Announcement

Collapse
No announcement yet.

Diagnostic help needed. What is going on here?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Diagnostic help needed. What is going on here?

    I am having a weird m20 issue I can't seem to figure out and was hoping you guys could help me out. When I bought my 89is it ran great and the A/C blew cold. Driving it home for the first time with the A/C cranking I noticed that at about half a tank of gas it started to miss on the highway, like it wasn't getting fuel for a second but then it would kick back in and be fine for a few more minutes. As the tank emptied the misses started to get more frequent.

    The PO said he didn't drive it much so I pulled over to get fresh gas thinking it was just old gas. Problem went away and I drive it below half a tank with no issues but I wasn't using the A/C. Cruising down the highway with 1/3 of a tank and I decide to kick on the A/C and the car immediately starts missing again on the highway and almost stalls getting off the offramp. I turn the A/C off thinking that's what did it but the missing continues to the point where the car flat out stalled and threw on the CEL. I get it going again and figure out if I just feather the throttle it wont miss and I can get to a parking lot.

    So I park it, go in and have a drink for a for about an hour to consider my options and try and figure out what just happened. Start the car again and its perfectly fine, drives home fine, drives to the gas station fine, fill it up and its fine. BUT then I realize the A/C now doesn't work. I can push the button in and it squeals a bit but the A/C doesn't engage, it doesn't blow cold and you cant feel the engine being pulled down by the compressor engaging.

    Stomp test shows 1221 but I dont see an 02 doing this. I was thinking maybe a compressor clutch freaking out and putting too much drag on the engine and now fully not working, but why with only less than half a tank of gas?

    I am stumped. Any one have a good idea? I would really not like to open up the R12 AC if I dont have to or just on a hunch.
    e30sport.net
    '15 Porsche GT3 - 7-speed PDK - Daily Driver
    '86 325es - s54b32tu - 6-speed - Mtech 1
    '89 325is - m20b25 - 5-speed - Individual

    #2
    I’m thinking you have a fuel supply issue. You have a bunch of crud in the tank. As the fuel level gets lower the crud clogs the filter on the bottom of the in-tank pump. After the car sits the crud falls off. Highway driving with the extra load of the AC increases the fuel requirement. With the tank low on fuel, pull the in-tank pump and look in the tank to see if there is a lot of rust or other crud in the tank.

    As for the AC not working, I think it’s unrelated but put the gauges on it and see what that tells you.
    2004 525i Manual - 1985 325E Coupe Manual

    Comment

    Working...
    X