91MR2

Thanks again guys, I'll take a picture of my afm later tonight, maybe some of you can weight in on how it looks...

Goce, funny you should ask about popping/crackle on decel - when the car is running bad, in that it has the stumbling, etc., the popping is quite noticeable. When the car is running well, it is not nearly as pronounced. Still hear little ones, but you can tell when it is running poorly that more unburned fuel is getting into the exhaust.

Hi Rabin, I do not have a fuel pressure tester, however can get access to one if needed. Regarding the fuel pressure regulator, it was replaced a couple weeks ago, it was a cheap part so I figured why not. The car actually ran flawlessly today. Again, I keep going back to fuel as what I suspect is the main culprit here. I just put in another 10 gallons of non-ethanol high-octane fuel this evening, and it just keeps running better and better. I'm not confident enough yet to say I am out of the woods with everything here, but I'm going to continue to drive it, and continue to run fuel through the system, it seems like that castle fireball actually helped out a lot. I still have the check engine light coming on and off throughout my drives, but again the light seems to only really come on when the car is under very light throttle or when you are coming up to a stop sign or stop light, when you are driving under any kind of load, the light is off pretty much all the time. Either way, I will take this as my only problem for the day… That of course, and my unbelievably rattly sunroof mechanism… This is driving me insane…

Goce/Mike, not sure how to verify, but maybe rockauto is just trying to dump them? Andre, I doubt that is my issue but will check the connection later tonight... How hard is it to do valve seals on these motors? Does the head need to come off?

Also, I'm not opposed to having the injectors cleaned, however Bosch injectors are 30 bucks each on rock auto, seems like a good idea to maybe just start with new ones, and then I could still have a backup set, maybe get them cleaned down the road at some point?

OK, but what would cause oil to get on the spark plugs? I have a brand new valve cover gasket, and my compression test resulted in near 180 on all four.

Another driving update, I went to take the car for a ride last night, similar to the night before, and it took a few cranks to get it to start and it idled quite poorly for the beginning, and did not go through the proper coldstart sequence. Also had a few stumbles for the first 20 minutes of driving, but again after that it smoothed out and ran very nicely. Again, this seems like a fuel issue to me, but would love other input. I ordered a new fuel filter and will install when it arrives, but I am wondering if I should also order 4 new Bosch injectors and a fuel pump to be safe. Thoughts?

No I did not get either of those codes and that is what was so confusing...

OK guys another interesting update… I came over to my garage this morning and fired up the car, and it started very nicely, went through what seemed like a normal cold start sequence, and also idled very nicely, so these are very encouraging things. Here's the confusing thing. I went to check the codes again because I still have a check engine light, but this is what happened. Bear in mind I was having my mother help me by releasing the ground and we may have not done it properly. The car never went through the one-two sequence to show test ready, but it kept giving me codes 91, 92, 93. These codes aren't even on the sheet. Any thoughts? I should also add that the idle air control valve was making some clicking noises while doing this test sequence… I don't recall this happening before…

Rabin, thank you for the info. on the tps, I'm not exactly sure how to test it, but I'm sure I can track down someone that knows how to... Interesting update right now, I went over to the garage several hours ago and pulled the plugs, and as I suspected, two and three, but specifically three looked fairly crappy. I cleaned them up with a rag and put them back in as well as the old IAC valve and went for a ride. Probably drove about 75 miles. It's stumbled a little bit in the 4-5000 RPM range for probably the first 20 miles, but for the last 50 or so miles, it ran fantastic. I don't think it's stumbled/hesitated once. I don't want to get ahead of myself, but I'm wondering if the castle fireball injection cleaner is working its way through the car and maybe I've just had some bad gas or a lazy injector all along...Seems too simple, but boy did it just run amazing right now…I would be ecstatic if this is the case… A good indication will be when I start the car again when it is cold. It has not liked starting since this problem has been going on, so if it fires right up when cold, I'm going to say that we are moving in the right direction here... To be continued…

Back to my running issues... I'm going to go back in the garage in the next couple days again and pull my plugs and see how they look. Last time I did this, the middle 2 were wet/fouled. New plugs got me going again but only until the running issue came back, so expecting the same thing. The new (used) Bosch IACV only made my running issues worse, so am going to put the old one back in, even if it is suspect. We did a compression test, and all 4 cylinders were near 180, so that is great, but only adds to the confusion, as so many parts have been replaced at this point... So far, this is what is new: plugs, cap, rotor, wires, O2 sensor, FPR. We also cut the cat out only to find that it was already completely hollowed out, so just welded it back into place. No intake or exhaust leaks found. I have an ignition coil on order as well as a fuel filter, although it does look recent enough...any other ideas? Again, issues are stumbling/breaking up usually around the 4K-5K rpm range, intermittent CEL showing code 52, and crappy idle and starting...

Robotic, I like your profile picture as well, ha. Sorry, I didn't do mine to copy you, I swear... I admire your efforts regarding the glovebox, I didn't quite go as far as I decided while repairing mine that it just wasn't necessary. I hate the way it is put together, and yes, while it can be re-engineered and made stonger, it just wasn't worth the time and effort to me. Plus I love being able to easily remove the cover and have instant access to the hvac/heater-core/sensors above... Andre, thank you for that info., very good to know someone has gone through the efforts to compile this information... This community has been great to be a part of, so much knowledge and passion, but I suppose that is all that's left to keep these cars going these days...

Some more updates, but nothing really good... We had reason to believe that the idle air control valve was not functioning properly, and an old friend of mine who used to be a Volvo tech had a bunch of these old Bosch IAC valves, so I put one in. Not only did the idle surging come back, but the car overall just ran terrible. I'm not sure what to make of all this… The good news is that the car is looking better than ever…so at least I can stare at it if nothing else...

Andre, Thanks for the post and glad to "meet" you. It was both Savo's threads and yours that got me to join here in the first place. Your car and the way you've gone about your restoration is very similar in my approach to mine, in that we both seem to be after a very nice and usable daily driver type in the end... I just ordered that iso pin connector that you linked above, thank you for that. I don't think I'll need any scans but will let you know if I do, seems I have all the info. I'll need now. Will advise once it arrives and is connected to my jvc unit... Regarding my running/stumble issue and cel, they are both still present. My shot catalytic is getting cut out tomorrow, we'll see if that helps...

Got most of the interior back together, just need to put on the steering column surround, and have my homemade floor mats (black house carpet from an old project) bounded at the local carpet store...while it may not run exactly right at the moment, at least it's starting to look good again... Funny point, the glovebox you see installed is in fact just the glovebox door itself. Since the factory glovebox arrangement is such a sad affair, I decided (even after painstakingly rebuilding the entire unit) it might just break again and be another area to rattle about the interior, so best to just attach the door only for interior look and continuity. I don't need a glovebox, never really use them on any of my cars, and especially in the case of this car, where it will just be a seasonal use daily driver, this just made more sense... Also, need to install the radio, however... Does ANYONE have a breakdown of what the colors on the factory connector pin correlate to?

Ha, yes I'm quite sure it is a stumble and not a power increase...it's almost like a a flat spot before the power comes back...still trying to sort...

And some photos of the interior re-assembly. I spent much time today using mineral spirits to remove all the deteriorating "soft touch" coating on the interior plastics. I must have spent 4 hours or so on this. I could shoot the idiot that came up with that product...

Goce, that vacuum line was fine...the search continues... I started cleaning and re-assembling the interior today, and took the car for a ride. It runs well enough where I can use it even with the occasional 4K-5K stumble. Ordered some Castle Fireball fuel injector cleaner, heard good things. And decided for sure that the cat is getting cut out this week, with a straight pipe going in it's place. Since the cat is already shot and rattling, why not... Also, got the rear lowered now as well. Starting to come together...

Goce, thanks for the info., I'll check that vacuum line tomorrow... Tentative plan is to cut out the cat and put in a straight pipe in it's place... Good news is the car is down to just the CEL issue, as all the other issues (the surging idle and stumbling / breaking up issue) have been resolved. The CEL which is stil just showing code 52 only seems to come on when on decel and when idling at a stop light/sign. Once moving again, the light goes off and pretty much stays off. Boy, would it be nice if could be solved by removing the damaged cat...but I wait with baited breath on this one...

Good advice Bean, might be best to just order a new cat, they're only around $100... Regarding the wideband, I'll ask my mechanic tomorrow... I'm getting closer with the car, going to clean up really well and then reinstall the interior over the next few days, give it a proper wash and detail and get it out driving again...

We have checked for leaks, and have yet to find one, certainly on the intake side, I guess we can check further on the exhaust side. Here's a question… My catalytic converter has been quite rattly since I have on the car, at least when the car is called, do you think that could possibly be related? I had ruled that out, because the cat is downstream of the O2 sensor, but I'm sure it serves enough of a purpose where this could be a possibility…

Weather has been fine, 70's and 80's...

Some updates, all... We got the idle surge seemingly sorted. It had an issue with the throttle cable, and a simple adjustment fixed that. The stumbling/hesitation issue "seems" to be sorted as well. Between all the issues that were going on, my "new" plugs had developed some fouling issues on cylinders 2 and 3. Another new set of plugs and a fresh full tank of fuel made a huge difference. The car now has new plugs, cap, rotor, and wires. So far, the sum of these parts have gotten us somewhere, as it is running fantastic at the moment... The CEL is the last issue at the moment still frustrating us. The code was 52, which indicates an O2 sensor (most likely). We don't seem to have an vacuum leaks, and the ECU seems to have good communication. But a new O2 sensor hasn't really helped, as we are still getting code 52. My mechanic is going to continue some diagnostics on this tomorrow, but we have checked just about everything at this point. We have gotten it pretty much to the point where the CEL pretty much only comes on at idle, or when you're coming up to a stop sign or red light, and then when you take off again it goes off and pretty much stays off when the car is driving and under load. Any guidance or thoughts here would be welcomed...

Rabin, I certainly take them at their word, but with how few of these cars out there, and so few people into them, the more input the better...

So how about it guys, that wiring/taping look factory? Just looking for more opinions here... Also, more updates coming this week...