Car surges under partial throttle

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Dasfinc

New Member
My car under light or partial throttle sometimes surges/bogs randomly, but under WOT it moves out just fine. Here's the background:

I own a 1992 Civic CX, *D15B8 Block with 4 valve pistons*

I Did a 16 valve swap on it *D15B7 head, D15B7 intake manifold, D15B7 ECU*

I burned up my valve seals (Compression leak) and went all out for mini-me and got my hands on a D16Y8, which I had rebuilt, 3 angle valve job *2 replaced valves* and re-surfaced etc*

When its all said and done I'm running my P05 *Origional ECU* Chipped by Phearable.net for Vtec, and the setup I have. I'm using the D15B7 Throttle Body/map/tps on a D16Y8 Manual Intake manifold with my IACV Valve off the D15B7 intake manifold.

My cam timing is correct *1/2 tooth issue due to D16Y8 head on D15 Block, I purchased a adj. cam gear to correct it, which I did, it is set to 5* advanced (An additional .25* more than normal due to the re-surface/mill the head had done)

I BELIEVE my ignition timing is correct, but suspect it may still be part of the problem.

What else should I be looking for that causes surging/bogging issues under light throttle, another problem it is having is that it takes several cranks to start, and once started idles a little rough *Slight mis-fire* until it has started to warm up a bit, after which it is fine.

My mods are as follows:
Intake
Header
'high flow' cat
N1 style cat-back exhaust
Megan Racing UDP
AEM True-Time cam gear
Accel HEI Super coil
*OEM NGK plugs, wires*
new cap and rotor.
phearable.net ECU.

Ideas?
 
Id check and clean the fitv and iacv, if you havn't done so already. I would also check the ignition timing. If that doesn't do it, then id look at the tps. I am in the same situation as you with the light throttle bogging. I did the timing, and cleaned the idle valves, neither of which helped. I now have a new tps in the mail. Hopefully that does the trick.

From what I've heard, the tps goes bad over time causing the resistance it puts out to differ from what it should. So the computer thinks the throttle is open more or less than it really is. This causes the bogging/misfire. I'll let you know if the new tps fixes my problem.
 
99sidude said:
Id check and clean the fitv and iacv, if you havn't done so already. I would also check the ignition timing. If that doesn't do it, then id look at the tps. I am in the same situation as you with the light throttle bogging. I did the timing, and cleaned the idle valves, neither of which helped. I now have a new tps in the mail. Hopefully that does the trick.

From what I've heard, the tps goes bad over time causing the resistance it puts out to differ from what it should. So the computer thinks the throttle is open more or less than it really is. This causes the bogging/misfire. I'll let you know if the new tps fixes my problem.
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The thing about the TPS and MAP is that my throttle-body is off of my D15B7 intake manifold and at the time the car was working fine before the headswap.

where is the idler valve? is that the one below the throttle body thats attached to it with the coolant lines?

and where is what is the FITV?

*I'm sure I have un attached-re-attached all these bits, just don't know the names*
 
When I say idle valves, I'm refering to the iacv and the fitv, both which conrol the idle. The iavc is on the back of the intake manifold held on by 2 12mm bolts. Take it off and spray out the screened side with some carb cleaner. The fitv is located on the bottom of the throttle body. Pull it off and open it up. You should see a plastic valve and it can be unscrewed and removed you you can clean it. When your done make sure you screw the valve assembly back in all the way.

Google this. There are some nice writeups with pictures on cleaning both somewhere out there.
 
99sidude said:
When I say idle valves, I'm refering to the iacv and the fitv, both which conrol the idle. The iavc is on the back of the intake manifold held on by 2 12mm bolts. Take it off and spray out the screened side with some carb cleaner. The fitv is located on the bottom of the throttle body. Pull it off and open it up. You should see a plastic valve and it can be unscrewed and removed you you can clean it. When your done make sure you screw the valve assembly back in all the way.

Google this. There are some nice writeups with pictures on cleaning both somewhere out there.
Click to expand...

I dealt with the IACV, so I know about that (And I cleaned it back when I had to 'modify' my intake manifold *the B7 IACV Plug goes down so I had to cut part of the intake casting off for it to fit, just excess metal, didn't damage anything*)

and the FITV is that little valve thing that is attached to the coolant lines below the throttle body then. *Didn't clean that, but again, TB came off the working setup with the old head, so I don't think that could be it*

Anyone have O2 issues with Test pipes or 'high flow' cats on here?
 
A test pipe/high flow cat shouldn't cause problem on an obd1 car, because the sensor is located in front of the cat in the exhaust flow. You may be running very rich, which can ruin o2 sensors.
 
its hard to tell if I'm running rich by checking my gas mileage because the car has a CX tranny so almost no matter what the car gets above 28mpg no matter how you drive it. back when it was an 8 valve i could land 45mpg, that was awsome.
 
99sidude said:
28 mpg sucks for a d series. I get better than that on my s/c b18c. That could be it.
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I never even checked MPG, I just basically said "28" because thats what it got with its horrid compression leak, I haven't checked since the head swap since its not daily driven.
 
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