Reading KR with a genisys

I'll just throw this info in here: The 95 does indeed ignore knock until the engine gets to temp.

I'm running the factory PCM. I swapped the original PCM with the PA PCM, since they both have the same numbers on them. The car runs the same with either PCM. I have made no electronic performance mods besides cleaning the grounds. I've checked for ground continuity from the connectors. All ground pins are showing less than 1/2 ohm, now. Before, some of the grounds were showing open or greater than 4 ohms.

The operating temperature on the scantool is showing roughly 190-210, which reflects the temp gauge reading; despite having a 160 t-stat. With the lean misfires correlating to the EGR and IAC readings, I'd say the EGR and IAC are contributing to the lean condition. I agree they should not be opening when accelerating. Do the EGR and IAC share any inputs? I'm wondering if someone has messed with the wiring harness in the past. I'll have access to some diagrams tomorrow.

Thanks for the feedback, Andrew. That has been noted. Also the way the thing is running would suggest that the PCM is adjusting the EGR and IAC inverse to what ought to be happening.

I just found a Service Bulletin that says "Continuous Spark Knock" in the title if you'd like me to post it. It's something about Valve Seals with broken retaining bands allowing oil into the engine causing knock. It's for '93-'95 Rivs and the like.
It mentions nothing about the IAC or EGR. However, it might make sense that the PCM kicks the EGR into full duty cycle if it's trying to reduce knock. It might be worth a read.

Abaddon wrote:

I just found a Service Bulletin that says "Continuous Spark Knock" in the title if you'd like me to post it. It's something about Valve Seals with broken retaining bands allowing oil into the engine causing knock. It's for '93-'95 Rivs and the like.
It mentions nothing about the IAC or EGR. However, it might make sense that the PCM kicks the EGR into full duty cycle if it's trying to reduce knock. It might be worth a read.

(That sounds interesting regardless, I'd say post it.)

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So, since the rebuild I haven't been getting any KR registered but there is a knock count.

That's good info. You've never actually seen knock retard reported, and you haven't heard any audible knock since the rebuild, but you believe you have knock anyway because the raw output from the sensor makes it seem that way.

I think the 160º t-stat is playing tricks on you. Even without realizing you were running the 160, I brought it up on page 1 for example, because the PCM won't listen for knock below 158ºF, and it just seemed eerily familiar.

A long time ago, I had zero knock running a 160, thinking the t-stat was cooling things enough to suppress it. What was odd was the fact that at 158-160ºF every time, KR would appear suddenly from nowhere. Then, below 158 it would disappear completely. This strange behavior led to the discovery of knock activation temp on my 98 Riv (at the time very little tuning was done on Rivs, and it wasn't available knowledge).

What I'd do:

Ditch the 160 whenever ambient temps are below 65ºF.

Return the knock sensor to the proper location. Do a WOT run in a safe place, while logging KR. See if you can produce 1-2º (start off easy. If you see more, back it off). If you see KR, your system is working properly. If not, try a little 87 or 89 on an empty tank and see if things change. Once you see KR, you'll know things are right. If you still don't see any, maybe there is a problem.

I still feel like your system is working properly, excluding the 160 t-stat. The critical knowledge we need to know is: are the knock counts you're seeing relevant? There's always background noise that will be picked up by the sensor - it's the PCM's job to sort things out and determine what's knock and what's not.

The EGR/IAC discussion - I don't even see why it's relevant at this point for solving the knock issue, if any problem exists (keep EGR discussion in the EGR thread).

For some reason the knock, EGR and IAC all seem interrelated on my Rivi. As I've said before, I was having this issue before dropping to a 160. I get some knock counts and timing advance reduction even before the temp goes over 160. However, no matter what the conditions, either hot or cold does any KR register.

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As I've said before, I was having this issue before dropping to a 160. I get some knock counts and timing advance reduction even before the temp goes over 160. However, no matter what the conditions, either hot or cold does any KR register.

160 t-stat and knock counts aside, one thing we've seen before with members seeing zero KR is not pushing the engine hard enough to produce a detectable amount. Even a car with spark knock will not report any KR until it is subject to a considerable load. Have you loaded the engine to conditions that will produce KR? I'm talking about something like a 2-3rd gear shift at WOT.

Yes I have. It runs like a BOOH at WOT and the knock count gradually goes up with no KR. Even when the KS was in it's original location and the engine at 170+ deg. The lean stalls only occur after the engine is warmed up at part throttle, when the EGR and IAC are opening under acceleration.

By chance, does this knock count go up to say, 100, then back to zero and start over again?

It resets to Zero when I turn the key off. It always sets a 3 after I restart it. When I start driving, it gradually goes up.

Ok. So it's not just cycling from zero to the ceiling, zero, ceiling while running then. I'm not familiar with a Genisys system. I'm familiar with a Modus and Solus. I'm just trying to rule out the chance that were reading the actual cycle counter that the PCM uses to decide whether or not to turn on the SES (enough misfires/knock during a cycle). If you've ever seen a misfire counter on a Tech II you'd know exactly what I'm referring to.

I'm trying to make sense of this. Getting knock counts, but no Knock Retard is (obviously) confusing.
Do you have the USB or RS232 hookup for your scan tool to print with? Maybe you could "print" the page to computer and save it so we can see?

It's a Snapon Fastrack Scanner MT-2500. I used to use it professionally, before I retired in 2009. It has an LPT port on it. I'll see if I can find a USB adapter. I've never tried to print from it before. If all else fails I can take some pictures. I still haven't been able to get the photo uploader to work for me. Does it have a problem with Firefox?

We're at 100 degrees in Tucson this afternoon, BTW...

Ok. I'm absolutely not familiar with that scanner.
I just looked up that tool. This might be a really stupid question, but do you have the right cartridge for '95? The scanner can be hooked up no problem because it has the OBD II port (which you already know). Apparently the Fastrack needs this for '95-prior?

*For vehicles prior to 1996, use the MT25001099 Domestic Primary Cartridge.

Just trying to rule out the easy stuff.

EDIT: 100* YUCK.

The cartridges I have are for all domestic vehicles from 1980-2006. They used to have them broken down by 1994 and prior. In 2006 the last upgrade worked for 2006 and prior. It has adapter plugs for all the different diagnostic plugs. For most 95 and later OBD you use a "personality key" for the different makes.

I think I just found another problem. It appears the ignition switch is bad. For example you can touch the key guide with the key out and the key chime sounds off. Also, the AC is now intermittent from time to time. The gear indicator and the temp gauge go inop, and the radio takes a long time to energize. I've seen bad ignition switches cause a bunch of problems. No wonder the guy I bought it from never answered when I asked him if he had fun with the car, before he blew the engine. He obviously thought it was cursed by Lord Lucas...

What's your voltage when running? A bad (high) voltage regulator can cause weird problems like these.

When the engine is running it's between 13 to 14 volts. I haven't seen it run any higher than that.

This morning I double-checked the IAC and EGR functions. They are both opening with the throttle, even when cold. My guess is that the fuel mixture is rich enough, under ambient conditions, that the EGR gas and the extra air are not sufficient to cause a lean misfire. So, when the fuel mixture leans out, after the engine is warm, there is not enough fuel to compensate for the extra air allowed in by the IAC and the EGR gas.

I'm tempted to try another wiring harness or rip this one apart, to see if I can locate some chaffed wires. I have a spare PA harness, but I'd like to zero in on the exact cause of the malfunction. I don't see where there is any damage to the Rivi harness casing. Hell, for all I know there may be chaffing in the harness between the PCM and the firewall.