Yes, the valves are adjustable. It’s still in the shop getting put back together. Might as well have them check. I’ve gone this far...

Just to bring some closure here, when tested, engine compression read at 90/90/120/90 across the cylinders. Its probable this is the cause of the misfire and the bogging at 3000 rpm, and inability to rev past 5000 rpm under load. Up for sale soo will be a 99% complete, refurbished car with a barely beating heart and lots of spare parts.

Thanks for all your input guys.

I’m done with it. It’s going up for sale on eBay shortly. Maybe someone with more time and energy can figure out this problem.

Hello folks. Well, I think I've just about had it. I received all the o-rings, replaced them all. I cleaned the the FIT, and adjusted it to what I the measurements I think make sense based on how the valve opens and closes. Still has the surging idle. Still bogs down at 3k, will not rev past 5k under load. After a few minutes, the PGMFI light comes on.

 

To add insult to injury, there is a rattle that sounds like it's coming from the distributor...

 

I've sunk so much time, money, and effort into this thing, and it just doesn't want to run right. Very depressing.

Tested the TDC/CYL sensors today and both test dead center within the resistance specification.

Running out of sensors to test.

I ordered equivalents from Amazon. There’s a post on here that lists the o-rings and has the links to Amazon. A bit pricey at $46 for all, and they only come in sets of 10. Should be here by early next week.

Awesome! Much appreciated. I think I can resolve the high idle with the FIV (more accurate description than idle air control valve) clean and overhaul. It’s the 3k stumble and Code 1 that has me stumped to no end!

I like the forum much better than Facebook. I’ve used forums as a source of information with everything from cars to cassette decks. The Facebook page is all over the place. Good for shoutouts and WTB posts, but impossible to find any useful information there. At least for me anyway. Maybe I’m just old? Darn young folk and their new-fanged social media nonsense!!!!

IACV is out of the car. Looks like this is the cause of the high 2k idle, as the black cover may have screwed itself out over the years. That, or the poppet wasnt rising high enough to close off the flow of air as the thermal wax heats up and pushes the poppet up. Looks like the poppet is fully closed when there is a 3mm gap from the top of the poppet to the top of the black disk that covers it. I measured this with a depth gauge, and tested it by heating the IACV in a pot of boiling water to get the poppet to close. I can adjust it when its back on the car, but I have to wait until I get replacement o-rings which should be here by Friday.

However, I dont think thats going to resolve the bog at 3000 RPM and the code 1 on the ecu. Something producing an electrical signal is causing the ecu to go into closed loop mode. One solution may be to do a devac. This would eliminate the numerous sensors inside the black box on the drivers side of the car. Chances are those sensors are no longer being made and finding used replacements would be a crapshoot at best. But, eliminating all those sensors would leave TPS, MAP, TEMP, and crank angle (not sure if Im leaving anything out), Ive replaced and/tested the O2, TPS, TEMP, and MAP sensors, so not much left.

Oh, a replacement ECU is also on its way.

I would gladly pay for someone to diagnose the thing and say oh, its this ______, and it will cost $$$ to fix it. Otherwise, its trial and error. By the way, arent ANY Honda mechanics still alive out there who worked on these cars back in the day???

It says something when kids pull their faces out of their phones and tablets, roll down windows and point at the car. Especially here where I live, where supercars and big dollar luxury cars are not uncommon. I had a red 1986 Si purchased new in 1986. It had white Enkei wheel, and the same "Mugen Power" decal on the back, so the car is pretty special to me, if most on the road have never seen one.

 

Engine/harnesses/sensors seem to be original, except for those I've replaced. I have a spare throttle body that's been cleaned and has a known working TPS. If the TB i the car now is a full of grunge as the one I just cleaned, that could possibly be the cause of the problem. It is missing the IACV, so the old one will need to be transplanted from the TB in the car now. At the very least, it is the cause of the high idle at startup.

 

I have a strange feeling the issue lies with the TB/IACV/TPS. Code 1 on the ECU is O2 or fuel problem. The 2k idle on startup points to something in the TB/IACV/TPS throwing the ECU out of whack. Really, the ECU only uses TP, MAP, and O2, so if ELECTRICALLY the sensors are working, it's possible something mechanical and/or vacuum related is interfering. 

 

Thanks for all the input guys. I'll keep you posted.

I had a leaking injector when I first got the car, I bought an entire set of flow tested and balanced injectors. All the o rings are new as well.

Slowly narrowing it down by process of elimination. Throttle body is coming off to be cleaned and I’ll check the IACV while it’s off. There’s an IACV fix posted elsewhere that I want to try since the initial symptom on startup is the high/then surging idle.

On the plus side, I drove it early this morning and got a ton of compliments from little kids to older folks. Even a couple of dudes, one in a slammed 2000’s civic Si and the other in a WRX. That was at a gas station, so the second the I turned the car back on, the issues resumed until the PGMFI came on.

I’m having the same issue with my 1987 Si. I know this thread is over five years old, but I’ve been posting to another thread and thanks to much input from other members, it’s been really helpful to solve other problems.

Right now, I’m stuck with the exact same issues noted here, in the order in which they occur:
1. a high idle at about 2k rpm when cold
2. Rpms then settle down to about 1000 rpm after a few minutes, then starts to fluctuatate
3. Severe bog at 3000 rpm, you can push past it with more throttle
4. Hesitation at 3k under steady cruising
5. PGMFI light turns on, no more hesitation, no more bog
6. Bad fuel mileage
7. Bog just past 5k rpm
8. Turn the car off, repeat starting at step #1

I’ve done the following:
New fuel filter
New fuel pump
Cleaned out the fuel tank and addressed filtter/strainer issues
New temp sensor
New o2 sensor (which tests within specs)
Checked the tps, which tests within specs
Checked the MAP sensor, which tests within specs

Next step for me is to clean the throttle body and check the IACV. I’ll attempt to fix the IACV if there is a vacuum leak. Aside from that, I’m at a loss.

MAP sensor tests fine. Temp sensor has been replaced. I tested the connections back to the ecu, and those are fine too. Sadly, the problem persists.

Although the O2 sensor is new, it’s position has been relocated further down the exhaust path than the original. So it’s possible it’s not reaching the right temperature. A four-wire O2 sensor might help here as they are have a heater circuit provision.

A new fuel pressure regulator is on its way. It’s a cheap part and easy to replace. The car’s idle gets out of whack with the fuel pressure regulator disconnected (while plugging the manifold port, of course). My understand of this is that disconnecting the FPR from vacuum will result in max pressure. Seems odd that the idle would become erratic with it at full pressure.

Not sure if I sure go the DEVAC route and eliminate as many sensors, dashpots, and valves as possible. I’d be happy to run it in closed loop all the time and disconnect the PGMFI light in the gauge cluster.

In the driveway, I can rev past 3k even with the initial high, then surging idle. Seems to be an issue only under load.I'm going to test the MAP sensor tonight and replace the temp sensor (although that looks a bit difficult to get to). The thing runs beautifully in closed loop mode. If I can't figure out what the cause of the problem is, I would prefer it stay in closed loop mode. Is there any way to force it into staying in closed loop mode? 

Did some research and I think I answered my question regarding what the ecu is using to control the fuel mix. Based on what I’ve read, could be one of the following:

1. O2 sensor. Mine is new, but it’s been welded into the collector pipe just below the exhaust manifold. This shouldn’t affect the idle, but replacing it with a four wire (heated) sensor, is an easy and inexpensive test/fix.
2. The temp sensor under the distributor. I have a new one sitting in a box, and that’s an easy fix as well.
3. The MAP sensor. Expensive, but easy to replace.

I can’t think of anything else the ECU can bypass, and since the engine runs fine in closed loop mode, I think it’s likely to be one of these things.

Thoughts?

Well, I took it out tonight after dark (no AC, and this is Florida). Idle bounced up and down a few times and the the PGMFI light came on (code 1). Afterwards, idle was relatively smooth, and there was no bog at 3k rpm. In fact, it was actually fun to drive.

Car has a new O2 sensor, doesn’t mean it’s not faulty or the wire back to the ecu isn’t bad. So what other than fuel to the injectors does the ecu control that is out of the circuit when it goes into closed loop mode?

Got the car back today. Fuel tank has been cleaned out, filter is new, pump is new, strainer has been bypassed and an external filter fitted in-line before the pump. So far, it hasn't stalled for lack of fuel. But, it bogs down big time at about 3000 RPM, until you push the pedal down and get past it. Idle is all over the place too. 

 

Just refuses to run right. 

 

I was thinking of going the devac route, but I am very close to giving up having spent a ton of $$$ throwing parts at the thing. 

Well, the mystery deepens!

 

I went to the shop and saw the work being done first hand. The sock filter looked ok, and when air was blown through the hose backwards from where it connects to the fuel pump it flowed through. There was a little tiny (1" x 3/8") plastic coffee strainer looking thing inside the hose that looked clearly past its prime. That was removed, and the fuel strainer will be bypassed while an external FRAM filter will be placed before the pump. There is some debris in the tank, but nothing major. That will be flushed out and the tank cleaned.

 

Not sure if any of those things is the cause of the problem as the car started up fine for the shop after the tow truck dropped the car off. They drove it a bit and noticed the same hesitation at 3k that I get, but the car did not shut off. Maybe having the car towed caused the fuel to slosh around enough to loosen whatever is impeding the flow??? 

 

I don't know. This little car is kicking my butt at every turn.

Ah! I hope thats it. It got towed to the shop this morning because I let it idle in the driveway (its sloped) and it died and would not start again. Tow truck dropped it off at 10:00 AM. I gave the shop a full explanation about the fuel system, the filter, the pump, and the strainer bypass, but I havent heard back yet.

Having a local shop drop the tank and have a go at either cleaning the strainer or bypassing it with an external filter before the pump. I took the car out last night and it started and drove well. A slight hesitation at 3k, but nothing major. The PGM FI light cam on (code 1 on the ECU). The o2 sensor has been replaced, but I'm going to check the wire going back to the ECU to make sure there's continuity. 

Update: I put in 2 gallons of fuel and primed the pump a few times until I saw fuel at the filer pressure relief screw. Guess what? It started! I drove it around the block a few times, and it ran fine, except for the occasional bog at 3k, but no where near as bad as it was before. I went around the corner and filled up the tank, and it only took 1.7 gallons to bring it to the overflow point, so I don't think I really was out of fuel. 

 

Thanks for the tip about the internal filter Leadfoot, and to the rest of you guys for your suggestions. Sounds like replacing the filter and pump were part of the problem, with the internal filter needing to be done next. 

 

If I can get it to my Honda specialist, I'll add that to his list of things to do aside from setting the timing and checking the condition of the timing belt. I also need new oil pan and valve cover gaskets replaced as well.  

There is NO pressure at the filter now. Pulled the pump from the car, disconnected the hard line, but kept the tank line and electrical connections on. Pump primes, but no fuel from the pump. Repeated the test several times, no fuel. Ok, put the original pump back on. Same story - primes, not pulling any fuel!

First thought - Im out of gas! I dont think so, I filled the tank about a week ago, and drove the car maybe 30 miles tops. Maybe a clogged screen filter in the tank?

Well, replaced the fuel pump and filter. Car refused to start - turned over, but would not start. Disconnected the battery, when I reconnected it a few minutes later, it started and ran just fine. The hesitation was gone. About an hour later, I started it again, and it started fright away. Pulled it out to the driveway and let it idle while I went back into the garage to get something. As I walked up to the car, it started to sputter, and died. Again, now it turns over, but will not start!!!
 
I can hear the fuel pump running and priming
There's fuel pressure at the filter
I disconnected the battery again and waited, but still does not start
There's spark at the plugs

Voltage is .527 closed and 4.289 at WOT. Numbers change nice and smooth along with throttle operation. Impedance seems good. Voltage seems good. Puzzling. Now I'm really confused as to what is causing the bog and hesitation.

Now that I didn't do. I'll check both of those when I get home tonight.

I checked the resistance on the TPS per the service manual and got 5.7 ohms - right in the middle of the acceptable range of 3.2 to 7.2 ohms. On a hunch, I'm going to try replacing the fuel filter. After that, I'm at a loss. Coil? Fuel pump?