2seater

The Memcal contains the PROM along with other things and is replaceable, but generally don't go bad. It is possible the ECM itself is bad, and is unfortunately not really uncommon. The good thing is they are relatively inexpensive from most good auto arts store but you need to switch the old Memcal into the new ECM. Before I would go to that extreme, the suggestions to double and triple check everything that was done already are very good. There have been a few instances where the rear plug boots were not fully seated, particularly if they have the stock metal heat shield on the boots. They can be a bear to get them all the way on. Check the harness that runs across the front (passengers side) of the engine. It connects the cam sensor and crank sensor to the ignition module and there have been instances where a wire has been rubbed through from the moving parts in the area.

Code 041 is the cam sensor. Was the magnet (interuptor) replaced when all the other work was done? Two of the possible things for an erratic idle. One is the ECM needs to relearn the operating parameters if the battery was disconnected, which it should have been. The second item would be if the check engine light is on and the cam sensor is inoperative. The ECM has to guess at the correct sequence for the injectors to fire. If it has it wrong, it will probably have a rougher feel to the engine at low speeds but will be fine at higher rpm. It starts the sequence every time the engine is started, so it may hit it right one time and wrong the next. The engine will operate okay without the sensor, but it may not be as smooth.

Not directly related, but my work beater Saturn has been doing that also with the onset of cold temps. It does idle down after a bit, but it will hold the idle higher for a little while for some reason, and no codes of any kind? It may be programmed in? In any case, our system will advance the timing when it sees cool incoming air temperatures. There is a table in the programming that varies the timing a little based on air temperature. That will have the effect of raising engine speed but the ECM should still compensate the idle speed through the IAC. If the TPS is questionable, it certainly seems like the place to start.

The potting material surface should be relatively smooth and firm. If it looks like it is melting, it probably is, and indicates a defect or overheating.

Injectors rarely actually go bad, but it is possible to have a buildup causing failure to close or maybe a poor spray pattern. Before I would start replacing them, I would have them professionally cleaned. My preference is to remove them and have them done in a reverse flush or ultrasonic cleaner but they can be done on the car using a different method. You can also purchase reconditioned injectors for about 1/4-1/3 of the cost mentioned, or brand new Accel 19# injectors for $30-$35 each in a set of six. As pointed out in several other posts, a rough idle can have many causes. The hard part is trying to narrow the search as much as possible without buying a bunch of expensive parts. It would seem that at some point, you did have the problem solved, at least temporarily, so it seems likely you may have already found the problem area, or somehing closely related, such as new plugs or wires helping a weak ignition?

A check of the fuel pressure will give you a better indication of the condition of the fuel system. If the pressures are where they should be it will help determine if the regulator is doing its job and if the pump is suppling enough pressure. If the pressure remains reasonably stable for a short time after shutdown it will give some indication of a leaking injector. I do not know this for a fact, but it would seem reasonable a bad spray patterm from an injector may show up in the idle or low speed performance and would tend to be covered up at higher engine speeds? If these are the Bosch 901 injector, they have multiple holes for the outlet, so it could be possible to have only partial flow, and the ECM can only compensate for the entire engine, not one or two weak ones. It is also possible the coil pack or ICM may be weak. I again do not have direct experience, but several people on several different forums indicate a smoother idle with the later style Delco coil setup. By the way, you can turn the individual injectors on and off from the diagnostic system in the overide mode. You can also ramp up the idle with the IAC overide, disconnect it and then turn injectors on and and off to do a crude cylinder balance check. If nothing turns up, you might want to check the cylinder compression or have a leakdown test done. These engines are pretty robust and usually do not have a lot of internal problems.

The steering should take care of itself with a Camaro front clip, except maybe getting the steering column connected to the box. Maybe a Mustang II front clip also, another popular hot rod front end. Weight shouldn't be an issue as either one can be configured for the largest engines available, but the GN 3.8 or a Buick 455 if you like a V8, which weighs about the same as an SBC. I agree with your desire for an independant rear end. The unsprung weight is way better than a 300# Ford 9" and will ride better with a short wheelbase like ours. Underbody room will be at a premium unless a fair sized tunnel is constructed. The footwheels in a unibody car are set down pretty low under the car. It sounds like a fun project, and a big one.

The engines from '88-'90 should be interchangeable. I know the camshaft lift and duration between an '88 and '90, I have tested them, but it doesn't matter in the operating system itself. They should interchange without problem.

The modulator modifies the line pressure inside the transaxle changing the firmness of the shift. The adjustable ones allow you to tailor the shift feel by changing the amount of vacuum the modulator sees. The shift firms up naturally at greater throttle openings due to lower manifold vacuum. A bad vacuum line to the modulator can cause hard low throttle shifts also.

Usually excess NOX is a byproduct of high combustion temperatures, and the EGR is used to reduce and dilute the fuel mix. Not that other things don't effect it, and the suggestions are good, but the EGR primary function is NOX reduction. Is the low speed test at idle? If so the EGR isn't in play, but I wonder if there is a passage plugged if you get no malfunction codes? Just a thought.

Don't forget the steering, the rack is right where the bellhousng would be. Not impossible to be sure, but another headache. I always wondered about another fwd drivetrain added to the rear. I have heard of something like that with another brand of car with a single ECM running both engines. I have no clue how that would be done, but it would certainly be different.

I admit to be a little confused. The '95 donor engine has roller tip rockers? Is the pivot a roller also? In other words, is it what I would call a true roller rocker, with roller bearings in two locations? The rocker I have may or may not have been a Series II. I do not remember the application. I have often wondered why the factory did not use full roller rockers if they are truly beneficial. The cost is certainly higher and that may be the only reason, but if it would result in essentially free horsepower of any significance it would be good thing. Maybe the long term durability isn't as good? Intuitively, a roller would seem to be a good thing and would reduce friction. Oddly, I have read things like roller bearings for the camshaft have the opposite effect. The weight or inertia of the roller actually caused a greater drag than the cam rotating on a film of oil and a standard bearing.

What sort of rockers are in that later model L67 you borrowed the S/C from? I purchased one late model rocker several years ago and it appeared to be a powder metal part and it had a roller fulcrum only. The tip was the standard sliding design. The geometry was wrong for the LN3 engine and it wouldn't work even though the trunnion was drilled larger to fit the stock studs. We already have a roller cam as standard equipment. I am not sure they would be of great benefit unless the ratio was larger for more lift.

Yes, I have diassembled mine completely also, and it is a scary project. It wouldn't be so if it was already broken and I had new parts to install, but not so. As far as I know, the manual states the assembly is held together with black butyl rubber. I had a difficult time finding it as it has been phased out of modern automotive window sealing. It certainly appeared to be the same stuff when I cleaned the old stuff off. I have heard of others using silicone to reassemble, but it is very easy to get strings and such inside the lense and it squashes out unequally and is visible at the outer ends through the clear lense. The butyl rope is much easier to control.

Does BLM read 150 even while cruising at a steady speed? I have noted the same coast down fluctuation for a long time. I have watched the injector pulse width also and it will sometimes drop to zero occasionaly also so my gut feel is this is normal deceleration fuel cutoff programmed into the ECM. If the BLM reads a constant 150 while the integrator is normal, it has performed it's function and has adjusted to correct a long term deficiency. If the BLM stays consistantly high, it sounds like a vacuum leak. Neither the BLM or Integrator are constant numbers, they will vary up and down as the ECM adjusts constantly. They should circulate around the target number of 128 if everything is working properly.

It does sound like a possible backpressure problem, especially since that is the most recent change. Any idea what your engine vacuum reading looks like?

Ditto on Jim Finn. Great service and fair prices.

I had seen photos and the writeup in the past, but not the ongoing happenings with the parts and cars. I appreciate the update. The funny thing is this stuff has been no more than 25-30 miles from me for most of my life and I never heard a whisper about it before he died. A good friend lives even closer and has been more hardcore in the performance car arena from about the time this collection started and he knew little about it either. The guy did a good job of keeping a lid on his collection. The sad thing is most of this stuff was built to be enjoyed and used, but I guess when stuff is collectible, some of the enjoyment goes out the window (at least from my ppoint of view). The other thing is the collection is so large, it is almost impossible to manage and parcel out without a large staff to catalog, sort and dispense. Yeah, it is off subject and primarily Chevy stuff, but there is a bunch of history there.

It does appear to be the lower manifold for a Series II, no injector bosses in the manifold. It will be too narrow to fill the valley between the heads on the LN3. It would make a great base for a new upper intake if it would fit. Nuts.

As far as I know, there are two different filter adapters, one that hangs the filter essentially straight down at the rear of the engine and another style that is angled toward the passenger's side. I believe they are interchangeable on the engine but the two types depended on what chassis the engine was installed in. I have thought about trying the other type of adapter also, primarily because even a standard length filter hangs sorta low with an oil cooler adapter sandwiched in between. Another option would be to go to a remote filter setup where single or dual filters could be fitted. In a stock engine, I don't see where it would be necessary, but it's essentially impossible to keep the oil too clean.

There are ride height measurements in the manual and once upon a time there were shims made to fit under the ends of the spring to correct the height. Shimming the spring will raise the rear and while it might correct the camber, it seems to be the opposite direction most people would like to see. Shims for the spindle make more sense, and may even be necessary for a lowered car? Some negative camber will be good for handling as long as the tire wear is reasonable. Radials are made to lay the tread flat on the road even when cornering, that's why they generally have a handing advantage, so a few degrees of camber will likely not bother them much as Padgett stated.

Too heavy. It weighs as much or more than a LeSabre. A few hundred pounds lighter and it would be like free horsepower and it would likely handle better too. The ride might suffer some, but I would trade that for a little weight loss.

It could be tested with a frequency meter. Some better voltmeters have a frequency setting. Actually the diagnostics will read the air flow the ECM is seeing. The other common way to test it is tap on the black plastic cover with the engine idling with something like a screwdriver handle. If the engine stumbles, the MAF is bad. Cleaning the wires is a good first step also. Most other heated wire type MAF's have a "burn off" cycle that occurs when the engine is shut down. A higher than normal voltage is applied to remove contaminants. Our MAF does not use this feature and they can get "stuff" on the wires.

Price seems awfully high. I paid about $200 for an all 304 polished stainless steel Ultraflow muffler, so if they are using all high end parts, it could possibly be that high, but for conventional aluminized stuff that sounds at least double what it should be. The Camero muffler isn't that different than the stock muffler. It is still a single in and dual out, although it could have slightly lower backpressure if the flow tubes inside are larger, but 10 hp is a big increase for only a muffler change. Personally I don't think the stock muffler is bad at all, but of course the look may not be to your taste.

Welcome aboard. I hope you have fun here, the more the merrier.