Long time listener(1 month), first time caller.
Just picked up my first lude. I got a '98 base with 255k on the clock. Previous owner(a friend) said they had trouble smogging in October. Normally I'd pass it up, but the price seemed right and I'm usually competent enough and have enough people to tackle anything.
I have been through the forums endlessly the last couple weeks from troubleshooting to watching tutorials. Here's where I'm at.
When I bought it, it was surging due to internal fitv "nut". Cleaned, bled, fixed. While I was at it, cleaned egr and iac.
First time I went to smog it, I had seafoam in the tank. Was detecting high hc, low Co2(idle) and lean misfire. 2500rpm burns great. Tech said to run the seafoam out, try again with fresh gas.
Decided that before I went back, I'd take care of valve adjustment and check comp. Comp was 150-150-170-190. Pulled cover, checked lash before adjustment. Unsurprisingly, cyls 1 and 2 were close to spec but out. Cyl 3 was a little worse, cyl 4 was the worst, like .010 on exh. Set lash to spec.. 007-008exh .006-007 in. My method was to tighten so the thicker feeler could barely go in with forceful wiggling, thinner feeler went through with slight drag. After adjustment, it comp is 155-165 across the board(checked at wot).
Took it back to smog again. Same thing, except he didn't say anything about misfire. At 2500rpm, hcs drop to 40ish. About 7 sec after brought to idle, hcs start to climb, at about 15 sec they're in the 400 area. He plugged in his obd2 diagnostic and said it's trimming 20% fuel(presumably at idle). Before valve adjustment, 2 plugs were reading lean, now all 4. If it was bad plugs/dizzy I'd assume plug read would be rich to match the excess fuel that o2 sensor and sniffer is reading. If it was vac leak I'd assume o2 sensor would be showing lean to match plugs.
Picked the car up from a friend who said cat is 2 years old. Obviously cat testing with IR gun is on the menu but I'm inclined to believe that's not the problem. I was thinking upstream o2 was lazy, but that doesn't explain high HC with lean plug reads. I don't think downstream o2 does much for af trim, more so checking that cat is good and making small af adjustments?
My theory at this point is that fuel isn't properly atomizing through the injectors. Basically some vapor is burning but since most is larger droplets, the majority gets sent down the pipe. Just seems odd it would be all 4 injectors if it was a situation of dirty injectors unless all 4 seats(don't know correct term) managed to just wear out..
Overall, the car doesn't really run bad. Maybe lacking a little power low to mid rpm but mid all the way through vtech seems good. It happily chirps into second without clutching it up.
Sorry for the TL;DR just figured I'd give as much info as possible. It's possible I forgot something and I'll probably be adding more info to this thread as the days go on until I get her butthole clean.
(also posted on prelude power. Didn't want to be a gnat, waiting for post approval and just hoping for a broader range of possibilities)
Just picked up my first lude. I got a '98 base with 255k on the clock. Previous owner(a friend) said they had trouble smogging in October. Normally I'd pass it up, but the price seemed right and I'm usually competent enough and have enough people to tackle anything.
I have been through the forums endlessly the last couple weeks from troubleshooting to watching tutorials. Here's where I'm at.
When I bought it, it was surging due to internal fitv "nut". Cleaned, bled, fixed. While I was at it, cleaned egr and iac.
First time I went to smog it, I had seafoam in the tank. Was detecting high hc, low Co2(idle) and lean misfire. 2500rpm burns great. Tech said to run the seafoam out, try again with fresh gas.
Decided that before I went back, I'd take care of valve adjustment and check comp. Comp was 150-150-170-190. Pulled cover, checked lash before adjustment. Unsurprisingly, cyls 1 and 2 were close to spec but out. Cyl 3 was a little worse, cyl 4 was the worst, like .010 on exh. Set lash to spec.. 007-008exh .006-007 in. My method was to tighten so the thicker feeler could barely go in with forceful wiggling, thinner feeler went through with slight drag. After adjustment, it comp is 155-165 across the board(checked at wot).
Took it back to smog again. Same thing, except he didn't say anything about misfire. At 2500rpm, hcs drop to 40ish. About 7 sec after brought to idle, hcs start to climb, at about 15 sec they're in the 400 area. He plugged in his obd2 diagnostic and said it's trimming 20% fuel(presumably at idle). Before valve adjustment, 2 plugs were reading lean, now all 4. If it was bad plugs/dizzy I'd assume plug read would be rich to match the excess fuel that o2 sensor and sniffer is reading. If it was vac leak I'd assume o2 sensor would be showing lean to match plugs.
Picked the car up from a friend who said cat is 2 years old. Obviously cat testing with IR gun is on the menu but I'm inclined to believe that's not the problem. I was thinking upstream o2 was lazy, but that doesn't explain high HC with lean plug reads. I don't think downstream o2 does much for af trim, more so checking that cat is good and making small af adjustments?
My theory at this point is that fuel isn't properly atomizing through the injectors. Basically some vapor is burning but since most is larger droplets, the majority gets sent down the pipe. Just seems odd it would be all 4 injectors if it was a situation of dirty injectors unless all 4 seats(don't know correct term) managed to just wear out..
Overall, the car doesn't really run bad. Maybe lacking a little power low to mid rpm but mid all the way through vtech seems good. It happily chirps into second without clutching it up.
Sorry for the TL;DR just figured I'd give as much info as possible. It's possible I forgot something and I'll probably be adding more info to this thread as the days go on until I get her butthole clean.
(also posted on prelude power. Didn't want to be a gnat, waiting for post approval and just hoping for a broader range of possibilities)
