, not rich, so I'm not sure what is what. I have noted that it almost sounds like the intake is much louder than what I remember, but I cannot verify that.
So, with all that stated, any thoughts? I've been banging my head for the past few days trying to figure out what to check or look for. My next step is to get an intake manifold gasket kit and swap those out, since I reused my old manifold gaskets.
EDIT: Also to note, I am getting absolutely no codes. I got a few initially for some minor things I had to fix in my wiring harness, but those were resolved and have not come back.
1) Painted (not related, but was the impetus for everything else)
2) New wiring harness created and installed
3) Upgraded lifters
4) New pushrods for upgraded lifters
5) Ported heads installed (swapped over springs/valves from old head, had valve seats cut and heads resurfaced, new valve stem seals installed)
6) New head gaskets / bolts
7) New plugs, gapped to 0.55
Prior to this I did a cam swap with TSP 228R and did a street tune on it that was running great. After I got the car back, I started to reinstall everything to work out any bugs, and thus far there hasn't been anything major...except when I got to drive it, at which point it wants to stumble and bog down and is barely driveable.
I initially thought it was the O2 sensors crapping out because I checked the scanner and saw that they would start off low voltage and then start to climb up to about 900+ mV, however once the car got up to temp they would start cycling. There was also a period where the LTFT for bank 1 showed 25% and bank 2 was -1.6%, both of these constant and unchanging, with the STFT being 0% on each side without any change. When the car finally got up to temp the as well, this seemed to resolve with them averaging about 3-5%.
I do know that the car is absolutely dumping fuel. Black soot out the tailpipes and a horrendously strong smell of fuel, enough so that just being behind the car burned the eyes and was noxious.
Now, the heads were just some hand ported 241s, nothing wildly major from the stock 241s I had on there, and with these being installed I would *think* that I would just run slightly lean, not rich, so I'm not sure what is what. I have noted that it almost sounds like the intake is much louder than what I remember, but I cannot verify that.
So, with all that stated, any thoughts? I've been banging my head for the past few days trying to figure out what to check or look for. My next step is to get an intake manifold gasket kit and swap those out, since I reused my old manifold gaskets.
EDIT: Also to note, I am getting absolutely no codes. I got a few initially for some minor things I had to fix in my wiring harness, but those were resolved and have not come back.
Last edited by Shigun; 05-25-2017 at 03:09 AM.
05-25-2017, 07:59 PM
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Update: all the brand new plugs were fouled, jet black, presumably because of the vacuum leak I had early on and maybe one with the intake manifold given I changed those gaskets too. Bought a new set, car runs good, however either the valve train is super super noisy, or I've got an exhaust leak, not sure which yet.
05-26-2017, 11:10 AM
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Moving used parts from one head to another is not usually a good idea. Did you check your preload with the new lifters? If you aren't within the manufacturers specs, you're going to have some noise in there and shorten the lifespan of the lifters and possibly the springs.
05-26-2017, 12:41 PM
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Moving used parts from one head to another is not usually a good idea. Did you check your preload with the new lifters? If you aren't within the manufacturers specs, you're going to have some noise in there and shorten the lifespan of the lifters and possibly the springs.
I did check the preload on the lifters, though admittedly that was a bit of a feat given that I've never done it before and had to come here for some guidance, that thread is here.