I have an annoying idle problem with my jdm h22a swapped lude. It's not throwing any codes, however the idle just sux *****. I've done searches about topics, but none have helped. Such as mgags7's "THE END OF ALL Idle Surge - Bounce - etc Problems Thread" (awesome thread by the way) I've used seafoam, used TB cleaner and unfortunetly, the problem is still occuring. Checked timing and it's good. Thought it might have been the TB, switched it and no go. Next i switched Intake manifold and the problem is still there. Driving the car is fine, but coming to a stop or making a turn causes the idle to drop low to even stall the engine. Also at warm temp the idle stays between 1k-2krpm. But a light tap on the pedal will help. It doesn't bog or anything. What could be causing this weird idle problem?

 

Idle serges are caused by a leak in the vaccum system somewhere, usally.

If you have chaged everything from the Intake Mainfold to the TB, well then there is something reeally strange.

here is a list of posible things
1. GAskets(look for cracked, chipped, missing)
2. Vaccum lines(look for holes, feel for air, make sure its connected)
3. Bad sensors(TPS may be broke)

 

Fast Idle thermovalve under the throtle body could the problem couldn't it. The valve could be sticking open perhaps?.

The intake manifolds you swapped had two different FITVs though didn't they?

Either way its gotta be a vacuum leak, something your overlooking.

I'd go over all the vacuum lines from your manual. Also, spray wd-40 around seals (if someone knows a better liquid than speak up, I use it and seems to be safe for the car itself) and if the idle flucuates than the leak is around where you sprayed. I would start around Intake manifold gasket if you feel nothing else fixes your idle.

Did you use a new gasket and clean both mating surfaces?? Did you use a liquid gasket aswell? Did you tighten the bolts in the right pattern to right torque aswell to make sure it seated perfectly?

 

Not sure about JDM IM's, but don't forget about EGR ports on the IM. Not sure why you would be getting a fast idle at operating temp, but I know what you're talking about with the dropping idle and/or stalling. Are you OBD1 or OBD2? I know for me it has a hard time idling when I reset the ECU, but eventually it will "learn" about the problem and go away after about a week and from what I've read, this is typical of clogged EGR ports (not just the EGR valve). Not sure why you would have problems with a different IM though. Keep us updated...

 

I've used TB cleaner spraying all around vacuum line/area while the engine is on and it seems fine. I used new gaskets all around. I cleaned the FITV, EGR valve & port beforing install the IM onto the engine. As for the TPS, the voltages are correct. I thought it might've been an ECU problem but it wasnt. Still tripping the CEL code 1

 

Have you tried a valve adjustment?

 

ya, a buddy of mine checked it out and adjusted them for me.

 

are you absolutly sure you have the right ecu, all connectors are right and all sensors are good? you could have a bad ground or an ignition rotor worn out

 

2 P13 ecus one USDM, one JDM. Checked all the wirings. Had another Prelude side by side to check the wiring harness. Replaced Cap, rotor, plugs, plug wires, etc.

 

any other suggestions? thnx

 

Take off your FITV, replace it with your buddies FITV and see if it changes. Maybe the wax in your FITV is F*cked? I don't know, but if you have access to another fitv (your buddie's prelude) it would eleminate the fitv from being the problem
completely.

Get your Ignition timing checked too for sh*ts and giggles. With a Timing Light too, not by some backyard method. Remember to adjust on obd1 you'd have to jumper the blue connector (service connector) to alter ignition timing! (I think anyway, from what my manual dipicts)

 

Cool, I'll exchange the FITV this weekend to see if it'll take care of the problem. The problem is driving me nuts
I don't want to take it to a shop just yet. If i do end up taking the car to a shop, anyone from the NorCal who knows a respectable shop that deals with a lot of hondas?

 

I seemed to taken care of the stalling issue. My buddy's TB seemed to have done the trick....We took out the FITV from both TB and looks definitely the same, so that stumped us. Now the car is just throwing Oxygen Sensor code. Its a new sensor on the pipe. We were planning on running the wires straight to the ECU. Can anyone help me out with the wiring? thnx

 

help?

 

Let me get this straight. You fixed the idle problem but now you have an o2 sensor fault? What does it say the fault is? Short to ground ect.?

 

I have been getting an O2 code and the idle problem. The idle problem have been dealt with. Just remains is the CEL 1 code for O2. I don't know if there's a ground short or not. I'm currently trying to get a diagram of how to tap the O2 lines to run it straight to the ECU.

 

first before u rewire ur o2 sensor, check the resistance and connectivity on the wires, if they got perfect connecectivity than there's no need to rewire. All u need is a multimeter.

 

I would invest in a ecu real time reader I don't recall how much they are but they come in handy when things like these happen.

 

This past weekend i was able to check the o2 sensor with a multimeter and there were connectivity. So looks like the o2 is working yet I still can't determine why the CEL is still on...My brother tried using a different ecu to see if it'll have any difference. The ecu he used was a stock P28. After plugging everything up the CEL was still on this time 2 codes are showing. One for o2 and the other for vtec pressure switch...However, switching back to the P13 only the o2 would still be on. I'm really stumped on this problem....can a diagnostic target the problem?

 

ttt

 

anyone?

 

Problem solved. Was really weird however, wouldn't have ever guessed. Yet we managed to take away the CEL. We switch the intake manifolds JDM to USDM and that managed to cure the problem. WTF was up with that? I appreciated the suggestions guys