D-Jet Conversion not going as planned., Car starts but will not run. Options

[rjames]

With the smoke test, I get smoke coming out each side of the throttle shaft. Is there a bushing kit for this? Is it rebuildable or can I pack with grease?

Each side? Assuming you've sealed the top of the TB when testing, there are only 3 possible areas from the TB itself where leaks could occur (unless there is a crack somewhere):
Idle screw
Vacuum port 1 (for advance- facing rear of car)
vacuum port 2 (for retard facing front of car- not all cars had this port)

When doing the smoke test, plug both vacuum ports.

Are you sure the leak isn't coming where the throttle body sits on the plenum? You may just need to tighten the bolts holding it down, or more likely you need a new throttle body gasket.

[slapshot]

With the smoke test, I get smoke coming out each side of the throttle shaft. Is there a bushing kit for this? Is it rebuildable or can I pack with grease?

Each side? Assuming you've sealed the top of the TB when testing, there are only 3 possible areas from the TB itself where leaks could occur (unless there is a crack somewhere):
Idle screw
Vacuum port 1 (for advance- facing rear of car)
vacuum port 2 (for retard facing front of car- not all cars had this port)

When doing the smoke test, plug both vacuum ports.

Are you sure the leak isn't coming where the throttle body sits on the plenum? You may just need to tighten the bolts holding it down, or more likely you need a new throttle body gasket.

From what I could tell it is coming from both sides of the shaft holes. nothing from the new vacuum hose on the body. The gasket on under the TB is new. I'll check the bolts again.

[slapshot]

I set the timing even though I'm confused on where TDC is for #1 now. It runs pretty descent. Idle is still a little high at 1150 after the AAR closes and with the throttle adjust screw all the way in. There's a hole in my throttle plate. Is there suppose to be? If I plug it with my finger the RPMs drop down and I can then open the throttle screw to bring idle up to 900 or so. Here's a link on how the car sounds now. Idle after timing

[emerygt350]

That throttle shaft leak will add some rpms, is your vacuum retard port plugged? I see the hose running off somewhere. If your distributor is set for retard and you have it disconnected, that might be what you need to bring the idle down. I have found the retard does not work on my 123dizzy but it is not the Bluetooth version. I think you would be best served by just plugging that port at the throttle body and not using retard at all. At worst your dizzy is set for advance and it is getting the advance signal when the throttle is closed and no other time.

1150 is very close. Yes the hole is supposed to be there. Also, try plugging the hole inside the throttle body with your finger. Sometimes that idle screw does not seal perfectly. And by hole I mean the one in the casting not the butterfly.

[slapshot]

I have the retard hose plugged into the dizzy but I have the MAP curve set to 0 for all pressures. I'll plug it and see if that helps.

I took it for a drive. It went okay. It seemed to misfire or sputter at a couple RPM spots. I believe its the TPS so I'm going to order a new sensor board. Comparing to my Webers, it didn't seem to have the pull between 3-5k RPMs. I thought it was running lean but I checked plugs 2&4 and they looked pretty good.

[r_towle]

What is your dwell?
Timing set with no vacuum?

[r_towle]

Also, have you cleaned and re greased the advance plates in the distributor?

[emerygt350]

It is a 123 towle, at least I think it is.

I wouldn't put much of anything into driving performance yet.

TPS might be it but I doubt it. Just disconnect the TPS entirely and try driving it. It really isn't necessary for most normal driving. The only time I have run into tps issues is at cruise and having a dead spot. That was actually from the new board. Went back to the original and it worked great. The new material just doesn't hold up like the original.

You will get a hesitation at tip in without TPS but that's about all unless you are really getting crazy.

[emerygt350]

I suspect your misfires and stalls are timing and mps related. Get the timing perfect and the we can start looking at other stuff. Have you verified tdc?

[slapshot]

I do have a 123 dizzy so no dwell to mess with and I have vacuum advance disabled.

I don't know what else to check to find TDC #1. I set the fan wheel to the timing mark, did a leak down to verify that the valves were closed on #1 and even opened the valve cover and verified #1 rocker arms where both loose. Oh and I did a leak down on #3 to verify that exhaust valve was open. Anything else to check?

I'll disconnect the TPS tomorrow and take it for another spin. I just got back from a ride, it cut out at least once as I would get on the throttle. Not as I would get on the throttle but some point as RPMs were increasing.

It seems to run cooler than before but that's base only on two short rides.

[emerygt350]

I use a boroscope to ensure tdc, but what you did works too. Idle is set at 3400 if I remember correctly (double check that). My car really likes 28.5 but each car is different. Since we have 123s I am not certain that old way of setting idle is really necessary. I find 8ish at idle equals where I want to be all in. However, if your idle is high you are stuck doing the high rpm timing anyway.

I am not familiar with setting the curve in Bluetooth dizzys but I do know there are some suggested curves to start with for d-jet.

If you are getting a miss and your timing is good I would suspect mps tuning at that point. You probably have lean spots at particular vacuum rpm combinations. Do you have afr gauge set up? I found having a vacuum gauge and an afr in the cab allowed me to tune the mps relatively easily in the car.

Oh, and if you have bad spots in your TPS, the whole engine stops (the ECU seems to stop the injectors or something). Like a whole engine miss. It's really disturbing and only tends to happen when you are cruising (that's where the bad spot develops).

[Geezer914]

There are throttle body shaft seals you can order.

[slapshot]

There are throttle body shaft seals you can order.

Good deal. I'll be looking for some. If you know a part # for a 2.0 let me know. Thanks

[slapshot]

I use a boroscope to ensure tdc, but what you did works too. Idle is set at 3400 if I remember correctly (double check that). My car really likes 28.5 but each car is different. Since we have 123s I am not certain that old way of setting idle is really necessary. I find 8ish at idle equals where I want to be all in. However, if your idle is high you are stuck doing the high rpm timing anyway.

Here's how I set the timing. Set TDC #1, turn the dizzy CCW til the light turns off, then turn it CW til it turns on making sure there is not slack in the rotor. I then set the dizzy on the app @ 20 degrees for all RMPs and set my timing gun to 20 degrees, start the car and turn the dizzy CCW til the timing light is in the "V". Turn timing up to 28 in the app and checked it again at 3000 RPMs. If this is wrong LMK cause it does sounds like the timing is off or maybe MPS calibration is wrong. How about the ECU knob? I've got it 5 click CCW from total CW. I'm still trying different clicks.

I am not familiar with setting the curve in Bluetooth dizzys but I do know there are some suggested curves to start with for d-jet.

See attachment for my curve. This is what worked best for my Webers.

If you are getting a miss and your timing is good I would suspect mps tuning at that point. You probably have lean spots at particular vacuum rpm combinations. Do you have afr gauge set up? I found having a vacuum gauge and an afr in the cab allowed me to tune the mps relatively easily in the car.

I found and fixed another vacuum leak going to the decel valve. I will probably get a rebuilt MPS from a repealable supplier. I don't have an AFR.

Oh, and if you have bad spots in your TPS, the whole engine stops (the ECU seems to stop the injectors or something). Like a whole engine miss. It's really disturbing and only tends to happen when you are cruising (that's where the bad spot develops).

I unplugged the TPS and went for a ride. The engine misses stopped. Before it was like you described where it seemed that the engine would dang near stopped. My body would jerk forward in my seat.

[emerygt350]

Well, looks like that TPS board is in your future.

Timing seems fine. I would verify with a light of course.

That knob in the ECU is only supposed to affect idle richness. However, the ECU determines idle by the TPS, so if your TPS isn't behaving...

[JamesM]

That's a lot of advance at idle. Likely kicking up you idle speed.

set a flat line at 8 degrees between 500-1200 and see what happens

[emerygt350]

That's a lot of advance at idle. Likely kicking up you idle speed.

set a flat line at 8 degrees between 500-1200 and see what happens

Ahh, yes, I didn't see that. That makes me wonder if they weren't anticipating vacuum retard? That kind of advance down there would add a couple hundred to the old idle for sure. I would start adding timing around 1200 like mentioned above.

[slapshot]

That's a lot of advance at idle. Likely kicking up you idle speed.

set a flat line at 8 degrees between 500-1200 and see what happens

Ahh, yes, I didn't see that. That makes me wonder if they weren't anticipating vacuum retard? That kind of advance down there would add a couple hundred to the old idle for sure. I would start adding timing around 1200 like mentioned above.

I set it to 8 degrees up to 1200 RPMs. It did lower it to about 1000-1050RPMs after warmup.

The engine seems to miss here and there from my ear. Its not a smooth as I think it should run. I took all the plugs out and did a compression test. I didn't have time to do a leak down test on all cylinders. The compression was about 100 on all cylinders. That's what it has always been since I bought it in 11-2022. The engine has about 3000 miles since it was rebuilt by its previous owner.

Plugs 1, 2 and 4 showed lean running with 3 showing normal. I sprayed starting fluid around #3 intake. It didn't change RPMs.

[emerygt350]

That's a lot of advance at idle. Likely kicking up you idle speed.

set a flat line at 8 degrees between 500-1200 and see what happens

Ahh, yes, I didn't see that. That makes me wonder if they weren't anticipating vacuum retard? That kind of advance down there would add a couple hundred to the old idle for sure. I would start adding timing around 1200 like mentioned above.

I set it to 8 degrees up to 1200 RPMs. It did lower it to about 1000-1050RPMs after warmup.

The engine seems to miss here and there from my ear. Its not a smooth as I think it should run. I took all the plugs out and did a compression test. I didn't have time to do a leak down test on all cylinders. The compression was about 100 on all cylinders. That's what it has always been since I bought it in 11-2022. The engine has about 3000 miles since it was rebuilt by its previous owner.

Plugs 1, 2 and 4 showed lean running with 3 showing normal. I sprayed starting fluid around #3 intake. It didn't change RPMs.

I can't remember, are these new injectors? If not some fj67s are cheap and quick.

[emerygt350]

If it's looking lean and you want to richen it without hitting the MPS, you can give it a little bit more fuel pressure. Again, I wouldn't leave it there but if it is a lean miss you are feeling a couple lbs extra pressure should address it. Then you can go back and check on those injectors/fuel delivery issues.

also, remember on a djet, vacuum leaks do not result in lean mixes. Just rpm increases.