Hi i have GM RamJet 350 crate engine with the MEFI4 controller and it has about 10k miles on it and gets about 6 gallons a mile.. my problem is it stalls when put into gear when cold unless i give it gas. it idles at 900-1000 rpms. i have gone to arizona speed and marine and got a new computer and still does the same thing... ive taken it to our local gm dealer and couldnt find the problem... right now im looking more into the IAC sensor. i just order one and should get it tomorrow... ive read alot of RamJet owners have the same problem with stalling.. im not getting any codes. and the sprak plugs look good. i want somes opion what it could be.. i need help fast. thanks
Joseph

 

I only have 20 miles on mine yet. Low mpg, high idle, hard to start cold.. check the CTS. In the green service manual there is a chart for the resistance to temp readings. It is possible for the CTS to read low temp and not throw a code.

http://www.sallee-chevrolet.com/Disc...tml?1187655512
Good info on the RJ, they know it pretty well.

 

Can you change the tuning in the ecm? Try running more initial timing to help with the stalling and bad mpg if you can't change the tuning in the ecm.

Sounds like it isn't rich enough when cold also?

 

The engines starts right up when cold.. the only problem is when its not warmed up. It stalls in gear but when its warm theres no problems when shifting into gear.. even when its cold the engine runs strong... the best way to describe is when i put into gear the engine doesnt get any air through the throttle body and shuts off... theres times it hestitates but wont but wont stall... we already replaced the iac and tps.. and same results... i check the timing and got 20* atdc. that seems to much for me but idles and runs good... manual calls for 10* btdc. im not sure if thats the cause of the stalling when cold... i wish these efi would be easy to retune... just the software and cable cost about $1800.. Thanks
JJ

 

Put it on a 122730...........

 

i can put it on a 730 ecm but i would have to get the ecm and wire harness.. it would be more work.. ill have to check acouple things before i think about going this route. thanks Jj

 

S10Wildside sells a 730 harness (www.eficonnection.com) that works great and also the 0411 computer changeover in the TPI forum stickies is what I'm using in my Ramjet project. I am using 4L60E trans, and he built the harness for the OBDII setup. The Ramjet setup is a L31 Vortec truck motor with a marine injection setup from Mercruiser, and built by Eldebrock from what I know. The L31 timing cover, reluctor, and dist worked fine on the Ramjet engine with a little tweeking on the fuel rails, but the 730 setup would be easier.
Ron

 

Have you tried bottoming out the IAC and setting the base idle speed within 50 RPM of the target idle speed? This will lessen its control on minimum idle speed, but give it greater range of motion to increase air flow when/if needed.

 

by bottoming out the iac do you mean taking it out and pressing in the pintle? can you give me instruction on how to bottom out the iac? remeber it only does this when its cold..

ive seen lots of people use the 730 ecm. its easier to tune..

on the mefi4 controller everything runs good... besides getting really bad gas mileage. about 8 mpg.. yeah.. but i think the issue is something rather easy..
Jj

 

Does your mefi4 manual tell you how to set the base idle (spark advance disabled and IAC bottomed out (plunger fully extended - air port closed)). It is real easy to do this with the 730 and I assume there is a way to do it with the mefi4.

The reason to try this is that it should give you more range of motion with the IAC to increase airflow as needed (like in a cold start/putting engine into drive).

At idle (750 rpm/manual trans) my IAC is roughly 10 counts out.

 

ive read the ramjet manual and the only thing it says about installing the iac is that it should prest manufacture. and it give instruction on how to let the computer adjust it by starting the engine run it at about 2k rpm for 1o seconds, turning te egnition of for 5 sec and turing back the ignition on..the thing is i cant check how many counts its open at idle without the tuning software... im trying to find the mefi4 difintion files to use with scannerpro...
Jj