Stalls when engaging Rear gear

[matuva]

Hi all,

title says it all.

I started testing my soon Blazer . She runs almost fine, though we still have to fix some little issues before she can pass the inspection and be allowed
to go back on the road.

The PCM throws no code, except one saying there's a little problem with the advance, probably stepper motor on IP.

One weird thing is that, sometimes - not always-, when I go from D to R, she stalls. She fire up right away after, but that looks a bit odd to me.

Anybody have any idea of what may cause that?

 

[WarWagon]

Timing is power.
Fix your little issues so the engine runs right.
Shock from drive to reverse will stall an engine that doesn't have enough power to keep running under the sudden load.
Loose wires can also cause this. A wiggle test at idle may help. Imagine how much the engine moves from drive to reverse on old engine/trans mounts. It could even momentarily pinch a fuel line.

 

[bison]

What he says^^
//i would check first the grounds at the rear of pass side head for loose or broke inside the insulation.

 

[matuva]

Checked grounds, they are fine.

I remark that, when going from D to R, if I stop a while at N, she doesn't stall, though as I said, she doesn't stall each time I go straight from D to R :skep:

Here are the DTCs I can find :



BTW, what does - 34 injection stepper motor fault? Stepper motor to change or ULSD woes?

 

[ak diesel driver]

I wonder if the stall could be related to the 2 APP codes?

 

[bison]

Historic codes are issues of the past and have no bearing on the stuation today
No codes now.
I say you got electrical connection issues or maybe a tranny issue(dirt in a orifice somewere blocking hydr flow to/from the TC)
The nonstalling in the N stop over suggest the latter IMO

 

[matuva]

Well, today, she stalls again, after I goes from gear 2 to R.

I have checked all grounds before, and that doesn't improve.

One other thing I remark is that, when parked, in N the "service engine soon" light is OFF.
As soon as I engage a gear, whatever it is, the lamp comes ON.
If I rev a bit the engine, she goes OFF, and comes back to ON when back to iddle and with gear engaged. It goes OFF in N, wathever RPMs the engine is.

While cruising, "service engine soon" light is OFF as long as engine is above average 1 000 rpms, when rpms goes close iddle, e.g. when I release accelerator pedal before braking or just let her go, light comes ON, and so, and so....

No codes, she runs fine, gear go up & down smooth, no hiccup

TC related? What would you suggest in that case?

 

[WarWagon]

Check the glow plug controller harness for falling apart and shorting out. Loss of 5v 'reference' can stall the engine. Clear codes and recheck them as the SES light is indicating a 'current' problem. You may have to do a wiggle test on wiring harnesses till the engine stalls in park.

 

[great white]

Clear the history.

Take it for a drive.

Drive it in the regimes that illuminate the SES.

Pull the codes again even if there's no SES light once parked.

The history codes will be what triggered the SES light when you were driving.


Post 'em up here.

 

[bison]

SES light on got to set a code,might be a pending code.

 

[matuva]

No codes, that's weird...

 

[bison]

I think you might have a tranny issue.
Check the tranny pass trough connector for pin corrosion,loose/broke wire or oil in the connector halves

 

[matuva]

Would excessive level of ATF cause this?

 

[JiFaire]

What year is it, Al? Is the TCC operating as normal?

 

[matuva]

Hi Jim,

that's for my 1994 Blazer. The trans shifts perfect, TCC is fine. I really don't understand this SES light. :dunno:
I will do as Simon suggests and check the harness

 

[JiFaire]

I think he's on to something, Al.. the 4L80e generates a lot more pressure in reverse, and if there's a solenoid issue, that would explain your problem.

The thing never has this issue when going from N to R? (ie: you put it in N, pause, then shift to R?)

 

[matuva]

from N to R, never yet Jim

 

[Bushido]

from N to R, never yet Jim

Sorry for reviving an old thread, I just wanted to ask if you did get it sorted? I'm experiencing similar problems with my truck... Although, mine doesn't stall very often. But every once in a while, as soon as I put it in gear (be it reverse or drive) going from P it stalls. Similarly to your truck, it doesn't seem to stall if pausing at neutral (although, that could just be a case of not being one of those rare times it would've stalled anyhow). I also had it stall on me once while driving on the road. was aproaching a red light and backed off the throttle and started breaking and all of a sudden I lost the break servo. Engine had stalled for no apparent reason... She starts right away after stalling though, but sometimes stalls again when trying to put her in drive for the second time. Any ideas?

 

[matuva]

I just remarked that when engaging from gear to R, I sometimes hit the key at the ignition cylinder with my hand.... and she stalls. Now everything is OK

 

[Bushido]

I just remarked that when engaging from gear to R, I sometimes hit the key at the ignition cylinder with my hand.... and she stalls. Now everything is OK

Huh, interesting. I'll have to check that out, might be the same for me. Cheers.