Engine Dies When Placed In Gear***Split from Spittybug...EFI***

[lazabby]

Just to give an update on my car - I've been having an issue with the car stalling when moving from Park into Reverse or Drive (I have automatic). The initial idle is too high and the idle drops too much under load. I'm making progress with changes in the programs but not quite there yet. I'm running closed loop so I don't know if the high idle is due to a setting in closed loop or if it's the spark advance. I've posted my current table for review. My idle starts out about 1400 RPM and settles to about 1200 RPM at 33% load. The butterfly valves should be fully closed.

[lazabby]

As some of you know I have been having an issue with my car stalling when moving from Park to Drive or Reverse because the load on the engine was causing the RPMs
to drop too much. I have been playing with the idle advance trying to get more advance as the load increases and the RPM decreases in order to "catch" it
before it stalls. There has been minimal success. All along I have been assuming that it was a Megasquirt issue or settings in Tuner Studio.

Last week I was talking to a co-worker and I described the problem I was having. He mentioned that sometimes when an automatic is low on transmission
fluid that the transmission can cause greater strain on the engine. I immediately thought of the time when I had let my car warm up fully before
shifting and it did shift then without dying. I assume that was because the fluid had warmed up and expandied doing what it does when warm. When we were
doing the EFI conversion on my car we had accidentally moved the transmission filler tube in such a way that it cause the fluid to leak. I had to drain the
transmission and fix the seal on the tube and replace the fluid. Measuring the amount of the fluid can be a bit tricky because the car has to be warm and
even after putting fluid in you have to wait a while before checking again. I thought I had the proper amount of fluid in there. I decided to check again
today and it appeared to be low. I don't have a leak. I put in the remainder of the AT fluid I had on hand and the car never died on shifting after that.
It seemed to do fine now whether hot or cold. Further testing will prove that but I think that issue is now solved. I may still need a little more fluid but I don't have any available at the moment.

With that out of the way (hopefully), I can now concentrate on the other issues. I need to get my idle right as it's a bit too high. It still wants to
idle around 1200 RPM when warm. That may be the advance table.

[Ron]

Last week I was talking to a co-worker and I described the problem I was having. He mentioned that sometimes when an automatic is low on transmission
fluid that the transmission can cause greater strain on the engine.
There shouldn't be any more drag on an engine when a transmission is low of fluid (unless this causes it to go into limp mode, which deloreans do not have). The most common symptom in a D would be slipping when pulling off in 1st or reverse, if it pulled at all.
I can't offer any help with the MS, but I bet Spitty will have an idea or two....

[lazabby]

There shouldn't be any more drag on an engine when a transmission is low of fluid (unless this causes it to go into limp mode, which deloreans do not have). The most common symptom in a D would be slipping when pulling off in 1st or reverse, if it pulled at all.
I can't offer any help with the MS, but I bet Spitty will have an idea or two....

You may be right. Another Delorean specialist said the same thing as you. I googled the issue and found this:
http://www.justanswer.com/dodge/2r86y-truck-stalls-when-stopped-getting-ready-go.html

The person having the similar issue as me is an airplane mechanic. He thought that the problem was electrical or something else. At the bottom of the page he found out he was low on transmission fluid and serviced the vehicle. After that he had no problems with stalling. When he described that to the on-line auto expert the expert said the same thing you. So the customer did an experiment. He took out two quarts of AT fluid and the symptoms returned. Just like him, once I could get the car going the car would shift normally. It's curious and may make a good discussion on this forum.

[Spittybug]

Just read your link.... good catch. I too would have found it hard to believe, but after seeing the issues that both you and Ian have had that have hindered our progress on getting you fully EFI'd, I guess I shouldn't be surprised.

I was helping Ian a couple of days ago. Couldn't get car to run worth a crap out in the middle of New Mexico somewhere. Pulled everything apart to check plugs, injectors, everything. Turns out he had a tank of bad gas...yes, bad gas. Who experiences bad gas anymore? True enough though, fresh tank and his problem went away. Hopefully there isn't more to it than just what he told me, but who knows.

Electrics, check. Grounds, check. Good gas, check. Plug, cap, rotor, wires, check. Transmission fluid, check. Seems that the EFI is the only thing that HAS worked properly!

[Ron]

First, don't drive your D (or any other vehicle) with the fluid that low for any reason, it is VERY hard on it.
There is no need to try that test anyway because deloreans do not have lock up torque converters...
(FWIW- Limp mode could put the Monaco in 2nd gear, but it doesn't affect reverse.)
Low fluid can cause weird things to happen, but I can't see the symptoms you describe being one of them, not with the consistency anyway. If you have not and do not change anything, time will tell ;-)

David T and a few others play with them too and might have ran across some oddity or ??...I think a thread about it would be interesting.
But I'd take a wild guess and say your MS settings aren't right (mainly because of the above and it didn't do it when the engine was warm...), you disturbed a bad connection, or something else unrelated.

[lazabby]

Question for the Delorean community. There is a vaccum hose going from the manifold to the transmission in automatics. How much is air pressure affected between a low amount of fluid and high amount of fluid in the transmission? Will it affect the air pressure any? When you move the car from "Park" to drive does that change the air pressure in the manifold?

[Ron]

The fluid level has nothing to do with the amount of vacuum.

Vacuum is produced by the engine and used to tell the transmission the current load on the engine, which (along with the governor) causes the transmission to take the appropriate gear.

When you move from Park to Drive (assuming there is at least enough fluid for the trans to take gear) you increase the load on the engine which in turn can change the vacuum (this is normal).

[lazabby]

Ron, I'm trying to get to the nitty gritty of the RPM and load on the engine. Under normal circumstance when you move from Park to Drive and the load on the engine increases, the RPMs drop. What causes that drop? Is it the manifold air pressure (MAP). If it's the MAP that causes the change in RPM then what is causing the change in the MAP when the transmission is engaged? That's why I was asking about the vacuum hose connection between the transmission and manifold. I knew that the MAP affected shifting while driving but I was wondering about any affects while stationary and merely moving from Park to Drive.

[Ron]

The RPMs drops because putting an auto in gear is a lot like putting a manual in 1st and barely letting the clutch out, thus loading the engine...The engine is not running "free" because the torque converter is transferring power from the crankshaft and sending it on to push the vehicle, robbing RPMs (so to speak).
As I said in the other thread, I'm thinking that the problem is with MS (or its settings) because putting it in gear shouldn't cause a significant change in vacuum anyway, and, the idle control should compensate for the load added to the engine, at least well enough to keep it from dieing. As said, I haven't played with later series MS, but I would expect it to open an idle air control and/or feed it more fuel to accomplish this (similar to most EFI or Throttle Body setups...even a delorean ;-)...and have settings to adjust it.

[Spittybug]

Shannon's going to try and bring his car around next week and we'll get this all looked at. It certainly appears that adding the fluid has eliminated his stall problem, I think he just wants to understand why.
We need to adjust his idle air controller and fine tune his fueling table, but he's close.

[DMCMW Dave]

The vacuum line to the transmission is going into the vacuum shift modulator. This is a dead-end connection,i.e. it is simply pulling on a diaphragm which in turn varies the pressure valve in the transmission. There is no vacuum loss there unless the hose or modulator has been compromised, i.e. leaking, and in that case it would be a constant vacuuum leak and unaffected by gear lever position.

I agree with Ron - something in MS is not reacting fast enough to the sudden change in load when going in to gear and loading the torque converter (therefore the engine) compared to being in neutral. In the normal DMC controls, this is seen as an RPM drop that is compensated by the idle speed motor.

[lazabby]

Adding the transmission fluid eliminated the problem with the stalling. No adjustment to MS did it. Somehow, the lower AT fluid level caused a greater strain on the engine that adding AT fluid solved. I don't know why. Googling the issue on the internet turned up people who had a similar experience.

Ron, are you running MS on a stock Delorean engine? If so I would like to see your tune.

[Ron]

Adding the transmission fluid eliminated the problem with the stalling. No adjustment to MS did it. Somehow, the lower AT fluid level caused a greater strain on the engine that adding AT fluid solved. I don't know why. Googling the issue on the internet turned up people who had a similar experience.

Ron, are you running MS on a stock Delorean engine? If so I would like to see your tune.


I can't offer any help with the MS, but I bet Spitty will have an idea or two....

1669 has K-Jet on a modified engine.

I play with stock EFI systems and some racing stuff I'm sure is a lot like your MS but I don't know the user interface.

==========

I'm sorry I thought you still had problems with it dieing (ie returned)...

:dunno:

I too am interested in getting to "the nitty gritty of the RPM and load".
Particularly, what could possibly cause a D trans to load the engine enough that the idle speed control could not handle it?

[lazabby]

What I found out via research on the internet (everything is true on the Internet right?) is that low AT fluid causes problems with the torque converter. People such as myself would have problems at stop lights and when moving the transmission in gear. Everything worked better when warmed up, presumably because the fluid expands. Here are a few links on the subject:
http://jeepgarage.org/archive/index.php/t-1244.html
http://www.justanswer.com/dodge/2r86y-truck-stalls-when-stopped-getting-ready-go.html
tombirch.com/1/ppt/atstall.ppt - this one is a pdf
http://x.nissanhelp.com/forums/maxima/16646-1997-maxima-stalls.html

[Ron]

What I found out via research on the internet (everything is true on the Internet right?) is that low AT fluid causes problems with the torque converter. People such as myself would have problems at stop lights and when moving the transmission in gear. Everything worked better when warmed up, presumably because the fluid expands. Here are a few links on the subject:

Playing devil's advocate:

http://jeepgarage.org/archive/index.php/t-1244.html
This guy reported "...after a cold start my jeep will hesitate...no matter how much I hit the gas it just kinda went slow...no throttle response...BTW it still has a funky low idle and occasionally stalls out still."

He had several problems but only the first was resolved after being pointed to a factory TSB at http://www.wkjeeps.com/tsb/tsb_wk_2101505.pdf, which strictly deals with "Trans - Delayed Engagement Due To Cooler Return Filter Replacement". That is the problem they resolved.

I did find it "interesting" that one other guy in the thread did report having "the same problem" (didn't say which), but couldn't afford a half quart of fluid because he couldn't even get a job at McDonald's. LOL

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http://tombirch.com/1/ppt/atstall.ppt

The only thing I see related there is:
"Torque converter stall should not be confused with a transmission stall test."
...
"TC Stall can be caused by low fluid level, faulty torque converter controls or internal seals."

"Can be caused by" don't help us w/o knowing the type of vehicle or any explanation whatsoever???

"Faulty torque converter controls" addresses lock up type converters being told to lock at the wrong time by a bad TCC solenoid, ECU, etc. (You don't have a lock up type converter.)

"Internal seals" would not be resolved by adding fluid.

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http://x.nissanhelp.com/forums/maxima/16646-1997-maxima-stalls.html
One person here did reply with a list of stalling causes. One of which was low fluid, but it appears that he was just trying to be complete or he missed the OP saying, "I have been in the car when it has done it at highway speeds."
His torque converter should lock up at highway speeds! ...So, not his problem.

Anyway, this guys problem was never reported as resolved and totally different than your's anyway....

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http://www.justanswer.com/dodge/2r86y-truck-stalls-when-stopped-getting-ready-go.html
This is the one mentioned before and I find it the most interesting...and most convincing. But continuing to play devil's advocate-

Here we have a guy who did the regular maintenance, cleaned a few things and then started throwing parts at it! I counted 15, one of which was the PCM, which he says resolved the stall problem for a week (not a fluid problem). Then he says he serviced the transmission (total fluid and filter change) but later says it only needed topping off!?! After (kinda) blowing off the expert (...a team eventually) he says, "I went to my support equipment division..." where they told him about "hydra drive with TC, some of which have efficiency clutches just like a lock-up converter" (which you don't have ;-) and that they drained over 2 quarts out and drove it to prove it. That by itself sounds very convincing for that type of transmission (electronic) and converter (lockup). Besides not seeing a mechanic telling him to drive with it over 2 quarts low, ever, I have to ask myself why would a guy pay for and install all of those parts, strike out every time, then go to a "pay for information" site, instead of going to HIS "support equipment division" in the first place?
Maybe he ran broke after wasting all of his money on parts and didn't want to accept the answer and have to pay, but wanted to be able to come back for other problems. LOL
Seriously, that may well have been be his problem, but we should be careful about giving too much credit here since he has a totally different setup.

========

We need info for OUR type of drivetrain...at least one that doesn't have, electronically controlled lock up converters and a kitchen sink ;-)
There is a large torque converter rebuild shop near hear (thats all they do) where I get my TCs. I'll reach out to the owner tomorrow and see what light he can shed on it all...

EDIT: How low was yours total. And how much after it quit stalling to top it off?

[lazabby]

I put in 1/2 quart and it has run fine since.

[Ron]

McDonalds? :deviltail: