nexgen91

I searched and could not find any information directly related to my problem. I have a 96 Civic DX with a B18(R) swap in it, running stock ECU, only mods are shirt ram intake, and 3 inch stainless exhaust. The problem is after around 10 miles of driving the engine seems to bog down/loose power when accelerating uphill (this happens on even slight inclines) It will accelerate fine going down hill. It also seems to do this when accelerating on flat sections as well, just not as extreme. I have replaced the plugs, wires, and distributor, as well as reset the ECU, none of which helped. Im not sure if the operating temp has anything to do with it, because even when at operating temp before 10 miles it will accelerate fine uphill, the sweet spot for it to start happening seems to be right around the 10 mile mark. This happens morning and night on my way to and from work, which is the only time I really drive the car. I have a fuel pressure tester, but have not tried it yet because I dont know if it could maybe be a fuel problem or not. Im getting fuel to the rail, and there is pressure (just not sure how much yet) Any ideas on what I should check? No CELs BTW

Oh one more thing, if I keep the revs above 3.5-4k it doesn't seem to happen as much, its mostly at low speed and low RPMs.

Went and hooked up the fuel pressure gauge, at idle its sitting at 41 PSI.

delsolintegra

Sounds like after warm up with ECU operating in closed loop it starts bogging.

Make sure the air filter is not shoved too far on to the air intake pipe that it would cause a internal restriction to air flow.

nexgen91

The filter was on to high, but moving it still did not fix the problem, and more ideas? Thanks

NotARaCist

iTrader: (1)

Stock DX ECU, or stock C5 ECU?

nexgen91

Stock Type R ECU (P73) its a JDM motor not USDM (96 Spec ITR)

TomCat39

I bet you it has to do with the exhaust manifold temperature. The higher the rpm the better it will climb the hill as the higher outflow will actually cool the manifold.

I remember doing a road trip in a 4 cylinder Toyota SR5 pickup that had a lift kit. We were doing freeway driving in the North West which is very hilly/mountainous.

Anyways, we were sticking in overdrive when climbing these hills and after awhile the power was next to nothing, even when downshifting after the power loss.

We pulled over and popped the hood and I saw the exhaust manifold glowing a bright red. The engine temp was still normal but that exhaust manifold was far from normal. We let it cool down for about 5 minutes, got back on the road and made sure do downshift to 4th every hill and didn't have a problem from that point out. The overheated exhaust manifold was robbing us of all the power even in lower gears.

The bogging of the motor with lower rpm fully loaded hill climbing really heats up the exhaust manifold.

At some point (sounds early in your car) it affects power considerably. You really have to downshift these 4 bangers when hill climbing to maintain peak power. Being low in the power band and loading the motor like that just isn't ideal and the car will talk back by losing power.

I really suspect this may be your issue as you said lower rpm, hill climbing. Our Toyota at the time let us push it really hard that way before talking back, your car doesn't seem to take being pushed very long that way.

nexgen91

That may very well be what is going on I have not pulled over to check the manifold for temp yet, I have a infrared thermometer and might have to try that though. It will climb ok if I stay in the lower gears, anything above about 3.2-3.5k rpm it doesnt seem to do it. Thanks for the suggestion

nexgen91

I don't think this is what is going on, checking the exhaust manifold after hill climb its close to the same temp as normal driving. Also I am not constantly going up and down hills,

Going to my job begins with a 6.2% grade climb (368 feet climb over 1.11 miles) the problem surfaces here after 10.6 miles of driving with a 5.4% grade (131 feet climb over .45 miles) it is not as drastic as the one on my way home.

The drive from my job to my house begins with a decent hill climb 5.4% grade (115 feet climb over .39 miles) in which the car does fine on, followed by gentle rolling valley driving (no major inclines at all) after 10.2 miles (seem familiar? its almost the exact distance as going to work) the car faces a 5.7% grade (262 feet climb over .86 miles), that is where the issue is most obvious, it loses power here the most, and the 5.7% grade is just part of it (its a total of 456 ft of elevation gain at a 5.9% grade over 1.43 miles) and the issue is present the whole time at engine RPMs below 3500.

The issue does not happen when there is a decline, going downhill car accelerates fine. Early in the drive both ways the issue is not present, and I can accelerate uphill in higher gears at lower RPMs, which I am unable to do after about 10 miles.

09chaplak

This might not be it at all but my bogging problem which started only until the car warmed up was the ground on the thermostat housing, G101. Maybe check your grounds and make sure everything is getting good contact as it should.

nexgen91

Thanks for the heads up, check it and its tight, no problem there.

On the other hand, some new information if the ambient outside temp is below about 50-60F it doesnt seem to do it.

White_EG1

Remove the ground and clean the contact points fully, I used a wire brush.

nexgen91

Did that to

09chaplak

Sorry if this is in here somewhere already but when's the last time you checked the TPS? Last time I installed mine, the screws came loose and the TPS went all whacky. Check to see if you're sitting at the right calibration.

nexgen91

I have not been messing around with trying to find the problem with this for some time (car has been sitting in the garage while I was in the process of traveling/moving/working) and am now revisiting this problem. I checked the TPS previously and it appeared to be ok, but I will take another look, anyone else have any more suggestions? What is weird is this is only happening going uphill after approx. 10 miles into driving. Someone has bound to have experienced a similar problem and maybe can shed some light on this? Thanks

Former User

Start with the basics - Do a full ignition system tune up.

delsolintegra

Check the engine coolant temp sensor. When the engine is cold it could run fine. After the engine warms up it could run rich and bog down with a bad ECT sensor.

Former User

You probably meant lean because running rich would not cause bogging.

delsolintegra

Doesn't the ECU use the ECT sensor to adjust fuel trim and timing for the given engine temperature?

Is the car hard to restart after the engine has been warmed up? It's been a while but I think that was another symptom of a bad ECT sensor. Sold that car a couple of years ago.

Former User

You are correct. But only a lean fuel trim will produce the symptoms.