420A Car dies while driving

[hughes_22]

Hey y'all. To start off, I have a 98 420a, 5 speed. The motor was just recently completely rebuilt due to a broken timing belt. I am still working on the break in process, have just over 200 miles on the rebuild. Driving home the other night, went to downshift before hitting the on ramp for the interstate, and the car spazzed out, died, and the oil light came on. Pulled over, checked all over, could see no leaks, and I do have oil in the engine. Let it set for about 10 mins, started up fine, and drove it home. Car died the same way as I pulled into my driveway, both times clutch was engaged. But, on that second part of the drive home, I had no speedo or odometer movement. I also do not smell oil or coolant out the exhaust. Any ideas whatsoever? Thanks!

 

[Widgmaster]

I just watched a video on this very problem... but it wont let me copy to paste it here..
This guy had the same issue and it turned out to be his fuel pump ..There`s was corrosion under the plate that screw down under the back seat.. He cleaned the terminals and all is well again.
Hopefully for you it is that easy..
Also.... do these cars have a shut down feature that shuts down the engine if the oil is low. ??

 

[dustyboner]

speedo odometer not working is usually cause of an issue with the vss (vehicle speed sensor)
did it die when you werent pressing the gas pedal? meaning the throttle body was closed. if so, it could be the IAC motor

 

[1999RSfwd]

Also.... do these cars have a shut down feature that shuts down the engine if the oil is low. ??

No they don't ... don't ask me how I know

 

[BLACK'98DSM]

The oil light always comes on if the engine stalls. That doesn't mean it's an oil pressure issue.

, it could be the IAC motor

I'm not sure about this. I accidentally drove my car for 2 days with the IAC compltely unplugged. It ran fine besides a high idle and a little lean.

No they don't ... don't ask me how I know

Correct. They do not.

 

[hughes_22]

Widg, that's great Intel, I'll have to take a look to see if I, too, have that going on.

Dusty, I had just let off the gas pedal so I could downshift, both times it died.

I have checked the speed sensor connection and all the plugs I can see from above. No wires melted, cut, or unplugged. Would the egr block off mod have anything to do with anything? I do have the surging idle that a lot of guys report getting. I have the vacuum line plugged that would go to the egr system, and the 50 ohm (I think that's what it is) resistor in the plug. The car drives fine, even cruise control still works - before and after the speedo and odo stopped. Is it possible the speed sensor gear has broke off? And would that cause any reason for the car to stall?

It's been a couple days, and I have no leak spots on the driveway either, just as a side note.

 

[dustyboner]

I'm not sure about this. I accidentally drove my car for 2 days with the IAC compltely unplugged. It ran fine besides a high idle and a little lean.

thats because it of the position it was in when you unplugged it. If the car was idling and you shut it off, the IAC will stay in that position till you turn the key back to the ON position (i think, it may be till you start it, i can't remember which one but you get the point)

But your right, my answer is off.
My memory sucks and i was incorrectly recalling a problem i had a long time ago.
I could explain but nobody cares.

so just ignore that answer

 

[hughes_22]

Okay, so I did some messing around with it today, and got the car to stall on me again. It seems to happen when I press in the clutch quickly and causing the engine to idle down quickly. If I ease it in, while slowing down to a stop, the engine idles back normal and stays running, but if I come to a quick stop and quick press of the clutch, it causes the car to idle waaaayyy low and causes it to stall. I still have no speedometer or odometer movement.

checked all my connections and plugs, all are fine. Even checked the fuel pump connections, no corrosion whatsoever. Could it be an idle sensor of some sort? Would that Idle Adjustment Screw thing work that some say to get when you do the EGR blockoff? That wouldn't help my speedo issue though...

 

[BLACK'98DSM]

Would that Idle Adjustment Screw thing work that some say to get when you do the EGR blockoff?

There is no idle adjustment screw on the 420a throttle body.

I just don't see how deleting the EGR could mess up the idle. I deleted mine and nothing changed.

 

[JeffGS-T97]

I would check to see if the vss got plugged in after the motor was put back in the car. I also would check the multi plugs on the ECU. Pull a plug out one at a time and check and see if the pins are whole and not bent or broken, and inspect the female end to see if the metal contacts got pushed out of place when plugged in.
If you have ever removed the instrument panel the lack of a speedometer and tachometer could be the result of the cluster not getting continuity from an improperly seated cluster.

 

[hughes_22]

There is no idle adjustment screw on the 420a throttle body.

I just don't see how deleting the EGR could mess up the idle. I deleted mine and nothing changed.

Correct, but I know there's an aftermarket one you can add that is supposed to fix any EGR delete issues. did you put on a resistor in the existing EGR plug? if so, what size?

 

[hughes_22]

I would check to see if the vss got plugged in after the motor was put back in the car. I also would check the multi plugs on the ECU. Pull a plug out one at a time and check and see if the pins are whole and not bent or broken, and inspect the female end to see if the metal contacts got pushed out of place when plugged in.
If you have ever removed the instrument panel the lack of a speedometer and tachometer could be the result of the cluster not getting continuity from an improperly seated cluster.

I was the one who put the car back in after the motor rebuild, and I made sure EVERYTHING got plugged back in. It's been working fine for nearly 200 miles, just when the car stalled out on me the first time when I posted, and I started it back up to drive home, that's when it was no longer working. Would it be possible that the plastic gear in the transmission broke off? Would that cause the issues of the engine idle to drop out when the clutch is engaged?

 

[JeffGS-T97]

I was the one who put the car back in after the motor rebuild, and I made sure EVERYTHING got plugged back in. It's been working fine for nearly 200 miles, just when the car stalled out on me the first time when I posted, and I started it back up to drive home, that's when it was no longer working. Would it be possible that the plastic gear in the transmission broke off? Would that cause the issues of the engine idle to drop out when the clutch is engaged?

I had a stall like that when i first got mine but the gauges weren't involved. So i guess my answer would be no. It is certianly a idle control issue if its the sensor i cant be certain. Are you getting any codes?

 

[BLACK'98DSM]

did you put on a resistor in the existing EGR plug?

My EGR is compltely deleted. Meaning I also removed the wiring for it.

 

[hughes_22]

My EGR is compltely deleted. Meaning I also removed the wiring for it.

Ahh, right on.

I had a stall like that when i first got mine but the gauges weren't involved. So i guess my answer would be no. It is certianly a idle control issue if its the sensor i cant be certain. Are you getting any codes?

Hmm, okay, I'm so confused then. Guess I'll have to just drive it around more then. The only codes I had was for the EGR system. And I think that's because I used the 50ohm resistor instead of the 100ohm (purely a guess, will be getting a 100ohm to see if it clears).

 

[dustyboner]

I deleted mine and nothing changed. I just don't see how deleting the EGR could mess up the idle.

me too. i suppose if the hole for the EGR on the back of the intake wasn't completely sealed it could mess with it.

---------------

You must be logged in to view this image or video.

You must be logged in to view this image or video.

---------------------

You must be logged in to view this image or video.

---------------------

 

[hughes_22]

Alrighty,
Lot more investigating this past week. Took the car for a short drive and it only dies when coming to a stop, and downshifting to 1st gear. If I rev the engine right when I push in the clutch pedal, and shift quick enough, the engine doesn't have a chance to die down. From what you all have said, and the research I have done on past threads here and many other forums, I believe that may be the IAC valve. New one is on the way, so we'll see if that fixes that specific problem.

Part 2: no speedometer or odometer. I have a spare gauge cluster that I know works, and popped it in, still nothing. Put the original back in and began testing the VSS. Pulled the sensor and gear out of the trans housing, put a drill on the gear, put the key in "on" position, and I can turn the gear from slow to fast and when the drill is maxed out, I read 85mph and the trip meter and odometer both increase as they should. I did happen to stumble across this thread on here:
www.dsmtuners.com/threads/speedometer-gear-inside-transmission.498452/
That gear on the internal part of the trans, the plastic one. I have the car in neutral, front end raised up currently. I can see inside where the VSS goes, and can barely see that gear. When I spin the driver side wheel, that gear inside either doesn't spin at all, or only goes for about 1/8th of a turn, then stops again. I do believe I have found the issue, that that plastic gear has fallen off inside the trans. I cannot tell if it is broken, or just slipped off.

Any idea if that would lead to the car stalling as it doesn't register it's moving? And is there any way to try and fix it w/o dropping the trans? In that post, he fixes it by using flange head self tap screws to keep it in place. Any better ideas? Or should I roll with that one?

 

[BLACK'98DSM]

Any idea if that would lead to the car stalling as it doesn't register it's moving?

That may actually be your issue. These cars are supposed to idle up a bit when in motion & in neutral. So if it doesn't know that it's in motion, it doesn't know to idle up. Maybe that's why it's dying?