1986 Oldsmobile Ninety Eight Regency No Start
 

I am willing to try anything at this point. Bought the car not running figuring I could get it going but have had no such luck.

Yellow 1986 Oldsmobile Ninety Eight Regency 3.8L V6 Auto 88,000 Miles
Cranks over but will not start

What I have found
-Has no spark
-Has no injector pulse

What I have replaced
-Computer
-Ignition Control Module
-Coils
-Crank Sensor
-Cam Sensor

What I diagnosed
-Injectors all have 7 ohms resistance
-Harmonic balencer key way is good and tone ring looks good
-Ohmed out wires going to both cam and crank

I have a running BLUE 1986 Oldsmobile Ninety Eight Regency that I bought in great shape that is now having backfiring issues when you snap the throttle and randomly loses spark and wont start. I bought the no start YELLOW Regency and swapped cam sensor, crank sensor, and ICM from both and the BLUE to the YELLOW and the BLUE one is still acting the same and the YELLOW one still has no spark. Im lost and im up for opinions. Im trying to get the YELLOW one running as the intake box is broken im guessing due to back firing just like the BLUE one is doing so in hopes of getting the YELLOW one to start and finding the problem im guessing it has the same issue the BLUE on has only its completely failed.

This video includes both cars for a reference of what they are.

Does it have any codes stored?

How is the wiring on the main culprits like crank sensor and cam sensor (like not just at the sensor and plug, but the whole way to wherever it goes) ?

I ohmed out the wires to the cam and crank sensor to the ICM and they had low resistance with no open circuits. I also pulled the wire loom back all the way and visual inspected the wires and they all look fine.

As far as codes the battery has been disconnected for several years so any codes up to the point that I owned it are well gone. The service engine light comes on when its keyed on so I know the computer is working. How will I know if it has codes and how do I get them?

Paperclip in the top row of pins, the two terminals on the right. Then it will flash codes with the check-engine light. Here's some more info: https://www.google.com/search?rlz=1C...IGOTWQ#imgrc=_

For code meanings: OBD-1 Diagnostic Trouble Codes

It will flash an [I am a happy computer] code first then will list out any other codes it has stored. all codes are 2-digit and have pauses between each code. When it returns to [I am happy] it has completed and started over again. It will do this as long as your paperclip is there and it has power. The [I am happy] is 12 , so flash pause flash flash pauuuussssse next code.

Well I found the problem. The cam sensor magnet was broken off. Not sure what happened first the bolt loosened up and the magnet took out the chain guide or the chain guide broke and hit the magnet. All I know is I have a mess and have to decide if its fixable.

Question is do I need
-Cam sprocket due to plastic chipped off all around it
-What is the disk on the front of the cam sprocket do and do I need a new one?
-Anything else other than timing chain guide kit, and a few gaskets.


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Well I just ordered and will be here tomorrow a timing chain kit with both sprockets, Timing chain tensioner, and a timing cover gasket set. A whopping $55. I already had the magnet as I was doing an amazon order and seen it was only $5 so I bought it without knowing if it was even bad. Should have the car up and going for $60.

Are the cam and crank still in time, i.e. the timing marks like up? These are supposed to be interference engines, and GM's choice to used the V8's style, pot metal and nylon camshaft timing gear condemned most of them to an early death in a rough, 90 degree V6.
The other bad news is most of the nylon heads right to the oil pump pick up. The good news is the oil pan is probably shockingly easy to remove. It is in the A-body, which has a very similar engine cradle, but slight motor mount interference. I didn't even remove the starter! The other good news is the timing cover will be much easier to install with the oil pan off.

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This is the odd little brother of the 3.8, the 3300 (a lot of improvements,1992 model).
That is the 'cam button' on the end of your camshaft gear. It is one way of control camshaft end play.

Well its been a busy day but I had time to do a compression check. Anyone care to share what they should be and were the timing marks are one these things.

Cylinder 1 - 145
Cylinder 2 - 135
Cylinder 3 - 150
Cylinder 4 - 165
Cylinder 5 - 130
Cylinder 6 - 105

Take into consideration this car has been sitting for 3 years.

I can't caution strongly enough that it is very important to keep ANY debris from the pressure and suction ports from the oil pump through the front of the block. Very easy to kill a Buick or old Cadillac engine with timing cover gasket debris. Small debris in the oil galley and can block lubrication that you won't find until shortly after the engine is running.
The oil galley ports are on the bottom right of the cover in the picture below;
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The 3300 and 3800 of this era had the same timing cover, but the 3300 is not drilled out for the camshaft position sensor, as it was only a MPFI engine rather than SFI like the 3800.

I will make sure to clean them out good thanks. I took the cover off and im taking it into work for a good cleaning.

Looks promising. Took a look at timing and its right on. Parts are here and ready to install. Going to remove the oil pan tomorrow and clean out all the debree and get to installing the timing chain. Cant wait to see if this thing runs.


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Glad to see it hasn't jumped, though your compression test confirmed it wasn't far enough to bend the valves.

Im a little worried about cylinder 6 but we will see what it does.

Yeah, it might start sealing up again when it runs a bit. If it sat a while with the exhaust valve open it may have built up some junk or rust.

Thats what im hoping for. I did spray some oil down the spark plug hole and try again but didnt change the compression so I know its not rings. Never thought about the valve getting crud on it.

Yeah, especially if it sat in a humid area.

Glad I pulled the oil pan. Thanks for all the help. This is great to have people who know these cars and are willing to share and help out. Appreciate it!

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Glad you did. Not a bad job, unlike some other GM FWD engines that are 'lower the engine cradle' jobs.

Blegh yeah glad you did too.

Well got it all back together and the car will run on starting fluid only. The gas tank is full of bad gas so now I have to get that pumped out and hopefully it will run all on its own. Im so happy I found the problem! All thats left to do is find an alternator, put on the water pump pulley, and slap the serp belt back on.

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Great to hear that you have gotten to hear it run.

Cool!

. . . and check for leaks now that it's run some oil through everything.

Well have a problem and some interesting news.

The Problem - Not sure im getting oil pressure. Ran the motor for about 20 seconds and pulled the oil fill cap off and dont seem to have oil coming out of the push rods when engine is running. Not sure how much would come out but I thought I would at least see a steady flow. My option at this point is to go buy a oil pressure gauge and pipe it in I guess unless you guys have any other ideas. Dummy light is not on and key on test it lights up. Also check wiring diagram and it will cut out the fuel relay if no oil pressure so I may have oil pressure just not to the heads yet.

Another Problem - Engine has I would say 1200 RPM idle. Checked for vacuum line leaks and found one going to the crews control. Dont see any way to adjust the idle via throttle plate or cables. Cables are free and not holding the idle up. Maybe just have to run it longer for it to do a relearn like an OB2 computer after being off so long?

Interesting news - Apparently these cars will run on starting fluid without a computer. Found that my fuel pump was not running and after checking fusees and chasing down the wiring I remember I pulled the computer. Sure enough keyed the car on and no SES light. Put the computer in and the car fired right up even on the 3 year old gas!

Thanks again for the help guys. It was great being able to find people who know these cars and help out. Not many forums out there for these cars anymore.

Did it make any unbecoming noises?

How long did it run?

Cool!

It's neat to see some still running and someone willing to keep them going.


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Nope no noises just worried as it sat for so long and I would hate to do engine damage to a car that is 30 years old with only 88,000 miles on it over something dumb like not checking oil pressure. Just ordered this .

Car only ran for 20 seconds on gas but I ran it for probably 30-40 seconds on starting fluid a few day ago.

Ah okay.

On that engine, if you take the oil cap off while it is idling (or high-idling) it won't likely sling any oil out through the fill neck. If it isn't getting any oil pressure to the top end it will make bad noises quickly.

For the idle, yes, 1,200RPM is fine for a cold engine. It will settle down over the next minute or two depending on how cold the ambient temperature is. This is how it starts reliably every morning, wakes up the catalytic converter more quickly, and runs more reliably cold if you don't wait (like a nice car owner would) and just slam it in gear and start driving right away.

I'm anxious to hear the results, looks like a handy and nice unit to have around. It would have sounded awful with no oil pressure, but why chance it?

Incidentally, it is a common misconception (or a bad schematic floating around) that low / no oil pressure will shut off the fuel pump on these era cars. The ECM doesn't monitor oil pressure (at least in this era) and will happily keep the fuel pump running until the engine locks up and loses ignition pulses.The corresponding oil pressure switch is only a backup in case the fuel pump relay fails. A relay failure will result in long cranking times to close the oil pressure switch. The Vega was the only old GM that I know of that triggered the fuel pump exclusively off oil pressure. Since it was carbureted (exc. Cosworth), that was easy.

Just noticed your location. Your cars don't look like Michigan cars.

Well I feel a lot better about what im hearing from you guys. I always thought if you didnt have the oil cap on a running car it would flick out oil and have had a few vehicles that I forgot to put the oil cap on and had some oil come out so thats what worried me. Also was reading some yesterday and they say to pack a new oil pump with petroleum jelly and it worried me that it would not prim. The motor didnt make any bad noises but I shut it off until I felt safe to run it. I will still wait to get the pressure tester as its on its way anyways.

It was about 50 deg F so a bit cold out and thats what I was kinda thinking as well that it just needed to warm up. Seemed a bit high like a vacuum leak but couldn't find any other than the one and that didnt change it at all. Maybe once I verify oil pressure if after 2 minutes ill worry about it and that will give me more time to look for any more vacuum leaks as in the 20 seconds it was running I was checking for oil pressure and making sure the throttle cables were good.

Ill have to take a look to see if thats maybe whats happening with the oil pressure switch. I looked like it was feeding the relay power though it but that dont make any since because if that was true you wouldnt get the 2 second fuel pump prim at key on. Im guessing you are aright CorvairGeek.

The Blue car is a one owner car that was probably an old lady who only drove it to church and back. By the looks of it the Blue one has never even been waxed and the under side of the car has no rust. Replaced the fuel filter on it and all the lines were rust free. Crazy nice for its age. The yellow one had an interesting story. I guess the owner died and it sat on a car hoist for 10 year. One of the kids finally took it down and he drove it for 4 years till it quit running on him. Sat for 3 year in his yard and sold it to me. I mostly wanted it for parts but the fun of trying to get it running was too much for me to not want to here it run. If you look at my videos the yellow car sat almost 1 1/2 inches higher. Im guessing thats because it sat on a hoist for 10 years off the susp.

Yours won't sling much out if any. Many cars will, and some have some air pressure in the crankcase that the cap's absence would defeat, but not yours. I've found it mostly on newer stuff.

Yeah that works well, but unless you had your oil completely drained for a few months or something you shouldn't have to worry about that.

50F will definitely make it high-idle for a bit.

Yeah, CorvairGeek is right. It also makes it so if the fuel pump relay fails while driving you don't stall out, get rear ended, maybe also crushed by a train, die, and then sue the bean counters.

By doing this, a failed fuel pump relay turns a huge problem into "My car takes a long time to start".

I had thought about that as well, and done it on the old pump in Buicks. Yours is the first year of the new gerotor pump (RWD Buick V6s continued with the old design, I think there may be some part number errors propagating with the difference too), which was a big improvement. I don't recall the shop manual mentioning packing the pump for initial start up with this in this design, but I could be wrong. Mine still had some oil in the pump at reassembly, and merely cranking the engine with the fuel pump fuse pulled built significant oil pressure (no distributor shaft to spin and prime with this design either).

Well checked the oil pressure and its about 50psi at 1600RPM. I cant get it to idle down and dont have any more time to work on it so I loaded it up on the trailer, took it to my parents house and drove it around the block and parked it in the field. Im going to hold onto it for about a year incase I need any parts off it then im going to sell it. Ill have to try to figure out the high idle but the cold weather is hear and I have other projects that need to be worked on. Till next year guys.

47 PSI at about 1600 RPM.
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Exhaust glowing red after setting at 1600 RPM for about 3 minutes.
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Exhaust glowing red at 1,600RPM and no load is a bad sign.

It might be a bit higher than 1600RPM and it was dark out so it was quite easy to see the exhaust glowing. Seemed to run fine and drove great just wish the idle would have come down.

Foot to the floor under a load and it shouldn't glow like that in one spot. Good thing it's a parts car.