Early Mercruiser EFI (Chevy TPI style)

SS. bcp

Recruit
Joined
Jan 24, 2006
Messages
4
Hi all, this is my first post here. I have been lurking for quite some time, and finally signed up.<br /><br />My question is about these early Mercruiser tunnel ram looking EFI systems. They look somewhat similar to a Chevy TPI. I am not sure about the year ranges of these systems, but the one in question is from a 1989 boat with a 350. I could buy this system for my carbureted 5.7 1995 mirage for about $200 bucks, just not sure if these things are any good? All the while I have been lurking, I have heard nothing about these older systems. Can anyone just tell me some general stuff about them Compatable with my later 5.7? much increase in hp? reliability? <br /><br />Thanks for your help.
 

TilliamWe

Banned
Joined
Dec 21, 2004
Messages
6,579
Re: Early Mercruiser EFI (Chevy TPI style)

I will be interested in this answer, cause I didn't think <ercruiser ever used GM's TPI. Their TBI was what i thought they used with the first fuel injected marine engines. And my 1997 5.7EFI is TBI.<br />The one thing I know about 1987 to 1995 small block chevies is that on TBI engines, at least, the two intake manifold bolts closest to the throttle body, on either side were at a different angle than the rest. If you can look at your engine and the one with TPI, check that first to make sure they are the same. The rest, I can't advise you.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Early Mercruiser EFI (Chevy TPI style)

Is this the EFI system you are talking about?<br /><br />
19.gif
 

newport dave

Chief Petty Officer
Joined
Nov 21, 2004
Messages
458
Re: Early Mercruiser EFI (Chevy TPI style)

I have never worked on one of those guys (320EFI), but I have talked to a couple of guys that have and they say they are quite problematic (they actually use other, more colorful descriptions). I don't think you would ever get it to run right. Even if the system was 100% complete and working, it is tuned (programmed) for a specific cam, heads, exhaust, ect.<br /><br />Dave
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Early Mercruiser EFI (Chevy TPI style)

marine power used that setup for a bit as well. talk about funny issues. glad they quit and went back to TBI then MPI.
 

SS. bcp

Recruit
Joined
Jan 24, 2006
Messages
4
Re: Early Mercruiser EFI (Chevy TPI style)

Dangit. I thought i was going to be able to score a good EFI system for $200 bucks. <br /><br />What id the difference between marine EFI and car EFI? Chevy TPI injection systems are reliable, tuneable, and cheap. there are companies that can make custom harness to run TPI that eliminates all the unnecassary wiring. what issues would i face converting my 350 to TPI?
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: Early Mercruiser EFI (Chevy TPI style)

the marine units carry CG rateings for use in and enclosed engine area.<br /><br />holley sells a marine rated unit but its not cheep<br /><br /><br />tommays
 

TilliamWe

Banned
Joined
Dec 21, 2004
Messages
6,579
Re: Early Mercruiser EFI (Chevy TPI style)

The other huge weakness of marine EFI systems, all of them, is no O2 sensor in the exhaust. So, it's an incomplete system. And can't perform as well in a boat as they do in a car.
 
Top