95 850T rough, no power, video. UPDATE: CEL codes

[850TurboTurtle]

This is a continuation of the process of dropping a 96 850T tranny into a 95 850T.

In last week's episode our hero had solved a backfiring problem by reinstalling the intake manifold. Then the ABS and tranny threw CEL codes. This was cleared by reversing the polarity of the jumper wire hack from the old speed sensor plug near the back of the tranny to the drivers side wheel ABS speed sensor. Now the speedo and tranny appear happy, HOWEVER:

The car is running very strangely with a lot of missing and power loss under acceleration. If I floor it from idle it will not get up past 3500rpm and runs roughly. If I don't floor it it will smoothly get up into the redline zone. Driving around the block, when accelerating from a stop, it starts up slowly, gets better around 10mph, loses power around 20mph, and gets stronger around 40, then drops off again. Even in neutral it doesn't seem to have any power: when given much gas it just chokes itself. Here is a video of operation in neutral:


1. flooring from idle
2. gently increasing throttle
3. bring up to mid rpm then floor it

--It seems to choke itself out around 3500 rpm when floored unless already well above that point.


Just in case anyone else ever looks at this thread with the same symptoms, I'll post the eventual solution. Meanwhile, towards that hopeful end, anyone have ideas why it is running so poorly? I drove it 2 miles and no CEL yet... But it is running awful.

[Scholz]

It almost sounds like your ignition timing is too retarded.

[850TurboTurtle]

I wonder if vacuum lines to the turbo might be guilty? I'll check to make sure none got loose when reinstalling the intake manifold the other day.

[850TurboTurtle]

Drove it 3 more miles and got some CEL codes:
A1, tranny:
1-1-1, all OK

A2, Fuel:
414 boost pressure regulation
451, 452, 454, 455 - misfires on 1, 2, 4, 5
543 misfire
545 misfire, 3-way cat damage

A3, ABS
311 (no A3-311 in the MVS codes chart, but there is an A2-311 for VSS signal


Checked all the vac lines I could find for routing and solid connection. Seems OK there.
It now will accelerate to full RPM if I floor it from idle, which is a change.
But still totally gutless: worse than my old 740!

The turbo seems to come on at random, then die away in a few seconds. Punchy when it works, but then gutless.

[850TurboTurtle]

When at a stop the tranny shudders like the car doesn't want to drop to idle speeds. When I slip it into neutral, the engine races up to about 2k rpm, then drops down to about a 750 idle rpm. But if I run the rpms up for a while in neutral then let it drop off, it drops right down to a nice idle. For what it's worth...

[abscate]

Could be a bad TCV but I would rig and pressure test the induction system for one of those nasty opening slits.

[Sommerfeldt]

The turbo seems to come on at random, then die away in a few seconds. Punchy when it works, but then gutless.

That's probably a bit of a clue... Are you absolutely sure that you're not losing pressure somewhere?
Scholz and Abscate has the best pointers here, I think. 2 good places to start.

- S

[850TurboTurtle]

I tested the fuel pressure at the injector rail Schraeder valve and it was only 10psi, not 40 ish. I pulled the fuel pump and found the internal hose running vertically from the pump to the outlet tube had come loose at the top and was just resting on the mouth of the tube. When the pump ran it provided enough fuel for idle but not for acceleration, thus the feeling that whenever the engine started to kick in to power it choked out again.

Replaced the pump with the spare from my donor car and VROOM! Everything is happy now, including the owner/mechanic. Thanks everyone for the help and ideas!