H22A4 Idle surge in 2000 Civic

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butterz

New Member
Whats up Honda Swap!?

I've been lurking here for a long time as a guest and finally decided to post and ask about a swap I just did. I've searched and searched to no avail, so hopefully I get some answers here.

I recently put a OBD2b H22A4 in my 2000 Civic sedan (came stock with an OBD2b D16Y7). It runs strong with the exception of it idle surging from about 1500 - 3500 rpm.

The Facts:

- 1 CEL code (Code 20 - Electrical Load Detector)
- P13 ECU (OBD1)
- Civic harness
- Converted to internal coil
- Fire & fuel to all cylinders, and it's not in limp mode.
- Car was automatic, and I did the 3 wire to 2 wire IACV conversion with my 5 speed swap.

My questions:

1. When I extended the wiring for my alternator, there were 3 wires on the civic harness and 4 wires on the H22 alternator. I left 1 wire disconnected (Green/White) which I later found out needs to run to the 'ALT D' pin on the ECU. Would this throw the ELD (Code 20) and make the car idle surge? Starting the car with the alternator unplugged makes it run the exact same.

2. The EGR is disconnected, would that make the car idle surge?

3. Unplugging the IACV make the surge change from 1000 - 3500 to 1000 - 1200. Is this a sign that the surge is caused by something else?

Any help or insight is appreciated fellas! I previously had a boosted OBD1 D16A in the car, so I'm not a noob when it comes to this stuff.

Thanks.
 
Also, check your FITV and make sure that the plunger inside is tightened down where it should be. That and the IACV are the main reasons for idle surging. Also make sure you dont have a vacuum leaks.

also check and make sure there arent any air pockets in your coolant system. this will also cause an idle surge.
 
Thanks for the fast reply!

I didn't mention that the engine ran perfect in the Prelude before I pulled it out, so I have a good feeling that the FITV isn't the culprit.

Someone suggested I run a Civic IACV on the H22. Has anyone else done this?
 
OBD2 motors do not have a FITV (cold idle is controlled by the ECU instead)

OBD1 ECU doesn't control it and needs a FITV. Did the prelude run this OBD1 ECU too??

May not be your issue but thought I'd let you know.

Code 20. I think it deals with the ELD and it should be located in the fuse box in the engine bay. Check all connections to alternator, starter and battery too.
 
I thought you had to match the OBD's of the motor and ECU unless you converted some stuff on the motor? At least that's what I've heard. From what I gather you're running a OBD2 motor off of an OBD1 ECU. Unless I missed the part about you converting the motor to OBD1.

Sorry I can't be of more help. But that's the extent of my knowledge on the subject so this is just me putting in my two cents and bumping your thread.
 
I appreciate the feedback fellas.

CAFROG - I wasn't aware that the FITV controlled idle for OBD1 motors. I checked it and although it was a little loose, it didn't make a difference - the car still surges like a whore.

Chaz - I'm running a conversion harness from my harness to my ECU. You can run any engine with any computer as long as it has all the correct sensors - which I do in this case.

Small update:

I took the car for a little drive today to see if I could find anything new out. The speedometer was acting all crazy with made me believe it might be a grounding issue. I'm going to try a D series IACV soon just to see what happens.
 
So.....it's an OBD2 motor but there is a FITV on it? Where? Bottom of the TB?

I must apologize for my knowledge of OBD2 not having a FITV is for sure in B and D series but I may be wrong for H series... Never owned one.

I don't think grounds are the issue with the surge (if it pulls fine). I'm skeptical that the code 20 is a culprit too.

And you've cleaned/soaked the IACV with something like carb cleaner?

Does it surge on start up? Or not until it gets warm?
 
Also....my knowledge (based on myself being bull crap idle situations ) is that the FITV and IACV control idle. They both have coolant lines and use temp as a dictator in their involvment. The FITV on OBD1 B/D series is mounted directly under the TB. With the intake piping off, there is a hole inside (bottom near butterfly towards firewall). It should have huge suction when the motor is running but cold still. As the motor gets up to temp....suction stops at that location (per Helm's manual) and the location to the IACV takes the control.

What did you mean by the FITV being "loose" and you fixed it? Can you take a picture of it?
 
There is a FITV on it? Where? Bottom of the TB?
And you've cleaned/soaked the IACV with something like carb cleaner?
Does it surge on start up? Or not until it gets warm?
The FITV is attached to the throttle body on the bottom, just like a D series.
I cleaned the IACV and I've confirmed that it's working.
The car idle surges right from start up.

After spending a few hours diagnosing I think i've narrowed it down to being a vacuum leak. I can hold my hand over the intake - with the idle screw completely closed - and the car doesn't shut off. I also think it's a vacuum leak because I took the intake manifold off before i put the engine in and didn't replace the gasket (which I'm now kicking myself for).

I'm going to get some carb cleaner and spray around the intake manifold where it bolts to the motor and see if there's any change in idle. And i'm going to drop the motor down and take the intake manifold off so I can replace the gasket.

Hopefully this solves my problem, I'll update soon!
 
Reminder....the torque setting on IM bolts is very light. I would guess the H series is close to B and K series....around 17lbs. Re-check after the motor gets warmed up the first time.
 
Update

I changed the Intake manifold gasket today. The car is still surging, but it's acting a little differently. The surge seems to raise slower than before. I can also cover the throttle body with my hand and the car idles down, but still surges.

I've also found that if I unplug the TPS while the car is running, it will stop surging but it idles at about 3000 rpm. Is this the sign of a bad TPS?

I'm running out of options here.
 
Have you tried to test the TPS with a multi-meter?

Got a good spare one to install and calibrate?

Checked for vacuum leaks yet?
 
Thanks for the fast reply!

I haven't checked the TPS yet, I'm going to do that tomorrow. I don't really have a spare one around that I know of, but I'm going to see if I can't borrow an H22 throttle body from a buddy.

I've checked all the vacuum lines and I don't see anything unplugged. I'm almost certain there's no leaks.

I'll update tomorrow.
 
I just lightly spray some starter fluid around the vacuum lines and joints. It can be dangerous but if you don't spray too much....it's fine. If idle changes......leak in the spot you sprayed.
 
Alright so I took off the IAC and throttle body, and thoroughly cleaned both with some Throttle body cleaner. When i put them back on, the idle surge seemed to have dropped quite a bit so I'm guessing the IAC had been part of the problem.

I went over each of the intake manifold nuts and made sure they were tight and to my surprise, one of them was only hand tight! So i torqued it down nice and tight and the high idle and surge stopped! The car idles at 1200 rpm and idle surges on occasion, which means i probably need to double check all of the nuts again, but the Intake manifold gasket was the culprit.

Just wanted to say thanks to everyone that helped me out. The car goes in to get the exhaust lined up tomorrow, so I'll get to see how it pulls once that's done.

For future reference with anyone having this problem:

Problem resolved

Symptoms
- High Idle
- Idle surge (fluctuation from 1500 - 3000 rpm)

Resolution
- Vacuum leak caused by leaking intake manifold gasket

Diagnosis
-
Sprayed Throttle Body cleaner over each intake manifold nut until the idle of the car changed
- Checked and re-checked the tightness of each intake manifold nut
 
A little eye candy of my swap.
458625_10150705685046338_568306337_9743316_855958379_o.jpg
 
Nice :thumbsup:

My idle was surging some after I drove it a while but wouldn't do it from cold start up to running temp. I fixed it by raising my idle to 875-925rpms.

In terms of the high idle (1200rpm's)....I would check timing with a gun to make sure you're within spec (I like 2 degrees advanced)

If that isn't the problem....try to re-set the idle. It's a little more involved than many think. I cannot say the procedure for H series but B/D is done with the IACV elec. unplugged, them start the car and idle adjustment screw tunes it to around 450rpm (idles really low w/IACV unplugged). Once it's set....turn car off. Plug IACV back in. Unplug "back-up" fuse (engine bay) for 15-20 seconds, plug back in and start car back up.
 
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