Scan tool results
#1
Registered User
Thread Starter
Join Date: Jun 2006
Location: Saucier/Gulfport, MS
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Scan tool results
I finally managed to get a scan tool on my 99 454 mag mpi....A quick run-down of what it has been doing all summer long.....Runs great most of the time, but other times, it will just fall off RPM's, (engine won't die). Then will struggle to get over 2000 RPM's. If I let it sit for a few mins, it will run fine...Things done so far...All new sensors, fuel pump, regulator, I've went thru the pick-up tube & vent, & a complete tune-up....Now the results.
Nothing definete, but one thing that was odd, the timing was all over the place. It would go from -5 to +18, it does this constantly, & regardless of the RPM's. I checked for a loose timing chain, by watching the rotor button while barring the engine over, that seems fine. I'm leaning towards the ignition module (distributer mounted)....Does this seem to be a good direction, or...once again, am I way off base???
Nothing definete, but one thing that was odd, the timing was all over the place. It would go from -5 to +18, it does this constantly, & regardless of the RPM's. I checked for a loose timing chain, by watching the rotor button while barring the engine over, that seems fine. I'm leaning towards the ignition module (distributer mounted)....Does this seem to be a good direction, or...once again, am I way off base???
#3
Registered User
Thread Starter
Join Date: Jun 2006
Location: Saucier/Gulfport, MS
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
I can't tell you more than this, the logo on the top of the tool was "Quicksilver". I had a mechanic run the scan, & he seems to think that the module is a good direction to go. He ran a pretty detailed scan & found nothing out of the norm, except the timing being all over the place.
I know from my personal experience with street rods, even a radical cam'd engine...the timing will smooth out when the RPM's go up (that is watching a timing light). So, I did find it quite odd, that the timing would never smooth out.
I know from my personal experience with street rods, even a radical cam'd engine...the timing will smooth out when the RPM's go up (that is watching a timing light). So, I did find it quite odd, that the timing would never smooth out.
#8
Registered User
Thread Starter
Join Date: Jun 2006
Location: Saucier/Gulfport, MS
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
I did remove all the grounds & cleaned them real good. All were tight & I didn't find any corrision, but however, when I removed the module from the distributer, I noticed a white residue all over the mounting plate, & even under the module. I was able to wipe it off, just not sure if it was some sort of dielectric grease or corrision preventive. I do know that I should put the grease under the module, but should I also cover the entire mounting plate?
As for the knock sensor....It does have one, but the scan tool showed that there was no "signal" that was indicating a knock. So I would assume that the sensor is working correctly?
As for the knock sensor....It does have one, but the scan tool showed that there was no "signal" that was indicating a knock. So I would assume that the sensor is working correctly?
#9
Registered
Join Date: Sep 2001
Location: Houston, TX, USA
Posts: 2,287
Likes: 0
Received 0 Likes
on
0 Posts
The ecm is moving timing all over the place to keep the motor's rpm constant. Since it is quicker to change the timming than to have the IAC change.