I am needing some help with my 1988 4+3 with 52,000 miles. I am having an ongoing issue with code 44. The car has a bad time of keeping a steady idle. In open loop, it will idle around 900-1000. Then in closed loop it will go to 1100-1200 and then stall if I don't keep my foot on the gas. I have installed a new MAF, IAC, fuel/burn off relays, fuel pump, eliminated the fuel pulse damper, blocked off the AIR system, new oxygen sensor, cleaned the EGR valve, new fuel regulator diaphragm. I have set the TPS to .54v, and set the IAC correctly. Timing has been set at 6 degrees following the service manual. My fuel pressure is 40 with key on and 38 when running. The fuel pressure will drop quickly when off. I have pinched the fuel line and return line and pressure still drops. I pulled the fuel rail with injectors still attached with pressure, there was no leaking. Not sure where the pressure is going. I recently changed gaskets on the upper/lower intake. There was an oil leak on the rear China wall. I have performed a smoke test and only found smoke coming from the sides of the throttle body. I put a new BBK throttle body of and it had the same amount of smoke coming from it, so I put the original throttle body back on. I have checked all the vacuum lines and I can't find any leaks. I have a Snap On MT2500 scanner and ran a check. I have all the numbers from the scan but I'm not sure what I am looking at. Any help would be appreciated. Wife is saying if this is not fixed it has to go. Please help.

 

First of all, tell the wife to chill out.............

I fought a high idle in my 85. The culprit was a vacuum leak, and a sticking IACV. A vacuum gage showed only 15" of vacuum. I found a loose hose, and now my vacuum is 20", normal idle.

I know you said you can't find any vacuum leaks, but I would use a vacuum gage to measure the actual vacuum at idle (warmed up)... A healthy vacuum at idle is 17-21" (at sea level). When you hit and release the throttle, it should drop to near zero and bounce up to 22-25ish before returning to normal.
This is the best way to determine a vacuum leak because they can be hard to find unless something is completely disconnected.

I recommend you follow the FSM instructions for dealing with a Code 44 and get that cleared first. I have attached the FSM pages for Code 44 from a 1988 FSM.

 

I have tried that before, I will try again. I believe I used the brake booster line to attach my vacuum gauge last time, is that the correct location?

 

I went back out to check vacuum. I attached the vacuum gauge to the small line near the distributor. The lowest steady idle I could get was at 1000 rpm and the vacuum gauge stayed mostly around 18. I also sprayed starter fluid all around the intakes, throttle body and vacuum lines, no change in idle.. Earlier today, I had the scan tool hooked up and it showed the engine staying in open loop on a hot engine and the idle started going up and down till it died. I had the fuel pressure gauge on at this time and it was showing 38-40 when running and soon as the engine died, it fell to 0 within 15 seconds. My IAC counts on a cold engine are 144 and when engine gets warmer, the counts go to 60-70 range and RPMs are 1200. I have tried to lower the counts with the throttle adjusting screw and adjusting the TPS trying to stay around .54v, but as soon as the IAC counts start going lower, the engine dies. I have had the throttle body off and cleaned all passages. I believe the fuel pressure is not where it should be, since it won't hold pressure after the engine is shut off. Not sure where to check next.

 

18" is decent vacuum so you are good there....


You said you changed the IACV. Did you get the right IACV pintle head. There a few different types and you must match it to the original one (see below). Also there should have been instructions with the IACV on how to adjust the length before installing. Did you check the length of IACV extension before installing?


We really need to solve the Code 44 before proceeding. Did you follow the Code 44 instructions from the FSM I posted earlier?