Went for a really great drive on a twisty road and then had some very tasty seafood chowder; short on time to get back to Moncton so hit the four lane and smoked her home at a good clip. Temperature gauge actually got vertical, first time that has happened, car ran smooth the whole time, a few hours after getting home I went to put it away in the garage and it wouldn't idle, actually stalled. What has caused this??

Ian Stott
Moncton
Canada

Sounds to me like pluged idle jets, Just remove them( becareful not to drop

the O ring on each one . blow them out good) that should work. The hard part

is figure out where in the fule system the crap came from. Dave

I'm factory fuel injected, I think you are referring to a carbed engine. Fuel not in question at this point as I wasn't alone and we all fuel at the same place.

Ian

Ian: Sorry i jumped to the wrong conclusion. F.I. Hummm well that is an other can of worms. Dave

Hello Ian,

Questions are -

Engine size?

DJet or LJet?

Miles on engine - Last rebuild? Total or just heads?

Ambient Temp when you were speeding?

Last Oil Change - Filter - DID YOU CHECK the oil level when home? More engines are lost on new oil than old, espeically aircooled

How much metal on the oil plug last time?

Last time oil screen changed?

Ever change the Oil Cooler? - Do you have an aux cooler?

Where is your fuel pump, and what type?

Last fuel filter change?

Last time tuned?

Why RCMP did not catch you and impound the car?

Best regards,

John

Forgot to ask the Model Year?

73 or 74, since you say DJet 2.0L means that you may have had vapor lock.

If the Fuel Pump is under the engine tin, move it to the front of the car.

Auto Atlanta has a move kit that is complete. You can't run the car that hot and not have the fuel pump overheat and cause vapor lock.

Did it idle today or when it cooled down last night?

If it did not, you may have a broken CHTS wire, or you have a serious vacuum leak somewhere.

With the temp gauge pointing straight up, I would be very concerned. You ran it to the limit, and all kinds of things can happen. Like scoring a cylinder so fast that it would need new jugs and pistons. valves can tighten up when heat stressed. I have never had a car get that hot, not in 35 years, over 6 914 2.0L Djet engines.

Not even in California 100 degree heat, when I know it was 125 on the freeway asphalt.

The last question is, did you start it today, and what happened?

John

"Why RCMP did not catch you and impound the car? Can't answer that one!"

73 2.0 I am of the opinion it should be able to run like that all day long, I lived in Germany for 4 years and I was in the same range as Autobahn speeds, not trying to be a smart ass, just ambient temps are lower here and I wasn't near the red on the oil temp gauge, yes the needle was vertical, I mentioned that as I had never seen it there before. At no time was it pedal to the metal, traffic was very light and the person ahead of me (my brother from Jersey) had a radar detector. Car is running fine today! Sustained 85 to 100 MPH in these cars should be normal YES?NO??

Ian Stott
Moncton
Canada

i think your saying it got hotter than normal,no? that with the poor heat soaked idle i'd suspect you were running lean. aux. air regulator malfunction, as mentoned, vapor lock. another thing that could show up on the ocassional hard run is gummed up/sticking advance misc. in the distributor.

Every engine history is different, but I never in my life heard of a needle at 12 o'clock.

If it idles well again, maybe you are running lean?

Hard to say. I still think 12 noon is high on a functional oil temp gauge.

I would have pulled over. It may be that something in the oil sensor is bad, or something else oil-related is wrong.

We all drive cars that are temperature time bombs for moving parts.

Tis the nature of the beast. I have run 914's in NJ, MO and CA, and never had a heat issue, and I have had vapor lock in 80 degree weather.

I would check ohm output of the oil temp sensor. I forget where the indicator is, maybe on rennlist pbanders?

John

Personally, doesn't sound like vapor lock at all to me. If it was vapor lock, the car wouldn't start, not just not idle. I would check valve adjustment, and the advance in the dizzy first. My guess is you got the heads nice and warm so the valve clearances were off. I've also had one CHT fail when it got hot, but I don't think thats very common.

I have seen the stock TEMP gage vertical lots of times with no ill effects. I assume you were talking about the stock gage? If you weren't getting close to the red zone, you shouldn't be running too hot as far as oil temp goes. Head temps are another thing altogether.
Sounds like you may have been having some type of vapor lock problem. Did it start and run OK after cooling completely?
Does anyone have any idea what temp vertical would be? Or the first of the red zone?
Tom

Several things to check, do all the rubber seals between the body tin and engine tin fit together well and tight? If not it is an excess heat into the intake system causing the system to lean out and the engine will run much slower. The heads and intake runners will get very hot and take quite a while to cool down. Second, try to see if the injector seals are leaking as the heads heating up will cause poor seals which will loose you compression and cause a slow running engine. Finally, how are the valve clearances, as if the engine gets real hot from sitting the valve clearances will change, I.E. exhaust valves will cool off and worse yet the intakes will heat up and some possible will not be closing completely or as much as before so the engine will be way off in power. Good luck checking things.

Thanks to all who chimed in, I will be setting the valve clearances before my next road trip and will also check the timing/dwell. I will also ensure the engine seals where they meet the engine tin are sealing properly, I have new injector seals and the proper curved injector hoses, as well as all new gaskets and hoses. I don't think I am running lean based on the colour of my exhaust pipe and I did the anlyzer check which I think is for your idle. I am wondering about the vapor lock suggestion, wouldn't it just not start? I know you California and Southern USA guys deal with way more heat than we ever will have in Atlantic Canada, if it hits 90 we start dropping like flies! I find it a mystery, am I wrong thinking you can run at 85 to 95 for over 1/2 an hour with no problem, and if my oil temp was still quite a ways away from the red how can that be bad, I'm thinking the Porsche engineering guys made the engines with the capability to handle more heat than I get here in Canada.

Ian Stott
Moncton
Canada

12 O'clock on the stock, un-numbered, console oil temperature guage is nothing...
I don't know what everyone is worried about.

I have often noticed a hot teener to not hold its idle or have a different idle after a long drive. I'm sure it will start up and be fine the next time. I alway attributed it to changes in head temp (CHT values) or even intake manifold heat soak and carb mixtures being impacted on carbed cars.

(I even think carb'd car idles can be impacted by heat expansion of the motor, and how that stretching can effect carb linkage adjustments on a hot motor)

none of the above items listed will hurt... but no need to over think it either
the sky is not falling in my opinion!

brant

Nope. Back in the day I did it all the time up and down the 401. 85 would probably been my top - only bursts over that. Couple of trips across the prairies too running all day in the heat. As long as you are moving things are just great. Stop and go traffic - not so much.

Do you think the engine was cold when you tried the restart or would it still have been pretty hot. Thinking about the AAR.

Ian,
Your problem may be similar to this hard to start when warm/hot problem.

For a fuel injected car this is a common problem in very hot weather (on some cars, not all). I have had it and finally got an answer from Brad Anders.
When it is hot out the engine gets really warm. Then you shut it off for a while ( 10-15 minutes or so) and it doesn't want to start. The cylinder head temp sensor in the head controls the richness of the mixture for the injectors. The core of the engine( barrels, pistons, and case) cools off much slower than the heads. Since the heads are cooling more quickly, the cht thinks the engine needs a richer mixture, hense no fire up.
A solution on very warm days is this, when you first get in the car, put the gas pedal to the floor. Then try to start. Putting the pedal to the floor after turning on the key will cause a extra rich first injector pulse for the injectors' It works for me.
Tom

When I got home I shut the car off and went on a photo shoot that lasted maybe an hour, the car restarted but wouldn't idle without me feathering the accelerator, when I took my foot off the gas to brake after entering the garage it died. Next day it started fine, idled fine and runs as great as ever. I think the above comment about the heads cooling off much quicker than the rest of the engine and "fooling" the ECU seems what is likely going on.

Ian Stott
Moncton
Canada

hmm - the need to feather can also be a sign of FI problems. The enrichment pulses from the tps are a separate cct from the normal pulse. IIRC neither the MPS nor the trigger points are involved in the enrichment pulse. Did you have to keep feathering it or just when the rev's dropped? IE if you give it some steady gas would it run? Probably a red herring but keep that in mind if it happens again.

This can be a fairly common problems as the idle was probably adjusted when the engine wasn't Hot enough.
Idle mix must be adjust with the engine HOT>its too rich.
Readjust the idle mix after running the engine on some nice 15 minute drive running it hard to get the temps up.
Then set the mix with the ECU screw and air bleed to spec. Now when its cold the idle should start out a 1500+rpms and then after 5 mins or so settle down to a nice 950.

I noticed the throttle body plate has a small hole in it that has a screw in it, should that be there?

Ian Stott
Moncton
Canada

My throttle body plate has the hole forward of the actual throttle body and NO, it does not have a screw in it.

All my cars (all 73 2.0L Djets) had that hole, about the size of a cigarette, and none were screwed closed.

I am not too sure what reason there is for that hole, but maybe remove the screw?

I am pretty damn certain it must be open and clean.

Some day I will take my throttle body manifold off and look at it to see what the hell it is.

Good luck!

John

I vote heat soak related issue, though i am leaning more towards heat soak of the temp sensors rather then vapor lock.

I used to suspect issues like this were related soley to the CHT sensor as i had heard it mentioned in the past however after running Megasquirt with the stock d-jet sensors and being able to see what the sensors were actually reading at i believe it might have a lot to do with the intake air sensor heat soaking. The stock air temp sensor is not in the best location, not very well insulated from the manifold, and seems pretty easy to heat soak.

After a a pretty hard drive up the mountain one day i shut my car off for a few minutes and when i restarted it was running real lean, very similar to what happens sometimes with d-jet when you do the same thing. A quick check of my systems was showing that my intake air temp sensor (the stock d-jet one) was reading around 160 deg with air flowing over it, this is on a 70deg day in the mountains. With EGO correction off the false reading from the heat soaked air temp sensor was causing my mixute to hit 18:1 at idle. When the air temp sensor crept back down into normal ranges everything smoothed out.

I cant say for sure how much of this translates directly to d-jet systems. but i can say for sure that the d-jet air temp sensor has a problem heat soaking and i suspect that it is part of the hot start/hot running issue.