I_s2k

Ah okay sweet, I'll have to look into the ISA then. I pulled the IAT the last time i messed with the jeep and the thermistor on the end looked like it was snapped it why I was asking. Like it's still attached but cracked and looking pretty rough even after cleaning it.

Okay, that would make sense to me too but its confusing because of the fact that it runs with the MAP vac unplugged do you think its just forcing a ton of extra fuel to accommodate that? Obviously it does run really rich. I havent messed with the ISA just because I know how finnicky they can be. On a side note, would a bad IAT cause any issues like this?

In my ownership, the ISA has not been messed with other than unplugged just to get the connector cleaned and what not but it has been at least unplugged before as the retainer on the connector was broken off. The ISA does work as it should but I have no idea if its out of wack.

Oh whoops Ill edit that, typo, it is indeed an AX-4 and not the AW4. Sorry its my monday and I'm still waking up after a long weekend haha. I cannot find any vac leaks or issues any where else from bumper to bumper, all electrical connections have been cleaned from bumper to bumper per Cruiser's guide, TB was rebuilt by myself, all new gaskets and regulator, I've tried 3 new MAP sensors, new TPS and correctly adjusted, new fuel filter and fuel, no leaks(shocker, not even an oil leak) fuel pressure is unknown but I'm gonna say is fine because it can and does run/drive just very poorly I'm assuming due to the MAP issue. Unfortunately the guy I got it from had bought it from the original owner with intentions to fix it up but never got around to it and I believe it sat for 2 years before I got it. The original owner had every fuse pulled out of the box at your feet and wire nuts all over the place. I've already gone through and removed all of the wire nuts and they were all tied into the radio and some added speakers as well as some really weird hidden winch. So as of now I'm at a loss other than checking the ECU unless anything else can thought up as to why it's having this issue. It's a bizarre one for me haha.

Hey all, I acquired an '86 not too long ago (january of this year) and have yet to figure out what the problem is with it. To make a long story short, It will not start or run with the MAP sensor vacuum connected unless you hold it almost WOT. If I unplug the vacuum from the sensor, it will fire and run poorly but on its own with no assistance but starts to give out past like 1/4 throttle. If you look at my recent posts I'm sure you can see all the past topics Ive started trying to solve this but so far, no dice on everything I've tried. Anyways, what all ECU's will fit my Jeep? Its a 1986 with the 2.5 and the AX4. Ive read that there was some year ranges where there was an internal update for better fuel stability and and more HP? Also, I plan to pull the ECU this week and crack it open to look and see if any of the capacitors are shot, does anyone have a link or the know how to repair this? I can't imagine it would be rocket science haha. TIA Edit: AX-4 not AW4

With MAP vacuum plugged in, I have to rev it up pretty high for it to stay running, no tach so I have no idea how high it actually goes but audibly I have rev it up and hold it. It also hunts for an RPM, I can't get it to sit at a constant speed. I plan on buying a tach and connecting per your write up for the ISA.

When i get home, yes. If my memory serves me correct....the hex head is at least touching the throttle. I have no idea if it is fully extended or not but as mentioned in another thread. When the Jeep stalls out, the ISA motor does its 3 taps and i can feel it move the gas peddle as its engaging. But it's also safe to say that at one point the PO has done something with it as the retainer on the plug is broken off and was like that before I looked at it. I also wanted to ask, is there anything different I would need to do with the procedure for adjusting the ISA considering the MAP vacuum will be unplugged to get it running and up to operating temp?

So got a quick chance to throw in a 3rd MAP and I’m wondering if maybe the ECU is shot, I don’t have the chance today to hook a voltmeter up to it to verify again with this MAP but any last ditch efforts you can think of that I can try? Also if we’re assuming it is ECU, anyone have a line on a brand used one or a reliable repair service?

Okay for sure, thanks. Unfortunately I can’t today as the wind is horrible right now but when I can I’ll do that and report back.

For sure….assuming that the voltage drops out, what would that tell me? I’m assuming something wrong with the MAP correct? I’m at gym right now, will test when I get home.

Okay I’ll have to check as soon as the new MAP sensor comes in, went ahead and ordered a cheap one off Amazon that had good reviews and returned the Autozone one. I can test with the OE sensor.

Yeeee, that’s it

Here we go. I was going based off of this to check voltage and I believe I got the the ohm procedure off of cruiser54 tips if I remember correctly.

I believe so but I was trying to see the resistance going to the MAP. I’m trying to find the website I got the info off of for reference.

By chance do you have a link or name? I’m on Autozone #2.

Okay, warrantied the old MAP and put a different one on, replaced the grommet for the brake booster, and made the two gaskets for the EGR and still no dice. And this is with everything plugged in. It will still fire up with the Vacuum line unplugged from MAP sensor. Is it possible that I’m just getting junk sensors? As soon as I start to plug the vacuum in, the ISA or whatever it’s called will retract a bit I’m just guessing that’s because the MAP is sending the ECU bad readings if the MAP is bad. I find it kinda odd that it’s even idling kinda nice even with the vacuum disconnected.

That’s awesome man! Ima look into that.

Oh wow I had no idea that was a thing. Cool to know thanks and I’m good, I don’t think I’ve had a vehicle that’s ever had one working or there haha. Gonna try and warranty that MAP sensor and get some gasket material and see if I can’t make the two gaskets for the EGR as those both look like they’re smoked.

Ah okay gotcha, well if this thing had a good light it’s long gone and it’s a 2wd so that makes sense. This does have the load sensing brakes, is that what mean?

Would also like to add that these are also unplugged and I have no idea what they are for. The 3 and the square one are all by the blower motor. The one by itself is below the alternator.

Supply voltage to it is 5.05v with - to A and + to C.

Okay I’ll have give it a snort. Currently testing the MAP voltage. Now the engine is warm to the touch, like you can lay your hand on the valve cover and be comfortable with it. It’s currently reading 3.89 with + to B and - to A. I read it’s supposed to be 4-5v and between 1.5-2.1v hot. Is this MAP bad then?

Ah okay i figured it had something to do with something along the lines considering it’s placement, I'm not worried about it haha.

Anyone happen to know what this is? Seems like it’s broken or missing a spring.