´74 Olds Delta 88 straight out of hibernation, troubleshooting , now the Quadrajet´s acting up, pg.4

Last weekend I gave the Olds its first wash in probably 15-20 years .. the interior is perfect, the paint has a few bubbles beneath the rear glass. Other than that the car is absolutely rust free. I‘m gonna fix the rust and try to touch up the paint in the catwalk area. Someday. Now it is time to go cruising !

 

@Baumi great to hear your efforts are going to be enjoyed.
While I dig the solo pictures highlighting the car, I'd like to see one or two in town with local cars.
These could have been taken in the midwest of the US.

 

Great job, a nice cruiser.
Greetings Harald

 

.... sooo good...

Yes!

Fwiw, the engine will be snappier if you attach flexible dryer ducting to the snorkel and the rad support mounted scoop. Sometimes the scoop goes mia if the ducting has deteriorated.
Just get the hose in front of the radiator for fresh air.
It doesnt need to be a ram air setup.
Those 70/80s engine bays can get oven hot. Hot air intakes are no bueno. when heat soaked the throttle looses a bit of response(less dense air).

Check the snorkels hot air stove valve. If the diaphragm is blown it's just a vacuum leak. If so, cap off the vac hose to it. Spring in the valve defaults to open for cold air.

*somehow I goofed the imaging, will fix later.... maybe*

 

Not unless we’ve started using European traffic signs. Zoom in on them. They are not American signs.

 

That‘s the only photo I‘ve got that is in perspective to normal European traffic. I´ve got to get to work early when I´m taking the Olds to work, otherwise I would be blocking the whole parking lot in front of our shop. So I´m the first in and the last out ( as usual) The street in front of our shop is pretty crowed when shifts switch at BMW. 20k employees going to and out of work causes a lot of traffic at certain times in our small town, but we are glad to have them, those a very good jobs.
The big aluminum building behind the gas station is a BMW plant, it is Werk 2.1 in Dingolfing. They are making all the differentials and axle subframes in that building. Dingolfing is actually a small town in a rural area, I guess 2/3s of the city area is covered by BMW buildings. Also our license plates are giving a clue from which county we are from, M would be Munich, LA Landshut, PAN is Pfarrkirchen and DGF is Dingolfing, for example.

 

@Baumi thanks for the picture! The others are great for highlighting the car and maybe they could be geospotted as not in the US, but that shot shows the scale of the car in a different place.
We have the smaller modern stuff here too, although a lot of places are mostly populated with pickups and SUVs, something missing in the last picture.

Thanks for the license plate info too. I don't dig into those like some do, but it may sink in and be useful at some point. It is interesting that yours is different than every one in the latest picture. Here it could be a Vintage plate. It might be a import plate there. The US uses different plates at the state level, so there are lots of variations even without the specialty plates many states have.
Here in Arizona, they have a large selection of specialty plates.
https://azdot.gov/mvd/services/vehicle-services/plates-and-placards/plate-selections-gallery

 

At a different parking lot

 

Ok, friends, I need your help again. I ´ve put about 1000 miles on the new motor, it purred like a kitten until it just stumbled and quit on me at a stop light. At first I thought I just ran out of gas, poured some in, still no start. Spark was there, so I poured some gas through the vent tube, started and idled, but not enough power to drive. I thought a bad fuel pump or clogged in tank filter sock, so I put in an electrical unit and pulled fuel from a canister, limped it home.

I had the Q-Jet apart for 2-3 times to check everything, checke the meh pump and fuel flow,all clean and nice inside, fuel is plenty to the carb running a clear filter. Now the car starts nicely when cold, but starts to miss, stumble and shoot out the exhaust during warm up and after about 4-5 min of the godawful poppin and missing it finally clears up and runs and drives like a sewing machine. I´ve already checked timing and the distributor, everything´s in spec there.
Also worth mentioning is I ´ve been noticing a hissing sound from the drivers side of the carb since my first break down, but I could not identify any vacuum leaks externally or internally, all gaskets are good and spraying brake cleaner doesn´t change anything.

I suppose the problem has something to do with with the choke circuit, since it only does it while warming up...I´m mot familiar enough with Q-Jets to understand what would cause this, maybe you guys can help me out with ideas once again.
Thanks a ton in advance!

Here a short overfew:

Starts perfectly
Stumbles and misses, pops out the exhaust, down on power, undrivable during warm up, wants to die
Clears up and runs perfectly smooth, has power in all ranges after warm up

Scratching my head as we speak, hahaha

 

Are the vacuum choke pull offs all working?

 

Thank you for your idea!In case you´re referring to the little vacuum canister on the passenger side front of the Q-Jet, yes, it pulls back once the car is started, and the choke blade is opening like it should, there is also no binding withing the choke linkage. I also applied vacuum to it and it does hold vacuum.

 

These are interesting symptoms, poor cold performance , running bad , mis-firing , bad drivability then it clears up when hot. This sounds like the vacuum break/choke pull off is not letting the choke open far enough and creating a rich situation. The front one should have a phillips screw to adjust it , I would look at that and it might just need more opening to lean it out when cold. I have no idea what the settings would be , just adjust as needed. lol . Or maybe the choke is set to tight ?

 

If the choke is set to tight it will want to close when you open the throttle and the pull off won't overcome the spring pressure of the choke. This would be with the motor running.

 

You also said it is popping out the exhaust, as a general rule back firing out the exhaust is usually ignition related and looking back through your thread the muffler looks like it has had some back firing going on. More than just a cylinder missing. Just a thought.

 

Good, detailed info on the issue. Since it's only during warmup, that helps narrow the focus.
There are specs for setting the choke and the pull-off or vacuum break. I'd start with those. Consider them to be good starting points, though. It may need a bit more or less choke, or a bit more or less of the pull-off. Both adjustments should be outlined in the rebuild kit instructions. If you don't have those, you can search the web for videos and guides. I haven't watched these, but there are a few that are an hour long. I would hope they cover each adjustment fully.
https://www.ecosia.org/search?method=index&q=rochester+quadraject+rebuild+adjustments

I'd also check each vacuum line by pinching it off during the poor running and once warmed up. This period of the 70s had lots of thermo switches for vacuum. A vacuum gauge is a good tool for diagnosing, too. There are more guides on what to expect on a vacuum gauge online.

 

Thanks for your input. I see I´ll have to study and understand the Q-Jet some more. The sudden appearance of the issue and combined with the hissing noise make me think that there might be an internal vacuum leak but I couldn´t find anything wrong on the carb on 2 tear downs. It´s totally possible the hiss is coming from elsewhere and I´m just looking at carb... All above is great advice and I´ll go after each one step by step. I kinda love troubleshooting ,it´s a good feeling once you find that little thing that´s wrong, but sometimes it´s hard to not pull my little remaining hair out, hahahah

 

Try tracing the hiss with a rubber hose (fuel line or smaller heater hose - whatever you have available). One end goes against your ear.

Be very careful around fan blades and rotating parts...

 

I should have thought of that! Thanks for the hose idea!

 

Vacuum leak?

 

Remember if the choke coil is not electric it should have a small vacuum leak there. Very small.

 

With the motor warmed up and idling just cup your hands over the carb, if it picks up RPM it has a leak, if it chokes down no leak. Or use a rag !

 

Use a piece of cardboard, or card stock, to 'wall off' around the carb to try to locate the sound. When the sound changes, you've located where the sound is emanating from.
Check the PCV hose and valve.
Check the brake booster line as well as the check valve and booster is not leaking.

Verify fittings are snug and tight.

Hot air stove diaphragm on air cleaner snorkel can rupture at this age causing an uncontrolled vacuum leak. It is supplied vacuum only when cold via a TVS located attached to the air cleaner underside.
Diaphragm>hose>tvs>hose>carb.
That is the vacuum line that must be detached when removing air cleaner housing from carb. Plug that line at carb if suspect leak. Stove is spring loaded and should fail open. Check for functionality by exercising stove flap manually. It should spring open for snorkel while closing off hot air stove.

4M Qjet has several fittings up front for vacuum. Verify those ports are properly used or plugged.

Check EVAP connections and functionality. If the system is not purging correctly it could cause a vacuum in the tank which would prevent fuel flow. But you stated bypassing pump and tank so this may not be any issue.

Choke housing should have a gasket between itself and the carb body.
Threaded hard line from the choke housing should go down to the choke heater tube(U loop that bolts into crosover on manifold) and the other hardline should loop back up to the backside of the carb, use a 1" length of vac tubing to secure it to carb. The whole choke tubing is not really vacuum tight, its a controlled air bleed.
If worried the choke is not fully opening, loosen choke adjustment screws and manually rotate choke to lock it fully open. But also verify choke coil has not failed, if broken it might seem to function normally but allow the choke to close while driving.


Edit:
Also verify the distributor is functioning correctly, fly weights and springs allowing the rotor to advance and return smoothly.

 

A ballpark initial setting of choke when cold is loosen 3 screws that hold choke coil and rotate till choke blade just shuts.
Now take a length of hose and hook to the choke pull off. Suck on the end of hose and retract pulloff.
Adjust so blade is open about .125 between back side of blade and choke housing on the airhorn.
Also when doing this apply suction to choke pulloff and cap hose with your tongue.
Pulloff should stay compressed. If it has a small leak in diaphram, I have seen them leak back pretty slow so hold it for a bit to watch.
Could be that a slow leaking pulloff works when warmed up and engine is pulling a little more vacuum.

 

Have you opened up your gas tank to see if there is a filter sock or what ever the damn things called. Pull the sending unit out and if that P.O.S. is hanging on the end, it could be a major problem. If I’m correct, you owe me a beer.

 

Ok,thanks so much for your support and your ideas , fellers! So, here´s the update and how I solved the issue...
Using the subber hose method I could verify the hissing noise came from the driver´s side of the carb, so I sprayed a little brake cleaner there and violá, it smoothed out a bit. Ok, I may have found an intake manifold leak. So off came AC mounts, Alt mounts , carb etc to pull the intake ( which had already lost most of it´s fresh paint due to my testing and gas spillage) just to find that the gasket was sealing perfectly. Was a little bummed that I still was chasing my tail but went on and disassembled the manifold to make it nice and shiney again... taking the EGR valve off I noticed that it had cracked at it´s base and the gasket had burnt through between the exhaust and intake side, so the engine was pulling exhaust gasses into the intake, hence the poor running and hissing from the EGR valve. I fabbed up a delete plate and sealed it off with some itchy fiberglassinfested hitemp putty that seems to hold up well.
Now the engine starts easily, runs smooth as glass and lays rubber as it should. I set the mechanical timing at 36° total for now, was a little more conservative before.It seems to really like the added advance.

But I also noticed that the see through fuel filter I added in front of the carb is not completly filled all the time, sometime it´s almost empty to the point the engine misses and then the pumpshots are visible again and the filter fills back up quickly....

I bet I owe you at least one beer if not three. Next step: I´ll be pulling the tank and removing the sock, I´m sure it´s still in there , as there is no evidence that car has ever been apart or messed with.

I´m glad I got some professional help from both you guys and our son Xaver, he showed me how to fix this mess.

 

I just pulled the tank, removed the sock,the tank is clean as a whistle inside, even the top is perfectly clean. The car fired up nicely, but went back to popping and missing again after a few minutes. I swapped the coil just to see if that´s the problem, no, still did it with a new coil. After a while of erratic idleing it smoothed out and ran fine for about 15 miles. Pulling into my driveway it started missing and popping again... Marvel Mystery Oil is my next step....

Maybe I should pull the distributor once more and see if I can the vacuum advance get stuck wide open....

 

I was thinking leaking egr but you told its hissing drivers side and i went check my 455 intake and egr was on passenger side...
About popping...when you take engine out for repair, you sure you got engine ground wire back?
If you have points ignitin, try new condenser and if hei ignition, change hei module.
Also you did paint the block so check that distributor housing getting good ground.

 

Ok, drove to work today, mostly ran smoothly and had good power, but I have a feeling that after sharp turns, hard braking or steep downhill/ uphill driving it tends to pop. It´s really smooth most of the time. I guess I need to check the float level again and see if I can make it stick. I also thought about throwing an Edelbrock on just for testing, to see if that makes any differance. I don´t want to swap the Q-Jet for an Edelbrock, cause it ´s just running so nicely with the Q-Jet. I´ll also ask around and try to find another distributor and see if that changes anything... I hate to fire the parts cannon. I have a good working Edelbrock here, I just need to find an adapter to the Q-Jet manifold. The Olds distributor will be a bit harder to find...