DJet help bucking, stuttering

[akokarski]

Hello,

Got almost the whole day to the fastback and I got almost all of the answers to questions above.

1) CHT Cold 3.02 kOhms. Warm 114 Ohms just driving a few blocks

2) Timed at 0* pretty steady, dwell 47* and it is only deviating as I reved to about 1* idle @900rpm
3) Checked vac on advance canister, leaking about 1" per min
4) Fuel pressure is at 28psi, I am using a decent fuel pressure tester that measures up to 100 PSI, with resolution to 2 lbs. It did not fluctuate as I reved, no more than 1 if even.
5) Valves, here is where it gets interesting... valves were adjusted about 80 miles ago all are good, but #3 exhaust tight .005". Readjusted it to .008, turned engine over to check found it on a looser side. Pulled adjuster to see if it's worn out and I find this:




I am loosing clearance fast here. Not only does it tightens up, my adjuster is getting pounded to shreds. Last time I've adjusted valves I found this sucker with no clearance I had to back it out before I could even get any filler gauge in between. This is pretty consistent and seems like getting progressively worse. For now I replaced adjuster and left it at .008

6) Checked trigger points again, .4 and .5ohms


Checked vac on the MPS 1" per min
15-7 resistance 95.1 ohms
10-8 resistance 380 ohms
MPS PN: 0 280 100 007
311 906 051C

Epoxy is still over the 1/2 inch slotted adjuster.




I don't think my distributor is 180* out, it's been in the same position as when car has arrived, it was running ok but not perfect.

Distributor PN
JFUR X 4
0 231 163 008
311 905 205 A-B

ECU PN# 0 280 000 019 I don't think it have adjustment pot, I don't remember seeing it.

I have not touched anything today to keep everything consistent, it drove a little better with that valve adjusted, but I didn't drive much just a few blocks. Also as it warmed up a bit, idle was horrible almost stalling. I bet if I were to drive it more it would back to where it was.

These #3 exhaust valve situation makes me wonder if I should even try to do anything as far as FI goes, or just admit that I have an issue with the valve and start looking into a rebuild at least of top end. It's got 140K+ on the clock and from what I can tell, nobody did a valve job on this car. I have all the maintenance records, not a word about heads. Also last compression test wasn't too exciting either, 80 on the #3 and 90 something on others.

In the mean while, should I put original TVS on the car and adjust it per Ray's instructions? Check the valve again see if the tvs is making it worse?



Here are the pics of the exhaust, looks like t3? (this came up earlier in the discussion regarding o2 sensor...





This 3/4 side i was thinking of putting o2 sensor here..

[akokarski]

here is a video of it idling like crap after a bit of warm up:

http://www.flickr.com/photos/volksnut/5 ... otostream/


Oh almost forgot, I couldn't get PN off the CHT, cause I cannot get a wrench on it either from the top or side. what size wrench is it supposed to be? Maybe I can grind a deep socket to get a wrench on it.


Thanks again,
Anton

[zooty]

5) Valves, here is where it gets interesting... valves were adjusted about 80 miles ago all are good, but #3 exhaust tight .005". Readjusted it to .008, turned engine over to check found it on a looser side.

I am loosing clearance fast here. Not only does it tightens up, my adjuster is getting pounded to shreds. Last time I've adjusted valves I found this sucker with no clearance I had to back it out before I could even get any filler gauge in between. This is pretty consistent and seems like getting progressively worse. For now I replaced adjuster and left it at .008

Engine sounds like it have an valve seat problem.

Checked vac on the MPS 1" per min
15-7 resistance 95.1 ohms
10-8 resistance 380 ohms
MPS PN: 0 280 100 007
311 906 051C

Epoxy is still over the 1/2 inch slotted adjuster.

But the screws looks used so the MAP/MPS was open maybe you need an new alignment at the end.

I don't think my distributor is 180* out, it's been in the same position as when car has arrived, it was running ok but not perfect.

Your Distributor is driven by an "pulley" that can also out of target (was it 15°?)

Measure or/and change the Condenser too.

[raygreenwood]

A few things...you distributor is NOT driven by a pulley.....its a gear. But i think I know what you are getting at !


(1) Your valve adjuster screws need to be replaced. They are too soft and are worn past the hardening.
(2) do not adjust your valves to .008"...that is FAR too loose. Factory spec was .006". .005" is acceptable if its a smooth fit. That alone can hammer the screws.
(3) Your fuel pressure is acceptable for the moment but a 100 psi gauge will be too innaccurate to see fluctuation. The extra range has a tendency to damp the needle.
(4) the accuracy of the gauge is probably at best 2% of middle of the scale but is probably 4%. Its ok for now.

NOTE!!!
Should your ignition timing be timed at "0"? Check this with the motor # please.

Why does everyone ALWAYS suspect a sinking valve seat first? I would suspect stem stretching first. they are know to do this. Both can kill the engine. I would pull the head and look. Or at least pull the rocker arms and check the valve stem evenness.

The leakage on the vacuum advance...is marginally acceptable...but should not be happening. It affects the accuracy and amount of advance. I would replace that ASAP.

The readings on the MPS are good....and it probably does need an adjustment but that is the last thing on the list.

the way to do the CHT sensor...is to get a deep, thin wall 13mm socket and grind a V-notch in the side of it just below where the ratchet fits in it. In this way you can thread the wire connector through the V-notch to allow teh socket to slide on. Keep that tool in the gl;ove box it can save you walking someday.

But...this last set of readings does not sound too far out...maybe slightly high on the top end but not horrible. The lower end 114 ohms...is about what I would expect.


Zooty makes a good point, make sure your three pin plug to the distributor trigger points are plugged in properly...check the bevel....and change the condensor for good measure.

Also...check the resistance on your injectors. It should be about 2.3 to 2.5 ohms each.
Get new injector seals. DO NOT USE THE STOCK INJECTOR SEALS. Ask for seals for an 83 Saab 900 or an 80 model rabbit with CIS injection. You will get these small donuts....that fit very tightly and seal better.

Ray

[raygreenwood]

From your video...you still either have a small vacuum leak or its a combination of fuel mixture and slight advance changes at idle....or likely all three.

When you disconnect and plug the advance line, does it change anything at idle or does it change the stability of the timing mark at idle under the strobe? Ray

[akokarski]

Hi Guys,

I don't think distributor drive pinion is missaligned. I can double check that if you feel strongly. I highly doubt that it is out of order as these symptoms got progressively worse, not after pulling distributor...

I have replaced adjuster screw on the problem valve, should I go ahead and just swap them all?

I will dial it down to six thou.

Timing at 0* as it is a 1970, I will get engine # to confirm.

Cannot pull the head Not because I am uncapable, but I don't have facility to do this right now. I can get the rocker off and see if valve stems are all even.

I have another vac advance can, need to see if it holds vac, but it is off 311 905 205L distributor....

And will get that temp sensor 1 out to get part #

trigger points plug is always in correct way, I always double check for the bevel. I do feel that contacts in the receptacle might need cleaning. When i was checking resistance, if I touche em wrong way I would get different reading.

Condenser is pretty new.

Will get resistance reading of the injectors. Also injector seals are new, I did use cis doughnuts. And I will play with advance vac.

Thanks!
Anton

[vwbill]

Sorry to jump in but isn't that a T3 Djet ??? Not a 411/412???? Looks like my brother's 1970 t3 Wagen T3 Djet setup..... Are you checking the specs for that engine??? The MPS is a different MPS. Ray is great at Djet FI issues! It usually is a Vacuum issue and the valve adjustment is a issue too; Not to be ?? but you did the TDC check on the #1 by looking at the number two exhausting... and checking the static mark on the dist.) and check the Braided ground on the point plate in the dist.!! That was a issue with my car and my brothers! Also check the FI points in the bottom of the Dist too! Timing is a big issue too! Bill,jr.
Sorry but did you see http://members.rennlist.com/pbanders/djetparts.htm he does the run through to getting the FI right! Did you check the Fuel pressure at the Fuel rail left tee? On my brother's car it was a clogged Injector. Check your spray pattern and pull each injector plug to see if each in working... I thought the T3 1970 had diffent valve settings??? Do you have the T3 brown book???

[Lars S]

Right vwbill that should be a Type 3 MPS.
I have one in my collection, when I did my bench test that one (007) gave less Henrys att low pressure = leaner mix then the others wich are Type 4's most of them.

Pls see pink line in the diagram:
http://www.lsmteknik.se/MPS%20071229B.htm

Probably this unit can be adjusted to fit Typ4 spec.

/Lars S

[zooty]

Right vwbill that should be a Type 3 MPS.
I have one in my collection, when I did my bench test that one (007) gave less Henrys att low pressure = leaner mix then the others wich are Type 4's most of them.

Pls see pink line in the diagram:
http://www.lsmteknik.se/MPS%20071229B.htm

Probably this unit can be adjusted to fit Typ4 spec.

/Lars S

I have only seen two different style MAP/MPS that is what I have called short and long MAP/MPS in this Thread.
The long ones are tweaked to the Engine pressure.
Don't know what's happen to the short ones in this.

So it seems to be an good idea to control if an long MAP/MPS can work here in this 1600i Engine.
In the US and other EU States some D-Jet Parts are different so maybe this longer MAP/MPS is OK.

[raygreenwood]

A note for everyone....this car is in fact a type 3. It was suggested by me that he bring the problem here because collectively we have a lot of experience dealing with D-jet....and a good succes rate....so to clear the conclusion...remember that this is a type 3 system he is working with.
Ray

[Piledriver]

Semi-OT, no Djet content
Re: The adjuster screws...

Don't replace all of them unless they all look like that...

The "new" ones are frequently junk.
I have had great success refinishing used OG ones by folding up some 400 grit wetordry in my palm and spinning the screw in a drill to reestablish the radius---It's impossible to get a good adjustment on a knife edge that gets beaten down in a few miles..

I finish up with 600/2000 and crocus cloth.
Pull and inspect each valve adjustment, replace any that bugger up again.
(should just have a polished contact stripe, no wear/galling)
Might take a few iterations... If the valve tips are cupped, all bets are off.

If you have 8mm screws, I strongly urge you to convert to 911 screws (and preferably HD studs and solid spacers) that ends all this.

Note--- This is a high load metal-to-metal point contact wear area.
If your oil lacks sufficient ZDDP you may see it here first before the cam goes.
When I switched from GTX to Rotella (and started refinishing) my adjuster issues stopped, did the 911 screws later.

Castrol belatedly now admits GTX is not suitable for our engines anymore.

[akokarski]

Thanks Piledriver, I will take a look at other adjusters when I pull the rockers off. I did notice lots of side play on the rocker. I know that solid shaft assemblies can/have to be shimmed to .004". Can, should I do the same for the stock assembly.

I'll keep in mind 911 adjusters, for now I just want to sort this out.

Always running Rotella in all A/C engines


Anton

[Piledriver]

Thanks Piledriver, I will take a look at other adjusters when I pull the rockers off. I did notice lots of side play on the rocker. I know that solid shaft assemblies can/have to be shimmed to .004". Can, should I do the same for the stock assembly.

I'll keep in mind 911 adjusters, for now I just want to sort this out.

Always running Rotella in all A/C engines


Anton

The solid spacer kits actually need to be sanded down to set the clearance.
(They get hardened washers on both sides)

I wouldn't waste time on the stock setup side play, just get the valve adjustment screws working right so you can sort through the DJet issue.

[akokarski]

I am back.

Got valves readjusted to .006" . Pulled rocker assembly off 3/4 side and #3 exhaust valve is sticking out about .010 Couldn't really measure it but it is visible with straight edge. Rest of the valves are perfectly even.

Measured in injectors all came up with 2.7ohm.

Engine number U0315346. Looking at bentley and it says to do 0* for my year (1970) As far as timing marks on the fan go I have 4

| ||| first one is tdc. When I checked the timing it was set to 2nd notch (5*btdc?!) It is a at 0* now, and seemed to help during warm up. Engine was not hunting as badly to the point of almost stalling.

Still working on getting cylinder head temp sensor out.

Also tried to disconnect and plug vac advance hose no change. Resprayed boots and injectors looking for vac leaks, still tight.

Anton

[raygreenwood]

What are you spraying them with? The problem with looking for leaks this way...is that on those parts...you will not find the leak. The easiest way to be sure runner boots have no leaks is to clamp them. The easiest way to make sure injector seals have no leaks...is to replace them. When its new and its known...its rare that it leaks. One valve being .010" higher is only something to keep an eye on. It is most probably stretching...and you are not too far from needing a valve job.

The best way to remove the CHT sensor is to take a deep socket and kridn a V-notch almost halfway through it on a bench grinder...or with a dremel and cut-offf wheel. This allows the pigtail to poke through the side of the socket while you loosen it with a ratchet.

The next few things to get into are the TPS adjustment...then fuel injection harness condition...and then the MPS adjustment.
You have a few more things to look at on teh distributor and vacuum advance units first. Ray