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Username Post: Smelly Ramjet 350        (Topic#124607)
cpoul 
Member
Posts: 8

Reg: 02-19-06
02-19-06 06:01 PM - Post#878658    

I was looking for info regarding my 350 when I came across your great web site. I just purchased a vehicle with a Ramjet 350...the exhaust smells really bad and there is black deposits in the tail pipe...I just purchased the car and am trying to figure out if the engine has a major problem or just needs an adjustment. If anyone could shed some light I'd be very gtateful. thank you.



 




monty56 
"14th Year" Gold Supporting Member
Posts: 1376
monty56
Loc: Chandler(it's a dry heat)...
Reg: 04-26-04
Re: Smelly Ramjet 350
02-19-06 06:18 PM - Post#878659    
    In response to cpoul

Is it a Ramjet III or IV? (IV has O2 sensor)

Monty
'56 3100 Short Stepside Someday
2001 Chevy Suburban 2500
2009 Saturn Vue w/20's

Member: Desert Classic Chevy's Inc.
Monty's 56 Truck
Avatar is my Truck


 
cpoul 
Member
Posts: 8

Reg: 02-19-06
Re: Smelly Ramjet 350
02-19-06 06:45 PM - Post#878660    
    In response to cpoul

I don't know...is there a simply way of identifying...I do have a picture of the engine.



 
monty56 
"14th Year" Gold Supporting Member
Posts: 1376
monty56
Loc: Chandler(it's a dry heat)...
Reg: 04-26-04
Re: Smelly Ramjet 350
02-19-06 07:24 PM - Post#878661    
    In response to cpoul

In one of the exhaust pipes probably close to the end of the headers or manifold is a fitting (bung) with a sensor wired back to the MEFI unit. If it is a three you probably need to get a MEFI IV kit, and if it is a 4 w/ sensor then a new O2 is a good start. The numbers are on the bottom of the ECM also. Did you get the "service tool" such as it is? w/ your ramjet?

Monty
'56 3100 Short Stepside Someday
2001 Chevy Suburban 2500
2009 Saturn Vue w/20's

Member: Desert Classic Chevy's Inc.
Monty's 56 Truck
Avatar is my Truck


 
cbernhardt 
Senior Member
Posts: 558
cbernhardt
Loc: Lexington,NC
Reg: 08-28-00
Re: Smelly Ramjet 350
02-20-06 01:46 AM - Post#878662    
    In response to cpoul

I have one of the original (No O2 sensor, MEFI3) Ram Jets in my wife's 62 Corvette. It runs great but very rich. Since the Ram Jet computer is not user programmable, I installed a wide band O2 sensor and an adjustable fuel pressure regulator in an effort to lean it out. I was able to reduce the fuel pressure to around 36psi and still feel safe with the A/F ratio. However it still runs slightly rich in the 1500-2000 rpm range which is where I cruise on the highway. All of the Ram Jet owners that I have talked to tell me that their cars run rich, so you are not alone. I ordered an MEFI4 upgrade kit for the engine but have not received it yet.

There is a good forum on the Ram Jets on the Sallee Chevrolet site. http://www.sallee-chevrolet.com/Discus/Scripts/discus.cgi

Charles



 
monty56 
"14th Year" Gold Supporting Member
Posts: 1376
monty56
Loc: Chandler(it's a dry heat)...
Reg: 04-26-04
Re: Smelly Ramjet 350
02-20-06 06:47 AM - Post#878663    
    In response to cpoul

The part#'s are: MEFI III to IV conversion = 12499116, Manual = 12486611 , service tool = 12489400 & RamJet 350 Spec = 12368942 . You must have the basic service tool just to set "base" timing which is 10 deg. The MEFI IV was $590 at my local Chevy dealer, Service tool $84 at Scoggins Dickey.

Monty
'56 3100 Short Stepside Someday
2001 Chevy Suburban 2500
2009 Saturn Vue w/20's

Member: Desert Classic Chevy's Inc.
Monty's 56 Truck
Avatar is my Truck


 
cpoul 
Member
Posts: 8

Reg: 02-19-06
Re: Smelly Ramjet 350
02-20-06 07:36 AM - Post#878664    
    In response to monty56

Monty & Charles Thank a lot for the info. I ordered a manual and meter from Sallee.
Monty-I don't have anything in the exaust pipe so I guess it's a III. Thanks fo all of the part #'s...Do you have the conversion installed? If so results?
Charles- Will you post after you install, I 'd like to know how you made out.
Again, many thanks guys.



 
monty56 
"14th Year" Gold Supporting Member
Posts: 1376
monty56
Loc: Chandler(it's a dry heat)...
Reg: 04-26-04
Re: Smelly Ramjet 350
02-20-06 08:46 AM - Post#878665    
    In response to cpoul

Mine hasn't run yet, I put my RamJet together from pieces on top of a Vortec 330HP, but haven't fired it yet. I talked to a couple owners that Chevy parts guy knew had put RamJets in and they were satisfied with the install. That is where I got the RamJet specification pamphlet part number.

Monty
'56 3100 Short Stepside Someday
2001 Chevy Suburban 2500
2009 Saturn Vue w/20's

Member: Desert Classic Chevy's Inc.
Monty's 56 Truck
Avatar is my Truck


 
silvernblack 
Member
Posts: 108

Reg: 05-04-03
Smelly Ramjet 350
02-20-06 03:01 PM - Post#878666    
    In response to monty56

I also had a rich running RamJet 350. I ended up rewiring it and running it with a GM 1227730 ECM. I added the O2 sensor, Air Temp intake sensor, and VSS. I also bought a computer programming unit and ended up burning my own chips using "Tunerpro". I bought all but the programming interface stuff & chips at a junkyard.
Before all that I had bought an adjustable fuel pressure regulator but that didn't really cut down on the smell.



 
silvernblack 
Member
Posts: 108

Reg: 05-04-03
correction...Smelly Ramjet 350
02-20-06 03:03 PM - Post#878667    
    In response to silvernblack

I meant to say that I bought all BUT the programming interface stuff at the junkyard. All the wiring connections on the 90-92 V-8 TPI Camaro (and others GMs gather) are the same as those that existed on the ramjet 350. Even the wiring diagrams are similar.

Julian



 
cpoul 
Member
Posts: 8

Reg: 02-19-06
Smelly Ramjet 350
02-25-06 07:40 AM - Post#878668    
    In response to silvernblack

Ramjet 350 without O2 sensor.
Timing is 14.6 degrees BTDC @ 690 rmp

Have not received manual or service tool yet. At what rpm should timing be 10 degrees?
Can I adjust timing without service tool?

where timing is now...would this contribute to running rich?

I changed oil and filter...oil didn't smell right.

Many thanks



 
cbernhardt 
Senior Member
Posts: 558
cbernhardt
Loc: Lexington,NC
Reg: 08-28-00
Re: Smelly Ramjet 350
02-25-06 11:24 AM - Post#878669    
    In response to cpoul

Quote from Ram Jet installation manual: "In order to change base timing on the system, the ECM has to be entered into the "service mode" using the diagnostic trouble code (DTC) tool, GM Part Number 12489400."

Base timing is set to 10 at 700RPM (computer controlled)
Charles



 
cpoul 
Member
Posts: 8

Reg: 02-19-06
06-06-17 01:24 PM - Post#2694768    
    In response to cbernhardt

I'm idling around 700. In service mode (on) the idle increases substantially. At the higher idle in service mode i'm around 14 degrees. Shouldn't the idle be 700 in service mode?



 
acardon 
Ultra Senior Member
Posts: 10876
acardon
Loc: DFW TEXAS
Reg: 03-25-05
06-06-17 01:41 PM - Post#2694771    
    In response to cpoul

14 degrees is the reason for the fast idle. Change it to 10 degrees and see what happens.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
monty56 
"14th Year" Gold Supporting Member
Posts: 1376
monty56
Loc: Chandler(it's a dry heat)...
Reg: 04-26-04
06-07-17 08:58 AM - Post#2694915    
    In response to cpoul

Service mode removes any advance from the distributor so "base" timing may be set. set the timing at 10 deg. then switch to normal on service mode sw. Then you will be running with programmed advance, fuel, etc. Oh, I have mine running now and yes it is rich, but not enough to "blacken" the pipes. I plan to take mine to a shop that has the software to rewrite the MEFI and they have a chassis dyno to set it up properly.

Monty
'56 3100 Short Stepside Someday
2001 Chevy Suburban 2500
2009 Saturn Vue w/20's

Member: Desert Classic Chevy's Inc.
Monty's 56 Truck
Avatar is my Truck


Edited by monty56 on 06-07-17 09:04 AM. Reason for edit: No reason given.

 
cbernhardt 
Senior Member
Posts: 558
cbernhardt
Loc: Lexington,NC
Reg: 08-28-00
06-10-17 03:21 AM - Post#2695311    
    In response to monty56

My experience with the RamJet 350 is that the MEFI3 ran really rich (avg 25 mpg highway). With the MEFI4a upgrade, which includes an O2 sensor and IAT sensor, the engine runs a little leaner, but still too rich (avg 27 mpg highway). I purchased tuning software and now I am satisfied with the mileage (avg 30 mpg highway). I have the OBD Diagnostics MEFIBurn software and an Innovate LM1 air/fuel meter rigged so that I can data log the AFR with the software. Here is a link if you are interested.
http://www.carols62.com/ramjet/wideband.html
Charles



 
cpoul 
Member
Posts: 8

Reg: 02-19-06
06-11-17 04:07 PM - Post#2695528    
    In response to cbernhardt

Thanks for the responses. I'll try adjusting timing tomorrow to see what I get. Charles I saw the software but I don't think I'd be able to use it I think it would be to technical for me.

I'm also considering going MEFI4 and selling the MEFI3 or to send my MEFI3 to the same place that sells the software for a best guess calibration which will run about $270 with shipping.

My car is so bad that cars behind me keep their distance.



 
cpoul 
Member
Posts: 8

Reg: 02-19-06
06-12-17 06:54 AM - Post#2695639    
    In response to cpoul

I set timing to 10 degrees in service mode. The rpm's are about 990-1010
Out of service mode about 300 rpm less. 680-700

No change in exhaust. Car always runs great has nice gittyup.

I'm wondering if something else is going on with it or if the MEFI3 was messed with before I had it.





 
cpoul 
Member
Posts: 8

Reg: 02-19-06
06-12-17 07:25 AM - Post#2695646    
    In response to cpoul

My fuel pressure is 37 at idle, 45 with vacuum disconnected. Pressure fall to 0 immediately when turned off.



 
acardon 
Ultra Senior Member
Posts: 10876
acardon
Loc: DFW TEXAS
Reg: 03-25-05
06-13-17 06:20 AM - Post#2695778    
    In response to cpoul

  • Quote:
My fuel pressure is 37 at idle, 45 with vacuum disconnected. Pressure fall to 0 immediately when turned off.




You could have some leaking injectors.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 




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