GS-R refresh: bouncing idle problem

What’s up guys. So I need some help on a few things on this car that I just picked up a few weeks ago! All the help is much appreciated . I would also like to know if anyone has a good PDF version of what you use for a service manual. Thank you

so here it goes
it’s a 1992 gsr with the 1.7 it has 175k miles
everything is stock . No headers or cai or anything. It is exactly how it came. But I was told that the fuel pump went out and was replaced with a 255lh Walbro.

Here are the issues it has

the muffler was old and no good apparently and the guy removed it so it’s a tad noisy (looking for an oem replacement)

only on certain start ups ups it won’t let me run past 2k rpms! Right at 2 it like cuts off. So I shift below 2 for about 5 minutes and I’m good . Sometimes a cel will come on and it does not do it at all. I had a code for tps (7) and 41 but I had found that the tps wasn’t fully connected and I unplugged the o2 to make sure it would throw a code. I reset them by unplugging the battery and no codes. But I still get that same start up at times

i have pulled the plugs and they are the iriduims and a bit rich
im grabbing a set today
i replaced cap and rotor so far and it helped a bit in the midrange

my idle bounces and sputters from 500-800 and I’ve tried adjusting the distributor a bit but not much of a difference and I did move it around in service mode. I put it back where it was but I will be picking up a timing light.

im not sure where to go from here. It sounds like it backfires but the exhaust doesn’t help me much

I’m just looking to get this thing back up to minty condition again.

https://ibb.co/hYOx9v
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https://ibb.co/nKQzNF

I would try looking for a vacuum leak somwhere, this can make the idle bounce and give you trouble.

Above is some links to pictures of the car not sure if they show ok. I did find that the pcv was old and brittle and the hose going to the intake was too. Would you guys recommend removing the entire intake manifold and doing a deep cleaning and hose replacements? I was also thinking of putting on a newer oem intake manifold but not sure which ones fit the b17? Bad idea?

if your just trying to get the thing running right I would start with inspecting all the vacuum lines and replace any dr y cracked or brittle ones. also make sure none slipped off somehow and if you feel something like the pcv valve seems old and could use repacking I would replace it. I remember I once had the plastic valve coming from the brake booster in backwards and it made the car run like crap and have a bouncing needle and also wouldn’t let me rev high. double check that.

You can build yourself a DIY smoke tester (try youtube) to check for what sounds like a vacuum leak. You may also want to replace the TPS sensor.

Ok sounds good. So the pcv split in half leaving the bottom part stuck in between the intake cutout and the hose but it started to rain and I plugged up the intake manifold and let the breather box vent . With that being said I took off the iacv and sprayed it clean with some tb cleaner and it helped a bit maintain at 800 and when I press the gas lightly it didn’t drop way down anymore and bounce around the 500 range. I soon after got some gas and it’s back to rough idle and my problem with the cutting out at 2k rpms is still. Now I’ve inspected my hoses for leaks and everything seems ok. No cel light and still trying to get my hands on a timing light just to be safe. Im about to take a look at my ecu which is a p61 but no idea if it’s been chipped or what so I’m going to take a look. Just don’t know what to look for lol. Also when it’s idling rough it sounds like it’s missing. The wires are pretty new and spark plugs I picked up yesterday. What else would cause it to miss at low rpms and cut it off around 2k ?

How much do you know of the maintenance history?

At 175k I’d look into a valve lash adjustment, fuel filter, and AFR (o2) sensor.

I’ve been troubleshooting that hunting idle (800-400) on my obd0 DA9 for YEARS and tried all the tips and tricks on the Internet, finally got mine car running right after replacing the AFR sensor and completely rock solid idle after blocking off the FITV and properly bleeding the cooling system.

If you do decide on an AFR check O’reilly’s, I got my single wire Denso 2nd day air shipped for less than $40. (ask them to check factory availability, they won’t find it at a local DC).

As far as the not being able to rev past 2k I actually experienced this when I had my IACV disconnected to adjust base idle, so def check/clean that with throttlebody cleaner, but make sure its completely dry before starting back up.

Good luck.
Let us know.

thank you!

I don’t know too much on the history but I haven’t seen anything else replaced besides the plugs and wires and what I replaced my self. I have never ran into this issue with any other Honda and this had got me pretty lost. I’m testing out a tps sensor I got from a friend that is known to be good. I did think about replacing the fuel filter but I find it odd that it is right at 2k every time. It’s only for a short period of time and then it lets you go past it a few min later . I wish I could plug up my scanner to read the o2 sensors live data but all I can do is the jumper wire lol . I removed and cleaned out my iacv with tb cleaner and it sort of helped but same issue came back. Now the fast idle I’m looking to clean it out later today and see if maybe it’s not screwed in all the way and that will fix it somehow so let’s see. My problem is I get a code 7 and it runs perfectly fine when the cel is on but if it’s not, it will run ok but not as strong and my idle sputters low. I’m honestly thinking the tps and cleaning everything else out will surely help at least.

Seems like code 7 is def related to TPS, check out:
http://forums.g2ic.com/forum/assistance/stock-engine-bay-components/85541-cel-code-7

Check the resistance between the primary terminals and then the secondary terminals on your ignition coil. It is a very common problem and causes your symptoms. According to the Haynes manual your primary resistance should be between 0.6 - 0.8 ohms, secondary resistance, 9.76 - 14.64 K-ohms. If it’s out a new coil is only like 40 bucks