Timing on 97 Merc TBI 5.7L

[Insanegtp]

Re: Timing on 97 Merc TBI 5.7L

I really am super thankful for your replies.... I have not been able to determine what type of ignition system I have, I know it isn't Thunderbolt V... looks a little different than what I have read in the manuals.... this is what I got and maybe yall can assist me in figuring this out... Engine Model is MCM 5.7L EFI (but it does have an electronic throttle body) looks just like a 97-98 GMC Suburban setup with 5.7... the engine serial # is 0K007496

 

[John_S]

Re: Timing on 97 Merc TBI 5.7L

I really am super thankful for your replies.... I have not been able to determine what type of ignition system I have, I know it isn't Thunderbolt V... looks a little different than what I have read in the manuals.... this is what I got and maybe yall can assist me in figuring this out... Engine Model is MCM 5.7L EFI (but it does have an electronic throttle body) looks just like a 97-98 GMC Suburban setup with 5.7... the engine serial # is 0K007496

Maybe post a picture or two and highlight why you don't think it matches the book.

 

[Insanegtp]

Re: Timing on 97 Merc TBI 5.7L

*sigh* so... the model # and serial # don't help us ??

 

[John_S]

Re: Timing on 97 Merc TBI 5.7L

*sigh* so... the model # and serial # don't help us ??

I don't have access to a Mercuiser DB. Don or others might, but pictures will still be of value. You never know what else has been changed on a motor since it was made.

 

[Don S]

Re: Timing on 97 Merc TBI 5.7L

Your engine HAD a Delco EST, as I said before, the MSD 8366 distributor is a clone of the Delco EST distributor. So it should be the same thing, you work at MSD, check it out.

Go to the link below and downloade the OEM service manual and start reading section 5E. At least understand the first 21 pages. Then you have a fighting chance by at least understanding how it all works together.
http://www.4shared.com/file/119348856/b60b0d57/Mercruiser_Service_Manual_17.html

 

[Insanegtp]

Re: Timing on 97 Merc TBI 5.7L

I know the dist isnt the problem... and I have the manual... I do beleive after looking at it last night that I have the Thunderbolt V, I found the knock module, but cannot for the life of me find the ignition module, nor can I find ANY purple white test lead... I did splice into purple white off back of dist and send to ground.. started, idled to 1200 rpm, set timing, even worse now... I am gonna keep reading more, but figured I would at least update.....

 

[180shabah]

Re: Timing on 97 Merc TBI 5.7L

idled to 1200 rpm

It's only 500-600rpm too high....

 

[Insanegtp]

Re: Timing on 97 Merc TBI 5.7L

shhhh.... only post if u can help.... per manual you need to idle up to around 1200 rpm to get accurate readings...

 

[Bondo]

Re: Timing on 97 Merc TBI 5.7L

I did splice into purple white off back of dist and send to ground.. started, idled to 1200 rpm, set timing, even worse now...
shhhh.... only post if u can help.... per manual you need to idle up to around 1200 rpm to get accurate readings...

Ayuh,... The Purple wires are the Igntion circuit,... Grounding it Should Kill Everything....
Mercruisers are timed at Idle,... Not 1200rpms...
Just What manual are you readin',..??

After readin' through this thread,... Your answers to what is What, keep changin'....
At this point it Sounds like you have a Cobbed Up pile of Poo....
Is it T-bolt IV, or T-bolt V, or something Aftermarket, or Allota All of 'em,..??

 

[Don S]

Re: Timing on 97 Merc TBI 5.7L

I know the dist isnt the problem... and I have the manual... I do beleive after looking at it last night that I have the Thunderbolt V,

You did NOT have the Thunderbolt V ignition origianlly, it was not used with the EFI engines. Had you read the first 21 pages of the manual like I suggested, you would know that.
Look at page 5E-18. Then on 5E-19 it shows the ignition module and how it works. That is the module inside the EST distributor.

Yes, the EFI engines idle at 1200 in service mode to set the EST into base timing and stabilize the idle. It needs to be that high to stabilize the idle.

 

[Bondo]

Re: Timing on 97 Merc TBI 5.7L

Yes, the EFI engines idle at 1200 in service mode to set the EST into base timing and stabilize the idle. It needs to be that high to stabilize the idle.

Ayuh,... open mouth, insert foot,.... Danm 'puter motors....

 

[180shabah]

Re: Timing on 97 Merc TBI 5.7L

Sheeshh, Bondo - if you don't know absolutely every single thing about every single motor - you are of no use to the OP....

I'll be looking elsewhere for friends also......

 

[Bondo]

Re: Timing on 97 Merc TBI 5.7L

Sheeshh, Bondo - if you don't know absolutely every single thing about every single motor - you are of no us to the OP....

I'll be looking elsewhere for friends also......

(this is the sealoc book, not the Merc, but WAS told it was the same..)

Ayuh,... Arguein' with Seloc I guess...

 

[Insanegtp]

Re: Timing on 97 Merc TBI 5.7L

I keeping the sealoc, for just outdrive info, sucks for wiring... the manual I was reading was the one you guys were nice enough to give me a link to, thanks for backing me on the 1200 rpm deal..... I did read that in the Merc manual... the purple/white that I grounded according to wiring diagram is connected between knock module and ignition modul to set base time, it didn't fry everything, problem was my timing light (snap on b/s) was pre set to 8 BTDC to when I was timing to 8 degress it was actually 16... not good.. went back last night re-did it all (which now isn't very hard at all) and she runs amazing... grabbed 10 people off the dock, said lets go for a ride, she was on plane within 40-50 ft....

All of this back and forth I beleive could have been alot less if A.) I was smarter, which why I am here to learn...

B.) People read the whole thread and not make dumb comments / suggestions just to get their post #'s up....

I'm not trying to start anything and I am super thankful to the people that did assist, but the whole start to this says its a Merc 5.7L TBI (Throttle Body Injection) so we new it wasn't carbed... and all I said about not knowing what ignition system it was, was the fact it didn't look like what was in manual... ( I have a side cover where the computers and modules go...) no one I know has ever seen it like this, but I like it... keeps compartment clean...

And I did read the manual, the whole manual.... not just certain pages... the whole thing.... a few times... great bathroom material...