Phenolic Intake Manifold Spacer

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thesameguy
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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Thu Jan 24, 2019 11:46 am

Phase IV - Half-installed the "rebuilt" throttle body and reconnected the intake pressure tester. This time I was easily able to pump 20psi into the intake, with slight loss out the exhaust (guessing cam position error, maybe worn valve seats?) and slight loss out the oil dip stick (bottom end leak, engine was stone cold - 42*). Then a major leak appeared at the brake booster vacuum line, which was just a poorly installed fitting easily remedied. No apparent leaks from the lower intake manifold or any of the intake plumbing. I can't find anything truly wrong. :shrug:

I guess I will adjust the throttle stop and TPS on the new TB and head out for a road test. Maybe I lucked out!

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Re: Phenolic Intake Manifold Spacer

Post by andyofcolumbusmerkur » Fri Jan 25, 2019 8:03 pm

But you did a compression check. You'd have a low number if there was an issue. Also wouldn't at least one valve been partially open when you pressure up the intake? And why would you get air out the dipstick if you had good compression numbers? I mean some blow by sure but you hear it hissing out the opening? Makes me think something was changed as far as passages are concerned and now intake air pressure is going someplace it shouldn't. Did everything run really good then start acting up or did problems start right after doing the spacer?
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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Fri Jan 25, 2019 9:19 pm

I think you missed some stuff in this thread!

The spacer was installed in April of 2017.. this problem appeared a week and a half ago. A lot of time passed between install and this problem.

The compression test was done warm, but the intake test was done cold. A cold engine will usually have bigger tolerances than a warm engine - which is why you want to do the compression test warm when possible. The temperature difference totally explains loss of intake pressure via the bottom end. I suppose it could also be a PCV problem, but the valve is virtually new with very few miles, so it's as good as it's going to get. These are the only two ways air gets into a sump - past the piston rings or through the crankcase ventilation. In any case, I am not really worried about the airflow out the dipstick. If I really cared I could warm it back up and do a leak down test, I suppose.

I don't know the cam position - I didn't check to see if it's possible to set it in a position where all valves are closed (dunno what overlap is for the Lima) so I didnt bother to note the cam position - that is why I noted the possibility of a cam position error. Maybe there was a better position but I don't know. :) Holding 20psi and only losing air where I'd expect to is good enough for me. ;)

As I indicated, all these tests are positive in terms of engine health. I can't find anything really wrong. Unfortunately that leaves me with no explanation for the piss poor running... all I can do now is reset the idle stop and TPS and drive it some more... hope that the problem went away as suddenly as it appeared, or that it breaks catastrophically and shows me where my testing went wrong. :)

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Re: Phenolic Intake Manifold Spacer

Post by andyofcolumbusmerkur » Sat Jan 26, 2019 9:02 am

Well it sounds like your doing pretty well. Getting 300,000 miles out of any gasoline engine is pretty good. How about finding a spare longblock and swapping that out at some point to see what changes? If that solved issues then you would know it was time to rebuild the original motor and not some other problem.
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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Sat Jan 26, 2019 11:42 am

I have two good spare engines. One is a zero mile rebuild with forged pistons and the other is a 100k 'barn find' still in the car. I am buried in car projects and really hope I don't need to add XR4Ti engine swap to my list, but I guess if I do then at least I am prepared.

The engine in the car is a champ. Previous owner took very good care of it, and aside from mods I have as well. Prior to this it was running superbly - I hope I get back there!

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Sat Jan 26, 2019 7:33 pm

Got everything put back together. Set base idle at 750rpm and TPS at .94v:

Image

I'd never used the timing light to set base idle before, so plugging it in was a total "duh" moment. I was interesting to watch the specific sequence of setting idle this way. With the idle valve disconnected I set the base idle at 750rpm and did a final adjustment on the TPS. Then I shut it down and plugged the idle valve in and restarted. Over about 60 seconds the idle dropped from 1050rpm to 850rpm in steps - bouncing down +/-50rpm until it hit 850rpm and stayed. Neat.

I don't really have anywhere to go right now, so I guess I'll find out if this got me anywhere Monday when I head into work. Or call in late, depending. ;)

Hopefully it's positive, because the car is due for its smog check & registration within the next two weeks, so I don't have a great deal of time to mess with. The odd years make for a rough winter/spring - the Viggen, XR, Fiero, and SPG all need smog within two months of each other. Fun stuff.

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Sun Jan 27, 2019 11:54 am

I ended up having to make a Home Depot run last night, so took the XR. First mile wasn't good - same hesitation and stuttering as boost rose.

About a half mile in, I stopped at a light and some dudes towing a Volvo 744t asked what I was driving. "A Merkur," I told them. "Sick," one of them said. "It is right now" I offered.

The light turned green and the hesitation was 100% gone. Maybe all the car needed was a compliment?

I picked up my stuff from the Despot and headed back. It was hesitating around 2k rpm as boost came up, but drove pretty normally otherwise. By the time I got home, it was mostly normal - not quite perfect but far from how bad it had been.

My only real thought right now is maybe I have bad gas, or some water got in. I only buy high octane Chevron - the car has never had anything else - but the last fill up was from a station I never use. It's about a 1/4 tank so I will fill it up and see what happens. I am also wondering if maybe it's a sticky VAM. I have lucked out for 15 years with used ones. Maybe I will pick up a new one just for giggles. I am also thinking about some new ignition stuff - but really aside from the coil (MSD, came with the car) all the ignition is about six years and 20k old. Shouldn't be an issue.

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Re: Phenolic Intake Manifold Spacer

Post by Esteban » Sun Jan 27, 2019 5:38 pm

does it hesitate at the same RPM and gear? Sweep VAM and TPS if so.

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Mon Jan 28, 2019 12:23 am

It doesn't seem to actually be rpm dependent - I can't really find any dependence. Originally it seemed load triggered - anything more than just a little and I got a lot of hesitation. Last night it seemed more like just off idle. I think at this moment it is bad gas, but I cant really tell for sure if its fuel or ignition right now. Since it was doing very well with bigger throttle/more boost than before, I do think it's getting better.

The TPS isn't new but is different than the previous one. The one on there now is about 7 years/30k old. The previous one was 2 years/6k old. Since the original terrible performance cross the swap, I'm ruling out TPS.

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Wed Jan 30, 2019 1:28 pm

I have nothing useful to report. I don't have the time or reason to log real miles on the car, so it's stuck right now doing 8 miles drives to and from work.

The problem seems to have continued to improve - Monday was a bit rough off and on, but Tuesday seemed generally good. One thing I have noticed is that turbo lag feels a bit different, maybe a bit more pronounced? I am wondering if leaky throttle seals are the culprit there. But the core problem - the lack of power - seems best described as a byproduct of big throttle transitions.

Initially, when it was realty bad, anything more than a gentle nudge to the throttle resulted in stuttering and bucking. Over the weekend, that improved quite a bit to just lack of power, but not stuttering or bucking. As of yesterday, the problem is so slight I doubt a new driver would really even notice - it's just a lack of immediate response to big pedal movement. After just a moment, everything does what it's supposed to - I ran into a C4 enthusiast on the way home yesterday and had no problem reminding him just how $#!%^& Corvettes were in the '80s.

I am pretty sure that whatever the lingering problem is that it's fuel related - not enough fuel fast enough, so to speak. Kind of like a carb where the accelerator pump isn't happy. I do see how this could be a TPS problem, so I may swap back to the original one and see what that feels like. I'm also still looking at the possibility of contaminated gas - I've got 12 gallons of new gas but the balance is still old.

I've gotta get it smogged this weekend. There is a reasonable chance it will fail. I've got 12 years on my "two year Magnaflow" so I've been on borrowed time for a long time. ;) NOx emissions creep up every single year. That's a whole other problem, because I don't know how I'm going to get a replacement 3" cat under the 2009+ laws. Nothing's easy. :) But, uh, fingers crossed I get another two years and it's a problem for another day.

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Thu Jan 31, 2019 12:48 pm

This morning on the way in to work there was a 15 second moment in time where the car experienced a complete loss of power. I had been stuck behind a truck, rocketed around it, then nothing. Pedal down, no go. Felt like the pedal was completely disconnected from the throttle, or a massive vacuum leak and resultant no power. I started preparing my emergency get off the road plan, and eased into the throttle and everything was suddenly fine again. No further issues on the rest of the drive.

I think I am going to go in for a new VAM. After years of junkyard parts I wouldn't consider it a waste of money either way, and it's one of the few things I have never replaced on the car. Plus, I can't immediately think of anything else that would cause random and intermittent losses of power. Hmmm.

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Fri Feb 01, 2019 11:49 am

After the weird loss of power in the AM, the car performed great on the rest of its 30 mile daily function, and I was certainly not taking it easy. Because I never do. Easy is for chumps.

But I picked up a new VAM anyway - the only options in the world is seems are $600 BMW-branded parts or $100 Cardone reman parts. I chose the latter. Which was apparently a mistake.

With the Cardone part installed, the car ran so rich it wouldn't idle. I reset base idle and then the TPS - fortunately this time I replaced the Philips head screws on the TPS with hex head screws, so it was easy to adjust the TPS from the top. ;) After getting it to idle, it was still running so rich the exhaust burned my eyes. NICE.

I drove it to work anyway. I will say that "more fuel" eliminated whatever minor dead spots I had before, and low-engine-speed performance was pretty nice. But the car clearly lost a pile of power, and sometimes I can smell the fuel in the exhaust. Under heavy acceleration, the car suddenly STOPS, like a full fuel cut. Obviously this is not a long-term plan, but I do have some questions. Which I will ask in another thread.

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Re: Phenolic Intake Manifold Spacer

Post by andyofcolumbusmerkur » Fri Feb 01, 2019 4:02 pm

Can you swap in a different computer? If you have an extra just to see if anything changes?
You can barbecue it, boil it, broil it, bake it, saute it. There's shrimp kabobs, shrimp creole, shrimp gumbo, pan fried, deep fried, stir fried, pineapple shrimp, lemon shrimp, coconut shrimp, pepper shrimp, shrimp soup, shrimp stew, shrimp salad, shrimp in potatoes, shrimp burger, shrimp sandwich....

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Fri Feb 01, 2019 4:21 pm

I do have an extra (or two) and I've considered swapping it in the past. It may be on the to-do list this time.

I'm also entertaining the possibility that the BAP is problematic. It's easy to blame the new VAM for rich running, but at the same point it's just a resistor - how hard is that to get right in a reman scenario? Not very, not like a hot wire sensor. I think a bad BAP could change the relative handling of the VAM output, resulting in a messed up mixture.

I think I have a new BAP for the car, so I'll swap it in and see what changes before delving into an ECM swap. I don't *specifically* have a reason to doubt this one... yet. ;)

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Re: Phenolic Intake Manifold Spacer

Post by thesameguy » Fri Feb 01, 2019 6:27 pm

I swapped the BAP at lunch. Or mostly. The second screw was a PITA so I'm rocking one right now. No worries, they're getting replaced with torx screws ASAP.

I didn't have a new BAP like I thought I did, but I had two used ones. The part on the car was E3ZF-12A644-B1A, but I replaced that with E7EF-12A644-A1A which I *think* means it's newer (E3 vs E7). I did also have a E3ZF-12A644-B1A, but it had a crusty layer of dirt on it. :shrug:

Idle with the new BAP was much improved, and fuel smell in the exhaust much decreased. Neither was as good as it was with the old VAM, but better nonetheless.

Unfortunately, the FUEL CUT. FULL STOP was still in effect. I'm not talking "loss of power" or "sputtering," I am talking RAN INTO A BUS. The effect is not road speed, engine speed, or even directly boost dependent. Hard acceleration is what causes it - 2000rpm, 0psi lay into the throttle BAM. 3500rpm, 10psi, lay into the throttle BAM. I don't know what would cause this effect on an XR. On a Saab 900 with LH Jetronic you get this effect when rapid changes in airflow erroneously trigger the integrated overboost protection... this usually happens when you have a big exhaust, big intercooler, and a big turbo. I haven't been able to determine whether EEC has a similar function... but if it does, a goofy VAM would cause it just like a goofy MAF does on a Saab.

So I'm going to leave this other BAP in there and throw the old VAM back in, see where that gets me.

Edit: To be clear, my working theory is that this VAM is grossly overreporting airflow, hence the rich mixture, and thus leading to a premature fuel cut.

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