Fresh Rebuild, Runs but won't Idle...

I figured I was bound to have problems w/ this rebuild. First it wouldn’t even start, we tracked that down to a bad #2 injector. Now it will start (if given some throttle) and will run (already idled the engine at 2k for 20 min to initiate break-in) but will not idle on it’s own, it just stalls. We already tried adjusting the idle screw and that did nothing (as I figured). It’s not throwing any codes.

It’s late, so I’m going to bed and plan on doing as much research as possible tomorrow, but was figuring I’d get a jump on the game and see if anyone had any input.

Here’s all the info, I’ll try to list everything relevant:

92 GSR chassis
b17a block and head, standard rebuild machine work and parts
p30 pistons
ITR intake cam w/ spoon cam gears and ITR valvetrain
ITR intake manifold
unknown TB (probably b18c gsr, it’s been taken apart, cleaned, put back together)
stock injectors cleaned by cruzin performance
stock intake
Megan 4-1 header
SMSP cat
RS*R exhaust
stock intake
AEM fuel rail
B&M fpr (fp is currently right around 40psi)
stock p61 ecu
ngk plugs
ITR plug wires

This is definitely the most involved rebuild I’ve done, almost everything has been taken apart, cleaned, and/or replaced w/ OEM or better parts, so there are a lot of variables. Any knowledgeable input is appreciated. TIA!

map sensor vacuum? my car will run without it on but will not idle.

Edit: bbut you ran it for 20 minutes… did you check your tps to see if it was within spec?

Any way that you could have air in your coolant system? I struggled with idle for quite a while after my build, and it turned out to be air a little bit of air in the coolant system coupled with a slightly pinched coolant line going to the IACV.

gil, I’m assuming the MAP is OK since it’s not throwing any code. The TPS was removed from the TB so we calibrated it before trying to start the engine, it was pretty much dead on after we set it.

ninezero, issues w/ low coolant or bubbles in the coolant usual cause idle issues such as a bouncy idle, it shouldn’t prevent the engine from being able to maintain idle. As soon as I let my foot off the throttle it dies. There could be air in the system, but I doubt it. Bled and burped the system just like I’ve done a million times before and there wasn’t anything to indicate a problem.

vacuum leak? timing off?

:umno: Vacuum leak would cause an increase in idle speed. Timing is not off, neither mechanical nor ignition. Ignition timing was set by eye (which is good enough if you know what you’re doing) and since it won’t idle the ignition timing can’t be set w/ a timing light…

I knew I shouldn’t have even bothered posting this.

UPDATE. Checked the plugs this morning, 1, 3, and 4 were all lean. I went ahead and changed all the injectors that I hadn’t changed last night. That made it so I was able to get it to idle. Messed w/ the idle screw some more and that seemed to help. I was able to smooth out the idle enough to check the ignition timing, which was dead on. The idle still is a bit shaky for me, fairly smooth but will stall sometimes if you’re reving at 1-2k and then lift off the throttle. Hopefully this is just something they can work out on the dyno.

Checked the plugs again after running it some more w/ the different set of injectors. #1 is a bit lean, #2 is a bit rich, #3 looks good, #4 is a bit lean. Not sure what to do about that.

Check the adjustment on the set screw that the throttle rotor stops on

I read that your FP is set to 40 PSI so I can’t help but wonder what happens if you raise it to about 50, long shot I know. I run 56 PSI and in the past if I set it lower I’ve always had idle issues with it bouncing high or bouncing low. I’ve always associated it with the Mugen ECU because of the ridiculoulous fuel map.

Let me know what else you find as you go, I’ll be subscribed to this thread to check and see what you come up with and see if I can help at all.

Just curious, have you tried a different ECU? You could have a bad ECU, bad ground… etc. A vacuum leak could definitely cause a terrible idle and really bad vibrations. How old are your spark plug wires? Spark leak could cause some major problems as well. Don’t hesitate to call if you need anything bud.

ECU should be good, it was good last time I used it, and plug wires are brand new OEM ITR. Looks like my lack of idle issue was caused primarily by the fuel injectors. I’m never using Cruzin Performance again, it seems that all 4 of my injectors weren’t up to par after coming back from them, and one wouldn’t fire at all. After changing the injectors I got it to idle and after some tweaking the idle was pretty good. It’s still working itself out a bit though. Fuel pressure was one of the things I tweaked to get it to run a little better, turned it up to about 50psi.

I performed the 20min at 2k warmup on friday night at about 1am with Nino helping out. Saturday I got it warmed up again and was able to go out and perform the load decel runs.

It still wants to stall occasionally when I let off the throttle, but not everytime, I’m hoping that’s something they can work on while it’s on the dyno.

It looks as if I’ve still got a very minor coolant leak from a port that I tried to plug, so that needs attention. And there was a minor leak associated w/ the fittings on the oil sandwich adapter, but after tightening those some more I think that leak is gone. There’s also some strange noises coming from the front suspension, especially turning sharp turns. But I only road tested the car for a couple miles so I didn’t have time to try and troubleshoot those. I figure it could be an issue w/ an axle or maybe something else is binding or maybe a brake heat shield got tweaked and needs to be moved.

I’ll hopefully have some time today to check out those leaks, check the plugs, look for the source of those strange noises, and maybe check the compression - any idea what kind of numbers I should be looking for at this point?

Thanks guys, I really appreciate the help :bowdown:

congrats on getting it running man:up: can you describe the noise in the front suspension at all. it is realy easy to tweek those dust shields and they make a horrific scraping sound

i suppose you don’t have a wideband to see what your afr is at? is the problem the same cold and hot?

Glynn, I feel like an idiot regarding the strange noises up front. Put the car up on jackstands to day and then loaded the suspension to look for any binding or anything. Couldn’t find a thing, everything checked out. Then my dad questioned the wheels… duh! I had completely forgotten about that. I got the shell w/ some EF civic Si wheels on it and haven’t thought about it since (got the shell last november). The civic wheels aren’t made for the Integra brakes and don’t clear the calipers! It’s close, but there was slight contact between the inside of the wheels and the calipers. Put my slipstreams on and bam, problem solved.

redtegra, no, I don’t have a wideband, but I did put an extra o2 bung on the cat so that one could be installed. I’ll have it tuned on a dyno with a wideband by Church.

The engine seems to be running really well now, took it out and put about 20-25 miles on it this afternoon. The engine runs really smooth, except at stop signs the rpm drops to about 400-500rpm, but at least it’s not stalling. I’m hoping this can be tuned to work properly.

I also spoke w/ Nino today and he brought up something I had forgotten - the fact that I’m not running an FITV. The ecu is a stock p61 so it’s expecting the cold idle to be handled mechanically rather than through the ECU. Nino had a similar problem w/ his build. In the end it’s not really a problem since they can remedy that when they tune it.

Some other very minor problems I already have figured out but just need to be actually taken care of:

  1. Slight coolant leak. There’s a really small coolant leak from a coolant nipple which I removed and plugged w/ an aluminum plug. I put some Hondabond on it as temporary fix. I have a spare thermostat housing so I think I’m just going to take it to a local shop and have them weld that hole up.

  2. Slight oil leak. There’s a very small leak coming from the fittings on my sandwich adapter. I thought the fittings were tapered pipe and sealed themselves but apparently not. I’ll be using some liquid teflon to seal them.

  3. Slight fuel leak. During all the troubleshooting I swapped all the injectors from my old motor. I didn’t bother changing the injector o-rings since they looked OK and weren’t all that old. One of them is leaking, which isn’t at all a surprise. I have an extra set of o-rings so I’ll put those on and that problem will be solved.

I’m SO excited, I finally got to drive the car! It’s been ages and it felt SO good. Engine feels smooth, trans is amazingly smooth, smooth like I’ve never had before, suspension needs some tuning but I’ll get to that eventually. Man, I can’t wait to get this thing out on the track. As soon as my shoulder heals and I can drive again I’ll need to sign up for a track day! woohoo!

Oh yeah, forgot to mention that I checked the plugs after doing my ring seating load decel process and they look good now. All cylinders are a nice milk chocolate color. Might not be perfect but still an indicator that things should be OK, the small tweaking and perfecting will be done during tuning.

After you get it broken in, and or maybe after the first oil change i would check the comprestion. Just to make sure the valves are sealing and so are the rings. I dont know what you would be expecting but as long as all the 4 are give or take close i would think it would be ok.

I dont have much experiance with rebuilding these engines, but the deere diesels i have done this would be a must to make sure everything wears rights and no premature failure.

Great job on the build, im hoping my B20vtec build comes out ok once i get time to do it. :rockon:

Yeah, I plan on doing a compression test before I take it to the dyno and then again after the dyno. I wouldn’t be surprised if the rings aren’t fully seated yet.

Good shit, you figured out your idle issues.
What are you running for your drivetrain?

Just being curious. :slight_smile:

[QUOTE=AllmansTEG;2059667]Good shit, you figured out your idle issues.
What are you running for your drivetrain?

Just being curious. :)[/QUOTE]
YS1 case
ITR Gearset
Honda MTF (may switch to synchromesh, still undecided)
Exedy Organic Clutch
Exedy Flywheel
Raxles Axles

Every trans I’ve had in the past has had some sort of grind, so this thing is like a dream so far! It’s also going to be fun to finally have a limited slip :smiley:

Who built that beast for you C?

OH wait…I did.

Thanks for the props :angel:.

[QUOTE=.J.;2059680]Who built that beast for you C?

OH wait…I did.

Thanks for the props :angel:.
Haha, I almost mentioned that it as a J. trans :bowdown: I just wasn’t sure if you wanted all the attention (I figure you already get more trans related requests than you’d care to deal with). I’ve been bragging in private, and if you don’t care then I’ll go ahead and brag in public too :smiley: