Turbo Dodge Forums banner
1 - 20 of 28 Posts

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #1 ·
... because I'm confused at this point. I thought it was the Baro-read solenoid, but I've replaced that and traced the wires and the code will not go away. I had a technician put it on a Chrysler scan tool and it said part throttle lock solenoid, but isn't that only for cars equipped with a lockup converter? Evidence would seem to point to it being a bad baro-read solenoid because intermittently I'm getting MAP sensor hiccups (4 different Mopar MAP sensors do the exact same thing, goes into limp mode and throws a 13 which lasts for a minute or 2 and then goes away). If the Baro-read isn't giving the MAP a pressure feed when it's supposed to it could cause this I suspect. The vacuum lines are all in excellent shape. The car pulls almost 20 vacuum. This 37 has been there since I bought the car over 4 years ago and I've since installed a different engine and used a different computer along the way. Any thoughts on what could be going on here?

Car is a 90 Daytona Shelby, 2.5 T1 auto (only modification is a factory intercooler with 1G BOV setup and a grainger valve, but it was having this problem long before any of those went in).
 

· Administrator
Joined
·
26,469 Posts
Here are all of the fault code descriptions for 1990 MPFI straight from the 1990 Chrysler Manual. (codes 65 and 67 are on the 3rd page which i did not scan)



 

· Registered
Joined
·
522 Posts
and if your car was ever converted to manual from an auto and no one changed the computer you will have a code 37, but will not effect the problem you are describing.

but if you have changed the baro and map and still get a 13 but then it goes away I would start replacing and checking your vaccum lines and routing
 

· Administrator
Joined
·
26,469 Posts
I understand what you are saying but those code descriptions came directly from a 1990 Chrysler, Fuel, Electrical, Emissions service manual in the T1/T4 section so......
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #7 ·
See, this is exactly my problem. NAJ's info from Chrysler matches the scanner and the technician's info. But then I've seen things like the MiniMopar fault code page that say Baro solenoid. It's my understanding that only cars with lockup converters would have a part-throttle unlock solenoid. And since my car doesn't have that, being a turbo car, I would lean towards it being a baro solenoid issue. I just don't know why.

Anyways, thanks for the info so far and the scans NAJ. I should probably get a set of 90 FSMs for all the weird things I've had happen with this car.

How often should the baro switch over and test atmospheric pressure while the car is running? I'm thinking this may be an electrical problem, but I have continuity on the wires so maybe the signal isn't getting sent to turn the solenoid on/off.
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #8 ·
Okay, make the totals 4 MAP sensors, 3 baro solenoids, and 4 times rebuilding the vacuum system with good lines. Everything is ziptied down and the vacuum block isn't leaking for sure. So I think I can safely rule out a vacuum problem at this point. It has to be electrical. The lines were showing good continuity to the computer last I checked. I'll check them again when I get another free moment. Anyone know how often the computer activates the baro solenoid? With the car running at idle it is not clicking at all. Obviously I can't listen to it going down the road, but it seems it should be polling the atmosphere at least a little bit whenever the car is running. Anyone have info on how the system works in reguards to the computer polling the MAP and Baro (as in how often and under what conditions)?

The weird MAP hiccups are happening more frequently now, so I'm approaching desperate on figuring it out.
 

· Administrator
Joined
·
26,469 Posts
The baro is only an on/off solenoid, the controller looks at baro info when you turn the key on and updates during no load cruising situations, how often I do not know.
If the car has a boost gauge use it for diagnostics, tee the line in between the baro and map and watch vacuum when your problem occurs.
If you can get a hold of a scanner you can actuate the baro to see if it is blocking and releasing vacuum when commanded to do so.
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #10 ·
I have the factory boost gauge in the dash. And I could run a second one to the MAP line to see if they're different when it happens. As far as a scanner, I might know someone with one. I'll ask. I do understand how these solenoids work and I knew it took a reading when you first turned the key to ignition, just not sure of when it cycles after that. I guess I need to get someone to turn the car on while I listen. It's obvious when it clicks on/off, but I have a stethescope with a needle on it for listening to car noises so it'll be plainly clear if it's activating or not. The solenoid works when given 12v power, I tested that much. Just not sure it's getting a signal when it's plugged into the harness.

After I got to thinking about it more, I'm not sure if the computer in the car is the original or not. I tried a second computer when I was having the electrical issues back at New Years, but I think the original is back in it now. If I trace the wires and everything else seems like it's functioning properly, I'll try the other computer again.
 

· Administrator
Joined
·
26,469 Posts
The baro solenoid will not be actuated when you turn the key on to start, when the key is moved passed the on position to start the baro info is supplied thru the Map sensor, when driving the baro will be actuated and vacuum to the map will be momentarily blocked to the Map and baro info will be updated then the baro will open, venting the blocked vacuum thru the open port and then normal Map readings will be resumed.
You can read baro info thru the scanner.If you can get a scanner you can read Map voltage while you are driving.
I can post the flow chart for the baro solenoid if you like.
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #12 ·
Yeah, if you don't mind. I'm going to try to get my hands on a scanner this weekend if at all possible. After I swapped solenoids and rebuilt the vacuum system, it did not do anything suspicious on the drive to my parents' house and back. But it acts up so randomly I have no way of knowing if I actually did anything to fix the problem. At this point, I'm not even sure the 37 is related to this issue at all. But based on the idea of 37 being a baro-read error code, I assumed it was related. Anyways, thanks for clearing up how and when the baro-read actuates.

You know, it figures; I finally stopped my overheating on the interstate (my lower air dam was missing) and this happens. Oh the joys of an older used car. It's annoying, but man do I love it when the car is running correctly. :thumb:
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #14 ·
Wow, thanks again NAJ! If you keep this up you'll have scanned and posted the entire FSM. :thumb:

I've done some of that already, but I'll go in order and make sure I'm not missing anything. I probably won't be able to run the tests until this weekend. I'll post what I find.
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #16 ·
Sorry, I forgot to post the results. Turns out I had a bad Baro-read solenoid afterall. It was apparently working sometimes and then it just died completely. That was what was causing my MAP code and the fuel problems. But I still have the code 37. The car is running beautiful aside from my gas mileage being a little low (average 21-22 with combined highway and city driving). So thanks again for the replies and to NAJ for all the scans. As long as everything else is working fine, I'm not going to worry about the 37 right now.
 

· Registered
90 Daytona Shelby, 96 Jeep XJ, '13 300C
Joined
·
5,968 Posts
Discussion Starter · #19 ·
I'd like to tell you I have a magical cure for your problem, but I don't. The code 37 persisted for years and then one day, after a battery reset, it stopped. I haven't seen it since.
 
1 - 20 of 28 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top