Well, #1 and #5 were a little sooty, but not really crudded up. Of more interest to me was that they don't appear to have been installed new under my ownership; we're probably due for new plugs. Cleaned and reinstalled and ran a little better, but not perfect.
Pushed the track night entry to next month, too damn hot and too much other stuff on my plate to try to jump through my ass and get it ready by tomorrow morning.
Think I'll get a set of plugs and see if that changes anything. Beyond that, probably looking at welding a bung in and throwing the wideband in for some diagnostic insight.
In the meantime, I'll see if I can con somebody into getting some action shots of backroad shakedown shenanigans for posterity.
You have a pic of all plugs in firing order? 1/5 don't share a thing but if they are old it's hard to say anything definitive anyway.
You have the CEL/scan port hooked up? Which ecu is it using (obd1/2)?
In reply to Paul_VR6 (Forum Supporter) :
Actually, looking at Google images, 2 and 6 were sooty, not 1 and 5. Front left and front right. No photos, I was out of daylight and the mosquitos were biting my ankles.
Don't think the CEL/diag is hooked up, at least not that I'm aware of. Pretty sure it's OBD1, ECU has "'96 Passat" written on it in paint pen.
Got a fresh set of plugs, will throw them in this evening and see where we stand.
Okay, plug pictures as the old ones came out, in firing order:
And the new plugs, after 5 minute rip with key shut off at the top of third gear, in firing order:
Ran pretty good with the new plugs, there's still a dead spot at about the normal driving throttle position. Makes kind of a whistling noise like a blow-off valve when you ask for just a little more throttle than that, and hesitates like it'd rather not, until you go a little farther open, then it remembers what it was supposed to be doing and starts pulling hard.
Obviously all butt dyno data, I really need to get some diagnostic from the ECU or get the wideband put in so I can see some real values.
Old plugs don't look awful, I wouldn't call any of them "sooty" but there's defitely some oil (valve seals, rings) on #2 or maybe #5 (these are in 153624 order top to bottom?)
96 if that's correct is OBD2, it will have the throttle body with 7 pin connector and no idle valve. ECU will end in 259 (letter).
In reply to Paul_VR6 (Forum Supporter) :
Sorry, knew what I meant, but "firing order" wasn't it. Pics are in cylinder order, 123456. Two of them were slightly wet and I would have called it oil also. Not making oil smoke from the exhaust. 2 and 6 were dark the other evening, the others I'd have said looked about like plugs should.
I'll look at the ECU closer this evening. I have looked for an OBD port to no avail; not sure of the origin of any of the rest of the conversion components. Not sure how much mix-n-match you can do with 90's VW electronics.
You can do a LOT of mixing of 90's stuff as they used the same fuseblock from 90-99 and most stuff plugged in right there or into the little jumper boxes above the main fuseblock (12v accy power, vss, OBD K and L line... it's pretty easy to add the port though.
From what I remember the car came to me without an ECU. In Feb 2019 I bought a 1995 Passat ECU on eBay with part number: 021 906 258 BS. I'm pretty sure that's the one you are looking at, but I may have had two ECUs by the time you bought it.
Somewhere in that collection of stuff there is also a tuned chip that will have to be socketed or soldered to the board to use. I don't think that it's still available online anywhere, but you could contact Neuspeed to get more info about it. Here's the info from when I bought it: "Neuspeed Chip APS-CR1 651027 VR6". I have no idea at this point if that chip will be beneficial, but I had spent a few hours online checking it out when I originally bought it and thought it would be good.
If it is 258 its obd1 and there are a few flavors based on year that you have to get right. Big one in later years is 4 vs 6 pin maf (94/95 vs 93/94)
Looks like all 1995 stuff. It should have EGR if that's removed it can cause issues as well, if you cut ECM pin 10 (brown/white or white) it will disable it in software (for racing only of course). Also make sure you have the SAI solenoid, relay and the EVAP solenoid plugged in or the fuel trim feature is disabled.
You can scan these for codes but it's not as comprehensive as OBD2
In reply to Paul_VR6 (Forum Supporter) :
95% sure this doesn't have SAI or EVAP installed. Pretty sure I have an SAI solenoid in one of the boxes of parts.
docwyte
PowerDork
7/28/22 1:47 p.m.
Pretty sure 258 EA is the 1995 ECU code, not sure about the BS one you have
BS is a passat code, but they are functionally the same and use same eprom
Back to the first post in the thread, the engine in the car had an SAI delete; from the ad: "... 42DD SAI delete plug, ...". Not sure if that means it is the current state of the engine in the car now.
I remember the 42 DD plug in question, not sure if we moved it to the replacement head or not. Will have to look at that. Pretty sure I remember seeing it in one of the parts boxes. I KNOW the SAI solenoid is in one of the parts boxes, and doing some quick googling says I ought to hook it back up with the vacuum line looped back to itself to restore fuel trim.
The new head has the flat spot where the SAI valve would have lived and where the 42 DD delete plug would have lived, but there is no hole for either of them to live in. That's why it's in the box of unused things.
About to dig around for the SAI solenoid. Maybe having it plugged in will make all the difference.
Had TWO SAI solenoids in the box.
What I don't have is a plug on the harness for the SAI solenoid. Stripped the ends of the appropriate wires and rigged them up in a spare unused plug. Butt dyno results are not to be trusted. Still had a dead spot, but thought it was a little smoother getting into and out of the dead spot. Need to do some more looking for correct pinout, make sure I have the right wire in the right place. Also, I'm dubious about the fact that there are two solenoids in the box; may need to check both to find a good one.
As long as it has some resistance its probably good enough to fool the computer. Make sure the relay is still there too. Its mounted in the bay somewhere.
On obd1 because there is no 2nd o2 the computer can't tell if sai works or not, just trusts it if there are no open/short faults. Annoying bit is almost any codes related to fuel will cause fuel trims being inactive.
Also a common oops is mixinG the sai solenoid plug and iat. They are keyed the same. Iat will have one wire that is brown/stripe.
In reply to Paul_VR6 (Forum Supporter) :
The SAI plug is missing in action. Wires are there, plug was either cut off or pulled off accidentally at some point. Cut the plug from the IAT pigtail and am using it to cobble the SAI solenoid in.
I suppose I probably need to leave the battery unplugged for a bit to reset the fault codes and give it a fighting chance of working right.
Left the battery unplugged most of the day. Still got a flat spot this evening.
That should have done enough to reset. The fuel trims will take a little to feed in, if they are working. Probably worth getting that scan port wired.
Any chance of a small vacuum leak? All the rubber is 30ish years old.
In reply to AAZCD-Jon (Forum Supporter) :
Abso-berking-lutely.
