Jump to content
Sign in to follow this  
sandroosten

LS1 MEFI 4B need help

Recommended Posts

last time i had a problem you guys answered the question and helped me so much.

now my friend is having a problem.

he can start the car and run it hard with no issues, then if he putts around for a second or lets it idle and then trys to get back after hit he acts like it is in limp mode and wont reve above 4k RPM. i can shut the car off then turn it back on and start the process over again.

ideas?

Share this post


Link to post
Share on other sites

How long does the car have to idle, or put around for before it does that?

Share this post


Link to post
Share on other sites
53 minutes ago, acefuture said:

How long does the car have to idle, or put around for before it does that?

a minute or two.

Share this post


Link to post
Share on other sites

Does the car have an scanner port? See if it kicks any codes

Share this post


Link to post
Share on other sites

Are you sure its a time related thing or is it Engine Temp related??  (a scanner port would be REALLY helpful).

 

Share this post


Link to post
Share on other sites
1 minute ago, Bobalos said:

Are you sure its a time related thing or is it Engine Temp related??  (a scanner port would be REALLY helpful).

 

the stupid thing does not have a scan port, but i did look at which wires it takes to check codes and I am going to jump them and do a ghetto one just to see if it is throwing a code.

Share this post


Link to post
Share on other sites

It should be against the law to make an EFI system w/o a way to hook something to it, to see what is going on with it.  LOL.

 

Share this post


Link to post
Share on other sites
6 minutes ago, Bobalos said:

It should be against the law to make an EFI system w/o a way to hook something to it, to see what is going on with it.  LOL.

 

i could not agree more!

Share this post


Link to post
Share on other sites

As Bobalos said, make sure it's not temp related. The MEFI should have a temp shutdown on it so if the motor sees to high of temperatures it'll go into limp mode. 

Share this post


Link to post
Share on other sites
1 hour ago, acefuture said:

As Bobalos said, make sure it's not temp related. The MEFI should have a temp shutdown on it so if the motor sees to high of temperatures it'll go into limp mode. 

unless my temp gauge is messed up its not a temp problem.

it cruises around at 180-190 and maxes out around 210. If im not mistaken the mefi goes into limp mode around 235 degrees

Share this post


Link to post
Share on other sites

I would guess the temp gauge is a different sending unit from the temp sensor that goes to the ECM.  but........... if you cant see inside the ECM, then how would you know????   I guess just swap out the sensor & see if that fixes it, but thats shotgunning @ its finest............ 

 

Share this post


Link to post
Share on other sites
12 hours ago, sandroosten said:

unless my temp gauge is messed up its not a temp problem.

it cruises around at 180-190 and maxes out around 210. If im not mistaken the mefi goes into limp mode around 235 degrees

Your temp sender for the PCM could be faulty, and showing the PCM that the temp is high, even though it is not.

Share this post


Link to post
Share on other sites
1 hour ago, 2DASAND said:

Your temp sender for the PCM could be faulty, and showing the PCM that the temp is high, even though it is not.

This.  Your gauge uses a different sender then the PCM.  Should be a standard chevy sensor.  Ohm it out and check the chart to see if its reading correctly.

Share this post


Link to post
Share on other sites

Mine was doing this too. It was the intake temp sensor. It was thinking the intake air temp was too high and sending it into limp. Turns out the p.o. put the sensor in the wrong place and it would get heat soaked. Moved it, and problem solved.

Share this post


Link to post
Share on other sites
8 minutes ago, r3meyer said:

This.  Your gauge uses a different sender then the PCM.  Should be a standard chevy sensor.  Ohm it out and check the chart to see if its reading correctly.

awesome we will give this a shot, thank you for the input.

Share this post


Link to post
Share on other sites
2 minutes ago, The looney duner said:

Mine was doing this too. It was the intake temp sensor. It was thinking the intake air temp was too high and sending it into limp. Turns out the p.o. put the sensor in the wrong place and it would get heat soaked. Moved it, and problem solved.

this actually makes a lot of sense, we just put a different intake on it before the problem started.

Share this post


Link to post
Share on other sites

was talking to lance Dunehoon and he was also saying that they like to see the airintake sensor in the manifold for turbos but for natural they want to see it in the Airfilter intake tube before the throttle body,

Share this post


Link to post
Share on other sites
1 hour ago, sandroosten said:

this actually makes a lot of sense, we just put a different intake on it before the problem started.

My intake sensor is actually connected to a little mount next to the air filter outside of the intake. I double checked with CBM to make sure it was satisfactory and they said yes no problem because in theory it'll be the same air temperature as it would be just past the filter into the throttle body. So if you want to do a cheap and easy test, take the intake temp sensor and zip tie it somewhere in the area of the filter and go run it. If that solves the problem you can work on a mounting system or figure out where to move it on the intake 

Share this post


Link to post
Share on other sites
2 hours ago, acefuture said:

My intake sensor is actually connected to a little mount next to the air filter outside of the intake. I double checked with CBM to make sure it was satisfactory and they said yes no problem because in theory it'll be the same air temperature as it would be just past the filter into the throttle body. So if you want to do a cheap and easy test, take the intake temp sensor and zip tie it somewhere in the area of the filter and go run it. If that solves the problem you can work on a mounting system or figure out where to move it on the intake 

Kinda similar to how mine was, it was zip tied to the fuel rail, then it ended up between the fuel rail and intake, obviously it gets too hot there. I machined the sensor base, turned the threaded section down, turned it into a barb, and put in the intake boot just before the throttle body. 

15729897806642836525684240078025.jpg

Share this post


Link to post
Share on other sites
3 minutes ago, The looney duner said:

Kinda similar to how mine was, it was zip tied to the fuel rail, then it ended up between the fuel rail and intake, obviously it gets too hot there. I machined the sensor base, turned the threaded section down, turned it into a barb, and put in the intake boot just before the throttle body. 

15729897806642836525684240078025.jpg

Yep exactly. Except my filter mounts straight to the throttle body so I didn't have the room to do this so I machined a mount that bolts to the side of the throttle body and the sensor goes on that. Hope this helps the OP solve his issue

Share this post


Link to post
Share on other sites
4 hours ago, acefuture said:

Yep exactly. Except my filter mounts straight to the throttle body so I didn't have the room to do this so I machined a mount that bolts to the side of the throttle body and the sensor goes on that. Hope this helps the OP solve his issue

thanks for all the help.

hoping to get this thing out before the weekend to test, Ill keep y'all updated.

Share this post


Link to post
Share on other sites

kind of makes sense, it has a ProComp Aluminum Intake and the old intake was the plastic one

Share this post


Link to post
Share on other sites
15 hours ago, sandroosten said:

thanks for all the help.

hoping to get this thing out before the weekend to test, Ill keep y'all updated.

Hope it helps you get it figured out. It does make sense, having the air blow over the top of the intake helps keep it a bit cooler, but sitting and idling could cause the iat to see more heatsoak and put it into limp. If you're out in the dunes this weekend my car will be at the ceremony and you can see how I mounted mine. A cheap and easy fix

Share this post


Link to post
Share on other sites

I just got done babbling this same exact issue..... Took me two trips.

Share this post


Link to post
Share on other sites

Call me if you want 714 321 0748

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Preview Post
Sign in to follow this  

More Links

©2001 GlamisDunes.com.
All rights reserved.

×
×
  • Create New...