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KA24DE running funny

2K views 9 replies 3 participants last post by  Katfan27 
#1 ·
hey all, been a while since I have been on here, but ive been pretty busy! Just recently got an S13 KA24DE motorset and swapped it into a 1993 hardbody, but im having some issues. well first, here are a couple pics:





Anyways, it seems to run pretty good, i think the engine has close to 300k on it, but i was told it was bought from an older guy that just dailied and babied it. fair enough, got a pretty good deal on it all.

BTW, yes, I did search. I set the TPS correct, i have new plugs, i ohmed out all the spark plug wires and injectors.

So in neutral, it seems to rev up pretty good, however at idle it is missing slightly. trying to adjust timing via rotating the distributor doesnt seem to do anything, even with brand new NGK plugs. when I drive it, on partial throttle it hesitates and misses a bit, but if Iput the pedal all the way down, it seems to run smooth (even though a bit slow lol). when i take my foot off the pedal, and let it coast in gear, it backfires like crazy (full 3" exhaust with 2 resonators in-line). However, I was messing around with the TPS today, and found that if I disconnect the TPS, it seems to run better, and doesnt backfire at all when driving.

I set the TPS at idle to 0.49 volts, which is in spec, but could the TPS still be bad?

I also ordered a new O2 sensor and new timing kit, since im not sure when it was last changed.

Any help is greatly appreciated!
 
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#2 ·
Sounds like you have an over fueling issue.

Have you checked for codes on the ecu? I'd start there...you might a leaky injector code or something similar.

Also check all your piping for your intake make sure none of your couplings are loose or cracked because its possible you could be getting in unmetered air which can and will cause similar problems.

If you still can't find the problem maybe pull the injectors and make sure they have good orings on them as well as that the pintle cap is still in place on them.
 
#4 ·
havent checked for codes, I can try and do that today after work.

all the piping is good and clamped down, the couplers and piping are all brand new.

as for the injectors, when I first got the engine, i found one injector was dead, and another had high resistance, so i replaced them. took them all out, cleaned them up good, made sure the o-rings were good on them. but i guess i can double check the o-rings too. might need to order a new set of them. they all have the caps installed snug.

yes i did warm the engine up and unplug TPS to mess with the distributor timing....ill have to actually put a light on it sometime though and try again.
 
#8 ·
didnt think of a dirty MAF, however I know (well, 99% sure...) its working. when i was swapping the engine in and making up my intake and such, i would start it sometimes without the MAF plugged in, and it would sit at idle at around 2k RPMs. when i plugged the MAF in, it dropped to a more normal idle. but I can clean the MAF no problem, ill give that a try.

and yes, I used grease on the injector o-rings when I was putting them in, even put a small amount in the fuel rail itself to help the injectors go in even easier.

I also put seafoam in the oil, gas tank, and some in a vac line, as well as some Lucas injector cleaner in the tank. have already run through that whole tank of gas and am about to change the oil again. so hopefully fresh fuel, fresh oil, clean MAF, new timing kit, and new O2 sensor helps!
 
#9 ·
update: got the truck running great!! Katfan was right, it was an over-fueling issue. decided to pull the fuel rail again to check for leaks, and one of the injectors was pouring out fuel when just the pump was on. replaced all o-rings and it runs like a champ!
 
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