Surging LT1 Conversion

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Nov 27, 2006 | 09:10 PM

chree

Thread Starter

Staging Lane

Joined: Oct 2005

Posts: 86

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From: Atlanta, Georgia

Surging LT1 Conversion

First off, thanks go to Andrew (Camaroholic) from AKM Cables. Great cable, fast shipping.

My problem: Intermittent surging at idle after warmed up. The idle RPM goes up and way down - I'm not sure how low becuase the tach doesn't work yet. The car will cut off if I coast to a stop in 5th or 6th.

Car specs: (I bought the car already converted, see more photos/videos in my sig)

'86 Volvo 740 Turbo Wagon
'94 LT1/T56, 16188051 PCM
Harness and tune (circa '97ish) by Dr. K
No Mass Airflow Sensor
PCM sticker lists "NO VATS & SPD DNSTY / 3.73 K73" (the car actually has 3.31 gears)

The PCM has the following DTC codes:

MALF 11: MIL Lamp Fault
MALF 13: Left O2 Fail (there is only a single O2 in the right header)

The .uni file I recorded with Datamaster is here. It's just idling and revving in nuetral because the ALDL port is under the hood and I need to find a way to get the cable through the firewall.

Any help appreciated. I have no idea what is going on. I can get more information or datalogs if needed.

Thanks!

Nov 27, 2006 | 09:25 PM

Camaroholic

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From: Waco, TX

Well, from the looks of the Datamaster file, it looks like the idle rpm is set to 588 RPMs. Yeah, that'll do it.

The M6 needs to idle 750-800 RPMs minimum. Do you know if the PCM file was originally for an automatic? The A4 can idle at 600 RPMs, but the M6 needs more. Looks like you need new PCM firmware. Let me know if you need help with that, I can hook you up with an M6 file and all that.

Oh, and you really do need that other O2 sensor...

Last edited by Camaroholic; Nov 27, 2006 at 09:30 PM.

Nov 28, 2006 | 07:41 AM

chree

Thread Starter

Staging Lane

Joined: Oct 2005

Posts: 86

Likes: 0

From: Atlanta, Georgia

Quote:

Originally Posted by Camaroholic

Well, from the looks of the Datamaster file, it looks like the idle rpm is set to 588 RPMs. Yeah, that'll do it.

The M6 needs to idle 750-800 RPMs minimum. Do you know if the PCM file was originally for an automatic?

Unfortunately I know nothing about the PCM programming or the harness. I called the original tuner but got an answering machine.

Quote:

Originally Posted by Camaroholic

Looks like you need new PCM firmware. Let me know if you need help with that, I can hook you up with an M6 file and all that.

Yes please! I'll do the reading if you can point me in the right direction.

Quote:

Originally Posted by Camaroholic

Oh, and you really do need that other O2 sensor...

I could probably add it, if I can get the plug out of the other collector... and I need to find out where it wires into the custom harness.

Thanks!

Nov 28, 2006 | 09:00 AM

Ed Wright

9-Second Club

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Joined: Feb 2002

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From: Tulsa, OK

Hate to hijack a thread, but Andrew, do you have USB OBD1 cables? I added a card to me new machine here to have a com port, but it doens't work worth a darn. I have to fire up my laptop to do an OBD1 LT1 PCM.

Thanks, Ed

http://www.fastchip.com/Ed-995.mpg

Nov 28, 2006 | 11:15 AM

Camaroholic

TECH Senior Member

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From: Waco, TX

Hi Ed, yes, I do, and I sent you a PM.

Sent you a PM too, Chris.

Dec 1, 2006 | 06:00 PM

chree

Thread Starter

Staging Lane

Joined: Oct 2005

Posts: 86

Likes: 0

From: Atlanta, Georgia

Now I have a serious problem, but I'm not sure if it is related to the surging. I had this happen intermittently before but now it seems permanent. The car feels like it is missing several cylinders (with corresponding serious loss of power). It happened yesterday on my commute home and then today on my commute to work. The first thing to do would be to check wires with my inductive timing light to see if I am getting sparks... but someone has borrowed my timing light...

Until I can do that test maybe there is something evident in my Datamaster logs?

Before (disregard the A/T transmission label):

http://chrislindh.googlepages.com/ch...olvo112906.uni

After:

http://chrislindh.googlepages.com/ch...olvo120206.uni

Any help / ideas appreciated. The DTC codes are still "MALF 11: MIL Lamp Fault" and "MALF 13: Left O2 Fail".

Thanks!