No start issue ... ECM?

[johnyk56]

Here is the issue on my well maintained 1995 Base Roadmaster with 102K, It all started last December when the car wouldn't start.

I knew she needed a few more parts changed and this was the opportunity I needed to get her ready for a summer of camper pulling road trips.
So I replaced the following parts:

New (in tank) Fuel Pump ... a lot easier to replace then I thought.
New Fuel Filter ... wish I would've had the fuel line removal tool ... $9.00 at Harbor Freight
New Fuel Pressure Regulator ... why did they have to mount it in the back of the engine ... GRRRRR
At that point I thought I was done ... and she started up just fine ... But the next morning she wouldn't start ... back to changing parts.

2 New Catalytic Convertors. I thought they had broken apart internally .... I kept hearing a rattling noise coming from the right one) Oddly enough ... and when I took out the 02 sensors she started right up ... didn't run well at all but at least she started ... in the process I broke 2 blots removing them ( serious Pain in the B---) so I changed all of the Exhaust Manifold Bolts. My (Bosch) O2 sensors only had 9K on them and they looked clean, so I put them back in the new Cats.
Well that didn't fix the issue either ... still no start

One of my friends and and fellow aircraft mechanic has a new Snap On diagnostic computer (a lot of $$$) we used it at each step of this no start issue, through out the entire process the (expensive) Snap On diagnostic tool gave us no more information then the on board diagnostic computer in the air conditioning controller ...
Good job General Motors ... you should have put one in my 2006 CTS-V.

Back to changing parts...

New Opti Spark from Napa Auto Parts ... since I was there I also Changed the Water Pump.
New Water Pump and all new engine block seals ... installed correctly.

I finally got all that done about 2 months ago, and she started and Ran just fine, the two times that I drove her... I then went out of town on business, till this week. So the car sat for 6 weeks. I drove the car 5 times this week and everything was fine ... Until yesterday ... she wouldn't start.

So now at a point where I'm lost ... the only thing I can think of is the ECM is bad. But I'm not sure ... I found a company on E-bay that will program one from a salvaged vehicle for $139.00.

Could it be the ECM ... and what is a chassis ECM? they run about $50.00 do they just control the Airbags?
Any ideas?

 

[buickwagon]

What is the "Security" light doing? Have you bypassed the PASS-Key system yet?

 

[Maine RM]

On an unrelated note what kinda aircraft you work on I used to do 135 out of North Dakota then I did Saab 340 it some Lear always interested to hear of a Peabody owner was also a jet mechanic.

 

[johnyk56]

No I have not by-passed the Security Pass Key system yet ... but I can definitely look into it.

 

[johnyk56]

😎 Unrelated: I work on commercial airliners now mostly on CRJ-700/900 aircraft ... I'm a system specialist for wide body aircraft (747's, MD-11's, A320's). In the past I've worked on Saab-340, I have a lot of respect for the Saab's ... they were outstanding commuter / regional airplanes that never broke down and operated in all sorts of severe weather. But the flying public is scared of propellers ... so all of the majors air carriers went to regional jets.

 

[Maine RM]

Ya I'm a jet troop. we worked a jet lease program mostly buying them wholesale in Africa transferring them back here stateside. rebuilding them in selling them

 

[Large Car]

Do you smell gas when it won't start?Tries to start sometime just won't runs like flooding?

 

[johnyk56]

Well its not the Security Pass Key, it's working just fine and I verified the fuel pressure after the fuel pressure regulator and its fine. What I don't know is, what the ECU controls or how to verify if it's functioning correctly? At this point I'm just going to order the ECM and see what happens. Worst case scenario it costs me $139.00 and I have an extra one.

 

[Large Car]

Mine was kinda doing same turned out temp sender at water pump was telling ecm it was -163 deg and was stopping it from starting

 

[torres7]

Did you take the ecm to the auto part store? They'll test it for free, that's how I found out mine was bad. Make sure they test it at least twice...