99 OBS, engine swap, delta cams, low rpm missing/hesitation

[blk99obs]

Hey everyone, I'm having some problems with my daily driver. I'm in a pretty bad financial situation at the moment, so I was hoping to narrow it down, and not have to go with the shotgun approach on replacement parts. Sorry I wrote a book here but I wanted to be thorough.

 

Car is a 99 OBS, has the phase 2 EJ22, Cali emissions, has MAP sensor rather than MAF like on most subies I've seen.

 

I've spent a lot of time wrenching, so this is far from my first dance with engine swaps.

 

The story on the car is, the old engine developed a rod knock and had to be replaced. Aside from the knock, it ran like a top.

 

I ordered a low mileage motor, I forget the stated mileage, but was under 100k.

 

Heres what I did: I pulled the cams on the new to me motor, sent them to Delta for the torque grind, and when they came back, I installed them per the instructions that were floating around at the time.

I then tore the old motor out, and transferred the intake manifold with new gaskets, put I'm pretty sure every sensor, timing components, etc on to the new motor from the old one (old one had just gotten timing belt service before the rod knock appeared)

 

Now from what I can tell, the new to me motor had different emissions equipment on it, the injectors looked a little different, the notched ring that goes on the crank, for the crank position sensor to read, had less notches in it, etc. So I simply transferred all of that stuff from the old motor to the new one. I put new plugs in it for good measure, and back in she went, with new exhaust gaskets, fresh oil, coolant, etc. 

 

The motor starts fine, idles smoothly, and runs good in the high revs, but when you mash on it at lower rpm it will hesitate "pop pop pop" and then after a second or two take off like normal. Also, if I free rev it from idle, it will do the "pop pop" and hesitation, and then rev as normal. No codes other than occasionally getting a p0420 code from the car, but it hasn't done that in a while. I always figured it was just the rear o2 sensor crapping out, and the car has popped that code occasionally since I've owned it, pre-swap, and pre-front o2 sensor change, so I kind of doubt if its related to my problem.

 

To sum it up I have:

a sub-100k mile ej22 phase-2 motor

Delta Torque Cams

K&N drop in filter

Aftermarket muffler

New NGK plugs

*Fairly recent front o2 sensor, but that is suspect at this point, due to the symptoms

*Plug wires were replaced not too long ago, though I don't know if they are very good, so they are suspect at this point.

Fuel filter has been changed not too long ago

Tried replacing coil pack with another used one

Tried seafoam in gas incase the fuel system is plugging up

Tried another set of plugs

 

I've read everything from it could be my plug wires, to crank sensor, to o2 sensor, to fuel injectors, TPS sensor, to fuel pump failing, or maybe I adjusted the valves wrong. I don't have nearly the money/time to attack all of that at this point. So I'm hoping someone can point me in the right direction. Thanks!

Edited April 21, 2015 by blk99obs

[Crawlerdan]

i recently had the same symptoms. i discovered that the stock high mileage fuel pump was fine on the stock engine, but the cams allowed more air and fuel (duh) and the pump couldnt keep up at higher rpms. replaced it with a new one and tahdah

 

not sure if that will help, but thats what happened here

[blk99obs]

Hmm yea that may be whats at fault here, although my problem is at low rpm, and it runs good up top. I asked a local mechanic today, and he said it sounds like plug wires. So I'm gonna pull those off and check them out with my multimeter, see what I get. If ignition checks out then I'll be looking to the fuel system next.

[blk99obs]

Update: I went to a local mechanic I trust very well, and asked a guy at the junkyard who's been working with cars probably twice the time I've been alive. They both said spark plug wires. So I grabbed my multimeter and tested my wires in the parking lot, got about 7k ohms on all but cyl 3, which I couldn't get any sort of read on. So I went and got some new NGK wires. According to their computer at NAPA, Bosch is the OE replacement, but they only come with a one year warranty, where as NGK is lifetime. The price difference is a dollar, so the obvious choice for me was NGK. So far, so good! I launched the beast at low rpm (being as nice to the tranny as possible, not so much the clutch haha) and it took off pretty good, no popping or anything like before! Did it again on my gravel road, and it broke loose the front tires for a chirp, then took off spitting gravel on both ends, which isn't easy to do with 27" all terrains... So I think that problem is solved. I'll see in the coming days if I end up replicating it during my normal driving. Anyway, the lesson learned here, is to not buy cheap rump roast wires, because those ones I got from Kragen only lasted a couple years and maybe 20k miles.

[AdventureSubaru]

Subarus are tough on plug wires. NGK and Subaru are the only ones I've heard recommended. Glad it was a simple fix!

[lstevens76]

This isn't a recommendation, just correcting the misinformation that NAPA gave you.  Bosch plug wires carry a lifetime warranty as well.  I put them on my '90 Legacy and have the boxes for them which go on and on about there warranty.

 

Just remember, a warranty doesn't mean a product is good or bad.  And I can't vouch for Bosch as they haven't been on the car long enough.

Edited April 22, 2015 by lstevens76

[blk99obs]

I agree that the warranty doesn't necessarily mean they are any good, but it does mean I can exchange them rather than buying another set for the forseeable future. I know NGK to make good plugs, and I never had trouble with their wires on my civic, even used ones that came with a JDM motor I bought, and were who knows how old, never gave me problems. At any rate, seems like its fixed but I'll see the next couple times I drive it. Now I just need to chase down a coolant leak. I saw some coolant on the bottom of the rad on the passenger side, and a small drip where the bottom hose connects to the plastic elbow on the bottom of the block, so I'm thinkin I'll probably be in for a new rad and hoses. Anyone running one of those aluminum rads off of ebay? Figure I'd like to lose the plastic tanks if I'm gonna replace it.

[lstevens76]

You don't mention if your OBS is a standard or automatic. I ordered a TYC radiator this week for mine. Being an automatic I couldn't find an all aluminum radiator.

 

If your OBS is a standard the all aluminum are readily available.

[blk99obs]

You don't mention if your OBS is a standard or automatic. I ordered a TYC radiator this week for mine. Being an automatic I couldn't find an all aluminum radiator.

 

If your OBS is a standard the all aluminum are readily available.

My bad, has a legacy 5 speed in it I've found them on ebay, like this one, just wanted to see if anyone is running something like that.  http://www.ebay.com/itm/SUBARU-IMPREZA-WRX-GC-GC8-MT-MANUAL-TWO-ROW-CORE-ALUMINUM-RADIATOR-12-BLACK-FANS/150698980304?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3Dc7c63559d2b14751bcec90486e089100%26pid%3D100033%26rk%3D1%26rkt%3D4%26sd%3D150698980304

 

I suppose you could run an aluminum rad, and add a separate stand-alone tranny cooler for your auto?

Edited April 22, 2015 by blk99obs