Horrible night. Car pissed. Never ran horribly like this before.

[Powertechn2]

When you do get a chance to look at it,
i would start with checking to see if the crankshaft sensor mounting bracket was securely being held in place by the 2 bolts and haven't loosened some allowing the crank sensor to move around.
I'd unhook the connector from the crankshaft sensor and would carefully pull the wiring going to the crank sensor up top to where you can inspect it completely without being under the car. I would also see if the contacts on the sensor itself and on the connector had any debris or something causing there to be intermittant contact issues.
You can also check for any hidden breaks on any of the wires that go to the crank sensor connector while you have it unhooked at eye level by using a small thin paperclip to probe each pin opening on the connector without messing it up to see if you gently move the wire around if there are any signs of intermittant wire connection issues on a volt meter or other testing device.
Verify the crank sensor hadn't made contact with any of the rings that pass through the sensor ears, if it has made serious enough contact then the ears get smacked and it'll run weird cause of damage.


Hope you get a chance to look at it in between your to do list items you mentioned.
Hope it's just something as simple as the crank sensor needing to be changed or fixing a simple wire intermittant connection issue scenerio.

Ever since the previous owner had it rebuilt, when they had picked it up was it having any backfire issues? Before it was torn down, did the previous owner have any backfire issues?
Wonder if the grounds that connect to the block under the ignition control module area possibly aren't tightened down enough.

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I did unhook the connector and look at the terms, they all looked good and were locked in place. The sensor is mounted solid and best I could tell had not contacted the ring.

i dunno if the car had backfire issues before he did the resto. I just know that when he first bought the car it ran like a dog. He did manage to pull some decent numbers at the track after, just he said he had the backfire issue and could never figure it out, but he also said it never ran shitty like it did for me on last friday night, and has since then.

_______________________________

I did inspect the ignition control module plug when I replace the module and it was clean, no corrosion, nothing looked out of the ordinary.

_______________________________

I could replace the O2, I wish it were a 3 or 4 wire sensor as I have a bunch of them in my box at work.

The O2 readings have all been kinda lazy, I wasn't sure if the scanmaster would read like an actual wideband O2 gauge or not, I figured the kind of relaxed 1/2 second changes were normal.
Under boost it would move more rapidly, but aside from that it is typically 1/2-1 second between changes.


The crank sensor is mounted solid, nothing odd like it is bouncing around.

I did notice that Napa sells a connector with wiring for the sensor as well as a sensor which comes with a new bracket attached. I might just go that route as it is cheap, but not sure if that is the issue now.

I am starting to think it is an issue somewhere between the harness and the ecu.

 

[Nascar83Fan]

If it's throwing a code 42, is running poorly , the timing is being controlled via the ignition control module which is to limp you solely back home on. That's why your spark and fueling is not where they need to be for the performance mods on the car and todays fuel that required a different programmed timing setup from that which the limp home mode is programmed for causing your backfiring issues.
The ECU is being bypassed on timing control which means the aftermarket chip settings in the ecu which differ from the calpak limp you home chip settings arent being used, so when the Ign control module that is underneath the coil pack is controlling the timing ithe car will never run optimally until whatever is causing that fault is fixed.
There is a ground issue or something had failed in a part in the spark control system.
Could be a faulty crank sensor, could be the grounds on the ignition control module aren't making complete contact with the underside nuts on the ICM mounting plate it is mounted on with, the 2 nuts and 1 bolt that you secure the mounting plate to the engine with may not be fully tight, could be a faulty coil pack, could be a slightly loose connection at the battery, maybe the power wire to the ecm that goes to the battery has something going on with it causing it. There's a couple other things, but start with the simple stuff first.
Is there any way you can swap some stuff with another TR to see if you can eliminate the issue by one by one trying something to find the culprit?

Wished you were nearby where i am, i'd come over and help you with it.


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[Powertechn2]

Thanks for the suggestions. When I get a chance I will start with the simple stuff.
I know that the ignition module is tight to the plate as I replaced the module, and the plate is tight to the 3 mounting points. This made no change, nor did the coil as I replaced that too. I made sure to clear the paint at the mounting points for the ignition module too, so it should have a good ground. I will start checking resistance through items to ground with a DMM. I think I will just replace the crank sensor also because it is fairly cheap and looks to be original. I did find that there is a replacement connector kit so I will also replace that as the current wires are kinda puffy from being old and oil soaked.

 

[Nascar83Fan]

If the wires going to the crank sensor are looking iffy, that could where your problem is but can't hurt to put a new crank sensor in also.


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[Powertechn2]

So, been busy.

Of course, finally had a chance to dig.

Swapped the ecu with a TR that had a good ecu, and swapped my ecu into that car, of course swapping chips as his was stock. NO change. Well, for about 3 minutes, then limp mode again.

Been searching and found that it could also be the connector for the ign. module. Found a splice kit online. Also have a new crank sensor kit with plug and about 12" of wire. Hopefully I get a chance to work on the car this weekend as summer is getting near the end and I haven't even had the car out yet this year.

At least we were able to take his car out tonight, cruise woodward. Saw a bunch of tr's at Staples near Sq Lake, so cruised through the lot. Better than nothing.

 

[GNRick]

I don't mean to be sarcastic but you could have replaced the crank sensor a year ago...and saved all the time and effort it took explaining why the crank sensor hasnt been replaced. And who knows...it might even fix the problem!

 

[Powertechn2]

Yes, it might very well have...
Then again, once I opened the ecu and found that it had water stains inside all over the board, I assumed it had fixed it.

It did fix it, in the middle of winter, when it was 10° and salty out. Once I could finally get the car out and drive it it started acting up again.

I also fixed some previously repaired wires on the car, as well as a few other things.

Problem is that when you are working 60 hours a week you don't have much down time. Add to that when you get free indoor storage and the buddy that supplies said storage area has a 532 bbc that has issues and asks for a hand... You being the nice guy with free indoor storage decides to help him and finds blown head gaskets and burn't valves, get that all set then 2 passes later when he has pinched rings due to a bad tune on a huge amount of nitrous, you end up helping out yet again.

A few hours turns into what amounts to your only free time dedicated to helping out someone else. He did tell me I could take his car out all this weekend, but with a wonky sometimes working powerboost I passed.


After reading up most said the crank sensor when/if it goes bad will cause no ignition. This could be false. I don't know. After testing resistance in winter through the wires found nothing wrong with wiring, no high resistance up to where it goes into the loom. Sensor looked ok after cleaning it up. I guess none of that rules it out.

For all I know I could just have simply two bad ignition modules. First one was at least 10 years old. One I replaced it with was from the company formerly known as Murray's, and the box looked very dusty. The prongs seemed to have had terminals on them before, but assumed it was just from the factory.

 

[GNRick]

A couple months ago my car would lose power at around 40 mph. If I pressed the go pedal it would pick back up. A new crank sensor fixed it. So give it a shot and let us know. BTW I'll be at Woodward Fri. And Sat. If you see a gnx clone from Illinois stop over and say hi. Oh, a module shouldn't look like it had terminals connected to it. So you could have had two bad ones.

 

[Chuck Leeper]

Do you have a scanmaster?

Agree...
Like the song says, "A little less talk, a lot more action

I don't mean to be sarcastic but you could have replaced the crank sensor a year ago...and saved all the time and effort it took explaining why the crank sensor hasnt been replaced. And who knows...it might even fix the problem!

What Rick said...Reading your posts brings a country song by Toby Keith, to mind: A little less talk, and a lot more action."

Just the facts will do!

 

[gsgnnut]

Please the suspense is killing me. Please change the crank sensor it's cheap and takes only minutes!!!!!!!

 

[ttypewhite]

Forgive me for saying this.... but why eat up your summer trying to find something you really have no true understanding to? You have got plenty of shops in your neck of the woods that deal with Turbo Buicks. You have wasted a ton of time that you will not get back. Pack it up, and send it out, or pay someone local with a good grasp of these sort of things to remedy your problem. As it sits, it's worth nothing, it's frustrating, and summer is almost done. You need to stop the bleeding and get someone with a better skill set to relieve you of all this. Don't follow the lead of the previous owners...... They ended up selling the car and passing the buck.

 

[Powertechn2]

In all honesty, I have only spent about an hour with the car all summer. Wasted most of summer working.

It seems like you all think I have spent countless nights tinkering with my car, which I haven't.

I have other hobbies which I got to do instead, like riding my quad.


Sensor is going in tomorrow.

 

[Powertechn2]

Replaced the crank sensor. The old one had signs of rubbing.
The car started, runs better, still have code 42. Not going into limp mode and popping, so it seems the sensor was one of several issues.

Cel is off now though. How long will the ecu retain old code info? The code still shows in the scanmaster, as well on a Snap-On solus Ultra. I plugged that in to see if I could drive and read more info at a faster rate.

 

[whitehot1]

Replaced the crank sensor. The old one had signs of rubbing.
The car started, runs better, still have code 42. Not going into limp mode and popping, so it seems the sensor was one of several issues.

Cel is off now though. How long will the ecu retain old code info? The code still shows in the scanmaster, as well on a Snap-On solus Ultra. I plugged that in to see if I could drive and read more info at a faster rate.

Unplug the connector by the battery with the orange wire that supplies power to the ECM to reset and clear the trouble code.

 

[Powertechn2]

I actually disconnected the batt when I installed the sensor.

I disco'd it again after the code came back.

Now the code only comes back if you lean into it. I can clear it, and if you just cruise and stay in low boost/low rpm it stay's away. Before replacing the crank sensor it would pop the cel and go into limp mode regardless of what you were doing, even just sitting there with it running.
Now I am thinking it might be in the questionable ign module. I will swap it back and install the see if it re-appears. Before with the first module never had a cel till the night it went into limp mode.

I did probe connections and have continuity through the module plug, doesn't seem to be the issue. I also did the touch/jiggle test on all connectors and wires in the harness to make sure there wasn't something loose.

Thanks again to everyone for the input and help.

 

[Powertechn2]

So I started thinking. I also replaced the plugs initially. Used r45ts as that was what was in the car. Gapped to .032.

The code only pops up when hitting about 10psi and above. Limit is set to 15 currently. I am starting to wonder a lot of things about the build also.

I know the car has a 212/212 cam, but don't know the springs/rockers/pushrods. Being as the person who built the car was young at the time, it is possible that he hodged parts together.

Something that gained my attention but I never realized is that a few months back he gave me the stock ecu from the car. Said when he got the chip it was in the ecu in the car, so it was used. Maybe everything was used. It seems really hard for me to imagine a 16-18 year old kid had the money to do a proper build without a lot of great deals or using used parts.

He did manage 12.50's on pump, but said the car always seemed to flatten out on the big end. Said that was at 18lbs. Also said he thought the car needed a larger turbo, but seemed like it also had an ignition issue at high rpm/high boost in third. Had a 1.60 60' and 12.01 fastest time @114mph, which seems like something was wrong with the mph and time unless the car just launches like a mother and then always flattened out. I have been told alot that it should have been faster, but I dunno. This is coming from friends with nitrous big blocks. Might be different figures for them.

Also said the car never ran 100%. Got sick of messing with it trying to make it right, which is why he parked it.

It has never ran right for me., but I am wondering if I am chasing down one issue when there are other more major issues at hand.

What performance should someone actually see with p&p stock iron's, precision ta/te60 (I forget which the car has, it is not the more stock appearing of the two), a precision front mount, Th down pipe, full exhaust with cutout, headers on a 28x12.50 tire?


*Edited as the last owner text back with info. Previously he had told me different times.

 

[Pronto]

Maybe the valve springs are too light.

 

[Powertechn2]

If a maf, or a translator had an issue, that could also cause the 42 code, and poor top end, yes?

 

[Chuck Leeper]

Did you check crank end play?

 

[Powertechn2]

No, not to measurement anyways. I did try to push/pull the crank to see if it seemed to have excessive play though, and it didn't. It has not rubbed the current crank sensor as of yet. The sensor I pulled out didn't have wear that shows end play, just seems to not have been adjusted correctly. Wear only on the inner area of the sensors middle element. Slight, but likely enough to cause an issue there.

I am wondering if the cam has excessive play. Still seems like an electrical issue based on the code 42. I want to get this thing running correctly before I pull the engine and start over, that way I know I am not chasing previous issues.