4.3 MPI Possible ECM issues

rustybronco

Petty Officer 2nd Class
Joined
Oct 24, 2021
Messages
134
ECT has a temperature Vs resistance chart. MAT is a thermister. MAP outputs a voltage. IAC should be the same. TPS is for sure.

One should be able to test/measure most of the sensors on it with a DVOM and a way to measure frequency.

"I am leaning towards a fualty ECM but that's just a hunch. Also suspicious on the raw water pressure switch mounted on the power steering cooler. Would love to test but don't know the resistance values across the 3 pins."

Buy a generic sensor and substitute?

 
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QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Hi, my thought around this are that around asking if you might have a mix of components here after an engine transplant. I ask this only because I have it in my head that there might not have been such a thing as an mpi 4.3 in 2001 ? I may be wrong...I am aware there were some early v8 mpi from late 90's...but not sure I know of a 4.3 mpi being about until late 2002 and more commonly from 2003 onwards. There was an efi though. Strange that you have one from that year. the ecu sure sounds like an mpi unit. Is there any history or chance that there are some parts in there that aren't talking to each other, perhaps as a result of being for a different engine ?
 

QBhoy

Fleet Admiral
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Mar 10, 2016
Messages
8,348
also wondering about the mention of the fuel pump staying on. does it cut off a few secs after the beep when turning ignition on (but not starting) ? There are two fuel pumps on these, as you'll know too.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
If @Whitey_83 you are still looking for help...

I have a 2006 4.3MPI, same ECM as you have. I'm home now so can do some checks.

1. Fuel pump starts up immediately you turn the key, and runs for about 5 seconds, then stops.

Chris......
 

Whitey_83

Cadet
Joined
Feb 4, 2022
Messages
9
Hi Guys, just wanted to close out this thread. I had my ECM repaired which bought it back to life. The ECM had a fried clock chip as first thought. Thanks for your assistance anyway. Cheers Chris
 

Whitey_83

Cadet
Joined
Feb 4, 2022
Messages
9
If @Whitey_83 you are still looking for help...

I have a 2006 4.3MPI, same ECM as you have. I'm home now so can do some checks.

1. Fuel pump starts up immediately you turn the key, and runs for about 5 seconds, then stops.

Chris......
Thankyou Chris. All sorted now thankfully!
 
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