theiceman

i love watching CIS video's, I have mine set up and it works fine . I was going to installan AFR meter just out of curiosity, since i have a bung on my SSIs . But i figured if i do that i might start playing with it again lol.

david05111

I think this is the most likely scenario also. I'm doubting the cams thing upon further reflection.

The shop knows what they're doing on a lot of things, but I think this is an area where they fall short. Their deal is that they service and rebuild a bunch of stuff, but they can't really tune anything. So they rebuilt the top end and rebuilt the CIS, but set the latter up as best they could based on when it came into the shop. They don't have a way to meter the exhaust, and they aren't much of a tuning shop. They just replace or rebuild what's came in.

So I'm sure the CIS isn't set up properly. I think it's relatively safe to assume there isn't a major vacuum leak issue, but it's something I'm going to have investigated anyway. When the top end was rebuilt, all the gaskets involved including the manifold, etc. were replaced. So there's shouldn't be something bleeding air into the system. It's sort of why we ruled it out. I would test it myself on a basic level by pulling the oil cap, but with the idle as wonky as it is at the moment when warm, I'm not sure that test would yield much of a useful result. And I'm a little scared to start spraying starter fluid around in there.

Regarding the warm up regulator, I'm not sure. When the car cold starts, it almost immediately goes to around 2k RPM and holds there. And as it warms up, the idle drops. Now I know the WAR works throughout the engine cycle and that it isn't just the startup, but I would think that I'd run into cold-start issues with improper idle or something that would point to that. I only run into issues when the engine is already warm.

I should note that the car does need a few throttle pumps to start sometimes. It usually is when it stalls/quits and I have to restart. It'll turn over a few times and with some pumping here and there, it starts. I know that's not normal, which is why I think it's CIS.

I'm not sure if they did fuel pressure measurements when they were getting it running. It's not something I asked, even though I should have.

I've been wary of messing with the CIS myself. I'm content that the engine is at least safe if it's running rich. If I make a mistake and lean it out too much when tinkering with the CIS, I think that's far more risky.

I did find another local shop who does Porsche tuning and they say that they can handle the CIS and they have the proper equipment to measure AFR. I'm considering taking it over to them when they can get the car in (and hopefully out the same day).

I drove the car yesterday to an event at the local Porsche dealer. The engine seemed to run well, and man does it make a great noise. It only gives me fits when I have to stop. If I don't keep feeding it a little gas to keep the RPMS at 1500-2000, it get's really inconsistent.

The issue I have to tackle before I get to the CIS now though is the shifter coupler. They replaced some of the bushings in the shifter, but didn't mess with the coupling and that was a mistake. I pulled the panel myself tonight and it's totally worn out. I was having lots of issues finding gears yesterday, so as soon as I can get that replacement coupling, I'm installing it and getting it properly set up. After that, I'll try and deal with that other shop to dial in the CIS or figure out what else is causing this.

turbo23dog

I heard from a friend with a stock 1980 SC that his car is set up to run with the O2 sensor disconnected. He says it runs much better without it. IDK exactly how this might apply to your situation but offer the info as another data point for you to consider.

david05111

We removed them on mine. When the heat exchangers went in the car, the O2s weren't put in. There are bungs on the exchangers themselves for them, but I can't remember why we opted out. In any case, I've heard the same thing that you suggest. Apparently, they're just used to fine-tune the mixture a bit, but aren't really necessary on these cars and most run better without them.

Not sure what to do about the light on the dash, but maybe I'll pull that bulb or something.

david05111

I haven't had an opportunity to get the car over to the tuning shop yet, but I have run into something peculiar. Maybe one of you has heard of this.

When I turn the car over, if it doesn't immediately start, the Speedometer needle rises up to like 15-20MPH. It doesn't peg like there's a short, and it works perfectly fine when driving down the road. But for some reason, when the car is in neutral and you turn it over, the speedo rises.

Now I don't profess to be an expert on the speedometer in these cars, but what I seem to understand is that there's a sending unit on the transmission itself. As the wheels turn, the transmission somehow through a series of magnets converts the wheel speed to a signal which is outputted via wire out of the transmission to the gauge. But with the transmission in neutral, I wouldn't think anything at all would be turning in there. And I'm pretty sure that I'm punching the clutch in as well when starting it (old habit), so there really should be no signal going through there.

Could this be a grounding issue or something? When the car starts, it goes right back to 0MPH. It only does this when it's turning over.

Mike Murphy

Thats very strange. However, I had a 68 Nova where the water temp gauge would move quite a bit when turning over, and that was caused by a bad negative ground cable between the engine and the chassis.

theiceman

sounds electrical ....

im a but curious when it comes to my car . if it were me i would unplug the sensor at the transmision and see if it still does it .. if it stops doing it i might replace the sender.

david05111

I'm knocking out little things on the car at the moment while I'm waiting for some parts and tools to come in. I tabled the speedo thing for the moment.

I just replaced the fuel sending unit in the car and was really, really happy to see that fuel gauge come back to life. I still don't have much movement at all in the fuel level part of that gauge though...not sure what to think about that. That's even after driving it around for a bit.

The one that's really bothering me at the moment is the oil temperature gauge. The pressure side of that gauge works great; absolutely zero issues that I can tell. But the temp side is seemingly dead. It doesn't really want to move at all.

Are the pressure sensor and the temp sensor one and the same? If so, is it common to have part of it go down but the other part still work? Are there separate leads to the back of the gauge? Trying to decide if I should pull it from the dash and check the connections if it's two separate wires.

I'd like to get this nailed down. I really get squeamish not knowing what the oil temp is, considering it's an air/oil cooled car.

EDIT: Just found this thread and I'm going to have a look and see what sender it is. I suppose with any luck since that thread is about an '80 and mine's an '80 that I'll have the horizontal sender and I can simply unbolt and replace it. If it is the same, I'll try that trick about grounding it and see if the gauge moves. If so, I'll replace the sender.

Mark Salvetti

I don't think you've ever posted a photo of your engine bay, but yeah, it should be the horizontal sensor next to the oil pressure sensor can. Take off the wire and the gauge should peg I believe. If the gauge doesn't move then you probably have an electrical issue.

There is an early sensor that won't match the calibration of the gauge, make sure you order the correct part. I think yours should be silver (the early one is brass). BTW, if you look way to the left under the gauge bezel with a flashlight, you'll see tick marks with temps in degrees C.

You can also buy a new gauge module that actually shows temperature, this comes with a new sensor: Oil Temp Gauge Upgrade You have to take the front of the gauge off to replace the module, which you can do yourself if you are careful.

Mark

david05111

UPDATE:

Firstly, I had a look at the oil temp sensor. I disconnected the wire and tried to ground it on something. I couldn’t find a good ground, BUT the gauge did jump periodically. The wire looks in good condition, as does the connector. I suspect that it’s fine and it jumping was just because the ground is lousy. Simply disconnecting the wire had absolutely no effect at all. Picture attached below; it’s the horizontal version.

I also smoke tested the car for vacuum leaks and I found at least one, perhaps more. I can’t tell because they’re right below the air box and I don’t really want to take that all apart. The air box is brand new, so I know that it’s not cracked or separated. I can tell that at least one of the rubber unions where the manifold meets the air box is leaking. Funny thing is that those are brand new; they must be loose, but there’s almost no way ti access them with it installed in the car. It’s also only on the passenger side; the drivers side ones are just fine.

I’m calling the shop tomorrow and telling them I’m having the car sent over and they’re going to fix it on their dime. They didn’t bother to do the test before it left, and I paid for the engine to be GTG.

theiceman

cant find a good ground ???
how about that massive block of aluminum the sensor is screwed into .. lol

But having said that you bring up a good point, since you have been having issues with a couple of these, id certainly get underneath and check the condition of that ground strap from the transmission to the body. Probably fine, but worth a look.

david05111

Funny thing is that I don't think I even thought to just try the housing. I was hitting the ac bracket and a few bolts. *Facepalm*

I just found this chart and WOW...I didn't know there were that many grounds on the car. I'm going to be poking around a bit looking at all these.

david05111

UPDATE:

Got the car back from the shop. They found the leak under the air box and corrected it. It had something to do with a clamp letting go or something.

I drove the car around and it still had the surging at idle when warm. My suspicion is that when they put the car back together, they couldn’t get it started with the mixture it went in with. Why? Probably because of that large vacuum leak. So they enriched it significantly.

So I brought the car back to my place and decided to do a test. With the car running, I pulled the filter and cover off and pulled/pushed on the CIS flapper. When pulled down, the idle improved significantly (too rich, as expected.)

I tried to dial the idle down to around 950 like the manual suggests and it was surging pretty wildly from like 800-1300. I adjusted the mixture a few clicks to the left and the idle got better, but shot back up to like 1300.

So I dialed the idle back down again and the surge returned. One or two more clicks on the mixture and the idle improved again, but once again the rpms increased to like 1300.

I think I did the process a third time and gave up for the night. The car starts and idles smooth at about 1100 right now. No surging from being too rich, no pops from being too lean. I think that if I dialed the idle down again to the 950 range, it would start to surge again and I’d have to lean it out some more. I did pull down a little on the flap again and the idle sped up and seemed to improve a bit more, so I think it’s still a hair rich. Not going to mess with it anymore tonight though.

I should mention a few other things.

1). It’s an ‘80, so it did at one point have an 02 sensor. I guess that makes it a lambda car. That said, it’s been disconnected since the rebuild, so I don’t think the system is fighting me. I’ll confirm everything is disconnected tomorrow.

2). The temp gauge in my car doesn’t work, as I mentioned before. I haven’t tracked down the issue entirely yet. I need to get the car in the air to check the ground strap underneath by the transmission, since the issue with the Speedo going to like 25 when starting is still there. There may be something weird electrically going on, though there seems to be no drain on the battery that I can tell. It turns over without hesitation every time, even after it sits a while.

Since the gauge/sensor doesn’t work, I’ve been unable to monitor the oil temp. I think I’m in the green there, since the idle was so obviously out of whack. That said, I’m not planning on driving the car any further until I can get a new sensor in there and I can confirm what’s happening with the temp.



Ultimately, this shop only vaguely knows what they’re doing, imo. It’s apparent that they REALLY enriched the mixture on this thing; dialing it down, I bet I completed a full rotation of the mixture screw. And it’s still a little rich. Then they dialed the idle screw way up to compensate for it, and the vacuum leak got compounded all of that.

I’m going to order the CIS fuel pressure tester and get numbers for all of that before I take it out again as well. Hopefully I can confirm they’re roughly where they need to be and what remains is just dialing this in a bit more closely.

EDIT: Here's a video of what the speedo does when starting. This was a medium-cold start (I had driven it around and then parked it for like 35-45 mins, so it wasn't ice cold and it wasn't warm) and prior to me messing about with the mixture. It doesn't like to start if it's just stalled or -- occasionally -- when it's cold. It's something I'm hoping I'll clear up when I get the rest of this sorted.

david05111

Just a follow-up on the above. It occurs to me that maybe my oil temp gauge is actually working. It does move, I just assumed it had to be wrong.

But I found this picture and I have style C. It looks like normal operating temperature would still be near the bottom of the gauge in that lower box, possibly creeping up a bit toward the top or slightly over the top of it. The actual middle of the gauge looks to be around 250 degrees F, which seems hot to me. It's gotten nowhere near that, and I honestly didn't think it was moving enough since it only seemed to move up a little in that bottom box.

I wish there was a way to confirm all is well. Maybe there's an external temp gauge I can screw into that port that can give me a readout of the temp. Someone suggested using a thermal heat gun, but I'm not sure what I'd aim it at.

Someone else also suggested using boiling water, but that would only seem to get it to the top of that bottom box if I performed that test.

david05111

I ordered some stuff this afternoon. I finally properly grounded the oil temp sensor wire to the engine case and it's solid; the needle jumped and stayed where at the top. Wiring is good. So I ordered a new sensor and washer/gasket.

I also ordered a CIS fuel pressure tester to measure the system, cold, warm, and residual pressures. One of the components I'm curious about is the WAR. I'll feel more comfortable knowing the pressures are in-spec and that's working correctly.

I'm having some troubles with it starting (has to crank over a lot) and I'm told that feathering the gas on CIS cars isn't recommended due to risk of backfire in the airbox. I'm hoping that these tests will help me start to isolate what the issue is.

In any case, I have an appointment set next week for the car to go to a shop to get the mixture dialed in. I've decided that I'd rather have an experienced shop with a sniffer that can monitor the exhaust get the thing dialed in. I'm just trying to knock out as much stuff as I can before the car goes in so that I don't get an enormous bill for it.

I do have some related questions. It seems to me that it's all well and good to measure the A/F ratio at the tailpipe and decide whether it's lean or rich. The more troublesome question in my head is: how do you know if an individual cylinder has the correct mixture? By that I mean, let's say we get all this set up and ready to go but in like 6 months, one of the cylinders develops an issue (say, an injector get's clogged up). I'm thinking there won't really be a telltale sign of that?

Even if I were to source a few wideband 02 sensors for the bungs in the SSI heat exchangers (one on each bank) and wire them up to two A/F gauges in the console, it still would only show me the A/F for 3/6 cylinders. If that bank seems a little lean, it might be indicative of a single cylinder having an issue, but when you're only measuring from the tailpipe, it concerns me a little bit.

As I understand it, part of the procedure of getting everything "in spec" is to make sure the injectors are all working at roughly the same rate so as to mitigate such an issue. And I know there's a device in the system (WAR maybe?) that increases fuel flow at wide open throttle to ensure a more rich condition and to make sure it doesn't lean out. I suppose I should track that down too.

Lots of reading to do, but I'm working on it. I'd like to have the engine and such 100% good-to-go in the next two weeks or so.