Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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mowog1
Rick Ingram
Central Illinois
(1523 posts)

Registered:
10/17/2007 09:36PM

Main British Car:
1974.5 MGB/GT 3.9l Rover

authors avatar
Tim Ringland needs your help in getting he and his car to Indy!
Posted by: mowog1
Date: June 29, 2015 04:18PM

E-Mail received today from Tim Ringland.....help....GO!
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

I need help! I want to drive it to Indy.


1980 MGB - conversion done in the fall of 2011 - ran perfectly all of 2012 and 2013. Now i have an intermitant problem. Starts runs, dies, starts right up. Sometimes runs great for a day or so, sometimes can't get it out of the driveway. Recently did an 1100 mile weekend and was great for 700 of those miles. The 400 miles tow home on a 10 ft. strap went smoothly though. Not wanting to do that again.
Engine is a 2006 LX9 from a 2006 Malibu - OBD1 1227730 ECM. I have chased this problem all of 2014 and now. All sensors have been replaced, fuel pump three times, fuel filter, rubber fuel lines, ignition switch, grounds everywhere, ECM twice with a newly programmed chip, ICM, new plugs, new wires, fuel tank has been pumped out twice and new fuel put in, CPS, CPS to ICM wire, redid all grounds and mounting for ECM and ICM - all good, coils switched out too.
The attachment is a datalog on the TunerPro software with it idling in my garage. The car didn't want to go anywhere that day. I can can do more datalogging with it on the street before it dies if that might help finding something.
Thanks,
Tim Ringland


74ls1tr6
Calvin Grannis
Elk Grove,CA
(1151 posts)

Registered:
11/10/2007 10:05AM

Main British Car:
74 TR6 / 71 MGB GT TR6/Ls1 71 MGB GT/Ls1

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Re: Tim Ringland needs your help in getting he and his car to Indy!
Posted by: 74ls1tr6
Date: June 29, 2015 11:14PM

Tim,

Have you checked your wiring at your cam sensor plug and your crank sensor plug. Make sure the contact is good and the wire is not frayed or broke or some of the strands in the sheath. I had this problem where it started great, then would shut off like you said, sometimes it wouldn't start at all. I replaced the plug ends and installed new lengths of wire to the plug, then replaced both cam and crank sensor.I haven't had a problem after doing the wiring. The wiring gets brittle by the block from heat after some years go by. You should be able to test the wiring to see if the right voltage is getting to each plug end.

Calvin

Good luck!


mowog1
Rick Ingram
Central Illinois
(1523 posts)

Registered:
10/17/2007 09:36PM

Main British Car:
1974.5 MGB/GT 3.9l Rover

authors avatar
Re: Tim Ringland needs your help in getting he and his car to Indy!
Posted by: mowog1
Date: June 30, 2015 09:38AM

Thanks, Calvin! See you in Indy!


mowog1
Rick Ingram
Central Illinois
(1523 posts)

Registered:
10/17/2007 09:36PM

Main British Car:
1974.5 MGB/GT 3.9l Rover

authors avatar
Re: Tim Ringland needs your help in getting he and his car to Indy!
Posted by: mowog1
Date: June 30, 2015 06:03PM

From Tim:
+++++++++++++++++++++++++++++
Thanks for your reply Calvin.
OBD 1 has no cam sensor. I have recently replace the crank sensor and the CPS to ICM wire with new plug ends.

I had it scanned yesterday and there were no codes. Today I put in a new TPS (throttle position sensor) and IAC (idle air control) with no change.

Thanks,
Tim


MGBV8
Carl Floyd
Kingsport, TN
(4511 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Tim Ringland needs your help in getting he and his car to Indy!
Posted by: MGBV8
Date: June 30, 2015 09:11PM

Told my girl I had to forget her, rather buy a new carburetor! I'm in love with my car!





Edited 1 time(s). Last edit at 06/30/2015 09:13PM by MGBV8.


MG four six eight
Bill Jacobson
Wa state
(324 posts)

Registered:
10/23/2007 02:15AM

Main British Car:
73 MGB Buick 215, Eaton/GM supercharger

Re: Tim Ringland needs your help in getting he and his car to Indy!
Posted by: MG four six eight
Date: June 30, 2015 10:44PM

Rick,

Are you using a simple code reader or an actual scan tool that you can view data with? Does the concern happen with the engine hot or cold?

Also did he make any repairs or changes to the car prior to when it started acting up?

For example any wiring changes such as relocating any wires or ground locations. Those old OBD 1 ECM's could cause problems if the multiple grounds are located to one stud/bolt due to RF noise.

Ideally you'll want to be able to read data so that you view RPM, coolant temp, Map sensor, etc. while the concern is actually happening. Sometimes a particular bit of data can be skewed enough to cause a poor run condition, but not far enough off to set a code. Especially with OBD 1 systems.

Also don't overlook a potential ignition module or coil problem. Usually I like to use an OTC ST-125 spark tester (they have them at Amazon for around $15) to check for a good spark. You'll want to check spark while the car is currently experiencing the problem and there should be a strong spark at the ST-125 on all 6 plug wires.

Bill


mowog1
Rick Ingram
Central Illinois
(1523 posts)

Registered:
10/17/2007 09:36PM

Main British Car:
1974.5 MGB/GT 3.9l Rover

authors avatar
Re: Tim Ringland needs your help in getting he and his car to Indy!
Posted by: mowog1
Date: July 02, 2015 09:49PM

Thanks Bill....I sent this on to Tim.



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