Welcome Visitor! Please take a few seconds and Greywolf
New Member
- Joined
- May 30, 2010
- Messages
- 2
- Reaction score
- 0
- Points
- 0
- Vehicle Year
- 1990
- Make / Model
- Ford
- Transmission
- Automatic
Hello everyone, my name is Ben and I've signed up to TRS (although long time lurker) as my friend's 1990 Ranger is driving me nuts. I've been working on Fords a long time but it's been a while since I've had a tough EEC-IV problem to troubleshoot.
It's an ex-Air Force truck, pretty nice condition with only 46,000 miles. Auto, no options, no rust, and until recently, no real problems (poor fuel mileage and knicknack stuff).
So a few weeks ago we took it off the road to do a tune-up and timing belt (pretty sure it was original...).
Items replaced on and since that day:
-Timing belt (and we've verified the timing marks a dozen times since)
-All 8 spark plugs and wires
-Replaced both coil packs with known good from Exploder V8
-O2 sensor (and exhaust from cat back--we did the suspension, brakes and exhaust but none of those have bothered us)
-Throttle position sensor (old one wouldn't go below 1.03V at idle; new one is at 0.92V), MAP sensor, IAC Valve (I had them all from my F150 which runs well and I know they're good)
-Thermostat and water pump (because we had the front of the engine apart anyway)
-Intake manifold/throttle body gaskets (and light spray cleaning of insides using Sea Foam Deep Creep intake cleaner)
-PCV valve
-Vacuum lines
-Crank position sensor
-Tested IAT and ECT sensors (both spot on).
...and probably some other stuff I've forgotten. I ran codes and got an O2 sensor code--it was a bad ground so fixed that and now I'm seeing it switch as it should. I'm not currently getting any codes and CE light is off.
I'm thinking there may be a vacuum leak around the PCV valve (quite loose in the oil-soaked hose--does anyone sell a replacement lower PCV hose?); I blocked off all the vacuum fittings except fuel pressure regulator, brake boster and MAP sensor, using vacuum caps.
Vacuum reading is steady at 18" when idling.
When engine is started, it idles at 1100rpm for a while, slowly dropping as temperature increases. By 180* on the ECT it has settled to 880rpm. Putting the transmission from park to neutral causes the rpm to shoot up a couple hundred rpm; once in drive it slowly settles to about 750.
When the throttle is "goosed" or held down and released, it takes about 5-7 seconds to return to idle.
It is acting like a vacuum or timing issue, or perhaps the timing marks (for the belt) are off? Where else might we have a vacuum leak? I tried propane and carb cleaner and didn't find any leaks but it's a tight area to check. I can't really check the ignition timing as the timing belt cover is broken; I've got to find a junkyard with one.
Anyone have ideas? It's making me nuts and I want to get it fixed so I can work on my own toys again.
Ben
It's an ex-Air Force truck, pretty nice condition with only 46,000 miles. Auto, no options, no rust, and until recently, no real problems (poor fuel mileage and knicknack stuff).
So a few weeks ago we took it off the road to do a tune-up and timing belt (pretty sure it was original...).
Items replaced on and since that day:
-Timing belt (and we've verified the timing marks a dozen times since)
-All 8 spark plugs and wires
-Replaced both coil packs with known good from Exploder V8
-O2 sensor (and exhaust from cat back--we did the suspension, brakes and exhaust but none of those have bothered us)
-Throttle position sensor (old one wouldn't go below 1.03V at idle; new one is at 0.92V), MAP sensor, IAC Valve (I had them all from my F150 which runs well and I know they're good)
-Thermostat and water pump (because we had the front of the engine apart anyway)
-Intake manifold/throttle body gaskets (and light spray cleaning of insides using Sea Foam Deep Creep intake cleaner)
-PCV valve
-Vacuum lines
-Crank position sensor
-Tested IAT and ECT sensors (both spot on).
...and probably some other stuff I've forgotten. I ran codes and got an O2 sensor code--it was a bad ground so fixed that and now I'm seeing it switch as it should. I'm not currently getting any codes and CE light is off.
I'm thinking there may be a vacuum leak around the PCV valve (quite loose in the oil-soaked hose--does anyone sell a replacement lower PCV hose?); I blocked off all the vacuum fittings except fuel pressure regulator, brake boster and MAP sensor, using vacuum caps.
Vacuum reading is steady at 18" when idling.
When engine is started, it idles at 1100rpm for a while, slowly dropping as temperature increases. By 180* on the ECT it has settled to 880rpm. Putting the transmission from park to neutral causes the rpm to shoot up a couple hundred rpm; once in drive it slowly settles to about 750.
When the throttle is "goosed" or held down and released, it takes about 5-7 seconds to return to idle.
It is acting like a vacuum or timing issue, or perhaps the timing marks (for the belt) are off? Where else might we have a vacuum leak? I tried propane and carb cleaner and didn't find any leaks but it's a tight area to check. I can't really check the ignition timing as the timing belt cover is broken; I've got to find a junkyard with one.
Anyone have ideas? It's making me nuts and I want to get it fixed so I can work on my own toys again.
Ben
